feature(flamegraph): Allow to override some colors of the dimmed colo…

…r provider

Refs: #80

fireplace-swing/src/main/java/io/github/bric3/fireplace/flamegraph/DimmingFrameColorProvider.java

@@ -36,6 +36,7 @@
 import io.github.bric3.fireplace.core.ui.DarkLightColor;
 
 import java.awt.*;
+import java.util.Objects;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Function;
 
@@ -47,40 +48,77 @@
 import static io.github.bric3.fireplace.flamegraph.FrameRenderingFlags.isHoveredSibling;
 import static io.github.bric3.fireplace.flamegraph.FrameRenderingFlags.isMinimapMode;
 
+/**
+ * Frame color provider that supports frame dimming and hovering.
+ *
+ * <p>
+ * This frame color provider is responsible for computing the color of a frame.
+ * It uses the actual frame and passes it to a basic <em>color function</em>
+ * that will apply the actual base background color to the frame.
+ * </p>
+ *
+ * <p>
+ * Then this base color can be altered or changed depending on the frame's
+ * flags.
+ * </p>
+ *
+ * @param <T> The actual type of frame.
+ */
 public class DimmingFrameColorProvider<T> implements FrameColorProvider<T> {
-    public static final Color DIMMED_TEXT = new DarkLightColor(
+    public static final Color DIMMED_TEXT_COLOR = new DarkLightColor(
             Colors.rgba(28, 43, 52, 0.68f),
             Colors.rgba(255, 255, 255, 0.51f)
     );
 
-    public static final Color HOVERED_NODE = new DarkLightColor(
+    public static final Color HOVERED_BACKGROUND_COLOR = new DarkLightColor(
             new Color(0xFFE0C268, true),
             new Color(0xD0E0C268, true)
     );
 
-    public static final Color ROOT_NODE = new DarkLightColor(
+    public static final Color ROOT_BACKGROUND_COLOR = new DarkLightColor(
             new Color(0xFFEAF6FC),
             new Color(0xFF091222)
     );
     private final Function<FrameBox<T>, Color> baseColorFunction;
+
+    /**
+     * Single instance to avoid too many allocations, only for the main canvas.
+     */
     private final ColorModel reusedColorModelForMainCanvas = new ColorModel(null, null);
+
+    /**
+     * Single instance to avoid too many allocations, only for the minimap.
+     * Since the minimap generation happens on a different thread, it is necessary
+     * to have a separate instance.
+     */
     private final ColorModel reusedColorModelForMinimap = new ColorModel(null, null);
 
     private final ConcurrentHashMap<Color, Color> dimmedColorCache = new ConcurrentHashMap<>();
 
+    private Color rootBackGroundColor = ROOT_BACKGROUND_COLOR;
+    private Color dimmedTextColor = DIMMED_TEXT_COLOR;
+    private Color hoveredBackgroundColor = HOVERED_BACKGROUND_COLOR;
+
+    /**
+     * Builds a basic frame color provider.
+     *
+     * @param baseColorFunction The color function that provides the frame's color.
+     * @see #withRootBackgroundColor(Color)
+     * @see #withDimmedTextColor(Color)
+     * @see #withHoveredBackgroundColor(Color)
+     */
     public DimmingFrameColorProvider(Function<FrameBox<T>, Color> baseColorFunction) {
         this.baseColorFunction = baseColorFunction;
     }
 
-
     @Override
     public ColorModel getColors(FrameBox<T> frame, int flags) {
         Color backgroundColor;
         Color foreground;
 
         var rootNode = frame.isRoot();
         if (rootNode) {
-            backgroundColor = ROOT_NODE;
+            backgroundColor = rootBackGroundColor;
         } else {
             backgroundColor = baseColorFunction.apply(frame);
         }
@@ -91,14 +129,19 @@ public ColorModel getColors(FrameBox<T> frame, int flags) {
         }
 
         if (!rootNode && shouldDim(flags)) {
-            backgroundColor = cachedDim(backgroundColor);
-            foreground = DIMMED_TEXT;
+            backgroundColor = dimmedBackground(backgroundColor);
+            foreground = dimmedTextColor;
         } else {
             foreground = Colors.foregroundColor(backgroundColor);
         }
 
-        if (isHovered(flags) || isHoveredSibling(flags)) {
-            backgroundColor = Colors.blend(backgroundColor, HOVERED_NODE);
+        if (isHovered(flags)) {
+            backgroundColor = hoverBackground(backgroundColor);
+            foreground = Colors.foregroundColor(backgroundColor);
+        }
+
+        if (isHoveredSibling(flags)) {
+            backgroundColor = hoverSiblingBackground(backgroundColor);
             foreground = Colors.foregroundColor(backgroundColor);
         }
 
@@ -108,6 +151,36 @@ public ColorModel getColors(FrameBox<T> frame, int flags) {
         );
     }
 
+    /**
+     * Compute the background color for a hovered frame.
+     *
+     * @param backgroundColor The background color of the frame to alter.
+     * @return The hovered background color.
+     */
+    private Color hoverBackground(Color backgroundColor) {
+        return Colors.blend(backgroundColor, hoveredBackgroundColor);
+    }
+
+    /**
+     * Compute the background color for a hovered sibling frame.
+     *
+     * @param backgroundColor The background color of the frame to alter.
+     * @return The hovered background color.
+     */
+    private Color hoverSiblingBackground(Color backgroundColor) {
+        return Colors.blend(backgroundColor, hoveredBackgroundColor);
+    }
+
+    /**
+     * Dims the background color.
+     *
+     * @param backgroundColor The background color to dim.
+     * @return The dimmed color.
+     */
+    protected Color dimmedBackground(Color backgroundColor) {
+        return cachedDim(backgroundColor);
+    }
+
     /**
      * Dim only if not highlighted or not focused
      * <p>
@@ -137,4 +210,19 @@ private boolean shouldDim(int flags) {
     private Color cachedDim(Color color) {
         return dimmedColorCache.computeIfAbsent(color, Colors::dim);
     }
+
+    public DimmingFrameColorProvider<T> withRootBackgroundColor(Color rootBackgroundColor) {
+        this.rootBackGroundColor = Objects.requireNonNull(rootBackgroundColor);
+        return this;
+    }
+
+    public DimmingFrameColorProvider<T> withDimmedTextColor(Color dimmedTextColor) {
+        this.dimmedTextColor = Objects.requireNonNull(dimmedTextColor);
+        return this;
+    }
+
+    public DimmingFrameColorProvider<T> withHoveredBackgroundColor(Color hoveredBackgroundColor) {
+        this.hoveredBackgroundColor = Objects.requireNonNull(hoveredBackgroundColor);
+        return this;
+    }
 }