[news.eclipse.platform.swt] Re: Problems with controls background laid o

["Grant Gayed" <grant_gayed@xxxxxxxxxx>]

Hi, sorry for the late response,

This is somewhat intentional, but is probably not the correct behaviour for
your case.  The 0.25 alpha is meant to emulate the way that a native group's
background is auto-set to be a bit darker than its parent (you can see this
in Interface Builder by nesting a few levels of groups).  However it
probably should not be doing this in your case since you're setting its
background explicitly.  I've logged
https://bugs.eclipse.org/bugs/show_bug.cgi?id=234240 .  This will not be
fixed for 3.4 because it's too late to consider changes like this.

Grant


"Yuliya" <julia.poleno@xxxxxxxxx> wrote in message
news:g0eulj$j6b$1@xxxxxxxxxxxxxxxxxxxx
> Hello everybody!
>
> We have faced such problem under Mac platform: if some control, except
> of Text, is laid on Group this control saves 25% of own background color.
>
>
> Here is the source code
>
> import org.eclipse.swt.SWT;
> import org.eclipse.swt.layout.FillLayout;
> import org.eclipse.swt.widgets.Display;
> import org.eclipse.swt.widgets.Group;
> import org.eclipse.swt.widgets.Label;
> import org.eclipse.swt.widgets.Shell;
>
> public class MacBackgroundDemo {
>
>    public static void main(final String[] args) {
>
>      final Display display = new Display();
>      final Shell shell = new Shell(display);
>      shell.setLayout(new FillLayout());
>
>      Group group = new Group(shell, SWT.SHADOW_NONE);
>      group.setText("Example");
>
>      group.setLayout(new FillLayout());
>
>      Label label = new Label(group, SWT.CENTER);
>      label.setText("...TEST...");
>      label.setBackground(Display.getCurrent()
>           .getSystemColor(SWT.COLOR_RED));
>
>      shell.pack();
>      shell.open();
>      while (!shell.isDisposed()) {
>        if (!display.readAndDispatch())
>          display.sleep();
>      }
>      display.dispose();
>    }
> }
>
>
> This code is respected under Windows platform totally, but under Mac
> platform we receive different background for Label.
>
> My best suggestion is: in Control we have drawBackground() method where
> we invoke getThemeAlfa() - which is normally looks like that:
>
> float getThemeAlfa() {
>    return 1 * parent.getThemeAlfa();
> }
>
> but in Group control under Mac platform this method is overridden like
that:
>
> float getThemeAlfa() {
>    return 0.25 * parent.getThemeAlfa();
> }
>
>
> The question is: was it maid intentionally or this is a bug? Will it be
> fixed in next version of Eclipse? (now I'm using 3.3.1.1)