expose color from render state

src/main/java/dev/jlibghostty/RenderCell.java

@@ -1,8 +1,18 @@
 package dev.jlibghostty;
 
-public record RenderCell(int column, int[] codepoints, boolean selected) {
+import java.util.Optional;
+
+public record RenderCell(
+    int column,
+    int[] codepoints,
+    Optional<RenderColor> foreground,
+    Optional<RenderColor> background,
+    boolean selected
+) {
     public RenderCell {
         codepoints = codepoints.clone();
+        foreground = foreground == null ? Optional.empty() : foreground;
+        background = background == null ? Optional.empty() : background;
     }
 
     @Override

src/main/java/dev/jlibghostty/RenderColor.java

@@ -0,0 +1,16 @@
+package dev.jlibghostty;
+
+public record RenderColor(int red, int green, int blue) {
+    public RenderColor {
+        red = checkChannel("red", red);
+        green = checkChannel("green", green);
+        blue = checkChannel("blue", blue);
+    }
+
+    private static int checkChannel(String name, int value) {
+        if (value < 0 || value > 255) {
+            throw new IllegalArgumentException(name + " must be between 0 and 255");
+        }
+        return value;
+    }
+}

src/main/java/dev/jlibghostty/internal/GhosttyLibrary.java

@@ -4,6 +4,7 @@ import dev.jlibghostty.GhosttyBuildInfo;
 import dev.jlibghostty.GhosttyException;
 import dev.jlibghostty.OptimizeMode;
 import dev.jlibghostty.RenderCell;
+import dev.jlibghostty.RenderColor;
 import dev.jlibghostty.RenderRow;
 import dev.jlibghostty.SizeReportSize;
 import dev.jlibghostty.TerminalOptions;
@@ -22,6 +23,7 @@ import java.nio.charset.StandardCharsets;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
 
 import static java.lang.foreign.ValueLayout.JAVA_BYTE;
 
@@ -74,9 +76,12 @@ public final class GhosttyLibrary {
 
     public static final int RENDER_STATE_ROW_CELLS_DATA_GRAPHEMES_LEN = 3;
     public static final int RENDER_STATE_ROW_CELLS_DATA_GRAPHEMES_BUF = 4;
+    public static final int RENDER_STATE_ROW_CELLS_DATA_BG_COLOR = 5;
+    public static final int RENDER_STATE_ROW_CELLS_DATA_FG_COLOR = 6;
     public static final int RENDER_STATE_ROW_CELLS_DATA_SELECTED = 7;
 
     private static final int GHOSTTY_SUCCESS = 0;
+    private static final int GHOSTTY_INVALID_VALUE = -2;
     private static final int GHOSTTY_OUT_OF_SPACE = -3;
     private static final int GHOSTTY_NO_VALUE = -4;
 
@@ -703,6 +708,8 @@ public final class GhosttyLibrary {
                 result.add(new RenderCell(
                     column,
                     renderStateRowCellGraphemes(cells),
+                    renderStateRowCellColor(cells, RENDER_STATE_ROW_CELLS_DATA_FG_COLOR),
+                    renderStateRowCellColor(cells, RENDER_STATE_ROW_CELLS_DATA_BG_COLOR),
                     renderStateRowCellsGetBoolean(cells, RENDER_STATE_ROW_CELLS_DATA_SELECTED)
                 ));
                 column++;
@@ -799,6 +806,24 @@ public final class GhosttyLibrary {
         }
     }
 
+    private Optional<RenderColor> renderStateRowCellColor(MemorySegment cells, int key) {
+        try (Arena arena = Arena.ofConfined()) {
+            MemorySegment out = arena.allocate(3, 1);
+            int result = (int) renderStateRowCellsGet.invoke(cells, key, out);
+            if (result == GHOSTTY_INVALID_VALUE) {
+                return Optional.empty();
+            }
+            checkResult("ghostty_render_state_row_cells_get", result);
+            return Optional.of(new RenderColor(
+                Byte.toUnsignedInt(out.get(JAVA_BYTE, 0)),
+                Byte.toUnsignedInt(out.get(JAVA_BYTE, 1)),
+                Byte.toUnsignedInt(out.get(JAVA_BYTE, 2))
+            ));
+        } catch (Throwable t) {
+            return rethrow(t);
+        }
+    }
+
     public void kittyGraphicsPopulatePlacementIterator(MemorySegment graphics, MemorySegment iterator) {
         try (Arena arena = Arena.ofConfined()) {
             MemorySegment out = arena.allocate(C_POINTER);

src/test/java/dev/jlibghostty/GhosttySmokeTest.java

@@ -43,6 +43,12 @@ public final class GhosttySmokeTest {
             if (!renderedHello) {
                 throw new AssertionError("render state should contain written text");
             }
+            renderSnapshot.renderRows().stream()
+                .flatMap(row -> row.cells().stream())
+                .forEach(cell -> {
+                    cell.foreground().ifPresent(GhosttySmokeTest::assertColor);
+                    cell.background().ifPresent(GhosttySmokeTest::assertColor);
+                });
             TerminalSnapshot snapshot = terminal.snapshot();
             if (snapshot.columns() != 80 || snapshot.rows() != 24) {
                 throw new AssertionError("unexpected terminal size: " + snapshot);
@@ -50,4 +56,12 @@ public final class GhosttySmokeTest {
             terminal.kittyGraphics().ifPresent(KittyGraphics::placements);
         }
     }
+
+    private static void assertColor(RenderColor color) {
+        if (color.red() < 0 || color.red() > 255
+            || color.green() < 0 || color.green() > 255
+            || color.blue() < 0 || color.blue() > 255) {
+            throw new AssertionError("invalid color: " + color);
+        }
+    }
 }