Create Font handles on demand

[ShahzaibIbrahim]

Creating a new static method to retrieve font handle. Handles will no longer be created during initialization. Also destroy condition is changed since handle being 0 doesn't mean that it was destroyed anymore.

How to test

• Run the following snippet with following VM arguments:

-Dswt.autoScale=quarter
-Dswt.autoScale.updateOnRuntime=true

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

public class SWTFontExample {
    public static void main(String[] args) {
        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setText("SWT Font Example");
        shell.setSize(400, 200);
        shell.setLayout(new FillLayout());

        Label label = new Label(shell, SWT.CENTER);
        label.setText("Hello, SWT with Custom Font!");

        FontData[] fontData = label.getFont().getFontData();
        for (FontData fd : fontData) {
            fd.setHeight(20); // Set font size to 20
            fd.setStyle(SWT.BOLD); // Make it bold
        }

        Font newFont = new Font(display, fontData);
        label.setFont(newFont);

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

• The correct formatting should be applied on the text same as before this change was made.
• This change should not produce any regression and the handle will only be created on demand not during initialization of Font object.

[github-actions]

Test Results

   545 files  + 6     545 suites  +6   38m 12s ⏱️ + 4m 41s
 4 376 tests +37   4 358 ✅ +35   18 💤 +3  0 ❌  - 1 
16 643 runs  +37  16 503 ✅ +35  140 💤 +3  0 ❌  - 1 

Results for commit 1b0ba0c. ± Comparison against base commit f10721a.

♻️ This comment has been updated with latest results.

[laeubi]

@ShahzaibIbrahim I once played around with making Fonts GC disposable here:

• [gtk] Make Fonts GC disposable #1054

do you think that would be applicable here as well? So wrapping the (long) handle inside an FontHandle object would then also make the usage of different booleans not required, because you can have a

FontHandle handle;

if (handle == null) {
  //never initialized
}

if (handle != null && handle.pointer == 0) {
   //was initialized but disposed
}

in the code.

[ShahzaibIbrahim]

do you think that would be applicable here as well? So wrapping the (long) handle inside an FontHandle object would then also make the usage of different booleans not required, because you can have a

FontHandle handle;

if (handle == null) {
  //never initialized
}

if (handle != null && handle.pointer == 0) {
   //was initialized but disposed
}

in the code.

@laeubi I personally like the idea. I could implement it, but just to be consistent with other resources in win32. I would like it to be handled as I have done with isDestoyed field.

Maybe we could do it for all the resources in a separate issue/ticket.

[fedejeanne]

I marked the new field fontData as final (and explicitly initialized it to null in 2 constructors). The code looks OK but some tests fail because when fontData == null, the newly added static method does an illegal call.

addressed

[HeikoKlare]

This PR is currently broken. The first commit is supposed to be an independent refactoring, but the code state does not compile.

[HeikoKlare]

Now the commit contents are the wrong way round and do not fit their commit messages: the first, refactoring commit contains the actual change (creating handles on demand) and the second change supposed to create handles on demand encapsulates the field and adds some additional checks and corrects formatting.