Description Veronika Irvine 2001-10-11 14:23:23 EDT

From eclipse corner post by Randy Hudson:

I was trying to create my own cursor when I noticed that all of the
resources that ship with Eclipse are switched.  BMPs with the "_source"
suffix are actually masks, and those with the "_mask" suffix are actually
the source.  This is quite confusing.

The constructor:
public Cursor(Device device,
    ImageData source,
    ImageData mask,
    int hotspotX,
    int hotspotY)
is actually treating the source as the mask, and the mask as the source.

I also tried to create a Cursor with just a source and no mask, but:
    new Image(null, source, mask).getImageData()
is returning an Image with depth of 32, even though both source and mask are
1-bit depth.  I could not figure out how to get a valid ImageData for
creating the cursor this way short of completely building the data in hex.
Could someone show me how?  I would like to just load a transparent GIF as a
cursor.

The class Image is treating masks and sources correctly.  Here is my test
case.  Notice that the cursor and the CLabel disagree on what the final
Image should look like (The cursor *appears* correct, but that is because
the resources are swapped).  Try "bottom_source.bmp" for an even better
example.  The resources from the org.eclipse.ui/icons were copied into a
default package for use with this test class:

//Default package
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.SWT;

import org.eclipse.swt.custom.CLabel;

public class CursorTest {

static Shell shell;

static Image image;
static Cursor cursor;
static ImageData source;
static ImageData mask;

static {
 source = new ImageData(
    CursorTest.class.getResourceAsStream("stack_source.bmp"));
 mask = new ImageData(
    CursorTest.class.getResourceAsStream("stack_mask.bmp"));
 image = new Image(null, source, mask);
 image.setBackground(new Color(null, 0,0,255));
 cursor = new Cursor(null, source, mask, 0,0);
}

public static void main(String args[]){
 shell = new Shell ();
 shell.open();

 CLabel label = new CLabel(shell, 0);
 label.setBounds(10,10,200,200);
 label.setBackground(new Color(null, 100,200,0));

 label.setImage(image);
 label.setText("foo");
 label.setCursor(cursor);

 shell.setLocation(100,30);
 shell.setSize(800,600);

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

}



NOTES:

Randy Hudson (8/29/2001 11:15:04 AM)
	Although duplicate 1FRSOOR was moved to inactive in November, this should be addressed.  In the very LEAST,
	you could name the parameters correctly on the constructor.  ITPUI should probably rename their
	.GIF resources to the correct names, since that can be confusing too.

	Even though I was aware of the bug, I spent about 3 hours trying to make one cursor.  I was using 2
	GIF files as the source, both were indexed with a Palette of just two colors, so they were 1-bit.
	No matter what I did, the area in the source that was inactive (masked out) was showing up as XOR instead
	of transparent.  I thought this was a problem with the mask, but when I finally switched to using a .BMP file for
	the source, with the same mask, the problem went away.
	I also tried providing just one ImageData parameter.  I did new Image(source, mask).getImageData().  The imageData
	that got returned had a depth of 32, even though both source and mask had depth of 1.  There are comments in
	Image.getImageData() about returning something compatible for Cursors, but it appears this is not working correctly.