[ wxwindows-Bugs-1530862 ] wxDC::DoDrawBitmap smears colors

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Bugs item #1530862, was opened at 2006-07-29 15:15
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Category: wxMSW specific
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: troelsk (troelsk)
Assigned to: Nobody/Anonymous (nobody)
Summary: wxDC::DoDrawBitmap smears colors

Initial Comment:
msw/wxDC::DoDrawBitmap smears colors when scaling.

How to reproduce:

1. Add scaling to
samples/image/image.cpp/MyImageFrame::OnPaint:

void OnPaint(wxPaintEvent& WXUNUSED(event))
{
     wxPaintDC dc( this );
     dc.SetUserScale(0.5, 0.5);
     //::SetStretchBltMode((HDC)dc.GetHDC(),
COLORONCOLOR);        
     dc.DrawBitmap( m_bitmap, 0, 0, true /* use mask */ );
}

2. Build and run samles/image, press Ctrl+O, choose 24
bit jpeg photo. Colors are smeared.

3. Uncomment the SetStretchBltMode line (above), build,
run and open jpeg photo again. Colors are good.

Remedy:
Use the StretchBltModeChanger class in
src/msw/wxDC::DoDrawBitmap, just like 
in src/msw/wxDC::DoBlit.

Using wxMSW 2.6.3 on Win2000.


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