Bug 317180 Screen cheese when starting fresh workspace
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/CTabRendering.java
Rectangle rect = null;
			gc.setClipping(rect);
			if (outerKeyline == null)
				outerKeyline = gc.getDevice().getSystemColor(SWT.COLOR_BLACK);
			
			
		}
	}
	static int[] drawCircle(int xC, int yC, int r, int circlePart) {
		int x = 0, y = r, u = 1, v = 2 * r - 1, e = 0;
		int[] points = new int[1024];
		int[] pointsMirror = new int[1024];
		int loop = 0;
		int loopMirror = 0;
		while (x < y) {
			if (circlePart == RIGHT_BOTTOM) {
				points[loop++] = xC + x;
				points[loop++] = yC + y;
			}
			if (circlePart == RIGHT_TOP) {
				points[loop++] = xC + y;
				points[loop++] = yC - x;
			}
			if (circlePart == LEFT_TOP) {
				points[loop++] = xC - x;
				points[loop++] = yC - y;
			}
			if (circlePart == LEFT_BOTTOM) {
				points[loop++] = xC - y;
				points[loop++] = yC + x;