[Mono-devel-list] Bugfixing: libgdiplus help needed

Jordi Mas jordi at ximian.com
Thu Nov 11 14:55:56 EST 2004

El dj 11 de 11 del 2004 a les 20:48 +0100, en/na Juraj Skripsky va
> Hello,
> I'm trying to fix Bug #69089 in libgdiplus. What I did so far is
> optimize the algorithms for speed and reduce rotate_90 and rotate_270
> two one function, which handles both cases. I attached the patch to the
> bug.
> Now I'm having problems with the last step of the rotation function. I
> need to switch height and width in all relevant data structures and
> replace the bitmap with its rotated counterpart. That's were I'm lost.
> Why does GpBitmap contain height and width twice? What other data
> structures have to be updated as well? What does result->data.Reserved
> && GBD_OWN_SCAN0 mean?

Hello Juraj,

GBD_OWN_SCAN0 means that the scan0 memory has allocated by libgdiplus
and it has to be free'd.

GDI+ has the width and the height of the image duplicated in the
BitmapData and the GpImage structures. You have to apply any changes to

If you do not want to waste time on this, I can also fix it. I will be
quick for me because I'm familiar with this stuff.



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