Custom cursor size is doubled with Eclipse 4.35

[wolfgang-ch]

This is the cursor with Eclipse 4.34 which has the correct size

This is the cursor with Eclipse 4.35 which size is about doubled

This happens since Eclipse 4.35 on a 4k display by running the app with -Dswt.autoScale=200

The custom cursor is create with this code

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

• • [?] All OS
• • Windows
• • Linux
• • macOS

JRE/JDK version
17 or 21

Version since
4.35

Workaround (or) Additional context
Any known workarounds for the problem? NO

[HeikoKlare]

I guess it's caused by this change:

• Non system cursors adaption to DPI scale changes #1603

It seems like cursors were changed to take the zoom of the context in which they are registered into account. Since you pass a zoom (auto-scale) of 200 to the application, the cursor is now probably also scaled to 200%.

@ShahzaibIbrahim @fedejeanne Can you please test with the snippet used for #1603 for the auto-scale settings given in the issue description again and see whether that PR introduced an issue?

[fedejeanne]

@ShahzaibIbrahim @fedejeanne Can you please test with the snippet used for #1603 for the auto-scale settings given in the issue description again and see whether that PR introduced an issue?

Spot on, thank you!
I created a PR to fix it: #2071

[wolfgang-ch]

With Eclipse 4.36 and Windows 10, I can still see, that the cursor is scaled.

This is the test cursor image which needs to be loaded in the snippet

The cursor image is 40x40 pixel but it has a different size in the test snippet. When swt.autoScale is not set or is 100, then the cursor image is scaled to 60x60 pixel but I expect that it should be 40x40 pixel.

Why is the cursor scaled?

This is the code for the snippet which is based on Snippet118

package org.eclipse.swt.snippets;

import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;

public class Snippet118 {

   public static void main(String[] args) {

      final Display display = new Display();
      final Shell shell = new Shell(display);
      Rectangle bounds = shell.getBounds();

      shell.setLocation((int) (bounds.width * 0.9f), 100);
      shell.setText("Snippet 118");
      shell.setSize(300, 400);

      final Cursor[] cursor = new Cursor[1];
      final ImageData[] imageData = new ImageData[1];

      Button button = new Button(shell, SWT.PUSH);
      button.setText("Load Cursor");

      Point size = button.computeSize(SWT.DEFAULT, SWT.DEFAULT);
      button.setSize(size);
      button.setLocation(10, 10);

      button.addListener(SWT.Selection, e -> {

         FileDialog dialog = new FileDialog(shell);
         dialog.setFilterExtensions(new String[] { "*.png", "*.*" });
         String name = dialog.open();

         if (name == null) return;

         imageData[0] = new ImageData(name);
         Cursor oldCursor = cursor[0];

         cursor[0] = new Cursor(display, imageData[0], 0, 0);
         shell.setCursor(cursor[0]);

         if (oldCursor != null) oldCursor.dispose();

         shell.redraw();
      });

      shell.addPaintListener(event -> {

         GC gc = event.gc;

         ImageData oneImageData = imageData[0];
         if (oneImageData != null) {

            gc.drawText("Cursor width %d  - height %d".formatted(

                  oneImageData.width,
                  oneImageData.height), 10, 50, true);
         }

         String property = System.getProperty("swt.autoScale");
         gc.drawText("swt.autoScale = %s".formatted(property), 10, 100, true);

         int yPos = 200;
         int tickHeight = 10;

         for (int tickIndex = 0; tickIndex < 11; tickIndex++) {

            int xPos = 100 + tickIndex * 10;
            int yOffset = 0;

            if (tickIndex % 3 == 1) {
               yOffset = 20;
            } else if (tickIndex % 3 == 2) {
               yOffset = 40;
            }

            gc.drawLine(xPos, yPos, xPos, yPos + tickHeight);
            gc.drawText(Integer.toString(tickIndex * 10),
                  xPos - 5,
                  yPos + 12 + yOffset);
         }
      });

      shell.open();
      while (!shell.isDisposed()) {
         if (!display.readAndDispatch())
            display.sleep();
      }

      if (cursor[0] != null) cursor[0].dispose();
      display.dispose();
   }
}

[fedejeanne]

I'll take a look at it tomorrow