Overfilled Rectangle in ControlExample on monitors > 100%

[akoch-yatta]

Description
If you execute the ControlExample on a primary monitor > 100% you'll see the following issue, when you change a color setting:

The filled rectangle overflows its border.

To reproduce:

1. Open the ControlExample on a primary monitor > 100%, best something like 175%, primary monitor = 150%
2. Change background color in "Colors and Fonts"

I assume the issue arises from the combination of GC#drawRectangle and a GC#fillRectangle which does not properly work on zoom > 100%. Start debugging with org.eclipse.swt.examples.controlexample.Tab#colorImage.

[laeubi]

By the way I think that painting here is done wrong (as outlined here eclipse-platform/eclipse.platform.swt#2874 (comment) )

The correct way for painting a filled rectangle with 1px border of one logical point would be

gc.fillRect(0,0, 100, 100);  //with border color, black in second example)
gc.fillRect(1,1, 98, 98);    //with background color, red in the second example)

this should reliable work with all zoom size.