images work

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

@@ -4,6 +4,8 @@ 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.KeyModifiers;
 import dev.jlibghostty.MouseButton;
@@ -30,6 +32,7 @@ import javafx.scene.text.Text;
 
 import java.io.ByteArrayInputStream;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 public final class TerminalCanvasView {
@@ -39,9 +42,15 @@ public final class TerminalCanvasView {
     private final Canvas canvas = new Canvas();
     private final TerminalWorkspace workspace;
     private final AppConfig config;
-    private final Map<Long, Image> kittyImageCache = new HashMap<>();
+    private final Map<KittyImageKey, Image> kittyImageCache = new HashMap<>();
+    private final Map<TerminalPane, PaneRenderCache> paneRenderCache = new HashMap<>();
     private String fontFamily;
     private double fontSize;
+    private Font cachedFont;
+    private FontMetrics cachedMetrics;
+    private String cachedFontFamily;
+    private double cachedFontSize;
+    private String lastRenderKey;
     private boolean mouseButtonPressed;
     private MouseButton pressedButton = MouseButton.UNKNOWN;
 
@@ -65,53 +74,111 @@ public final class TerminalCanvasView {
     public void setFont(String family, double size) {
         this.fontFamily = family;
         this.fontSize = size;
+        cachedFont = null;
+        cachedMetrics = null;
+        paneRenderCache.clear();
+        lastRenderKey = null;
     }
 
     public void render() {
         double width = canvas.getWidth();
         double height = canvas.getHeight();
         workspace.layout(width, height);
+        Font font = currentFont();
+        FontMetrics metrics = currentFontMetrics();
+        List<TerminalPane> panes = workspace.panes();
+
+        String renderKey = renderKey(width, height, metrics, panes);
+        if (renderKey.equals(lastRenderKey)) {
+            return;
+        }
+        lastRenderKey = renderKey;
 
         GraphicsContext gc = canvas.getGraphicsContext2D();
         gc.setFill(Color.rgb(16, 16, 18));
         gc.fillRect(0, 0, width, height);
         gc.setFontSmoothingType(FontSmoothingType.LCD);
 
-        for (TerminalPane pane : workspace.panes()) {
-            drawPane(gc, pane);
+        paneRenderCache.keySet().removeIf(pane -> !panes.contains(pane));
+        for (TerminalPane pane : panes) {
+            drawPane(gc, pane, font, metrics);
         }
     }
 
-    private void drawPane(GraphicsContext gc, TerminalPane pane) {
-        gc.save();
-        gc.beginPath();
-        gc.rect(pane.x(), pane.y(), pane.width(), pane.height());
-        gc.clip();
+    private void drawPane(GraphicsContext gc, TerminalPane pane, Font font, FontMetrics metrics) {
+        if (config.kittyGraphics() && paneHasKittyGraphics(pane)) {
+            paneRenderCache.remove(pane);
+            gc.save();
+            gc.beginPath();
+            gc.rect(pane.x(), pane.y(), pane.width(), pane.height());
+            gc.clip();
+            drawPaneContent(gc, pane, font, metrics, pane.x(), pane.y(), pane.width(), pane.height(), false);
+            gc.restore();
+            return;
+        }
 
+        PaneRenderCache cache = paneRenderCache.computeIfAbsent(pane, ignored -> new PaneRenderCache());
+        String cacheKey = paneCacheKey(pane, metrics);
+        int imageWidth = Math.max(1, (int) Math.ceil(pane.width()));
+        int imageHeight = Math.max(1, (int) Math.ceil(pane.height()));
+        if (cache.image == null || cache.canvas == null || cache.imageWidth != imageWidth || cache.imageHeight != imageHeight || !cacheKey.equals(cache.key)) {
+            cache.canvas = new Canvas(imageWidth, imageHeight);
+            drawPaneContent(cache.canvas.getGraphicsContext2D(), pane, font, metrics, 0.0, 0.0, imageWidth, imageHeight, true);
+            cache.image = new WritableImage(imageWidth, imageHeight);
+            cache.canvas.snapshot(null, cache.image);
+            cache.imageWidth = imageWidth;
+            cache.imageHeight = imageHeight;
+            cache.key = cacheKey;
+        }
+
+        gc.drawImage(cache.image, pane.x(), pane.y());
+    }
+
+    private void drawPaneContent(
+            GraphicsContext gc,
+            TerminalPane pane,
+            Font font,
+            FontMetrics metrics,
+            double x,
+            double y,
+            double width,
+            double height,
+            boolean clear
+    ) {
+        if (clear) {
+            gc.clearRect(x, y, width, height);
+        }
+        gc.setFontSmoothingType(FontSmoothingType.LCD);
         if (pane.floating()) {
             gc.setGlobalAlpha(0.96);
         }
         gc.setFill(Color.rgb(9, 10, 12));
-        gc.fillRect(pane.x(), pane.y(), pane.width(), pane.height());
+        gc.fillRect(x, y, width, height);
         gc.setGlobalAlpha(1.0);
 
         gc.setStroke(workspace.isActive(pane) ? Color.rgb(87, 166, 255) : Color.rgb(52, 57, 65));
         gc.setLineWidth(workspace.isActive(pane) ? 2.0 : 1.0);
-        gc.strokeRect(pane.x() + 0.5, pane.y() + 0.5, pane.width() - 1.0, pane.height() - 1.0);
+        gc.strokeRect(x + 0.5, y + 0.5, width - 1.0, height - 1.0);
 
-        Font font = Font.font(fontFamily, fontSize);
         gc.setFont(font);
 
-        FontMetrics metrics = measureFontMetrics(font);
-        int columns = Math.max(1, (int) ((pane.width() - 24.0) / metrics.cellWidth));
-        int rows = Math.max(1, (int) ((pane.height() - 24.0) / metrics.lineHeight));
+        int columns = Math.max(1, (int) ((width - 24.0) / metrics.cellWidth));
+        int rows = Math.max(1, (int) ((height - 24.0) / metrics.lineHeight));
         pane.resize(columns, rows, (int) Math.round(metrics.cellWidth), (int) Math.round(metrics.lineHeight));
 
-        double left = pane.x() + 12.0;
-        double top = pane.y() + 12.0;
+        double left = x + 12.0;
+        double top = y + 12.0;
         double baseline = top + metrics.baselineOffset;
 
         RenderStateSnapshot snapshot = pane.renderSnapshot();
+        Map<KittyPlaceholderKey, KittyPlaceholderBounds> placeholderBounds = config.kittyGraphics()
+                ? kittyPlaceholderBounds(snapshot)
+                : Map.of();
+
+        if (config.kittyGraphics()) {
+            drawKittyGraphics(gc, pane, KittyPlacementLayer.BELOW_TEXT, placeholderBounds, left, top, metrics.cellWidth, metrics.lineHeight);
+        }
+
         if (snapshot != null) {
             for (RenderRow row : snapshot.renderRows()) {
                 drawRow(gc, row, left, top, baseline, metrics.cellWidth, metrics.lineHeight);
@@ -123,9 +190,8 @@ public final class TerminalCanvasView {
         }
 
         if (config.kittyGraphics()) {
-            drawKittyGraphics(gc, pane, left, top, metrics.cellWidth, metrics.lineHeight);
+            drawKittyGraphics(gc, pane, KittyPlacementLayer.ABOVE_TEXT, placeholderBounds, left, top, metrics.cellWidth, metrics.lineHeight);
         }
-        gc.restore();
     }
 
     private static FontMetrics measureFontMetrics(Font font) {
@@ -134,13 +200,80 @@ public final class TerminalCanvasView {
         double lineHeight = Math.max(1.0, text.getLayoutBounds().getHeight());
         double baselineOffset = -text.getLayoutBounds().getMinY();
 
-        String sample = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
-        Text cell = new Text(sample);
+        Text cell = new Text("M");
         cell.setFont(font);
-        double cellWidth = Math.max(1.0, cell.getLayoutBounds().getWidth() / sample.length());
+        double cellWidth = Math.max(1.0, cell.getLayoutBounds().getWidth());
         return new FontMetrics(cellWidth, lineHeight, baselineOffset);
     }
 
+    private Font currentFont() {
+        if (cachedFont == null || !fontFamily.equals(cachedFontFamily) || fontSize != cachedFontSize) {
+            cachedFont = Font.font(fontFamily, fontSize);
+            cachedMetrics = null;
+            cachedFontFamily = fontFamily;
+            cachedFontSize = fontSize;
+        }
+        return cachedFont;
+    }
+
+    private FontMetrics currentFontMetrics() {
+        if (cachedMetrics == null) {
+            cachedMetrics = measureFontMetrics(currentFont());
+        }
+        return cachedMetrics;
+    }
+
+    private String renderKey(double width, double height, FontMetrics metrics, List<TerminalPane> panes) {
+        StringBuilder builder = new StringBuilder();
+        builder.append(width).append(':')
+                .append(height).append(':')
+                .append(workspace.version()).append(':')
+                .append(fontFamily).append(':')
+                .append(fontSize).append(':')
+                .append(metrics.cellWidth).append(':')
+                .append(metrics.lineHeight);
+        for (TerminalPane pane : panes) {
+            builder.append('|')
+                    .append(System.identityHashCode(pane)).append(',')
+                    .append(pane.renderVersion()).append(',')
+                    .append(workspace.isActive(pane)).append(',')
+                    .append(pane.x()).append(',')
+                    .append(pane.y()).append(',')
+                    .append(pane.width()).append(',')
+                    .append(pane.height());
+        }
+        return builder.toString();
+    }
+
+    private String paneCacheKey(TerminalPane pane, FontMetrics metrics) {
+        return pane.renderVersion()
+                + ":" + workspace.isActive(pane)
+                + ":" + pane.width()
+                + ":" + pane.height()
+                + ":" + fontFamily
+                + ":" + fontSize
+                + ":" + metrics.cellWidth
+                + ":" + metrics.lineHeight
+                + ":" + config.kittyGraphics();
+    }
+
+    private static Map<KittyPlaceholderKey, KittyPlaceholderBounds> kittyPlaceholderBounds(RenderStateSnapshot snapshot) {
+        if (snapshot == null) {
+            return Map.of();
+        }
+
+        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 void handleMousePressed(MouseEvent event) {
         canvas.requestFocus();
         TerminalPane pane = paneAt(event.getX(), event.getY());
@@ -244,7 +377,7 @@ public final class TerminalCanvasView {
             return null;
         }
 
-        FontMetrics metrics = measureFontMetrics(Font.font(fontFamily, fontSize));
+        FontMetrics metrics = currentFontMetrics();
         int columns = Math.max(1, (int) ((pane.width() - 24.0) / metrics.cellWidth));
         int rows = Math.max(1, (int) ((pane.height() - 24.0) / metrics.lineHeight));
         long cellWidth = Math.max(1L, Math.round(metrics.cellWidth));
@@ -325,15 +458,19 @@ public final class TerminalCanvasView {
             double lineHeight
     ) {
         for (RenderCell cell : row.cells()) {
+            if (cell.kittyPlaceholder().isPresent()) {
+                continue;
+            }
+
             double x = left + (cell.column() * cellWidth);
             double cellTop = top + (row.row() * lineHeight);
             cell.background().ifPresent(background -> {
                 gc.setFill(toFxColor(background));
-                fillCellRect(gc, x, cellTop, cellWidth, lineHeight);
+                gc.fillRect(x, cellTop, cellWidth, lineHeight);
             });
             if (cell.selected()) {
                 gc.setFill(SELECTED_BACKGROUND);
-                fillCellRect(gc, x, cellTop, cellWidth, lineHeight);
+                gc.fillRect(x, cellTop, cellWidth, lineHeight);
             }
             if (cell.codepoints().length == 0) {
                 continue;
@@ -346,14 +483,6 @@ public final class TerminalCanvasView {
         }
     }
 
-    private static void fillCellRect(GraphicsContext gc, double x, double y, double width, double height) {
-        double x1 = Math.floor(x);
-        double y1 = Math.floor(y);
-        double x2 = Math.ceil(x + width);
-        double y2 = Math.ceil(y + height);
-        gc.fillRect(x1, y1, Math.max(1.0, x2 - x1), Math.max(1.0, y2 - y1));
-    }
-
     private static Color toFxColor(RenderColor color) {
         return Color.rgb(color.red(), color.green(), color.blue());
     }
@@ -381,54 +510,174 @@ public final class TerminalCanvasView {
         }
     }
 
-    private void drawKittyGraphics(GraphicsContext gc, TerminalPane pane, double originX, double originY, double cellWidth, double lineHeight) {
+    private void drawKittyGraphics(
+            GraphicsContext gc,
+            TerminalPane pane,
+            KittyPlacementLayer layer,
+            Map<KittyPlaceholderKey, KittyPlaceholderBounds> placeholderBounds,
+            double originX,
+            double originY,
+            double cellWidth,
+            double lineHeight
+    ) {
         pane.kittyGraphics().ifPresent(graphics -> {
-            for (KittyPlacement placement : graphics.placements()) {
+            for (KittyPlacement placement : graphics.placements(layer)) {
                 Image image = imageFor(placement);
                 if (image == null) {
                     continue;
                 }
 
-                KittyRenderInfo renderInfo = placement.renderInfo().orElse(null);
-                double x = originX;
-                double y = originY;
-                double width = image.getWidth();
-                double height = image.getHeight();
-
-                if (renderInfo != null) {
-                    x += renderInfo.viewportColumn() * cellWidth;
-                    y += renderInfo.viewportRow() * lineHeight;
-                    width = renderInfo.gridColumns() > 0 ? renderInfo.gridColumns() * cellWidth : renderInfo.pixelWidth();
-                    height = renderInfo.gridRows() > 0 ? renderInfo.gridRows() * lineHeight : renderInfo.pixelHeight();
+                if (placement.virtual()) {
+                    drawVirtualKittyPlacement(gc, placement, image, placeholderBounds, originX, originY, cellWidth, lineHeight);
                 } else {
-                    width = placement.columns() > 0 ? placement.columns() * cellWidth : width;
-                    height = placement.rows() > 0 ? placement.rows() * lineHeight : height;
+                    drawPinnedKittyPlacement(gc, placement, image, originX, originY, cellWidth, lineHeight);
                 }
-
-                gc.drawImage(image, x + placement.xOffset(), y + placement.yOffset(), width, height);
             }
         });
     }
 
-    private Image imageFor(KittyPlacement placement) {
-        return placement.image()
-                .map(snapshot -> kittyImageCache.computeIfAbsent(snapshot.id(), ignored -> decodeImage(snapshot)))
-                .orElse(null);
+    private static void drawPinnedKittyPlacement(
+            GraphicsContext gc,
+            KittyPlacement placement,
+            Image image,
+            double originX,
+            double originY,
+            double cellWidth,
+            double lineHeight
+    ) {
+        KittyRenderInfo renderInfo = placement.renderInfo().orElse(null);
+        if (renderInfo == null || !renderInfo.viewportVisible()) {
+            return;
+        }
+
+        double sourceX = renderInfo.sourceX();
+        double sourceY = renderInfo.sourceY();
+        double sourceWidth = renderInfo.sourceWidth();
+        double sourceHeight = renderInfo.sourceHeight();
+        if (sourceWidth <= 0.0 || sourceHeight <= 0.0) {
+            return;
+        }
+
+        double x = originX + (renderInfo.viewportColumn() * cellWidth) + placement.xOffset();
+        double y = originY + (renderInfo.viewportRow() * lineHeight) + placement.yOffset();
+        double width = renderInfo.pixelWidth() > 0 ? renderInfo.pixelWidth() : renderInfo.gridColumns() * cellWidth;
+        double height = renderInfo.pixelHeight() > 0 ? renderInfo.pixelHeight() : renderInfo.gridRows() * lineHeight;
+        if (width <= 0.0 || height <= 0.0) {
+            return;
+        }
+
+        gc.drawImage(image, sourceX, sourceY, sourceWidth, sourceHeight, x, y, width, height);
     }
 
-    private Image decodeImage(KittyImageSnapshot snapshot) {
+    private static void drawVirtualKittyPlacement(
+            GraphicsContext gc,
+            KittyPlacement placement,
+            Image image,
+            Map<KittyPlaceholderKey, KittyPlaceholderBounds> placeholderBounds,
+            double originX,
+            double originY,
+            double cellWidth,
+            double lineHeight
+    ) {
+        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;
+        }
+
+        SourceRect source = sourceRect(placement, image);
+        if (source.width() <= 0.0 || source.height() <= 0.0) {
+            return;
+        }
+
+        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 = originX + (bounds.minColumn * cellWidth);
+        double y = originY + (bounds.minRow * lineHeight);
+        double width = bounds.columns() * cellWidth;
+        double height = bounds.rows() * lineHeight;
+
+        if (sourceWidth <= 0.0 || sourceHeight <= 0.0 || width <= 0.0 || height <= 0.0) {
+            return;
+        }
+
+        gc.drawImage(image, sourceX, sourceY, sourceWidth, sourceHeight, x, y, width, height);
+    }
+
+    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 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 boolean paneHasKittyGraphics(TerminalPane pane) {
+        return pane.kittyGraphics()
+                .map(graphics -> !graphics.placements().isEmpty())
+                .orElse(false);
+    }
+
+    private Image decodeImage(KittyImageSnapshot snapshot, byte[] data) {
         if (snapshot.compression() != KittyImageCompression.NONE) {
             return null;
         }
 
         if (snapshot.format() == KittyImageFormat.PNG) {
-            return new Image(new ByteArrayInputStream(snapshot.data()));
+            return new Image(new ByteArrayInputStream(data));
         }
 
         int width = Math.toIntExact(snapshot.width());
         int height = Math.toIntExact(snapshot.height());
         WritableImage image = new WritableImage(width, height);
-        byte[] data = snapshot.data();
 
         if (snapshot.format() == KittyImageFormat.RGBA) {
             image.getPixelWriter().setPixels(0, 0, width, height, PixelFormat.getByteBgraInstance(), rgbaToBgra(data), 0, width * 4);
@@ -454,4 +703,83 @@ public final class TerminalCanvasView {
 
     private record MouseTarget(MouseEncoderSize size, long screenWidth, long screenHeight) {
     }
+
+    private record KittyImageKey(long id, long number, long width, long height, KittyImageFormat format, int dataLength, long fingerprint) {
+        private static KittyImageKey of(KittyImageSnapshot snapshot, byte[] data) {
+            return new KittyImageKey(
+                    snapshot.id(),
+                    snapshot.number(),
+                    snapshot.width(),
+                    snapshot.height(),
+                    snapshot.format(),
+                    data.length,
+                    fingerprint(data)
+            );
+        }
+
+        private static long fingerprint(byte[] data) {
+            long hash = 0xcbf29ce484222325L;
+            for (byte value : data) {
+                hash ^= Byte.toUnsignedInt(value);
+                hash *= 0x100000001b3L;
+            }
+            return hash;
+        }
+    }
+
+    private record KittyPlaceholderKey(long imageId, long placementId) {
+    }
+
+    private record SourceRect(double x, double y, double width, double height) {
+    }
+
+    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;
+        }
+    }
+
+    private static final class PaneRenderCache {
+        private Canvas canvas;
+        private WritableImage image;
+        private int imageWidth;
+        private int imageHeight;
+        private String key;
+    }
 }

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

@@ -30,6 +30,7 @@ public final class TerminalPane implements AutoCloseable {
     private int rows;
     private int pixelWidth;
     private int pixelHeight;
+    private long renderVersion;
 
     private TerminalPane(Terminal terminal, int columns, int rows) {
         this.terminal = terminal;
@@ -114,6 +115,10 @@ public final class TerminalPane implements AutoCloseable {
         return renderSnapshot.get();
     }
 
+    public long renderVersion() {
+        return renderVersion;
+    }
+
     public Optional<KittyGraphics> kittyGraphics() {
         synchronized (terminal) {
             return terminal.kittyGraphics();
@@ -182,6 +187,7 @@ public final class TerminalPane implements AutoCloseable {
 
     private void refresh() {
         renderSnapshot.set(terminal.renderSnapshot());
+        renderVersion++;
     }
 
     @Override

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

@@ -9,6 +9,7 @@ public final class TerminalWorkspace implements AutoCloseable {
     private final List<TerminalPane> panes = new ArrayList<>();
     private int activeIndex;
     private int hiddenFloatingFocusIndex = -1;
+    private long version;
 
     public TerminalWorkspace(AppConfig config) {
         this.config = config;
@@ -38,10 +39,15 @@ public final class TerminalWorkspace implements AutoCloseable {
         return activePane() == pane;
     }
 
+    public long version() {
+        return version;
+    }
+
     public void focus(TerminalPane pane) {
         int index = panes.indexOf(pane);
-        if (index >= 0 && pane.visible()) {
+        if (index >= 0 && pane.visible() && activeIndex != index) {
             activeIndex = index;
+            version++;
         }
     }
 
@@ -79,6 +85,7 @@ public final class TerminalWorkspace implements AutoCloseable {
     public void navigate(Direction direction) {
         TerminalPane current = activePane();
         if (current.floating() && navigateFloatingStack(direction)) {
+            version++;
             return;
         }
 
@@ -87,7 +94,10 @@ public final class TerminalWorkspace implements AutoCloseable {
                 .filter(pane -> pane != current)
                 .filter(pane -> directionFilter(direction, current, pane))
                 .min(Comparator.comparingDouble(pane -> distance(current, pane)))
-                .ifPresent(pane -> activeIndex = panes.indexOf(pane));
+                .ifPresent(pane -> {
+                    activeIndex = panes.indexOf(pane);
+                    version++;
+                });
     }
 
     public void toggleFloating() {
@@ -105,10 +115,12 @@ public final class TerminalWorkspace implements AutoCloseable {
             hiddenFloatingFocusIndex = active.floating() ? activeIndex : firstVisibleFloatingIndex();
             floating.forEach(pane -> pane.setVisible(false));
             activeIndex = firstVisibleNonFloatingIndex();
+            version++;
         } else {
             floating.forEach(pane -> pane.setVisible(true));
             activeIndex = visibleIndexOrFallback(hiddenFloatingFocusIndex, panes.indexOf(floating.get(floating.size() - 1)));
             hiddenFloatingFocusIndex = -1;
+            version++;
         }
     }
 
@@ -116,12 +128,14 @@ public final class TerminalWorkspace implements AutoCloseable {
         TerminalPane pane = openPane(true);
         panes.add(pane);
         activeIndex = panes.size() - 1;
+        version++;
     }
 
     public void nextFloatingPane() {
         TerminalPane next = nextFloatingAfter(activeIndex);
         next.setVisible(true);
         activeIndex = panes.indexOf(next);
+        version++;
     }
 
     public void closeActivePane() {
@@ -136,6 +150,7 @@ public final class TerminalWorkspace implements AutoCloseable {
         active.close();
         activeIndex = adjustIndexAfterRemoval(previous, removed);
         hiddenFloatingFocusIndex = adjustHiddenFocusAfterRemoval(hiddenFloatingFocusIndex, removed);
+        version++;
     }
 
     private TerminalPane nextFloatingAfter(int index) {