Dim dirty tab bullet on inactive tabs in CTabFolderRenderer

The dirty indicator bullet inherited the tab text foreground color, which
only varies between selected and unselected tabs in dark themes via CSS.
In light themes the bullet looked identical on active and inactive tabs.

Apply a reduced alpha (140) when drawing the bullet on unselected tabs so
the active/inactive distinction works in any theme without CSS changes.

Fixes #3278

Author: vogella

bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolderRenderer.java

@@ -692,17 +692,17 @@ void drawBody(GC gc, Rectangle bounds, int state) {
 	}
 
 	void drawClose(GC gc, Rectangle closeRect, int closeImageState) {
-		drawClose(gc, closeRect, closeImageState, false);
+		drawClose(gc, closeRect, closeImageState, false, false);
 	}
 
-	void drawClose(GC gc, Rectangle closeRect, int closeImageState, boolean showDirtyIndicator) {
+	void drawClose(GC gc, Rectangle closeRect, int closeImageState, boolean showDirtyIndicator, boolean selected) {
 		if (closeRect.width == 0 || closeRect.height == 0) return;
 
 		// When dirty and not hovered/pressed, draw bullet instead of X
 		if (showDirtyIndicator) {
 			int maskedState = closeImageState & (SWT.HOT | SWT.SELECTED | SWT.BACKGROUND);
 			if (maskedState != SWT.HOT && maskedState != SWT.SELECTED) {
-				drawDirtyIndicator(gc, closeRect);
+				drawDirtyIndicator(gc, closeRect, selected);
 				return;
 			}
 		}
@@ -737,13 +737,18 @@ void drawClose(GC gc, Rectangle closeRect, int closeImageState, boolean showDirt
 		gc.setForeground(originalForeground);
 	}
 
-	private void drawDirtyIndicator(GC gc, Rectangle closeRect) {
+	private void drawDirtyIndicator(GC gc, Rectangle closeRect, boolean selected) {
 		int diameter = 8;
 		int x = closeRect.x + (closeRect.width - diameter) / 2;
 		int y = closeRect.y + (closeRect.height - diameter) / 2;
 		Color originalBackground = gc.getBackground();
+		int originalAlpha = gc.getAlpha();
 		gc.setBackground(gc.getForeground());
+		if (!selected) {
+			gc.setAlpha(140);
+		}
 		gc.fillOval(x, y, diameter, diameter);
+		gc.setAlpha(originalAlpha);
 		gc.setBackground(originalBackground);
 	}
 
@@ -1142,7 +1147,7 @@ void drawSelected(int itemIndex, GC gc, Rectangle bounds, int state ) {
 				}
 			}
 			if (shouldAllocateCloseRect(item)) {
-				drawClose(gc, item.closeRect, item.closeImageState, shouldDrawDirtyIndicator(item));
+				drawClose(gc, item.closeRect, item.closeImageState, shouldDrawDirtyIndicator(item), true);
 			}
 		}
 	}
@@ -1317,7 +1322,7 @@ void drawUnselected(int index, GC gc, Rectangle bounds, int state) {
 			}
 			// draw close or dirty indicator
 			if (shouldAllocateCloseRect(item)) {
-				drawClose(gc, item.closeRect, item.closeImageState, shouldDrawDirtyIndicator(item));
+				drawClose(gc, item.closeRect, item.closeImageState, shouldDrawDirtyIndicator(item), false);
 			}
 		}
 	}