[Win32] Emojis not displayed in text string when GC.setAdvanced(true)

[Phillipus]

Describe the bug
On Windows when GC.setAdvanced(true) an emoji is displayed as a square box.

To Reproduce
Run the Snippet below. Set e.gc.setAdvanced(false); to see the emoji.

import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class EmojiTest {
    
    public static void main(String[] args) {
        final Display display = new Display();

        final Shell shell = new Shell(display);
        shell.setText("SWT Test");
        shell.setLayout(new FillLayout());
        shell.setSize(300, 250);
        shell.setBackground(new Color(255, 255, 255));
        
        String emoji = Character.toString(0x1F600);
        
        shell.addPaintListener(e -> {
            e.gc.setAdvanced(true);
            e.gc.drawText("Hello World " + emoji, 20, 50);
        });
        
        shell.open();

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

        display.dispose();
    }
}

Expected behavior
Should see the emoji when advanced mode is true

Screenshots

With advanced mode false:

With advanced mode true:

Environment:

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

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

2. Additional OS info (e.g. OS version, Linux Desktop, etc)
   Windows 11
   Java 21

[HeikoKlare]

We see more and more flaws with GDI+. We also have to roll back the text layouting with GDI+ because of limitations with respect to text kerning:

• [Win32] Let GDI lay out text again unless GDI+ layout is required #3579

And there is no chance that anything improves, as Microsoft considers GDI and GDI+ as legacy with Direct2D being a more modern successor: https://learn.microsoft.com/en-us/windows/win32/learnwin32/overview-of-the-windows-graphics-architecture
I have no idea how much effort adopting Direct2D for SWT advanced mode may be, but it could be worth giving a try (with the help of an AI agent).

So I am not sure if there a solution for the reported issue. A quick search just revealed that "Segoe UI Emoji" seems to be the only font for emojis with GDI+.

[Phillipus]

@HeikoKlare Understood. Thanks for the feedback.

[laeubi]

I once made a little experiment moving to direct2d/directx and it seems doable but nothing for one weekend :-)

[laeubi]

I've proposed this work item to the IDE-WG Development Funding Initiative for potential funding:

• https://gitlab.eclipse.org/eclipse-wg/ide-wg/ide-wg-dev-funded-efforts/ide-wg-dev-funded-program-planning-council-top-issues/-/work_items/48

Please keep expectations in check — funding decisions and subsequent work will likely take some time. That said, anyone interested in helping move this forward is of course welcome, and funding from outside the IDE-WG program is always appreciated too. And if you'd like to have a direct say in prioritizing efforts like this one, consider joining the IDE-WG!