Bug 333391

Comment 1 Silenio Quarti 2011-01-04 14:53:10 EST

GTK/Motif when in advanced mode (running cairo) does not support XOR mode either. We would have to determine if cairo has added API for this. I had a quick look and it seems cairo_set_operator() with CAIRO_OPERATOR_XOR should do what we want, but we have to test.

http://cairographics.org/manual/cairo-cairo-t.html#cairo-set-operator

Comment 2 Scott Kovatch 2011-01-04 15:01:08 EST

The description of CAIRO_OPERATOR_XOR at http://cairographics.org/operators/ looks correct. They also have CAIRO_OPERATOR_DIFFERENCE, but there's no docs on what it does. Presumably it's the same as Carbon/Cocoa.

Comment 3 Scott Kovatch 2011-02-02 18:19:12 EST

*** Bug 336167 has been marked as a duplicate of this bug. ***

Comment 4 Andre Saibel 2012-06-20 04:15:15 EDT

No messages for one and a half years ... what is the state of affairs?

Comment 5 Arun Thondapu 2012-06-20 07:52:43 EDT

As far as I understand, we still do not have support for XOR mode on Linux with Cairo because the CAIRO_OPERATOR_XOR referred to in comment 1 does not provide a bit-wise XOR functionality.

Bogdan/Silenio, can you please confirm?

Thanks!

Comment 6 Silenio Quarti 2012-06-21 17:45:16 EDT

I think we implement XOR on linux not to long ago, but it only works with gtk 2.4.

Comment 7 Andre Saibel 2012-08-06 08:57:43 EDT

I'm not sure if CAIRO_OPERATOR_DIFFERENCE is the right operator – is CAIRO_OPERATOR_XOR not the appropriate one?
Does the topic only affect the cairo "path" of SWT on Linux

Comment 8 Silenio Quarti 2012-08-08 22:18:16 EDT

(In reply to comment #7)
> I'm not sure if CAIRO_OPERATOR_DIFFERENCE is the right operator – is
> CAIRO_OPERATOR_XOR not the appropriate one?
> Does the topic only affect the cairo "path" of SWT on Linux

I confirmed that we have implemented GC.setXORMode() on GTK. The implementation only works with cairo >= 1.10.

I believe CAIRO_OPERATOR_DIFFERENCE is the right operator. We use kCGBlendModeDifference on cocoa.

It should affect fillRectangle, fillArc, fillPath, drawRectangle, drawArc, etc, drawImage as well.

This snippet works for me:


import org.eclipse.swt.SWT;
/* 
 * example snippet: Hello World
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 */
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.graphics.*;

public class Snippet1 {

public static void main (String [] args) {
	final Display display = new Display ();
	Shell shell = new Shell(display);
	shell.addListener(SWT.Paint, new Listener() {
		public void handleEvent(Event event) {
				GC gc = event.gc;
				gc.setAdvanced(true);
				System.out.println(gc.getAdvanced());
				gc.setBackground(display.getSystemColor(SWT.COLOR_RED));
				gc.fillRectangle(10, 10, 200, 200);
				gc.setXORMode(true);
				gc.setBackground(display.getSystemColor(SWT.COLOR_BLUE));
				gc.setForeground(display.getSystemColor(SWT.COLOR_BLUE));
				Image image = new Image(display, 100, 100);
				GC gc2 = new GC(image);
				gc2.setForeground(display.getSystemColor(SWT.COLOR_BLUE));
				gc2.setBackground(display.getSystemColor(SWT.COLOR_BLUE));
				gc2.fillRectangle(0 ,0, 100, 100);
				gc2.dispose();
//				gc.drawImage(image, 20, 20);
				image.dispose();
//				gc.fillRectangle(20, 20, 100, 100);
				gc.drawRectangle(0, 20, 100, 100);
		}
	});
	shell.open ();
	while (!shell.isDisposed ()) {
		if (!display.readAndDispatch ()) display.sleep ();
	}
	display.dispose ();
}
}

Comment 9 Andre Saibel 2012-08-09 04:12:13 EDT

Alright. What does that mean for the request?

Comment 10 Andre Saibel 2012-11-20 10:31:08 EST

still @deprecated?

Comment 11 Eclipse Genie 2019-11-07 15:17:48 EST

This bug hasn't had any activity in quite some time. Maybe the problem got resolved, was a duplicate of something else, or became less pressing for some reason - or maybe it's still relevant but just hasn't been looked at yet.

If you have further information on the current state of the bug, please add it. The information can be, for example, that the problem still occurs, that you still want the feature, that more information is needed, or that the bug is (for whatever reason) no longer relevant.

--
The automated Eclipse Genie.

Comment 12 Andre Saibel 2019-11-08 02:17:51 EST

XOR is a basic graphics feature so for me there is no reason to keep the @deprecated tag just because this feature is not supported on older Linux resp. Cairo < 1.10.

Comment 13 Eric Williams 2019-11-08 09:15:28 EST

(In reply to Andre Saibel from comment #12)
> XOR is a basic graphics feature so for me there is no reason to keep the
> @deprecated tag just because this feature is not supported on older Linux
> resp. Cairo < 1.10.

Agreed, we don't support GTK3 versions with Cairo < 1.12, so we can definitely remove this tag.

Comment 14 Eclipse Genie 2019-11-08 10:38:01 EST

New Gerrit change created: https://git.eclipse.org/r/152338

Comment 15 Eclipse Genie 2019-11-08 16:50:43 EST

Gerrit change https://git.eclipse.org/r/152338 was merged to [master].
Commit: http://git.eclipse.org/c/platform/eclipse.platform.swt.git/commit/?id=1af84db9d9097f2c1d4b3b33cc3dc258334486cb

Comment 16 Eric Williams 2019-11-08 16:52:17 EST

(In reply to Eclipse Genie from comment #15)
> Gerrit change https://git.eclipse.org/r/152338 was merged to [master].
> Commit:
> http://git.eclipse.org/c/platform/eclipse.platform.swt.git/commit/
> ?id=1af84db9d9097f2c1d4b3b33cc3dc258334486cb

In master now.

Comment 17 Eric Williams 2019-11-19 08:55:05 EST

Verified in I20191119-0510.