- rect->X = 0; - rect->Y = 0; + /*The user maybe has called SetWindowOrgEx to change origin point*/ + POINT pt = {0, 0}; + GetWindowOrgEx(graphics->hdc, &pt); + rect->X = pt.x; + rect->Y = pt.y;
I don't think we should use GetWindowOrgEx in gdiplus. There are too many ways to change the mapping of co-ordinates for an HDC, and it doesn't make sense to specifically account for them all.
In get_graphics_bounds, we already have code that accounts for the HDC transform using DPtoLP. Maybe we should do that even when GetMapMode == MM_TEXT.
Transforming the region in alpha_blend_pixels_hrgn looks wrong to me, because we can't do that in the general case. Logical coordinates on the HDC may not be pixels.
Your test is very unclear. A good test for this should make it obvious how the HDC's transform affects GDI+ world coordinates. If I fill a rectangle at (0,0) using GDI+, on an HDC with window origin (5,5), what is the origin of that rectangle on the screen?