Re: Icons

[Joe Krahn <jkrahn at nc dot rr dot com>]

Joe Krahn wrote:
> Joe Krahn wrote:
>
> > One thing I found is that some Bitmap data are 16-bit aligned and some 
> > are 32-bit aligned. This is probably the source of horizontal line 
> > patterns, which I suspect occur for any not-divisible-by-32 size.
>
>
> A test: if 16 versus 32 bit alignment is the problem, then icons 33-48 
> bits wide should be broken, but 49-64 should work. Does someone have 
> some X client code handy to test this idea? If so, can you test both NET 
> icons, and traditional Pixmap icons?
>
> Joe

Wow... I see that 4 of 7 Active Contributors are working on icon 
support. I guess it's time to really get icon handling done right.

The alignments are definitely wrong. 32-bit alignment is for DIBs. Other 
Win32 bitmaps are 16 bit aligned. But, 32-bit may work sometimes by 
chance. I don't have problem icons, so someone else should test this:

In winmultiwindowicons.c, change these (first line occurs twice):

  stride = ((iconSize * effBPP + 31) & (~31)) / 8;
  ...
  maskStride = ((iconSize * 1 + 31) & (~31)) / 8;

to:

  stride = ((iconSize * effBPP + 15) & (~15)) / 4;
  ...
  maskStride = ((iconSize * 1 + 15) & (~15)) / 4;

I also prefer ">> 2" instead if "/ 4", but optimization should convert 
it to a shift anyhow.


I also noticed that winScaleXBitmapToWindows() seems to totally 
disregard mapping the pixel data to RGB. I assume this means that the 
device-dependent X Pixmaps have an identical data format as 
device-dependent Win32 bitmaps. However, image scaling is by 
nearest-neighbor only, and it does not handle monochrome bitmaps or 
NET_WM icons.

Also, there is too much duplicated but inconsistent stuff among the 
window-manager modes. I think the right thing to do is to extract all 
icons functions into one place. It would be good to consolidate some 
other things as well, like some of the Window functions.

Joe

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