private void rebuildPaint(Point start, Point end) {
		paint = new GradientPaint(start.x, start.y, START_COLOR, end.x, end.y, END_COLOR, true);
	}
Paints a rectangle showing the start and end points of a drag.
Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/renderer/MouseDraggedPaintableShape.java