[OpenJDK 2D-Dev] 6603887: Where are transparent areas filled with bgColor?

[Clemens Eisserer]

Hi Dimitri,

>    I'm having issues with reproducing the bug with
>    this or the original test.
>    I've tried on solaris and linux, it works fine in
>    both cases on all jdks I've tried. Weird.
>    What is your desktop bit depth?  I've tried on 24bit
>    systems.
My display also has 24bit depth, when I switch to 16bit, pixel has
some ~65535 value and everything works as expected.
I am using Fedora7, updated once or twice, my Laptop has an Intel
GMA950, using the i810 driver.

>    In the debugger I see that the pixel passed to
>    X11SD_GetPixmapWithBg is 0x00ffffff, not 0xffffffff,
>    so pixel+1 != 0 .
Wow thats really weird, however from the pixel-point-of-view it makes
sence - 24 bytes are 1.

I did some debugging, and that's the stack where I get the pixel-value from:
  PixelConverter$Xrgb.rgbToPixel(int, ColorModel) line: 143
  SurfaceType.pixelFor(int, ColorModel) line: 434
  X11SurfaceData$X11PixmapSurfaceData(SurfaceData).pixelFor(int) line: 835
  X11PMBlitBgLoops.BlitBg(SurfaceData, SurfaceData, Composite, Region,
Color, int, int, int, int, int, int) line: 90
  BlitBg$TraceBlitBg.BlitBg(SurfaceData, SurfaceData, Composite,
Region, Color, int, int, int, int, int, int) line: 211
  DrawImage.blitSurfaceData(SunGraphics2D, Region, SurfaceData,
SurfaceData, SurfaceType, SurfaceType, int, int, int, int, int, int,
Color) line: 957
  DrawImage.renderImageCopy(SunGraphics2D, Image, Color, int, int,
int, int, int, int) line: 575
  DrawImage.copyImage(SunGraphics2D, Image, int, int, Color) line: 71
  DrawImage.copyImage(SunGraphics2D, Image, int, int, Color,
ImageObserver) line: 1008
  SunGraphics2D.drawImage(Image, int, int, Color, ImageObserver) line: 3053
  ImageRepresentation.drawToBufImage(Graphics, ToolkitImage, int, int,
Color, ImageObserver) line: 764
  DrawImage.copyImage(SunGraphics2D, Image, int, int, Color,
ImageObserver) line: 1015
  SunGraphics2D.drawImage(Image, int, int, Color, ImageObserver) line: 3053
  BgRegTest.start() line: 39
  AppletViewerPanel(AppletPanel).run() line: 476
  Thread.run() line: 659

Its  simply returns the parameter we hand in from Color.getRGB(), my
SurfaceData-Object is a
sun.java2d.x11.X11SurfaceData$X11PixmapSurfaceData.
Could it be a bug or no clear specification in
PixelConverter$Xrgb.rgbToPixel(int, ColorModel) line: 143 be:

	public int rgbToPixel(int rgb, ColorModel cm) {
	    return rgb;
	}

	public int pixelToRgb(int pixel, ColorModel cm) {
	    return (0xff000000 | pixel);
	}

rgbToPixel simply returns the rgb value, but  pixelToRgb sets the
first two bytes. The question is why doesn't it look like:
public int rgbToPixel(int rgb, ColorModel cm) {
	    return rgb & 0x00ffffff;
	}

I am using jdk7b19, so maybe some things have changed already :-/

------------

I wonder how the code does/should behave in the 32-bit depth case?
Wouldn't be a -1 value be possible in this case?

lg Clemens