[Win32] Monospace font doesn't place nice with Transform

[ptziegler]

Describe the bug

Unlike other fonts like e.g. Arial, the FontMetrics returned for the Monospace font are scaled by the Transform.

To Reproduce

package test;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Transform;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class Test {
	protected static final Font DISPLAY_FONT = new Font(null, "Monospaced", 24, SWT.NORMAL); //$NON-NLS-1$
	public static void main(String[] args) {
		System.setProperty("swt.autoScale.updateOnRuntime", "true");
		
		Shell shell = new Shell();

		shell.addPaintListener(event -> {
			GC gc = event.gc;
			gc.setFont(DISPLAY_FONT);
			
			Transform t = new Transform(gc.getDevice());
			t.scale(3.0f, 3.0f);

			gc.setTransform(t);
			System.out.println(gc.getFontMetrics().getAverageCharacterWidth());
			
			gc.setTransform(null);
			System.out.println(gc.getFontMetrics().getAverageCharacterWidth());

			gc.setFont(DISPLAY_FONT);
			System.out.println(gc.getFontMetrics().getAverageCharacterWidth());

			gc.setTransform(t);
			System.out.println(gc.getFontMetrics().getAverageCharacterWidth());
			
			gc.dispose();
		});

		shell.open();
		
		Display d = shell.getDisplay();
		while(!shell.isDisposed()) {
			while(!d.readAndDispatch()) {
				d.sleep();
			}
		}
	}
}

In GEF, I even had a situation where the correct values are returned after calling these no-op operations. Which only works due to calling getFontMetrics() while gc.getTransform() is null:

gc.setTransform(null);
gc.getFontMetrics();
gc.setTransform(transform);

Output

• Linux (with Monospaced)
  15, 15, 15, 15

• Windows (125% zoom, with Monospaced)
  53, 53, 18, 18

• Windows (125% zoom, with Arial)
  18, 18, 18, 18

Expected behavior

The average char width should behave the same across all operating systems.

Environment:

1. Select the platform(s) on which the behavior is seen:

• • All OS
• • Windows
• • Linux
• • macOS

Version since

Probably since forever. I can see the same inconsistency with the 2023-12.