tests/org.eclipse.swt.tests.gtk/ManualTests/org/eclipse/swt/tests/gtk/snippets/Bug483791_setBackgroundGC.java

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 * The contents of this file are made available under the terms
 * of the GNU Lesser General Public License (LGPL) Version 2.1 that
 * accompanies this distribution (lgpl-v21.txt).  The LGPL is also
 * available at http://www.gnu.org/licenses/lgpl.html.  If the version
 * of the LGPL at http://www.gnu.org is different to the version of
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 * between the two license versions, the terms of the LGPL accompanying
 * this distribution shall govern.
 *
 * Contributors:
 *     Red Hat - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.tests.gtk.snippets;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.MessageBox;
import org.eclipse.swt.widgets.Shell;

/*
 * Title: Bug 483791 - [GTK3] setBackground overrides GC drawing in PaintListener
 * How to run: launch snippet and press button "CLICK"
 * Bug description: Label will have Cyan background but no line drawn through it
 * Expected results: Label should draw line through it regardless of bg color
 * GTK Version(s): 3.10+
 */
public final class Bug483791_setBackgroundGC {

	public static void main(String[] args) {
		final Display display = new Display();
		final Shell shell = new Shell(display);
		shell.setLayout(new GridLayout());

		final Label l = new Label(shell, SWT.None);
		l.setText("ASDQWE");
		l.addPaintListener(arg0 -> arg0.gc.drawLine(0, 0, arg0.width, arg0.height));

		final Button b = new Button(shell, SWT.PUSH);
		b.setText("CLICK");
		b.addSelectionListener(new SelectionAdapter() {

			@Override
			public void widgetSelected(SelectionEvent arg0) {
				l.setBackground(display.getSystemColor(SWT.COLOR_CYAN));
				// these don't help
				/*
				l.redraw();
				l.update();
				 */
				MessageBox mb = new MessageBox(shell);
				mb.setMessage("Background should not override GC drawing, but it does");
				mb.open();
			}
		});

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

	private Bug483791_setBackgroundGC() {
	}
}