GetPixel bug!!!

Ove Kaaven ovehk at
Fri Feb 16 07:56:09 CST 2001

On Fri, 16 Feb 2001, François Gouget wrote:

>    I just wanted to avoid copying the pixmap back into the DIB for the
> GetPixel case since obviously it has not been modified. That's what
> commit is here for of course. OTOH the subtleties of lossy are a bit
> lost on me. AFAICS it's always set to false so I'll just do the same.

The "lossy" is only meant for extreme optimization cases - "lossy"
suppresses the copying entirely, and is only meant to be useful when some
operation would completely overwrite/obliterate everything on the DIB
surface anyway, for example, a SRCCOPY blit that'd cover the entire
destination DIB. In such cases, it'd just be a waste to do a copy only to
have all of the copied data overwritten, it would be more efficient to not
copy anything then. But such optimization checks isn't being done yet.

I think the reason GetPixel/PutPixel hasn't done DIB updates yet is
because it's wasteful to copy the entire DIB graphic back and forth for a
single pixel, when it should really be easy to add code that could access
the DIB data directly... just that nobody did that yet. We're going to
need a proper DIB (aka FB) graphics engine someday...

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