fix call xseterrorhandler while gdk error trap is up

KeyEncoder mapped TAB to a plain tab regardless of Shift, so Shift+Tab sent the
same byte as Tab. Apps that use backtab for reverse navigation (fish completion
menu, helix theme picker) never saw it. Emit CSI Z when Shift is held.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
(cherry picked from commit 93d53fcef6)

.classpath

@@ -1,18 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<classpath>
-	<classpathentry kind="src" output="bin/main" path="src/main/java">
-		<attributes>
-			<attribute name="gradle_scope" value="main"/>
-			<attribute name="gradle_used_by_scope" value="main,test"/>
-		</attributes>
-	</classpathentry>
-	<classpathentry kind="src" output="bin/main" path="src/main/resources">
-		<attributes>
-			<attribute name="gradle_scope" value="main"/>
-			<attribute name="gradle_used_by_scope" value="main,test"/>
-		</attributes>
-	</classpathentry>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-21/"/>
-	<classpathentry kind="con" path="org.eclipse.buildship.core.gradleclasspathcontainer"/>
-	<classpathentry kind="output" path="bin/default"/>
-</classpath>

.codexsession

@@ -1 +0,0 @@
-019e6999-b7c8-7591-a8aa-ea51b89a7f7e

.gitignore

@@ -11,6 +11,10 @@ devenv.local.yaml
 # pre-commit
 .pre-commit-config.yaml
 build
-build
 .gradle
 bin
+.settings
+.project
+.worktrees
+.classpath
+.codexsession

.ignore

@@ -1,3 +1,4 @@
 .gradle
-result
 bin
+result
+.worktrees

.project

@@ -1,34 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<projectDescription>
-	<name>jprototerm</name>
-	<comment>Project jprototerm created by Buildship.</comment>
-	<projects>
-	</projects>
-	<buildSpec>
-		<buildCommand>
-			<name>org.eclipse.jdt.core.javabuilder</name>
-			<arguments>
-			</arguments>
-		</buildCommand>
-		<buildCommand>
-			<name>org.eclipse.buildship.core.gradleprojectbuilder</name>
-			<arguments>
-			</arguments>
-		</buildCommand>
-	</buildSpec>
-	<natures>
-		<nature>org.eclipse.jdt.core.javanature</nature>
-		<nature>org.eclipse.buildship.core.gradleprojectnature</nature>
-	</natures>
-	<filteredResources>
-		<filter>
-			<id>1779917652126</id>
-			<name></name>
-			<type>30</type>
-			<matcher>
-				<id>org.eclipse.core.resources.regexFilterMatcher</id>
-				<arguments>node_modules|\.git|__CREATED_BY_JAVA_LANGUAGE_SERVER__</arguments>
-			</matcher>
-		</filter>
-	</filteredResources>
-</projectDescription>

.settings/org.eclipse.buildship.core.prefs

@@ -1,13 +0,0 @@
-arguments=--init-script /home/anon/Src/eclipse.jdt.ls/org.eclipse.jdt.ls.product/target/repository/configuration/org.eclipse.osgi/58/0/.cp/gradle/init/init.gradle
-auto.sync=false
-build.scans.enabled=false
-connection.gradle.distribution=GRADLE_DISTRIBUTION(LOCAL_INSTALLATION(/home/anon/.sdkman/candidates/gradle/current))
-connection.project.dir=
-eclipse.preferences.version=1
-gradle.user.home=
-java.home=/nix/store/c3pl7bqrx3d2rc3dh98z6yaj0mv1p52g-openjdk-21.0.10+7/lib/openjdk
-jvm.arguments=
-offline.mode=false
-override.workspace.settings=true
-show.console.view=true
-show.executions.view=true

README.md

@@ -106,6 +106,7 @@ navigate_up = "ALT+K"
 navigate_right = "ALT+L"
 toggle_floating = "ALT+F"
 new_pane = "ALT+N"
+next_floating = "ALT+F12"
 close_pane = "ALT+X"
 new_tab = "ALT+A"
 previous_tab = "ALT+SHIFT+H"
@@ -120,6 +121,7 @@ open_scrollback = "ALT+S"
 - `Alt+n`: new pane — a floating pane when floating panes are shown, otherwise a new tiled
   pane (tiled panes are split equally across the width)
 - `Alt+f`: show or hide all floating panes
+- `Alt+F12`: cycle floating panes
 - `Alt+x`: close the active pane; closing a tab's last pane closes the tab, and closing the
   last pane of the last tab quits
 - `Alt+a`: new tab

config.example.toml

@@ -25,7 +25,8 @@ navigate_down = "ALT+J"
 navigate_up = "ALT+K"
 navigate_right = "ALT+L"
 toggle_floating = "ALT+F"
-new_pane = "ALT+N"
+new_floating = "ALT+SHIFT+F"
+next_floating = "ALT+F12"
 close_pane = "ALT+X"
 open_font_selector = "ALT+T"
 open_scrollback = "ALT+S"

flake.lock

@@ -70,11 +70,11 @@
         "nixpkgs": "nixpkgs"
       },
       "locked": {
-        "lastModified": 1780079529,
+        "lastModified": 1780272954,
-        "narHash": "sha256-AxlGTL8c5xSLcQHvWlm994IdOqxsN8iKrA02Cpv7vso=",
+        "narHash": "sha256-bVWY60iw8yPIu7I8FuRPf06T0H1TDvQDVUlzeHQs8UA=",
         "ref": "refs/heads/main",
-        "rev": "68121d50b52fb56038871c97c97e7a12ffe987c2",
+        "rev": "06a9d5d3ecf11c58f0e41214d1b59900e672dd3a",
-        "revCount": 20,
+        "revCount": 24,
         "type": "git",
         "url": "https://gitea.gregorlohaus.com/gregor/jlibghostty.git"
       },

src/main/java/com/gregor/jprototerm/AppConfig.java

@@ -37,6 +37,7 @@ public record AppConfig(
             "navigate_right",
             "toggle_floating",
             "new_pane",
+            "next_floating",
             "close_pane",
             "new_tab",
             "previous_tab",
@@ -95,6 +96,7 @@ public record AppConfig(
                         Map.entry("navigate_right", KeyBinding.parse("ALT+L")),
                         Map.entry("toggle_floating", KeyBinding.parse("ALT+F")),
                         Map.entry("new_pane", KeyBinding.parse("ALT+N")),
+                        Map.entry("next_floating", KeyBinding.parse("ALT+F12")),
                         Map.entry("close_pane", KeyBinding.parse("ALT+X")),
                         Map.entry("new_tab", KeyBinding.parse("ALT+A")),
                         Map.entry("previous_tab", KeyBinding.parse("ALT+SHIFT+H")),

src/main/java/com/gregor/jprototerm/Compositor.java

@@ -4,52 +4,60 @@ import dev.jlibghostty.KeyModifiers;
 import dev.jlibghostty.MouseButton;
 import dev.jlibghostty.MouseEncoderSize;
 import dev.jlibghostty.MouseInput;
-import javafx.geometry.Pos;
+import javafx.geometry.VPos;
-import javafx.scene.Parent;
+import javafx.scene.Node;
-import javafx.scene.control.Label;
+import javafx.scene.canvas.Canvas;
+import javafx.scene.canvas.GraphicsContext;
 import javafx.scene.input.InputEvent;
 import javafx.scene.input.MouseEvent;
 import javafx.scene.input.ScrollEvent;
 import javafx.scene.input.ScrollEvent.VerticalTextScrollUnits;
-import javafx.scene.layout.Background;
-import javafx.scene.layout.BackgroundFill;
-import javafx.scene.layout.CornerRadii;
-import javafx.scene.layout.HBox;
-import javafx.scene.layout.Pane;
 import javafx.scene.paint.Color;
+import javafx.scene.text.Font;
+import javafx.scene.text.FontSmoothingType;
+import javafx.scene.text.TextAlignment;
 
 import java.util.ArrayList;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
+import java.util.Objects;
 
 /**
- * Owns the window's tabs and exposes the terminal surface as a JavaFX scene graph. Each
+ * Owns the window's tabs and drives rendering and input. It composites only the current tab:
- * terminal pane is mounted as its own node, so JavaFX child order handles stacking and clipping
+ * each frame it lays that tab out, paints the panes bottom-to-top (so the active floating pane
- * between panes. The pane model still owns terminals, ptys, cell geometry, and snapshots; this
+ * lands on top) and lets each pane paint its own content, clipped to the region the layout gave
- * class handles tab/pane lifecycle, layout, focus, mouse routing, and frame scheduling.
+ * it. The cross-pane concerns live here — the dirty-frame bookkeeping, the tab strip, routing
+ * mouse/scroll to the pane under the pointer, and the tab/pane lifecycle that {@link Main}'s key
+ * bindings invoke.
  */
 public final class Compositor {
+    // Canvas background shown wherever no pane covers (gaps). Painted on a full recomposite.
     private static final Color GAP_BACKGROUND = Color.rgb(16, 16, 18);
     private static final Color TAB_TEXT = Color.rgb(225, 229, 235);
-    private static final Color TAB_INACTIVE_TEXT = Color.rgb(128, 136, 148);
+    // Thin tab strip shown at the top when more than one tab is open.
-    private static final Color TAB_ACTIVE_BACKGROUND = Color.rgb(45, 55, 72);
-    private static final Color TAB_INACTIVE_BACKGROUND = Color.rgb(22, 24, 28);
     private static final double TAB_BAR_HEIGHT = 22.0;
 
-    private final Pane root = new Pane();
+    private final Canvas canvas = new Canvas();
-    private final Pane paneLayer = new Pane();
+    // Kitty images are drawn as retained nodes layered over the canvas, not composited onto it.
-    private final HBox tabBar = new HBox(1.0);
+    private final KittyImageOverlay imageOverlay = new KittyImageOverlay();
     private final AppConfig config;
     private final TerminalMetrics metrics;
     private final List<Tab> tabs = new ArrayList<>();
-    private final Map<TerminalPane, TerminalPaneNode> nodes = new HashMap<>();
     private int currentTabIndex;
-    private boolean sceneDirty = true;
+    // Bumped on any structural change (tab switch, pane add/close/focus/move) so render()
+    // knows to recomposite. Terminal *content* changes are tracked separately through each
+    // tab's content version.
+    private long layoutVersion;
+    // Last content version drawn to the canvas per pane, so a content frame repaints only
+    // the panes that actually changed.
+    private final Map<TerminalPane, Long> paneContentVersion = new HashMap<>();
+    // Cheap per-frame dirty signal: skip the whole render when none of these changed.
     private double lastWidth = -1.0;
     private double lastHeight = -1.0;
+    private String lastFontFamily;
+    private double lastFontSize = -1.0;
+    private long lastLayoutVersion = Long.MIN_VALUE;
     private long lastContentVersion = Long.MIN_VALUE;
     private boolean mouseButtonPressed;
     private MouseButton pressedButton = MouseButton.UNKNOWN;
@@ -58,25 +66,27 @@ public final class Compositor {
         this.config = config;
         this.metrics = metrics;
         tabs.add(new Tab(config, metrics));
-
+        canvas.setFocusTraversable(true);
-        root.setFocusTraversable(true);
+        canvas.setOnMousePressed(this::handleMousePressed);
-        root.setBackground(new Background(new BackgroundFill(GAP_BACKGROUND, CornerRadii.EMPTY, null)));
+        canvas.setOnMouseReleased(this::handleMouseReleased);
-        root.getChildren().setAll(paneLayer, tabBar);
+        canvas.setOnMouseDragged(this::handleMouseDragged);
-        root.setOnMousePressed(event -> root.requestFocus());
+        canvas.setOnMouseMoved(this::handleMouseMoved);
+        canvas.setOnScroll(this::handleScroll);
     }
 
-    public Parent node() {
+    public Canvas canvas() {
-        return root;
+        return canvas;
     }
 
-    public void requestFocus() {
+    /** The kitty-image overlay, to be stacked directly above {@link #canvas()} in the window. */
-        root.requestFocus();
+    public Node imageOverlay() {
+        return imageOverlay.node();
     }
 
     public void setFont(String family, double size) {
         metrics.setFont(family, size);
-        nodes.values().forEach(TerminalPaneNode::discard);
+        paneContentVersion.clear();
-        markSceneDirty();
+        lastWidth = -1.0; // force a redraw on the next frame
     }
 
     // ---- Tabs and panes -------------------------------------------------------------
@@ -91,7 +101,7 @@ public final class Compositor {
 
     public void navigate(Direction direction) {
         if (!isEmpty() && currentTab().navigate(direction)) {
-            markSceneDirty();
+            layoutVersion++;
         }
     }
 
@@ -100,7 +110,7 @@ public final class Compositor {
             return;
         }
         currentTab().toggleFloating();
-        markSceneDirty();
+        layoutVersion++;
     }
 
     public void createPane() {
@@ -108,7 +118,25 @@ public final class Compositor {
             return;
         }
         currentTab().createPane();
-        markSceneDirty();
+        layoutVersion++;
+    }
+
+    /** Opens a new floating pane, makes it active, and returns it (null when no tab exists). */
+    public TerminalPane openFloatingPane() {
+        if (isEmpty()) {
+            return null;
+        }
+        TerminalPane pane = currentTab().createFloatingPane();
+        layoutVersion++;
+        return pane;
+    }
+
+    public void nextFloatingPane() {
+        if (isEmpty()) {
+            return;
+        }
+        currentTab().nextFloatingPane();
+        layoutVersion++;
     }
 
     public void closeActivePane() {
@@ -117,31 +145,33 @@ public final class Compositor {
         }
         currentTab().closeActivePane();
         if (currentTab().isEmpty()) {
+            // Closing a tab's last pane closes the tab. When no tabs remain the surface is
+            // empty and Main quits.
             tabs.remove(currentTabIndex);
             if (currentTabIndex >= tabs.size()) {
                 currentTabIndex = Math.max(0, tabs.size() - 1);
             }
         }
-        markSceneDirty();
+        layoutVersion++;
     }
 
     public void newTab() {
         tabs.add(new Tab(config, metrics));
         currentTabIndex = tabs.size() - 1;
-        markSceneDirty();
+        layoutVersion++;
     }
 
     public void nextTab() {
         if (tabs.size() > 1) {
             currentTabIndex = (currentTabIndex + 1) % tabs.size();
-            markSceneDirty();
+            layoutVersion++;
         }
     }
 
     public void previousTab() {
         if (tabs.size() > 1) {
             currentTabIndex = (currentTabIndex - 1 + tabs.size()) % tabs.size();
-            markSceneDirty();
+            layoutVersion++;
         }
     }
 
@@ -150,8 +180,6 @@ public final class Compositor {
             tab.close();
         }
         tabs.clear();
-        nodes.clear();
-        paneLayer.getChildren().clear();
     }
 
     private Tab currentTab() {
@@ -162,140 +190,143 @@ public final class Compositor {
         return tabs.isEmpty() ? List.of() : currentTab().panes();
     }
 
-    private List<TerminalPane> allOpenPanes() {
-        List<TerminalPane> panes = new ArrayList<>();
-        for (Tab tab : tabs) {
-            panes.addAll(tab.allPanes());
-        }
-        return panes;
-    }
-
     private boolean isActive(TerminalPane pane) {
         return !tabs.isEmpty() && currentTab().isActive(pane);
     }
 
     private void focus(TerminalPane pane) {
         if (!tabs.isEmpty() && currentTab().focus(pane)) {
-            markSceneDirty();
+            layoutVersion++;
         }
     }
 
     // ---- Rendering ------------------------------------------------------------------
 
     public void render() {
-        double width = root.getWidth();
+        switch (nextFrameType()) {
-        double height = root.getHeight();
+            case IDLE -> { }
-        long contentVersion = tabs.isEmpty() ? 0 : currentTab().contentVersion();
+            case LAYOUT -> renderLayoutFrame();
-        boolean geometryChanged = width != lastWidth || height != lastHeight;
+            case CONTENT -> renderContentFrame();
-        boolean contentChanged = contentVersion != lastContentVersion;
-        boolean syncScene = sceneDirty || geometryChanged;
-
-        if (!syncScene && !contentChanged) {
-            return;
         }
+    }
+
+    // Classify this frame and commit the change trackers. A layout change (size, font,
+    // tab/pane set, z-order, active pane) needs a full recomposite; otherwise a change to the
+    // current tab's content version repaints only the panes that changed; otherwise nothing
+    // changed and the frame is idle.
+    private FrameType nextFrameType() {
+        double width = canvas.getWidth();
+        double height = canvas.getHeight();
+        long contentVersion = tabs.isEmpty() ? 0 : currentTab().contentVersion();
+
+        boolean layoutChanged = width != lastWidth || height != lastHeight
+                || metrics.fontSize() != lastFontSize || !Objects.equals(metrics.fontFamily(), lastFontFamily)
+                || layoutVersion != lastLayoutVersion;
+        boolean contentChanged = contentVersion != lastContentVersion;
 
         lastWidth = width;
         lastHeight = height;
+        lastFontFamily = metrics.fontFamily();
+        lastFontSize = metrics.fontSize();
+        lastLayoutVersion = layoutVersion;
         lastContentVersion = contentVersion;
-        sceneDirty = false;
+
-        if (syncScene) {
+        if (layoutChanged) {
-            syncSceneGraph(width, height);
+            return FrameType.LAYOUT;
         }
-        renderVisiblePanes();
+        if (contentChanged) {
+            return FrameType.CONTENT;
+        }
+        return FrameType.IDLE;
     }
 
-    private void markSceneDirty() {
+    // Full recomposite onto the retained canvas: lay the tab out, clear to the gap colour,
-        sceneDirty = true;
+    // draw the tab strip, then paint every pane bottom-to-top (panes() puts the active
-    }
+    // floating pane last == on top).
-
+    private void renderLayoutFrame() {
-    private void syncSceneGraph(double width, double height) {
         double topInset = tabs.size() > 1 ? TAB_BAR_HEIGHT : 0.0;
-
-        paneLayer.resizeRelocate(0.0, 0.0, width, height);
-        updateTabBar(width, topInset);
-
         if (!tabs.isEmpty()) {
-            currentTab().layout(width, height, topInset);
+            currentTab().layout(canvas.getWidth(), canvas.getHeight(), topInset);
         }
-
         List<TerminalPane> panes = currentPanes();
-        retainNodes(allOpenPanes());
+        // Sync each pane's ghostty grid to its (possibly new) bounds; a no-op when unchanged.
-        List<TerminalPaneNode> orderedNodes = new ArrayList<>(panes.size());
         for (TerminalPane pane : panes) {
             pane.fitToBounds();
-            TerminalPaneNode node = nodeFor(pane);
-            node.resizeRelocate(Math.round(pane.x()), Math.round(pane.y()), pane.width(), pane.height());
-            orderedNodes.add(node);
-        }
-        paneLayer.getChildren().setAll(orderedNodes);
         }
 
-    private void renderVisiblePanes() {
+        GraphicsContext gc = beginFrame();
-        for (TerminalPane pane : currentPanes()) {
+        paneContentVersion.keySet().retainAll(panes);
-            TerminalPaneNode node = nodes.get(pane);
+        gc.setFill(GAP_BACKGROUND);
-            if (node != null) {
+        gc.fillRect(0, 0, canvas.getWidth(), canvas.getHeight());
-                node.renderIncremental(isActive(pane));
+        if (topInset > 0.0) {
+            drawTabBar(gc, canvas.getWidth(), topInset);
         }
+        for (TerminalPane pane : panes) {
+            paneContentVersion.put(pane, pane.paintFull(gc, isActive(pane)));
+        }
+        imageOverlay.sync(panes);
+    }
+
+    // Repaint just the panes whose content changed, directly on the retained canvas. Each pane
+    // clips itself to its rect minus the panes above it, so a lower pane's repaint can't bleed
+    // over one stacked on top — no restore pass needed. Bounds and grids can't have changed
+    // without a layout frame, so a content frame reuses the existing layout untouched.
+    private void renderContentFrame() {
+        List<TerminalPane> panes = currentPanes();
+        GraphicsContext gc = beginFrame();
+
+        for (TerminalPane pane : panes) {
+            Long drawn = paneContentVersion.get(pane);
+            if (drawn != null && drawn == pane.contentVersion()) {
+                continue;
+            }
+            paneContentVersion.put(pane, pane.paintIncremental(gc, isActive(pane)));
+            imageOverlay.updatePane(pane);
         }
     }
 
-    private TerminalPaneNode nodeFor(TerminalPane pane) {
+    private GraphicsContext beginFrame() {
-        return nodes.computeIfAbsent(pane, this::createNode);
+        GraphicsContext gc = canvas.getGraphicsContext2D();
+        gc.setFontSmoothingType(FontSmoothingType.LCD); // the per-cell renderer relies on LCD
+        return gc;
     }
 
-    private TerminalPaneNode createNode(TerminalPane pane) {
+    // Thin tab strip: one equal-width segment per tab, the current one highlighted, with a
-        TerminalPaneNode node = new TerminalPaneNode(pane, metrics);
+    // small 1-based number centred in each segment.
-        node.setOnMousePressed(event -> handleMousePressed(pane, event));
+    private void drawTabBar(GraphicsContext gc, double width, double barHeight) {
-        node.setOnMouseReleased(event -> handleMouseReleased(pane, event));
+        int count = tabs.size();
-        node.setOnMouseDragged(event -> handleMouseDragged(pane, event));
+        Font barFont = Font.font(metrics.fontFamily(), Math.max(9.0, Math.min(13.0, barHeight * 0.62)));
-        node.setOnMouseMoved(event -> handleMouseMoved(pane, event));
+        gc.setFont(barFont);
-        node.setOnScroll(event -> handleScroll(pane, event));
+        gc.setFontSmoothingType(FontSmoothingType.GRAY);
-        return node;
+        gc.setTextAlign(TextAlignment.CENTER);
-    }
+        gc.setTextBaseline(VPos.CENTER);
 
-    private void retainNodes(List<TerminalPane> openPanes) {
+        double gap = 1.0;
-        Set<TerminalPane> open = new HashSet<>(openPanes);
+        double segmentWidth = width / count;
-        nodes.keySet().removeIf(pane -> !open.contains(pane));
+        for (int i = 0; i < count; i++) {
-    }
+            double x = i * segmentWidth;
-
-    private void updateTabBar(double width, double barHeight) {
-        tabBar.setVisible(barHeight > 0.0);
-        tabBar.setManaged(false);
-        tabBar.resizeRelocate(0.0, 0.0, width, barHeight);
-        tabBar.getChildren().clear();
-        if (barHeight <= 0.0) {
-            return;
-        }
-
-        double segmentWidth = width / tabs.size();
-        for (int i = 0; i < tabs.size(); i++) {
-            Label label = new Label(Integer.toString(i + 1));
             boolean current = i == currentTabIndex;
-            label.setAlignment(Pos.CENTER);
+            gc.setFill(current ? Color.rgb(45, 55, 72) : Color.rgb(22, 24, 28));
-            label.setTextFill(current ? TAB_TEXT : TAB_INACTIVE_TEXT);
+            gc.fillRect(x, 0.0, segmentWidth - gap, barHeight);
-            label.setBackground(new Background(new BackgroundFill(
+            gc.setFill(current ? TAB_TEXT : Color.rgb(128, 136, 148));
-                    current ? TAB_ACTIVE_BACKGROUND : TAB_INACTIVE_BACKGROUND,
+            gc.fillText(Integer.toString(i + 1), x + (segmentWidth - gap) / 2.0, barHeight / 2.0);
-                    CornerRadii.EMPTY,
-                    null)));
-            label.setFont(javafx.scene.text.Font.font(metrics.fontFamily(), Math.max(9.0, Math.min(13.0, barHeight * 0.62))));
-            label.setMinSize(0.0, barHeight);
-            label.setPrefSize(Math.max(0.0, segmentWidth - 1.0), barHeight);
-            label.setMaxSize(Double.MAX_VALUE, barHeight);
-            final int index = i;
-            label.setOnMousePressed(event -> {
-                currentTabIndex = index;
-                markSceneDirty();
-                root.requestFocus();
-                event.consume();
-            });
-            tabBar.getChildren().add(label);
         }
+
+        // Restore the defaults the cell renderer relies on (left-aligned, baseline, LCD).
+        gc.setTextAlign(TextAlignment.LEFT);
+        gc.setTextBaseline(VPos.BASELINE);
+        gc.setFontSmoothingType(FontSmoothingType.LCD);
     }
 
     // ---- Input ----------------------------------------------------------------------
 
-    private void handleMousePressed(TerminalPane pane, MouseEvent event) {
+    private void handleMousePressed(MouseEvent event) {
-        root.requestFocus();
+        canvas.requestFocus();
+        TerminalPane pane = paneAt(event.getX(), event.getY());
+        if (pane == null) {
+            return;
+        }
+
         focus(pane);
         pressedButton = mouseButton(event);
         mouseButtonPressed = true;
@@ -303,38 +334,58 @@ public final class Compositor {
         if (target == null) {
             return;
         }
-        send(pane, target, MouseInput.press(pressedButton, localX(event.getX(), target), localY(event.getY(), target), modifiers(event)), true, event);
+        send(pane, target, MouseInput.press(pressedButton, localX(event.getX(), pane, target), localY(event.getY(), pane, target), modifiers(event)), true, event);
+    }
+
+    private void handleMouseReleased(MouseEvent event) {
+        TerminalPane pane = paneAt(event.getX(), event.getY());
+        if (pane == null) {
+            pane = activePane();
         }
 
-    private void handleMouseReleased(TerminalPane pane, MouseEvent event) {
         MouseButton button = pressedButton == MouseButton.UNKNOWN ? mouseButton(event) : pressedButton;
         MouseTarget target = mouseTarget(pane);
         if (target != null) {
-            send(pane, target, MouseInput.release(button, localX(event.getX(), target), localY(event.getY(), target), modifiers(event)), false, event);
+            send(pane, target, MouseInput.release(button, localX(event.getX(), pane, target), localY(event.getY(), pane, target), modifiers(event)), false, event);
         }
         mouseButtonPressed = false;
         pressedButton = MouseButton.UNKNOWN;
     }
 
-    private void handleMouseDragged(TerminalPane pane, MouseEvent event) {
+    private void handleMouseDragged(MouseEvent event) {
+        TerminalPane pane = paneAt(event.getX(), event.getY());
+        if (pane == null) {
+            pane = activePane();
+        }
+
         MouseButton button = pressedButton == MouseButton.UNKNOWN ? mouseButton(event) : pressedButton;
         MouseTarget target = mouseTarget(pane);
         if (target == null) {
             return;
         }
-        send(pane, target, MouseInput.drag(button, localX(event.getX(), target), localY(event.getY(), target), modifiers(event)), true, event);
+        send(pane, target, MouseInput.drag(button, localX(event.getX(), pane, target), localY(event.getY(), pane, target), modifiers(event)), true, event);
+    }
+
+    private void handleMouseMoved(MouseEvent event) {
+        TerminalPane pane = paneAt(event.getX(), event.getY());
+        if (pane == null) {
+            return;
         }
 
-    private void handleMouseMoved(TerminalPane pane, MouseEvent event) {
         MouseTarget target = mouseTarget(pane);
         if (target == null) {
             return;
         }
-        send(pane, target, MouseInput.motion(localX(event.getX(), target), localY(event.getY(), target), modifiers(event)), mouseButtonPressed, event);
+        send(pane, target, MouseInput.motion(localX(event.getX(), pane, target), localY(event.getY(), pane, target), modifiers(event)), mouseButtonPressed, event);
     }
 
-    private void handleScroll(TerminalPane pane, ScrollEvent event) {
+    private void handleScroll(ScrollEvent event) {
-        root.requestFocus();
+        TerminalPane pane = paneAt(event.getX(), event.getY());
+        if (pane == null) {
+            return;
+        }
+
+        canvas.requestFocus();
         focus(pane);
         int direction = scrollDirection(event);
         if (direction == 0) {
@@ -346,8 +397,9 @@ public final class Compositor {
         MouseTarget target = mouseTarget(pane);
         boolean sent = false;
         if (target != null) {
-            double ex = localX(event.getX(), target);
+            // The wheel sends one button press per scrolled row; resolve the position once.
-            double ey = localY(event.getY(), target);
+            double ex = localX(event.getX(), pane, target);
+            double ey = localY(event.getY(), pane, target);
             KeyModifiers modifiers = modifiers(event);
             for (int i = 0; i < rows; i++) {
                 if (!send(pane, target, MouseInput.press(wheelButton, ex, ey, modifiers), mouseButtonPressed, event)) {
@@ -357,11 +409,14 @@ public final class Compositor {
             }
         }
         if (!sent) {
+            // Not consumed by the app (e.g. mouse reporting off): scroll the local viewport.
             pane.scrollViewport(direction > 0 ? -rows : rows);
             event.consume();
         }
     }
 
+    // Forward an already-positioned mouse event to the pane, consuming it if the pane (i.e.
+    // the app running in it) acted on it. Returns whether it was sent.
     private boolean send(TerminalPane pane, MouseTarget target, MouseInput input, boolean anyButtonPressed, InputEvent event) {
         boolean sent = pane.sendMouse(input, target.size(), anyButtonPressed);
         if (sent) {
@@ -370,6 +425,17 @@ public final class Compositor {
         return sent;
     }
 
+    private TerminalPane paneAt(double x, double y) {
+        List<TerminalPane> panes = currentPanes();
+        for (int i = panes.size() - 1; i >= 0; i--) {
+            TerminalPane pane = panes.get(i);
+            if (x >= pane.x() && x < pane.x() + pane.width() && y >= pane.y() && y < pane.y() + pane.height()) {
+                return pane;
+            }
+        }
+        return null;
+    }
+
     private MouseTarget mouseTarget(TerminalPane pane) {
         if (pane.width() <= 2 * TerminalMetrics.PADDING || pane.height() <= 2 * TerminalMetrics.PADDING) {
             return null;
@@ -384,12 +450,14 @@ public final class Compositor {
         return new MouseTarget(MouseEncoderSize.of(screenWidth, screenHeight, cellWidth, cellHeight), screenWidth, screenHeight);
     }
 
-    private static double localX(double nodeX, MouseTarget target) {
+    // Resolve a canvas-space pointer position to a pane-local pixel coordinate, clamped to
-        return clamp(nodeX - TerminalMetrics.PADDING, 0.0, target.screenWidth() - 1.0);
+    // the pane's reported screen size (what ghostty's mouse encoder expects).
+    private static double localX(double canvasX, TerminalPane pane, MouseTarget target) {
+        return clamp(canvasX - pane.x() - TerminalMetrics.PADDING, 0.0, target.screenWidth() - 1.0);
     }
 
-    private static double localY(double nodeY, MouseTarget target) {
+    private static double localY(double canvasY, TerminalPane pane, MouseTarget target) {
-        return clamp(nodeY - TerminalMetrics.PADDING, 0.0, target.screenHeight() - 1.0);
+        return clamp(canvasY - pane.y() - TerminalMetrics.PADDING, 0.0, target.screenHeight() - 1.0);
     }
 
     private static double clamp(double value, double min, double max) {
@@ -437,6 +505,13 @@ public final class Compositor {
         };
     }
 
+    // What one render() pass should do, decided from the change trackers in nextFrame().
+    private enum FrameType {
+        IDLE,     // nothing changed since the last frame
+        LAYOUT,   // geometry/font/tab/pane set changed: clear and repaint everything
+        CONTENT   // only terminal content changed: repaint the panes that changed
+    }
+
     private record MouseTarget(MouseEncoderSize size, long screenWidth, long screenHeight) {
     }
 }

src/main/java/com/gregor/jprototerm/KeyEncoder.java

@@ -26,7 +26,7 @@ final class KeyEncoder {
         return switch (code) {
             case ENTER -> "\r";
             case BACK_SPACE -> "\u007f";
-            case TAB -> "\t";
+            case TAB -> event.isShiftDown() ? "\u001b[Z" : "\t";
             case ESCAPE -> "\u001b";
             case UP -> "\u001b[A";
             case DOWN -> "\u001b[B";

src/main/java/com/gregor/jprototerm/KittyImageNode.java

@@ -0,0 +1,32 @@
+package com.gregor.jprototerm;
+
+import javafx.scene.image.Image;
+
+/**
+ * A single kitty image to display, produced by the renderer and consumed by {@link
+ * KittyImageOverlay}. Images are not painted onto the canvas; each becomes a retained
+ * {@code ImageView} node positioned over the pane. The {@code source*} fields are the region of
+ * {@link #image()} to show (in image pixels); the {@code x/y/width/height} are where to put it,
+ * in scene coordinates (the same space the pane's clip {@code Shape} lives in).
+ *
+ * <p>{@code imageId}+{@code placementId} identify the placement so the overlay can reuse the
+ * same node across frames instead of recreating it.
+ */
+record KittyImageNode(
+        long imageId,
+        long placementId,
+        Image image,
+        double sourceX,
+        double sourceY,
+        double sourceWidth,
+        double sourceHeight,
+        double x,
+        double y,
+        double width,
+        double height
+) {
+    /** Stable per-pane key for node reuse. Packs the two u32 ids without collision. */
+    long key() {
+        return (imageId << 32) | (placementId & 0xffffffffL);
+    }
+}

src/main/java/com/gregor/jprototerm/KittyImageOverlay.java

@@ -0,0 +1,151 @@
+package com.gregor.jprototerm;
+
+import javafx.geometry.Rectangle2D;
+import javafx.scene.Group;
+import javafx.scene.Node;
+import javafx.scene.image.ImageView;
+import javafx.scene.layout.Pane;
+import javafx.scene.shape.Rectangle;
+import javafx.scene.shape.Shape;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Renders kitty graphics images as retained scene-graph nodes layered over the {@link Compositor}
+ * canvas, instead of compositing them onto the canvas. Each pane gets a {@link Group} clipped to
+ * that pane's region (the same clip {@code Shape} the canvas renderer uses), and each visible
+ * image placement is an {@link ImageView} inside it, reused across frames so an unchanged image
+ * costs nothing to redraw.
+ *
+ * <p>The overlay {@link #node()} is mouse-transparent and sits above the canvas in the window's
+ * {@code StackPane}; its children use scene coordinates, which line up with the canvas because
+ * both fill the same root.
+ */
+final class KittyImageOverlay {
+    private final Pane root = new Pane();
+    private final Map<TerminalPane, PaneOverlay> overlays = new HashMap<>();
+
+    KittyImageOverlay() {
+        // Input belongs to the canvas underneath; the overlay only shows pixels.
+        root.setMouseTransparent(true);
+        root.setManaged(false);
+    }
+
+    Node node() {
+        return root;
+    }
+
+    /**
+     * Full reconcile to {@code panes} (bottom-to-top): drop overlays for panes that went away,
+     * refresh each surviving/added pane's images and clip, and order the per-pane groups to match
+     * the pane z-order. Called on layout frames, after the panes have painted.
+     */
+    void sync(List<TerminalPane> panes) {
+        Iterator<Map.Entry<TerminalPane, PaneOverlay>> it = overlays.entrySet().iterator();
+        while (it.hasNext()) {
+            Map.Entry<TerminalPane, PaneOverlay> entry = it.next();
+            if (!panes.contains(entry.getKey())) {
+                root.getChildren().remove(entry.getValue().group);
+                it.remove();
+            }
+        }
+        for (TerminalPane pane : panes) {
+            updatePane(pane);
+        }
+        // Only panes that actually have images get a group; order those to match pane z-order.
+        List<Node> ordered = new ArrayList<>(panes.size());
+        for (TerminalPane pane : panes) {
+            PaneOverlay overlay = overlays.get(pane);
+            if (overlay != null) {
+                ordered.add(overlay.group);
+            }
+        }
+        if (!root.getChildren().equals(ordered)) {
+            root.getChildren().setAll(ordered);
+        }
+    }
+
+    /**
+     * Refresh one pane's images and clip (called on content frames for each repainted pane).
+     * Creates the pane's group if this is the first time it has shown an image.
+     */
+    void updatePane(TerminalPane pane) {
+        List<KittyImageNode> images = pane.kittyImages();
+        PaneOverlay overlay = overlays.get(pane);
+        if (overlay == null) {
+            if (images.isEmpty()) {
+                return;
+            }
+            overlay = new PaneOverlay();
+            overlays.put(pane, overlay);
+            root.getChildren().add(overlay.group);
+        }
+        overlay.group.setClip(clipFor(pane));
+        reconcile(overlay, images);
+    }
+
+    private static void reconcile(PaneOverlay overlay, List<KittyImageNode> images) {
+        Set<Long> seen = new HashSet<>();
+        for (KittyImageNode node : images) {
+            long key = node.key();
+            seen.add(key);
+            ImageView view = overlay.views.get(key);
+            if (view == null) {
+                view = new ImageView();
+                view.setManaged(false);
+                view.setSmooth(true);
+                view.setPreserveRatio(false);
+                overlay.views.put(key, view);
+                overlay.group.getChildren().add(view);
+            }
+            apply(view, node);
+        }
+        if (overlay.views.size() == seen.size()) {
+            return;
+        }
+        Iterator<Map.Entry<Long, ImageView>> it = overlay.views.entrySet().iterator();
+        while (it.hasNext()) {
+            Map.Entry<Long, ImageView> entry = it.next();
+            if (!seen.contains(entry.getKey())) {
+                overlay.group.getChildren().remove(entry.getValue());
+                it.remove();
+            }
+        }
+    }
+
+    private static void apply(ImageView view, KittyImageNode node) {
+        if (view.getImage() != node.image()) {
+            view.setImage(node.image());
+        }
+        view.setViewport(new Rectangle2D(node.sourceX(), node.sourceY(), node.sourceWidth(), node.sourceHeight()));
+        view.setFitWidth(node.width());
+        view.setFitHeight(node.height());
+        view.setLayoutX(node.x());
+        view.setLayoutY(node.y());
+    }
+
+    // The pane's occlusion clip when one is set (rect minus covering panes), else the pane's
+    // plain bounds so an image can't spill outside its pane. Matches Tab's pixel snapping.
+    private static Shape clipFor(TerminalPane pane) {
+        Shape clip = pane.clip();
+        if (clip != null) {
+            return clip;
+        }
+        return new Rectangle(Math.round(pane.x()), Math.round(pane.y()), pane.width(), pane.height());
+    }
+
+    private static final class PaneOverlay {
+        private final Group group = new Group();
+        private final Map<Long, ImageView> views = new HashMap<>();
+
+        private PaneOverlay() {
+            group.setManaged(false);
+        }
+    }
+}

src/main/java/com/gregor/jprototerm/LinuxPty.java

@@ -97,6 +97,7 @@ public final class LinuxPty implements AutoCloseable {
 
     private final Arena arena = Arena.ofShared();
     private final MemorySegment readBuffer = arena.allocate(65536);
+    private final MemorySegment writeBuffer = arena.allocate(65536);
     private final Object writeLock = new Object();
     private final int masterFd;
     private final int pid;
@@ -186,17 +187,20 @@ public final class LinuxPty implements AutoCloseable {
             return;
         }
         synchronized (writeLock) {
-            try (Arena a = Arena.ofConfined()) {
+            int offset = 0;
-                MemorySegment buf = a.allocate(data.length);
-                MemorySegment.copy(data, 0, buf, ValueLayout.JAVA_BYTE, 0, data.length);
-                long offset = 0;
             while (offset < data.length) {
-                    long n = callLong(WRITE, masterFd, buf.asSlice(offset), data.length - offset);
+                int chunk = (int) Math.min(writeBuffer.byteSize(), data.length - offset);
-                    if (n < 0) {
+                MemorySegment.copy(data, offset, writeBuffer, ValueLayout.JAVA_BYTE, 0, chunk);
+
+                long written = 0;
+                while (written < chunk) {
+                    long n = callLong(WRITE, masterFd, writeBuffer.asSlice(written), chunk - written);
+                    if (n <= 0) {
                         throw new IllegalStateException("write to pty failed");
                     }
-                    offset += n;
+                    written += n;
                 }
+                offset += chunk;
             }
         }
     }

src/main/java/com/gregor/jprototerm/Main.java

@@ -3,6 +3,7 @@ package com.gregor.jprototerm;
 import javafx.animation.AnimationTimer;
 import javafx.application.Application;
 import javafx.application.Platform;
+import javafx.geometry.Rectangle2D;
 import javafx.scene.Scene;
 import javafx.scene.control.ButtonType;
 import javafx.scene.control.ComboBox;
@@ -12,12 +13,15 @@ import javafx.scene.control.Spinner;
 import javafx.scene.control.SpinnerValueFactory;
 import javafx.scene.input.KeyEvent;
 import javafx.scene.layout.GridPane;
+import javafx.scene.layout.StackPane;
 import javafx.scene.text.Font;
+import javafx.stage.Screen;
 import javafx.stage.Stage;
 
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.List;
 
 public final class Main extends Application {
     private Compositor compositor;
@@ -31,7 +35,11 @@ public final class Main extends Application {
         metrics = new TerminalMetrics(config.fontFamily(), config.fontSize());
         compositor = new Compositor(config, metrics);
 
-        Scene scene = new Scene(compositor.node(), config.windowWidth(), config.windowHeight());
+        StackPane root = new StackPane(compositor.canvas(), compositor.imageOverlay());
+        compositor.canvas().widthProperty().bind(root.widthProperty());
+        compositor.canvas().heightProperty().bind(root.heightProperty());
+
+        Scene scene = new Scene(root, config.windowWidth(), config.windowHeight());
         scene.addEventFilter(KeyEvent.KEY_PRESSED, this::handlePressed);
         scene.addEventFilter(KeyEvent.KEY_TYPED, event -> handleTyped(event));
 
@@ -47,8 +55,31 @@ public final class Main extends Application {
         stage.setOnCloseRequest(event -> {
             compositor.close();
         });
+        // JavaFX centres a new stage on the primary screen; on X11 there's no "focused monitor"
+        // to honour, so place it on the screen under the mouse pointer instead.
+        centreOnActiveScreen(stage, config.windowWidth(), config.windowHeight());
         stage.show();
-        compositor.requestFocus();
+        compositor.canvas().requestFocus();
+    }
+
+    // Centre the stage within the screen the mouse pointer is on (the best proxy for the
+    // "active" monitor on X11, which exposes no focused-monitor concept to JavaFX).
+    private static void centreOnActiveScreen(Stage stage, double width, double height) {
+        Rectangle2D bounds = activeScreen().getVisualBounds();
+        stage.setX(bounds.getMinX() + ((bounds.getWidth() - width) / 2.0));
+        stage.setY(bounds.getMinY() + ((bounds.getHeight() - height) / 2.0));
+    }
+
+    private static Screen activeScreen() {
+        int[] at = X11Pointer.query();
+        if (at != null) {
+            // libX11 and JavaFX share a coordinate space on the X11 virtual screen.
+            List<Screen> screens = Screen.getScreensForRectangle(at[0], at[1], 1.0, 1.0);
+            if (!screens.isEmpty()) {
+                return screens.get(0);
+            }
+        }
+        return Screen.getPrimary();
     }
 
     private void handlePressed(KeyEvent event) {
@@ -70,6 +101,9 @@ public final class Main extends Application {
         } else if (config.keybindings().get("new_pane").matches(event)) {
             compositor.createPane();
             event.consume();
+        } else if (config.keybindings().get("next_floating").matches(event)) {
+            compositor.nextFloatingPane();
+            event.consume();
         } else if (config.keybindings().get("close_pane").matches(event)) {
             compositor.closeActivePane();
             event.consume();
@@ -153,17 +187,22 @@ public final class Main extends Application {
                     config = config.withFont(selectedFamily.trim(), selectedSize);
                     config.save();
                     compositor.setFont(config.fontFamily(), config.fontSize());
-                    compositor.requestFocus();
+                    compositor.canvas().requestFocus();
                 });
     }
 
     private void openScrollbackInEditor() {
         try {
+            // Capture the active pane's scrollback before opening the floating pane, since that
+            // makes the new pane active.
             Path file = Files.createTempFile("jprototerm-scrollback-", ".txt");
             Files.writeString(file, compositor.activePane().scrollbackText());
             file.toFile().deleteOnExit();
 
-            compositor.activePane().send(scrollbackEditorCommand(file) + "\r");
+            TerminalPane pane = compositor.openFloatingPane();
+            if (pane != null) {
+                pane.send(scrollbackEditorCommand(file) + "\r");
+            }
         } catch (IOException ex) {
             System.err.println("Could not open scrollback in editor: " + ex.getMessage());
         }

src/main/java/com/gregor/jprototerm/RenderTarget.java

@@ -0,0 +1,45 @@
+package com.gregor.jprototerm;
+
+import dev.jlibghostty.KittyGraphics;
+import dev.jlibghostty.RenderStateSnapshot;
+import javafx.scene.shape.Shape;
+
+import java.util.Optional;
+
+/**
+ * The read-only view of a pane that a {@link TerminalRenderer} draws: its on-screen rect, its
+ * current render snapshot, and its kitty-graphics state. Decoupling the renderer from
+ * {@link TerminalPane} through this interface lets the renderer be swapped (e.g. a debug
+ * renderer that just outlines bounds and clip bands) and unit-tested against a synthetic
+ * target without a real terminal.
+ */
+interface RenderTarget {
+    double x();
+
+    double y();
+
+    double width();
+
+    double height();
+
+    /** Whether kitty graphics should be drawn for this target at all. */
+    boolean kittyEnabled();
+
+    Optional<KittyGraphics> kittyGraphics();
+
+    /**
+     * Incremental snapshot: only rows that changed since the last frame are populated. May be
+     * {@code null} before the first snapshot exists.
+     */
+    RenderStateSnapshot snapshot();
+
+    /** Full snapshot with every row populated, regardless of dirty state. */
+    RenderStateSnapshot snapshotFull();
+
+    /**
+     * The region this target may draw into, or {@code null} to clip to its plain rect. Set at
+     * layout time (a tiled pane gets its rect minus the floating panes that cover it), so the
+     * renderer can clip its own output and never paint over a pane on top.
+     */
+    Shape clip();
+}

src/main/java/com/gregor/jprototerm/Tab.java

@@ -1,8 +1,12 @@
 package com.gregor.jprototerm;
 
+import javafx.scene.shape.Rectangle;
+import javafx.scene.shape.Shape;
+
 import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.List;
+import java.util.concurrent.atomic.AtomicLong;
 import java.util.stream.Stream;
 
 /**
@@ -30,7 +34,7 @@ final class Tab implements AutoCloseable {
     private double lastTopInset;
     // Bumped whenever one of this tab's panes changes content; the compositor reads the current
     // tab's value each frame as an O(1) "anything to repaint?" check.
-    private long contentVersion;
+    private final AtomicLong contentVersion = new AtomicLong();
 
     Tab(AppConfig config, TerminalMetrics metrics) {
         this.config = config;
@@ -51,7 +55,7 @@ final class Tab implements AutoCloseable {
     }
 
     long contentVersion() {
-        return contentVersion;
+        return contentVersion.get();
     }
 
     /**
@@ -75,13 +79,6 @@ final class Tab implements AutoCloseable {
         return List.copyOf(ordered);
     }
 
-    List<TerminalPane> allPanes() {
-        List<TerminalPane> all = new ArrayList<>(tiled.size() + floating.size());
-        all.addAll(tiled);
-        all.addAll(floating);
-        return List.copyOf(all);
-    }
-
     boolean isActive(TerminalPane pane) {
         return pane != null && pane == active;
     }
@@ -115,6 +112,51 @@ final class Tab implements AutoCloseable {
                     floatingWidth,
                     floatingHeight);
         }
+
+        assignClips();
+    }
+
+    // Give each pane its clip region for the next paints, so repainting a pane on a content
+    // frame can never bleed over one stacked on top of it. Each pane is clipped to its rect
+    // minus the union of the panes above it: floating panes are clipped by the floating panes
+    // higher in the stack, and tiled panes by the whole floating group. When nothing floats,
+    // every pane clips to its plain bounds.
+    private void assignClips() {
+        if (!floatingVisible || floating.isEmpty()) {
+            tiled.forEach(pane -> pane.setClip(null));
+            floating.forEach(pane -> pane.setClip(null));
+            return;
+        }
+
+        // Floating panes bottom-to-top, matching panes(): insertion order, active pane on top.
+        List<TerminalPane> order = new ArrayList<>(floating.size());
+        for (TerminalPane pane : floating) {
+            if (pane != active) {
+                order.add(pane);
+            }
+        }
+        if (floating.contains(active)) {
+            order.add(active);
+        }
+
+        // Walk top-to-bottom, accumulating the union of the panes above each one.
+        Shape above = null;
+        for (int i = order.size() - 1; i >= 0; i--) {
+            Rectangle rect = rectOf(order.get(i));
+            order.get(i).setClip(above == null ? null : Shape.subtract(rect, above));
+            above = (above == null) ? rect : Shape.union(above, rect);
+        }
+
+        // `above` is now the union of every floating pane; tiled panes sit under all of them.
+        for (TerminalPane pane : tiled) {
+            pane.setClip(Shape.subtract(rectOf(pane), above));
+        }
+    }
+
+    // Match the renderer's pixel snapping (round the origin, keep width/height) so the clip
+    // lines up exactly with where the floating panes are drawn.
+    private static Rectangle rectOf(TerminalPane pane) {
+        return new Rectangle(Math.round(pane.x()), Math.round(pane.y()), pane.width(), pane.height());
     }
 
     boolean navigate(Direction direction) {
@@ -160,6 +202,16 @@ final class Tab implements AutoCloseable {
         }
     }
 
+    void nextFloatingPane() {
+        if (floating.isEmpty()) {
+            createFloatingPane();
+            return;
+        }
+        floatingVisible = true;
+        int current = floating.indexOf(active); // -1 when the active pane is tiled
+        setActive(floating.get((current + 1 + floating.size()) % floating.size()));
+    }
+
     void closeActivePane() {
         TerminalPane closing = active;
         boolean wasFloating = floating.remove(closing);
@@ -205,11 +257,12 @@ final class Tab implements AutoCloseable {
         }
     }
 
-    private void createFloatingPane() {
+    TerminalPane createFloatingPane() {
         TerminalPane pane = openPane(true);
         floating.add(pane);
         floatingVisible = true;
         setActive(pane);
+        return pane;
     }
 
     private boolean navigateFloatingStack(Direction direction) {
@@ -240,7 +293,7 @@ final class Tab implements AutoCloseable {
     }
 
     private void markContentChanged() {
-        contentVersion++;
+        contentVersion.incrementAndGet();
     }
 
     private TerminalPane openPane(boolean asFloating) {

src/main/java/com/gregor/jprototerm/TerminalPane.java

@@ -12,28 +12,36 @@ import dev.jlibghostty.RenderStateSnapshot;
 import dev.jlibghostty.ScrollViewport;
 import dev.jlibghostty.Terminal;
 import dev.jlibghostty.TerminalOptions;
+import javafx.scene.canvas.GraphicsContext;
+import javafx.scene.shape.Shape;
 
 import java.util.Optional;
 import java.util.concurrent.atomic.AtomicLong;
 
 /**
  * One terminal: owns its ghostty {@link Terminal}, the {@link ShellSession}/pty driving it,
- * and its on-screen geometry and grid. It does not draw itself; {@link TerminalPaneNode}
+ * and its on-screen geometry and grid. It does not draw itself — it is a {@link RenderTarget}
- * reads snapshots from it and represents the visible rows and kitty graphics as JavaFX nodes.
+ * that a {@link TerminalRenderer} paints. {@link #paintFull}/{@link #paintIncremental} are the
+ * only rendering API exposed to the {@link Compositor}, and they just delegate to that
+ * renderer; the compositor decides z-order and which rect each pane occupies.
  */
-public final class TerminalPane implements AutoCloseable {
+public final class TerminalPane implements AutoCloseable, RenderTarget {
     private final Terminal terminal;
     private final TerminalMetrics metrics;
     private final boolean kittyEnabled;
     // Run on every content change so the owning tab can bump its content version — the
     // compositor's O(1) "did the current tab change?" gate.
     private final Runnable onContentChange;
+    private final TerminalRenderer renderer;
     private final MouseEncoder mouseEncoder = new MouseEncoder();
     // A persistent render state (reused across frames) is what makes ghostty's per-row dirty
     // tracking meaningful: update() accumulates dirty since the last resetDirty().
     private final RenderState renderState = new RenderState();
     private RenderStateSnapshot cachedSnapshot;
     private ShellSession session;
+    // Clip region for rendering (rect minus the panes covering this one), set at layout time;
+    // null means clip to the plain bounds. See RenderTarget#clip().
+    private Shape clip;
     private double x;
     private double y;
     private double width;
@@ -43,14 +51,15 @@ public final class TerminalPane implements AutoCloseable {
     private int pixelWidth;
     private int pixelHeight;
     private final AtomicLong contentVersion = new AtomicLong();
-    private volatile long snapshotVersion = -1;
+    private long snapshotVersion = -1;
 
     private TerminalPane(Terminal terminal, TerminalMetrics metrics, boolean kittyEnabled,
-            Runnable onContentChange, int columns, int rows) {
+            Runnable onContentChange, TerminalRenderer renderer, int columns, int rows) {
         this.terminal = terminal;
         this.metrics = metrics;
         this.kittyEnabled = kittyEnabled;
         this.onContentChange = onContentChange;
+        this.renderer = renderer;
         this.columns = columns;
         this.rows = rows;
     }
@@ -67,7 +76,8 @@ public final class TerminalPane implements AutoCloseable {
         int rows = heightPx > 0 ? metrics.rowsFor(heightPx) : config.rows();
         Terminal terminal = Ghostty.open(new TerminalOptions(columns, rows, config.maxScrollback()));
         terminal.setDeviceAttributesProvider(DeviceAttributes::xtermCompatible);
-        TerminalPane pane = new TerminalPane(terminal, metrics, config.kittyGraphics(), onContentChange, columns, rows);
+        TerminalPane pane = new TerminalPane(terminal, metrics, config.kittyGraphics(), onContentChange,
+                new GhosttyTerminalRenderer(metrics), columns, rows);
         pane.refresh();
         pane.attach(ShellSession.start(config.shell(), config.envOverride(), pane, columns, rows));
         return pane;
@@ -144,6 +154,7 @@ public final class TerminalPane implements AutoCloseable {
      * Snapshotting is deferred here rather than done in refresh(), so a burst of writes
      * between two frames collapses into a single snapshot.
      */
+    @Override
     public RenderStateSnapshot snapshot() {
         return takeSnapshot(false);
     }
@@ -152,6 +163,7 @@ public final class TerminalPane implements AutoCloseable {
      * Full snapshot with every row's cells populated. Used where the whole pane is redrawn
      * regardless of dirty state (the kitty-graphics path).
      */
+    @Override
     public RenderStateSnapshot snapshotFull() {
         return takeSnapshot(true);
     }
@@ -185,32 +197,34 @@ public final class TerminalPane implements AutoCloseable {
         return contentVersion.get();
     }
 
-    long snapshotVersion() {
+    @Override
-        return snapshotVersion;
-    }
-
     public boolean kittyEnabled() {
         return kittyEnabled;
     }
 
+    @Override
     public Optional<KittyGraphics> kittyGraphics() {
         synchronized (terminal) {
             return terminal.kittyGraphics();
         }
     }
 
+    @Override
     public double x() {
         return x;
     }
 
+    @Override
     public double y() {
         return y;
     }
 
+    @Override
     public double width() {
         return width;
     }
 
+    @Override
     public double height() {
         return height;
     }
@@ -222,6 +236,16 @@ public final class TerminalPane implements AutoCloseable {
         this.height = height;
     }
 
+    /** Set the clip region applied on the next paints (see {@link RenderTarget#clip()}). */
+    public void setClip(Shape clip) {
+        this.clip = clip;
+    }
+
+    @Override
+    public Shape clip() {
+        return clip;
+    }
+
     /** Recompute the ghostty grid from the current bounds and the shared cell metrics. */
     public void fitToBounds() {
         int columns = metrics.columnsFor(width);
@@ -258,6 +282,26 @@ public final class TerminalPane implements AutoCloseable {
         onContentChange.run();
     }
 
+    /** Paint the whole pane; see {@link TerminalRenderer#paintFull}. */
+    public long paintFull(GraphicsContext gc, boolean active) {
+        renderer.paintFull(gc, this, active);
+        return snapshotVersion;
+    }
+
+    /** Repaint what changed; see {@link TerminalRenderer#paintIncremental}. */
+    public long paintIncremental(GraphicsContext gc, boolean active) {
+        renderer.paintIncremental(gc, this, active);
+        return snapshotVersion;
+    }
+
+    /**
+     * Kitty image placements from the most recent paint, in scene coordinates. The compositor
+     * renders these as overlay nodes clipped to this pane (see {@link KittyImageOverlay}).
+     */
+    public java.util.List<KittyImageNode> kittyImages() {
+        return renderer.kittyImages();
+    }
+
     @Override
     public void close() {
         if (session != null) {

src/main/java/com/gregor/jprototerm/TerminalPaneNode.java

@@ -1,975 +0,0 @@
-package com.gregor.jprototerm;
-
-import dev.jlibghostty.KittyImageCompression;
-import dev.jlibghostty.KittyImageFormat;
-import dev.jlibghostty.KittyImageSnapshot;
-import dev.jlibghostty.KittyPlacement;
-import dev.jlibghostty.KittyPlacementLayer;
-import dev.jlibghostty.KittyPlaceholder;
-import dev.jlibghostty.KittyRenderInfo;
-import dev.jlibghostty.RenderCell;
-import dev.jlibghostty.RenderColor;
-import dev.jlibghostty.RenderCursorStyle;
-import dev.jlibghostty.RenderRow;
-import dev.jlibghostty.RenderStateSnapshot;
-import javafx.geometry.Rectangle2D;
-import javafx.scene.Node;
-import javafx.scene.canvas.Canvas;
-import javafx.scene.canvas.GraphicsContext;
-import javafx.scene.image.Image;
-import javafx.scene.image.ImageView;
-import javafx.scene.image.PixelFormat;
-import javafx.scene.image.WritableImage;
-import javafx.scene.layout.Pane;
-import javafx.scene.layout.Region;
-import javafx.scene.paint.Color;
-import javafx.scene.shape.Line;
-import javafx.scene.shape.Rectangle;
-import javafx.scene.text.FontSmoothingType;
-
-import java.io.ByteArrayInputStream;
-import java.util.ArrayList;
-import java.util.Comparator;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-
-/**
- * JavaFX node for one terminal pane. The pane is composed from JavaFX primitives: one node per
- * terminal row, kitty graphics as ImageView nodes, plus background/cursor/border nodes.
- */
-final class TerminalPaneNode extends Region {
-    private static final int DIRTY_PARTIAL = 1;
-    private static final int DIRTY_FULL = 2;
-
-    private static final Color DEFAULT_FOREGROUND = Color.rgb(225, 229, 235);
-    private static final Color SELECTED_BACKGROUND = Color.rgb(52, 92, 140);
-    private static final Color PANE_BACKGROUND = Color.rgb(9, 10, 12);
-    private static final Map<Integer, Color> COLOR_CACHE = new HashMap<>();
-
-    private final TerminalPane pane;
-    private final TerminalMetrics metrics;
-    private final Rectangle background = new Rectangle();
-    private final Pane belowImageLayer = new Pane();
-    private final Pane rowLayer = new Pane();
-    private final Pane cursorLayer = new Pane();
-    private final Pane aboveImageLayer = new Pane();
-    private final Rectangle topPadding = new Rectangle();
-    private final Rectangle bottomPadding = new Rectangle();
-    private final Rectangle border = new Rectangle();
-    private final Map<Integer, TerminalRowNode> rows = new HashMap<>();
-    private final Map<Integer, Long> rowFingerprints = new HashMap<>();
-    private final Map<KittyImageKey, Image> kittyImageCache = new HashMap<>();
-    private long drawnContentVersion = Long.MIN_VALUE;
-    private double drawnWidth = -1.0;
-    private double drawnHeight = -1.0;
-
-    TerminalPaneNode(TerminalPane pane, TerminalMetrics metrics) {
-        this.pane = pane;
-        this.metrics = metrics;
-        setPickOnBounds(true);
-        setClip(new Rectangle());
-        background.setFill(PANE_BACKGROUND);
-        border.setFill(Color.TRANSPARENT);
-        getChildren().setAll(background, belowImageLayer, rowLayer, cursorLayer, aboveImageLayer, border);
-        rowLayer.getChildren().setAll(topPadding, bottomPadding);
-    }
-
-    void discard() {
-        drawnContentVersion = Long.MIN_VALUE;
-        drawnWidth = -1.0;
-        drawnHeight = -1.0;
-        rows.clear();
-        rowFingerprints.clear();
-        rowLayer.getChildren().setAll(topPadding, bottomPadding);
-        belowImageLayer.getChildren().clear();
-        aboveImageLayer.getChildren().clear();
-        cursorLayer.getChildren().clear();
-    }
-
-    void renderFull(boolean active) {
-        prepareGeometry();
-        RenderStateSnapshot snapshot = pane.snapshotFull();
-        long renderedVersion = pane.snapshotVersion();
-        boolean withKitty = pane.kittyEnabled() && hasKittyGraphics();
-        updateRowsFull(snapshot);
-        updateKittyGraphics(snapshot, withKitty);
-        updateCursor(snapshot);
-        updateBorder(active);
-        markDrawn(renderedVersion);
-    }
-
-    void renderIncremental(boolean active) {
-        boolean geometryChanged = prepareGeometry();
-        boolean withKitty = pane.kittyEnabled() && hasKittyGraphics();
-        if (drawnContentVersion == Long.MIN_VALUE || geometryChanged || withKitty) {
-            renderFull(active);
-            return;
-        }
-        if (drawnContentVersion == pane.contentVersion()) {
-            updateBorder(active);
-            return;
-        }
-
-        RenderStateSnapshot snapshot = pane.snapshot();
-        long renderedVersion = pane.snapshotVersion();
-        int dirty = snapshot == null ? DIRTY_FULL : snapshot.dirty();
-        if (dirty == DIRTY_FULL) {
-            updateChangedRows(snapshot, snapshot.renderRows());
-        } else if (dirty == DIRTY_PARTIAL) {
-            updateDirtyRows(snapshot);
-        }
-        updateKittyGraphics(snapshot, false);
-        updateCursor(snapshot);
-        updateBorder(active);
-        markDrawn(renderedVersion);
-    }
-
-    private boolean prepareGeometry() {
-        double width = Math.max(0.0, pane.width());
-        double height = Math.max(0.0, pane.height());
-        boolean changed = drawnWidth != width || drawnHeight != height;
-        resize(width, height);
-        background.setWidth(width);
-        background.setHeight(height);
-        resizeLayer(belowImageLayer, width, height);
-        resizeLayer(rowLayer, width, height);
-        resizeLayer(cursorLayer, width, height);
-        resizeLayer(aboveImageLayer, width, height);
-        border.setWidth(Math.max(0.0, width - 1.0));
-        border.setHeight(Math.max(0.0, height - 1.0));
-        border.relocate(0.5, 0.5);
-        Node clip = getClip();
-        if (clip instanceof Rectangle rectangle) {
-            rectangle.setWidth(width);
-            rectangle.setHeight(height);
-        }
-        return changed;
-    }
-
-    private static void resizeLayer(Pane layer, double width, double height) {
-        layer.resizeRelocate(0.0, 0.0, width, height);
-    }
-
-    private void updateRowsFull(RenderStateSnapshot snapshot) {
-        if (snapshot == null) {
-            rows.clear();
-            rowFingerprints.clear();
-            rowLayer.getChildren().setAll(topPadding, bottomPadding);
-            return;
-        }
-
-        List<Node> ordered = new ArrayList<>(snapshot.renderRows().size() + 2);
-        ordered.add(topPadding);
-        ordered.add(bottomPadding);
-        Set<Integer> liveRows = new HashSet<>();
-        for (RenderRow row : snapshot.renderRows()) {
-            TerminalRowNode node = rowNode(row.row());
-            long fingerprint = rowFingerprint(row);
-            node.render(row);
-            rowFingerprints.put(row.row(), fingerprint);
-            liveRows.add(row.row());
-            ordered.add(node);
-        }
-        rows.keySet().retainAll(liveRows);
-        rowFingerprints.keySet().retainAll(liveRows);
-        rowLayer.getChildren().setAll(ordered);
-        updateVerticalPadding(snapshot);
-    }
-
-    private void updateDirtyRows(RenderStateSnapshot snapshot) {
-        List<RenderRow> dirtyRows = snapshot.renderRows().stream()
-                .filter(RenderRow::dirty)
-                .toList();
-        updateChangedRows(snapshot, dirtyRows);
-    }
-
-    private void updateChangedRows(RenderStateSnapshot snapshot, List<RenderRow> changedRows) {
-        if (snapshot == null || changedRows.isEmpty()) {
-            return;
-        }
-
-        Set<Integer> movedRows = moveShiftedRows(snapshot, changedRows);
-        for (RenderRow row : snapshot.renderRows()) {
-            if (!changedRows.contains(row) || movedRows.contains(row.row())) {
-                continue;
-            }
-            TerminalRowNode node = rowNode(row.row());
-            long fingerprint = rowFingerprint(row);
-            node.renderChanged(row);
-            rowFingerprints.put(row.row(), fingerprint);
-        }
-        for (RenderRow row : changedRows) {
-            updateDirtyVerticalPadding(snapshot, row);
-        }
-        syncRowChildren();
-    }
-
-    private Set<Integer> moveShiftedRows(RenderStateSnapshot snapshot, List<RenderRow> changedRows) {
-        if (rowFingerprints.isEmpty() || changedRows.size() < Math.max(4, snapshot.rows() / 3)) {
-            return Set.of();
-        }
-
-        ShiftPlan plan = detectShift(snapshot, changedRows);
-        if (plan == null) {
-            return Set.of();
-        }
-
-        Map<Integer, TerminalRowNode> oldRows = new HashMap<>(rows);
-        Map<Integer, Long> oldFingerprints = new HashMap<>(rowFingerprints);
-        for (RowMove move : plan.moves()) {
-            rows.remove(move.sourceRow());
-            rowFingerprints.remove(move.sourceRow());
-        }
-        for (RowMove move : plan.moves()) {
-            TerminalRowNode node = oldRows.get(move.sourceRow());
-            if (node == null) {
-                continue;
-            }
-            node.moveToRow(move.targetRow());
-            rows.put(move.targetRow(), node);
-            rowFingerprints.put(move.targetRow(), oldFingerprints.get(move.sourceRow()));
-        }
-        return plan.targetRows();
-    }
-
-    private ShiftPlan detectShift(RenderStateSnapshot snapshot, List<RenderRow> changedRows) {
-        int bestDelta = 0;
-        int bestScore = 0;
-        int rowCount = snapshot.rows();
-        for (int delta = -rowCount + 1; delta < rowCount; delta++) {
-            if (delta == 0) {
-                continue;
-            }
-            int score = 0;
-            for (RenderRow row : changedRows) {
-                int sourceRow = row.row() + delta;
-                if (sourceRow < 0 || sourceRow >= rowCount || !rows.containsKey(sourceRow)) {
-                    continue;
-                }
-                Long previous = rowFingerprints.get(sourceRow);
-                if (previous != null && previous == rowFingerprint(row)) {
-                    score++;
-                }
-            }
-            if (score > bestScore) {
-                bestScore = score;
-                bestDelta = delta;
-            }
-        }
-
-        int threshold = Math.max(4, (changedRows.size() * 2 + 2) / 3);
-        if (bestScore < threshold) {
-            return null;
-        }
-
-        List<RowMove> moves = new ArrayList<>(bestScore);
-        Set<Integer> targetRows = new HashSet<>();
-        for (RenderRow row : changedRows) {
-            int sourceRow = row.row() + bestDelta;
-            if (sourceRow < 0 || sourceRow >= rowCount || !rows.containsKey(sourceRow)) {
-                continue;
-            }
-            Long previous = rowFingerprints.get(sourceRow);
-            if (previous != null && previous == rowFingerprint(row)) {
-                moves.add(new RowMove(sourceRow, row.row()));
-                targetRows.add(row.row());
-            }
-        }
-        return new ShiftPlan(moves, targetRows);
-    }
-
-    private void syncRowChildren() {
-        List<Node> ordered = new ArrayList<>(rows.size() + 2);
-        ordered.add(topPadding);
-        ordered.add(bottomPadding);
-        rows.entrySet().stream()
-                .sorted(Comparator.comparingInt(Map.Entry::getKey))
-                .map(Map.Entry::getValue)
-                .forEach(ordered::add);
-        rowLayer.getChildren().setAll(ordered);
-    }
-
-    private TerminalRowNode rowNode(int row) {
-        return rows.computeIfAbsent(row, ignored -> {
-            TerminalRowNode created = new TerminalRowNode(metrics);
-            if (!rowLayer.getChildren().contains(created)) {
-                rowLayer.getChildren().add(created);
-            }
-            return created;
-        });
-    }
-
-    private void updateVerticalPadding(RenderStateSnapshot snapshot) {
-        List<RenderRow> renderRows = snapshot.renderRows();
-        if (renderRows.isEmpty()) {
-            topPadding.setVisible(false);
-            bottomPadding.setVisible(false);
-            return;
-        }
-
-        double width = pane.width();
-        double top = TerminalMetrics.PADDING;
-        double contentBottom = top + snapshot.rows() * metrics.lineHeight();
-        topPadding.setVisible(true);
-        topPadding.setFill(rowEdgeBackground(renderRows.get(0), true));
-        topPadding.relocate(0.0, 0.0);
-        topPadding.setWidth(width);
-        topPadding.setHeight(top);
-
-        bottomPadding.setVisible(true);
-        bottomPadding.setFill(rowEdgeBackground(renderRows.get(renderRows.size() - 1), true));
-        bottomPadding.relocate(0.0, contentBottom);
-        bottomPadding.setWidth(width);
-        bottomPadding.setHeight(Math.max(0.0, pane.height() - contentBottom));
-    }
-
-    private void updateDirtyVerticalPadding(RenderStateSnapshot snapshot, RenderRow row) {
-        if (row.row() == 0) {
-            topPadding.setVisible(true);
-            topPadding.setFill(rowEdgeBackground(row, true));
-            topPadding.relocate(0.0, 0.0);
-            topPadding.setWidth(pane.width());
-            topPadding.setHeight(TerminalMetrics.PADDING);
-        }
-        if (row.row() == snapshot.rows() - 1) {
-            double contentBottom = TerminalMetrics.PADDING + snapshot.rows() * metrics.lineHeight();
-            bottomPadding.setVisible(true);
-            bottomPadding.setFill(rowEdgeBackground(row, true));
-            bottomPadding.relocate(0.0, contentBottom);
-            bottomPadding.setWidth(pane.width());
-            bottomPadding.setHeight(Math.max(0.0, pane.height() - contentBottom));
-        }
-    }
-
-    private void updateCursor(RenderStateSnapshot snapshot) {
-        cursorLayer.getChildren().clear();
-        if (snapshot == null || !snapshot.cursorVisible() || !snapshot.cursorViewportHasValue()) {
-            return;
-        }
-
-        double x = TerminalMetrics.PADDING + (snapshot.cursorViewportX() * metrics.cellWidth());
-        double y = TerminalMetrics.PADDING + (snapshot.cursorViewportY() * metrics.lineHeight());
-        double cellWidth = metrics.cellWidth();
-        double lineHeight = metrics.lineHeight();
-        RenderCursorStyle style = snapshot.cursorStyle();
-        if (style == RenderCursorStyle.BAR) {
-            Line line = new Line(x + 0.5, y + 2.0, x + 0.5, y + lineHeight - 2.0);
-            line.setStroke(DEFAULT_FOREGROUND);
-            line.setStrokeWidth(1.5);
-            cursorLayer.getChildren().add(line);
-        } else if (style == RenderCursorStyle.UNDERLINE) {
-            Line line = new Line(x + 1.0, y + lineHeight - 2.0, x + cellWidth - 1.0, y + lineHeight - 2.0);
-            line.setStroke(DEFAULT_FOREGROUND);
-            line.setStrokeWidth(1.5);
-            cursorLayer.getChildren().add(line);
-        } else if (style == RenderCursorStyle.BLOCK) {
-            Rectangle rectangle = new Rectangle(x + 0.5, y + 1.0, Math.max(1.0, cellWidth - 1.0), Math.max(1.0, lineHeight - 2.0));
-            rectangle.setFill(Color.rgb(225, 229, 235, 0.28));
-            cursorLayer.getChildren().add(rectangle);
-        } else {
-            Rectangle rectangle = new Rectangle(x + 0.5, y + 1.0, Math.max(1.0, cellWidth - 1.0), Math.max(1.0, lineHeight - 2.0));
-            rectangle.setFill(Color.TRANSPARENT);
-            rectangle.setStroke(DEFAULT_FOREGROUND);
-            rectangle.setStrokeWidth(1.5);
-            cursorLayer.getChildren().add(rectangle);
-        }
-    }
-
-    private void updateBorder(boolean active) {
-        border.setStroke(active ? Color.rgb(87, 166, 255) : Color.rgb(52, 57, 65));
-        border.setStrokeWidth(active ? 2.0 : 1.0);
-    }
-
-    private void updateKittyGraphics(RenderStateSnapshot snapshot, boolean withKitty) {
-        belowImageLayer.getChildren().clear();
-        aboveImageLayer.getChildren().clear();
-        if (!withKitty || snapshot == null) {
-            return;
-        }
-
-        Map<KittyPlaceholderKey, KittyPlaceholderBounds> placeholderBounds = kittyPlaceholderBounds(snapshot);
-        addKittyGraphics(belowImageLayer, KittyPlacementLayer.BELOW_TEXT, placeholderBounds);
-        addKittyGraphics(aboveImageLayer, KittyPlacementLayer.ABOVE_TEXT, placeholderBounds);
-    }
-
-    private void addKittyGraphics(Pane layer, KittyPlacementLayer placementLayer, Map<KittyPlaceholderKey, KittyPlaceholderBounds> placeholderBounds) {
-        pane.kittyGraphics().ifPresent(graphics -> {
-            for (KittyPlacement placement : graphics.placements(placementLayer)) {
-                Image image = imageFor(placement);
-                if (image == null) {
-                    continue;
-                }
-                ImageView view = placement.virtual()
-                        ? virtualKittyView(placement, image, placeholderBounds)
-                        : pinnedKittyView(placement, image);
-                if (view != null) {
-                    layer.getChildren().add(view);
-                }
-            }
-        });
-    }
-
-    private ImageView pinnedKittyView(KittyPlacement placement, Image image) {
-        KittyRenderInfo renderInfo = placement.renderInfo().orElse(null);
-        if (renderInfo == null || !renderInfo.viewportVisible()) {
-            return null;
-        }
-
-        double sourceX = renderInfo.sourceX();
-        double sourceY = renderInfo.sourceY();
-        double sourceWidth = renderInfo.sourceWidth();
-        double sourceHeight = renderInfo.sourceHeight();
-        if (sourceWidth <= 0.0 || sourceHeight <= 0.0) {
-            return null;
-        }
-
-        double x = TerminalMetrics.PADDING + (renderInfo.viewportColumn() * metrics.cellWidth()) + placement.xOffset();
-        double y = TerminalMetrics.PADDING + (renderInfo.viewportRow() * metrics.lineHeight()) + placement.yOffset();
-        double width = renderInfo.pixelWidth() > 0 ? renderInfo.pixelWidth() : renderInfo.gridColumns() * metrics.cellWidth();
-        double height = renderInfo.pixelHeight() > 0 ? renderInfo.pixelHeight() : renderInfo.gridRows() * metrics.lineHeight();
-        return imageView(image, sourceX, sourceY, sourceWidth, sourceHeight, x, y, width, height);
-    }
-
-    private ImageView virtualKittyView(KittyPlacement placement, Image image, Map<KittyPlaceholderKey, KittyPlaceholderBounds> placeholderBounds) {
-        KittyPlaceholderBounds bounds = placeholderBounds.get(new KittyPlaceholderKey(placement.imageId(), placement.placementId()));
-        if (bounds == null) {
-            bounds = placeholderBounds.get(new KittyPlaceholderKey(placement.imageId(), 0));
-        }
-        if (bounds == null && placement.placementId() == 0) {
-            bounds = placeholderBounds.entrySet().stream()
-                    .filter(entry -> entry.getKey().imageId() == placement.imageId())
-                    .map(Map.Entry::getValue)
-                    .findFirst()
-                    .orElse(null);
-        }
-        if (bounds == null || bounds.isEmpty()) {
-            return null;
-        }
-
-        SourceRect source = sourceRect(placement, image);
-        if (source.width() <= 0.0 || source.height() <= 0.0) {
-            return null;
-        }
-
-        long gridColumns = gridColumns(placement, bounds);
-        long gridRows = gridRows(placement, bounds);
-        double sourceCellWidth = source.width() / Math.max(1L, gridColumns);
-        double sourceCellHeight = source.height() / Math.max(1L, gridRows);
-
-        double sourceX = source.x() + (bounds.minSourceColumn * sourceCellWidth);
-        double sourceY = source.y() + (bounds.minSourceRow * sourceCellHeight);
-        double sourceWidth = bounds.sourceColumns() * sourceCellWidth;
-        double sourceHeight = bounds.sourceRows() * sourceCellHeight;
-        double x = TerminalMetrics.PADDING + (bounds.minColumn * metrics.cellWidth());
-        double y = TerminalMetrics.PADDING + (bounds.minRow * metrics.lineHeight());
-        double availableWidth = bounds.columns() * metrics.cellWidth();
-        double availableHeight = bounds.rows() * metrics.lineHeight();
-        if (sourceWidth <= 0.0 || sourceHeight <= 0.0 || availableWidth <= 0.0 || availableHeight <= 0.0) {
-            return null;
-        }
-
-        double scale = Math.min(availableWidth / sourceWidth, availableHeight / sourceHeight);
-        return imageView(image, sourceX, sourceY, sourceWidth, sourceHeight, x, y, sourceWidth * scale, sourceHeight * scale);
-    }
-
-    private static ImageView imageView(Image image, double sourceX, double sourceY, double sourceWidth, double sourceHeight,
-            double x, double y, double width, double height) {
-        if (width <= 0.0 || height <= 0.0) {
-            return null;
-        }
-        ImageView view = new ImageView(image);
-        view.setViewport(new Rectangle2D(sourceX, sourceY, sourceWidth, sourceHeight));
-        view.setFitWidth(width);
-        view.setFitHeight(height);
-        view.setPreserveRatio(false);
-        view.relocate(x, y);
-        return view;
-    }
-
-    private boolean hasKittyGraphics() {
-        return pane.kittyGraphics()
-                .map(graphics -> !graphics.placements().isEmpty())
-                .orElse(false);
-    }
-
-    private Image imageFor(KittyPlacement placement) {
-        return placement.image().map(snapshot -> {
-            byte[] data = snapshot.data();
-            KittyImageKey key = KittyImageKey.of(snapshot, data);
-            Image cached = kittyImageCache.get(key);
-            if (cached != null) {
-                return cached;
-            }
-
-            kittyImageCache.keySet().removeIf(existing -> existing.id() == snapshot.id());
-            Image decoded = decodeImage(snapshot, data);
-            if (decoded != null) {
-                kittyImageCache.put(key, decoded);
-            }
-            return decoded;
-        }).orElse(null);
-    }
-
-    private static Image decodeImage(KittyImageSnapshot snapshot, byte[] data) {
-        if (snapshot.compression() != KittyImageCompression.NONE) {
-            return null;
-        }
-
-        if (snapshot.format() == KittyImageFormat.PNG) {
-            return new Image(new ByteArrayInputStream(data));
-        }
-
-        int width = Math.toIntExact(snapshot.width());
-        int height = Math.toIntExact(snapshot.height());
-        WritableImage image = new WritableImage(width, height);
-
-        if (snapshot.format() == KittyImageFormat.RGBA) {
-            image.getPixelWriter().setPixels(0, 0, width, height, PixelFormat.getByteBgraInstance(), rgbaToBgra(data), 0, width * 4);
-        } else if (snapshot.format() == KittyImageFormat.RGB) {
-            image.getPixelWriter().setPixels(0, 0, width, height, PixelFormat.getByteRgbInstance(), data, 0, width * 3);
-        }
-        return image;
-    }
-
-    private static byte[] rgbaToBgra(byte[] rgba) {
-        byte[] bgra = new byte[rgba.length];
-        for (int i = 0; i + 3 < rgba.length; i += 4) {
-            bgra[i] = rgba[i + 2];
-            bgra[i + 1] = rgba[i + 1];
-            bgra[i + 2] = rgba[i];
-            bgra[i + 3] = rgba[i + 3];
-        }
-        return bgra;
-    }
-
-    private static Map<KittyPlaceholderKey, KittyPlaceholderBounds> kittyPlaceholderBounds(RenderStateSnapshot snapshot) {
-        Map<KittyPlaceholderKey, KittyPlaceholderBounds> result = new HashMap<>();
-        for (RenderRow row : snapshot.renderRows()) {
-            for (RenderCell cell : row.cells()) {
-                cell.kittyPlaceholder().ifPresent(placeholder -> {
-                    KittyPlaceholderKey key = new KittyPlaceholderKey(placeholder.imageId(), placeholder.placementId());
-                    result.computeIfAbsent(key, ignored -> new KittyPlaceholderBounds()).include(row.row(), cell.column(), placeholder);
-                });
-            }
-        }
-        return result;
-    }
-
-    private static long gridColumns(KittyPlacement placement, KittyPlaceholderBounds bounds) {
-        if (placement.columns() > 0) {
-            return placement.columns();
-        }
-        return Math.max(bounds.maxSourceColumn + 1, bounds.sourceColumns());
-    }
-
-    private static long gridRows(KittyPlacement placement, KittyPlaceholderBounds bounds) {
-        if (placement.rows() > 0) {
-            return placement.rows();
-        }
-        return Math.max(bounds.maxSourceRow + 1, bounds.sourceRows());
-    }
-
-    private static SourceRect sourceRect(KittyPlacement placement, Image image) {
-        double sourceX = placement.sourceX();
-        double sourceY = placement.sourceY();
-        double sourceWidth = placement.sourceWidth() > 0 ? placement.sourceWidth() : image.getWidth() - sourceX;
-        double sourceHeight = placement.sourceHeight() > 0 ? placement.sourceHeight() : image.getHeight() - sourceY;
-        return new SourceRect(sourceX, sourceY, Math.min(sourceWidth, image.getWidth() - sourceX), Math.min(sourceHeight, image.getHeight() - sourceY));
-    }
-
-    private void markDrawn(long renderedVersion) {
-        drawnContentVersion = renderedVersion;
-        drawnWidth = pane.width();
-        drawnHeight = pane.height();
-    }
-
-    private static Color cellBackgroundColor(RenderCell cell) {
-        if (cell.inverse()) {
-            var fg = cell.foreground();
-            return fg.isPresent() ? toFxColor(fg.get()) : DEFAULT_FOREGROUND;
-        }
-        var bg = cell.background();
-        return bg.isPresent() ? toFxColor(bg.get()) : PANE_BACKGROUND;
-    }
-
-    private static Color rowEdgeBackground(RenderRow row, boolean firstCell) {
-        List<RenderCell> cells = row.cells();
-        if (cells.isEmpty()) {
-            return PANE_BACKGROUND;
-        }
-        return cellBackgroundColor(firstCell ? cells.get(0) : cells.get(cells.size() - 1));
-    }
-
-    private static Color cellBackgroundOverride(RenderCell cell) {
-        if (cell.inverse()) {
-            var fg = cell.foreground();
-            return fg.isPresent() ? toFxColor(fg.get()) : DEFAULT_FOREGROUND;
-        }
-        var bg = cell.background();
-        return bg.isPresent() ? toFxColor(bg.get()) : null;
-    }
-
-    private static Color cellForegroundColor(RenderCell cell) {
-        var fgOpt = cell.foreground();
-        var bgOpt = cell.background();
-        Color fg = fgOpt.isPresent() ? toFxColor(fgOpt.get()) : DEFAULT_FOREGROUND;
-        Color bg = bgOpt.isPresent() ? toFxColor(bgOpt.get()) : null;
-
-        if (cell.inverse()) {
-            return (bg != null) ? bg : PANE_BACKGROUND;
-        }
-        return fg;
-    }
-
-    private static Color toFxColor(RenderColor color) {
-        int key = (color.red() << 16) | (color.green() << 8) | color.blue();
-        Color cached = COLOR_CACHE.get(key);
-        if (cached != null) {
-            return cached;
-        }
-        if (COLOR_CACHE.size() >= 4096) {
-            COLOR_CACHE.clear();
-        }
-        Color created = Color.rgb(color.red(), color.green(), color.blue());
-        COLOR_CACHE.put(key, created);
-        return created;
-    }
-
-    private static long rowFingerprint(RenderRow row) {
-        long hash = 0xcbf29ce484222325L;
-        hash = mix(hash, row.cells().size());
-        for (RenderCell cell : row.cells()) {
-            hash = mix(hash, cellFingerprint(cell));
-        }
-        return hash;
-    }
-
-    private static long cellFingerprint(RenderCell cell) {
-        long hash = 0xcbf29ce484222325L;
-        hash = mix(hash, cell.column());
-        hash = mix(hash, cell.inverse() ? 1 : 0);
-        hash = mix(hash, cell.selected() ? 1 : 0);
-        hash = mix(hash, colorFingerprint(cell.foreground().orElse(null)));
-        hash = mix(hash, colorFingerprint(cell.background().orElse(null)));
-        for (int codepoint : cell.codepoints()) {
-            hash = mix(hash, codepoint);
-        }
-        if (cell.kittyPlaceholder().isPresent()) {
-            KittyPlaceholder placeholder = cell.kittyPlaceholder().get();
-            hash = mix(hash, placeholder.imageId());
-            hash = mix(hash, placeholder.placementId());
-            hash = mix(hash, placeholder.sourceRow());
-            hash = mix(hash, placeholder.sourceColumn());
-        }
-        return hash;
-    }
-
-    private static long colorFingerprint(RenderColor color) {
-        if (color == null) {
-            return -1L;
-        }
-        return ((long) color.red() << 16) | ((long) color.green() << 8) | color.blue();
-    }
-
-    private static long mix(long hash, long value) {
-        hash ^= value;
-        return hash * 0x100000001b3L;
-    }
-
-    private static final class TerminalRowNode extends Region {
-        private final TerminalMetrics metrics;
-        private final Canvas canvas = new Canvas();
-        private long[] cellFingerprints = new long[0];
-
-        private TerminalRowNode(TerminalMetrics metrics) {
-            this.metrics = metrics;
-            getChildren().add(canvas);
-        }
-
-        private void render(RenderRow row) {
-            prepareCanvas(row);
-
-            GraphicsContext gc = canvas.getGraphicsContext2D();
-            gc.clearRect(0.0, 0.0, canvas.getWidth(), canvas.getHeight());
-            gc.setFontSmoothingType(FontSmoothingType.LCD);
-            gc.setFont(metrics.font());
-
-            paintSidePadding(gc, row, canvas.getWidth(), canvas.getHeight());
-            drawRow(gc, row, rowTop(row), metrics.cellWidth(), metrics.lineHeight());
-            cellFingerprints = cellFingerprints(row);
-        }
-
-        private void renderChanged(RenderRow row) {
-            double oldWidth = canvas.getWidth();
-            double oldHeight = canvas.getHeight();
-            prepareCanvas(row);
-            long[] nextFingerprints = cellFingerprints(row);
-            if (cellFingerprints.length != nextFingerprints.length
-                    || oldWidth != canvas.getWidth()
-                    || oldHeight != canvas.getHeight()) {
-                render(row);
-                return;
-            }
-
-            GraphicsContext gc = canvas.getGraphicsContext2D();
-            gc.setFontSmoothingType(FontSmoothingType.LCD);
-            gc.setFont(metrics.font());
-
-            int runStart = -1;
-            int runEnd = -1;
-            for (int column = 0; column < nextFingerprints.length; column++) {
-                if (cellFingerprints[column] == nextFingerprints[column]) {
-                    continue;
-                }
-
-                int start = Math.max(0, column - 1);
-                int end = Math.min(nextFingerprints.length - 1, column + 1);
-                if (runStart < 0) {
-                    runStart = start;
-                    runEnd = end;
-                } else if (start <= runEnd + 1) {
-                    runEnd = Math.max(runEnd, end);
-                } else {
-                    repaintColumns(gc, row, runStart, runEnd);
-                    runStart = start;
-                    runEnd = end;
-                }
-            }
-            if (runStart >= 0) {
-                repaintColumns(gc, row, runStart, runEnd);
-            }
-            cellFingerprints = nextFingerprints;
-        }
-
-        private void prepareCanvas(RenderRow row) {
-            double paneWidth = ((Region) getParent()).getWidth();
-            double rowTop = rowTop(row);
-            double rowBottom = rowBottom(row);
-            double rowHeight = Math.max(1.0, rowBottom - rowTop);
-            resizeRelocate(0.0, rowTop, paneWidth, rowHeight);
-            canvas.setWidth(Math.max(0.0, paneWidth));
-            canvas.setHeight(rowHeight);
-        }
-
-        private void moveToRow(int row) {
-            double paneWidth = ((Region) getParent()).getWidth();
-            double rowTop = rowTop(row);
-            double rowBottom = rowBottom(row);
-            double rowHeight = Math.max(1.0, rowBottom - rowTop);
-            resizeRelocate(0.0, rowTop, paneWidth, rowHeight);
-            canvas.setWidth(Math.max(0.0, paneWidth));
-            canvas.setHeight(rowHeight);
-        }
-
-        private double rowTop(RenderRow row) {
-            return rowTop(row.row());
-        }
-
-        private double rowTop(int row) {
-            return Math.floor(TerminalMetrics.PADDING + row * metrics.lineHeight());
-        }
-
-        private double rowBottom(RenderRow row) {
-            return rowBottom(row.row());
-        }
-
-        private double rowBottom(int row) {
-            return Math.ceil(TerminalMetrics.PADDING + (row + 1) * metrics.lineHeight());
-        }
-
-        private void repaintColumns(GraphicsContext gc, RenderRow row, int startColumn, int endColumn) {
-            if (endColumn < startColumn) {
-                return;
-            }
-
-            double cellWidth = metrics.cellWidth();
-            double lineHeight = metrics.lineHeight();
-            double rowTop = rowTop(row);
-            double contentTop = TerminalMetrics.PADDING + row.row() * lineHeight;
-            double localCellTop = contentTop - rowTop;
-            double baseline = TerminalMetrics.PADDING + metrics.baselineOffset() + row.row() * lineHeight - rowTop;
-            double x = TerminalMetrics.PADDING + startColumn * cellWidth;
-            double width = (endColumn - startColumn + 1) * cellWidth;
-
-            gc.clearRect(x, 0.0, width, canvas.getHeight());
-            if (startColumn == 0) {
-                gc.setFill(rowEdgeBackground(row, true));
-                gc.fillRect(0.0, 0.0, TerminalMetrics.PADDING, canvas.getHeight());
-            }
-            if (endColumn >= row.cells().size() - 1) {
-                double contentRight = TerminalMetrics.PADDING + row.cells().size() * cellWidth;
-                gc.setFill(rowEdgeBackground(row, false));
-                gc.fillRect(contentRight, 0.0, canvas.getWidth() - contentRight, canvas.getHeight());
-            }
-
-            drawRowBackgrounds(gc, row, localCellTop, cellWidth, lineHeight, startColumn, endColumn);
-            drawRowText(gc, row, baseline, cellWidth, startColumn, endColumn);
-        }
-
-        private void paintSidePadding(GraphicsContext gc, RenderRow row, double paneWidth, double bandHeight) {
-            int columns = row.cells().size();
-            if (columns == 0) {
-                return;
-            }
-            double contentLeft = TerminalMetrics.PADDING;
-            double contentRight = contentLeft + columns * metrics.cellWidth();
-            gc.setFill(rowEdgeBackground(row, true));
-            gc.fillRect(0.0, 0.0, contentLeft, bandHeight);
-            gc.setFill(rowEdgeBackground(row, false));
-            gc.fillRect(contentRight, 0.0, paneWidth - contentRight, bandHeight);
-        }
-
-        private void drawRow(GraphicsContext gc, RenderRow row, double rowTop, double cellWidth, double lineHeight) {
-            double contentTop = TerminalMetrics.PADDING + row.row() * lineHeight;
-            double localCellTop = contentTop - rowTop;
-            double baseline = TerminalMetrics.PADDING + metrics.baselineOffset() + row.row() * lineHeight - rowTop;
-            drawRowBackgrounds(gc, row, localCellTop, cellWidth, lineHeight, 0, row.cells().size() - 1);
-            drawRowText(gc, row, baseline, cellWidth, 0, row.cells().size() - 1);
-        }
-
-        private void drawRowBackgrounds(GraphicsContext gc, RenderRow row, double localCellTop,
-                double cellWidth, double lineHeight, int startColumn, int endColumn) {
-            Color runBackground = null;
-            int runStartColumn = 0;
-            int previousColumn = -1;
-            for (RenderCell cell : row.cells()) {
-                if (cell.column() < startColumn || cell.column() > endColumn) {
-                    continue;
-                }
-                if (cell.kittyPlaceholder().isPresent()) {
-                    flushBackgroundRun(gc, runBackground, localCellTop, cellWidth, lineHeight, runStartColumn, previousColumn);
-                    runBackground = null;
-                    previousColumn = -1;
-                    continue;
-                }
-
-                Color background = cell.selected() ? SELECTED_BACKGROUND : cellBackgroundOverride(cell);
-                if (background == null) {
-                    flushBackgroundRun(gc, runBackground, localCellTop, cellWidth, lineHeight, runStartColumn, previousColumn);
-                    runBackground = null;
-                    previousColumn = -1;
-                    continue;
-                }
-
-                if (runBackground == null || background != runBackground || cell.column() != previousColumn + 1) {
-                    flushBackgroundRun(gc, runBackground, localCellTop, cellWidth, lineHeight, runStartColumn, previousColumn);
-                    runBackground = background;
-                    runStartColumn = cell.column();
-                }
-                previousColumn = cell.column();
-            }
-            flushBackgroundRun(gc, runBackground, localCellTop, cellWidth, lineHeight, runStartColumn, previousColumn);
-        }
-
-        private void flushBackgroundRun(GraphicsContext gc, Color background, double localCellTop,
-                double cellWidth, double lineHeight, int startColumn, int endColumn) {
-            if (background == null || endColumn < startColumn) {
-                return;
-            }
-            gc.setFill(background);
-            gc.fillRect(
-                    TerminalMetrics.PADDING + startColumn * cellWidth,
-                    localCellTop,
-                    (endColumn - startColumn + 1) * cellWidth,
-                    lineHeight);
-        }
-
-        private void drawRowText(GraphicsContext gc, RenderRow row, double baseline,
-                double cellWidth, int startColumn, int endColumn) {
-            for (RenderCell cell : row.cells()) {
-                if (cell.column() < startColumn || cell.column() > endColumn) {
-                    continue;
-                }
-                if (cell.kittyPlaceholder().isPresent() || cell.codepoints().length == 0) {
-                    continue;
-                }
-
-                gc.setFill(cellForegroundColor(cell));
-                gc.fillText(cell.text(), TerminalMetrics.PADDING + cell.column() * cellWidth, baseline);
-            }
-        }
-
-        private static long[] cellFingerprints(RenderRow row) {
-            int columns = row.cells().size();
-            for (RenderCell cell : row.cells()) {
-                columns = Math.max(columns, cell.column() + 1);
-            }
-
-            long[] fingerprints = new long[columns];
-            for (RenderCell cell : row.cells()) {
-                fingerprints[cell.column()] = cellFingerprint(cell);
-            }
-            return fingerprints;
-        }
-    }
-
-    private record KittyImageKey(long id, long number, long width, long height, KittyImageFormat format, int dataLength) {
-        private static KittyImageKey of(KittyImageSnapshot snapshot, byte[] data) {
-            return new KittyImageKey(
-                    snapshot.id(),
-                    snapshot.number(),
-                    snapshot.width(),
-                    snapshot.height(),
-                    snapshot.format(),
-                    data.length
-            );
-        }
-    }
-
-    private record KittyPlaceholderKey(long imageId, long placementId) {
-    }
-
-    private record SourceRect(double x, double y, double width, double height) {
-    }
-
-    private record RowMove(int sourceRow, int targetRow) {
-    }
-
-    private record ShiftPlan(List<RowMove> moves, Set<Integer> targetRows) {
-    }
-
-    private static final class KittyPlaceholderBounds {
-        private int minRow = Integer.MAX_VALUE;
-        private int maxRow = Integer.MIN_VALUE;
-        private int minColumn = Integer.MAX_VALUE;
-        private int maxColumn = Integer.MIN_VALUE;
-        private long minSourceRow = Long.MAX_VALUE;
-        private long maxSourceRow = Long.MIN_VALUE;
-        private long minSourceColumn = Long.MAX_VALUE;
-        private long maxSourceColumn = Long.MIN_VALUE;
-
-        private void include(int row, int column, KittyPlaceholder placeholder) {
-            minRow = Math.min(minRow, row);
-            maxRow = Math.max(maxRow, row);
-            minColumn = Math.min(minColumn, column);
-            maxColumn = Math.max(maxColumn, column);
-            minSourceRow = Math.min(minSourceRow, placeholder.sourceRow());
-            maxSourceRow = Math.max(maxSourceRow, placeholder.sourceRow());
-            minSourceColumn = Math.min(minSourceColumn, placeholder.sourceColumn());
-            maxSourceColumn = Math.max(maxSourceColumn, placeholder.sourceColumn());
-        }
-
-        private boolean isEmpty() {
-            return minRow == Integer.MAX_VALUE;
-        }
-
-        private int rows() {
-            return maxRow - minRow + 1;
-        }
-
-        private int columns() {
-            return maxColumn - minColumn + 1;
-        }
-
-        private long sourceRows() {
-            return maxSourceRow - minSourceRow + 1;
-        }
-
-        private long sourceColumns() {
-            return maxSourceColumn - minSourceColumn + 1;
-        }
-    }
-}

src/main/java/com/gregor/jprototerm/TerminalRenderer.java

@@ -0,0 +1,68 @@
+package com.gregor.jprototerm;
+
+import javafx.scene.canvas.GraphicsContext;
+import javafx.scene.shape.ClosePath;
+import javafx.scene.shape.LineTo;
+import javafx.scene.shape.MoveTo;
+import javafx.scene.shape.Path;
+import javafx.scene.shape.PathElement;
+import javafx.scene.shape.Shape;
+
+/**
+ * Draws a {@link RenderTarget} onto a JavaFX canvas. The {@link Compositor} owns positioning
+ * and z-order; a renderer only fills the target's rect, clipped to the target's {@link
+ * RenderTarget#clip() clip region} so a repaint can never bleed over a pane on top.
+ * Implementations can change the look entirely — {@link GhosttyTerminalRenderer} is the real
+ * terminal renderer; a debug renderer could outline pane bounds instead.
+ *
+ * <p>A renderer may hold per-target state (e.g. a decoded-image cache), so an instance belongs
+ * to a single {@link TerminalPane}.
+ */
+abstract class TerminalRenderer {
+    /** Paint the whole target into its rect, clipped to its clip region. */
+    abstract void paintFull(GraphicsContext gc, RenderTarget target, boolean active);
+
+    /** Repaint only what changed since the last frame, clipped to the target's clip region. */
+    abstract void paintIncremental(GraphicsContext gc, RenderTarget target, boolean active);
+
+    /**
+     * The kitty image placements produced by the most recent paint, for the compositor to render
+     * as overlay nodes above the canvas. Empty unless the last paint found visible images.
+     */
+    java.util.List<KittyImageNode> kittyImages() {
+        return java.util.List.of();
+    }
+
+    protected static void clipRect(GraphicsContext gc, double x, double y, double width, double height) {
+        gc.beginPath();
+        gc.rect(x, y, width, height);
+        gc.clip();
+    }
+
+    /**
+     * Clip to {@code region} if given (the pane's rect minus the panes covering it, computed by
+     * {@code Shape.subtract} at layout), otherwise to the plain rect. The region is a rectilinear
+     * path, so it replays onto the canvas as move/line/close segments.
+     */
+    protected static void clip(GraphicsContext gc, double x, double y, double width, double height, Shape region) {
+        if (region == null) {
+            clipRect(gc, x, y, width, height);
+            return;
+        }
+        var elements = ((Path) region).getElements();
+        gc.beginPath();
+        if (elements.isEmpty()) {
+            gc.rect(x, y, 0.0, 0.0); // fully covered: clip to nothing
+        }
+        for (PathElement element : elements) {
+            if (element instanceof MoveTo moveTo) {
+                gc.moveTo(moveTo.getX(), moveTo.getY());
+            } else if (element instanceof LineTo lineTo) {
+                gc.lineTo(lineTo.getX(), lineTo.getY());
+            } else if (element instanceof ClosePath) {
+                gc.closePath();
+            }
+        }
+        gc.clip();
+    }
+}

src/main/java/com/gregor/jprototerm/X11Pointer.java

@@ -0,0 +1,66 @@
+package com.gregor.jprototerm;
+
+import java.lang.foreign.Arena;
+import java.lang.foreign.FunctionDescriptor;
+import java.lang.foreign.Linker;
+import java.lang.foreign.MemorySegment;
+import java.lang.foreign.SymbolLookup;
+import java.lang.invoke.MethodHandle;
+
+import static java.lang.foreign.ValueLayout.ADDRESS;
+import static java.lang.foreign.ValueLayout.JAVA_INT;
+import static java.lang.foreign.ValueLayout.JAVA_LONG;
+
+/**
+ * Reads the X11 pointer location directly via libX11 ({@code XQueryPointer}). Unlike AWT's
+ * {@code MouseInfo}, this never calls {@code XSetErrorHandler}, so it doesn't trip GDK's
+ * "XSetErrorHandler called with a GDK error trap pushed" warning when JavaFX's GTK backend is
+ * already up. Returns {@code null} when not on X11 or libX11 can't be loaded.
+ */
+final class X11Pointer {
+    private X11Pointer() {
+    }
+
+    /** {@code {x, y}} of the pointer in X root-window (virtual screen) space, or {@code null}. */
+    static int[] query() {
+        try (Arena arena = Arena.ofConfined()) {
+            Linker linker = Linker.nativeLinker();
+            SymbolLookup x11 = SymbolLookup.libraryLookup("libX11.so.6", arena);
+            MethodHandle openDisplay = linker.downcallHandle(x11.find("XOpenDisplay").orElseThrow(),
+                    FunctionDescriptor.of(ADDRESS, ADDRESS));
+            MethodHandle defaultRootWindow = linker.downcallHandle(x11.find("XDefaultRootWindow").orElseThrow(),
+                    FunctionDescriptor.of(JAVA_LONG, ADDRESS));
+            MethodHandle queryPointer = linker.downcallHandle(x11.find("XQueryPointer").orElseThrow(),
+                    FunctionDescriptor.of(JAVA_INT, ADDRESS, JAVA_LONG,
+                            ADDRESS, ADDRESS, ADDRESS, ADDRESS, ADDRESS, ADDRESS, ADDRESS));
+            MethodHandle closeDisplay = linker.downcallHandle(x11.find("XCloseDisplay").orElseThrow(),
+                    FunctionDescriptor.of(JAVA_INT, ADDRESS));
+
+            MemorySegment display = (MemorySegment) openDisplay.invoke(MemorySegment.NULL);
+            if (display.address() == 0) {
+                return null;
+            }
+            try {
+                long root = (long) defaultRootWindow.invoke(display);
+                MemorySegment rootReturn = arena.allocate(JAVA_LONG);
+                MemorySegment childReturn = arena.allocate(JAVA_LONG);
+                MemorySegment rootX = arena.allocate(JAVA_INT);
+                MemorySegment rootY = arena.allocate(JAVA_INT);
+                MemorySegment winX = arena.allocate(JAVA_INT);
+                MemorySegment winY = arena.allocate(JAVA_INT);
+                MemorySegment mask = arena.allocate(JAVA_INT);
+                int onSameScreen = (int) queryPointer.invoke(display, root,
+                        rootReturn, childReturn, rootX, rootY, winX, winY, mask);
+                if (onSameScreen == 0) {
+                    return null;
+                }
+                return new int[] { rootX.get(JAVA_INT, 0), rootY.get(JAVA_INT, 0) };
+            } finally {
+                closeDisplay.invoke(display);
+            }
+        } catch (Throwable ignored) {
+            // Not X11, libX11 missing, or the call failed — caller falls back to the primary screen.
+            return null;
+        }
+    }
+}