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Fixed creating Cairo bitmap from wxBitmap (wxMSW).

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Iterating over bit values with wxAlphaPixelData sets the internal wxBitmap's "has alpha" flag but we want to left it unchanged so we have to save its original value and restore it afterward.
This commit is contained in:
Artur Wieczorek 2016-04-11 18:06:42 +02:00
parent bac5975b02
commit 0ee25aaa76
1 changed files with 47 additions and 33 deletions
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80
src/generic/graphicc.cpp
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@ -1414,43 +1414,57 @@ wxCairoBitmapData::wxCairoBitmapData( wxGraphicsRenderer* renderer, const wxBitm
if ( isSrcBpp32 )
{
// use the bitmap's alpha
wxAlphaPixelData
pixData(bmpSource, wxPoint(0, 0), wxSize(m_width, m_height));
wxCHECK_RET( pixData, wxT("Failed to gain raw access to bitmap data."));
// Using wxAlphaPixelData sets (on wxMSW and wxOSX) the internal
// "has alpha" flag but we want to leave it unchanged, so we need
// to save its current value now and restore it afterwards.
#if defined(__WXMSW__) || defined(__WXOSX__)
const bool hasAlpha = bmpSource.HasAlpha();
#endif // __WXMSW__ || __WXOSX__
wxAlphaPixelData::Iterator p(pixData);
for (int y=0; y<m_height; y++)
{
wxAlphaPixelData::Iterator rowStart = p;
wxUint32* const rowStartDst = data;
for (int x=0; x<m_width; x++)
{
// Each pixel in CAIRO_FORMAT_ARGB32 is a 32-bit quantity,
// with alpha in the upper 8 bits, then red, then green, then
// blue. The 32-bit quantities are stored native-endian.
// Pre-multiplied alpha is used.
unsigned char alpha = (bufferFormat == CAIRO_FORMAT_ARGB32) ? p.Alpha() : 255;
#ifdef __WXMSW__
// MSW bitmap pixel bits are already premultiplied.
*data = (alpha << 24 | p.Red() << 16 | p.Green() << 8 | p.Blue());
#else // !__WXMSW__
if (alpha == 0)
*data = 0;
else
*data = (alpha << 24
| Premultiply(alpha, p.Red()) << 16
| Premultiply(alpha, p.Green()) << 8
| Premultiply(alpha, p.Blue()));
#endif // __WXMSW__ / !__WXMSW__
++data;
++p;
}
// use the bitmap's alpha
wxAlphaPixelData pixData(bmpSource);
wxCHECK_RET( pixData, wxT("Failed to gain raw access to bitmap data."));
data = rowStartDst + stride / 4;
p = rowStart;
p.OffsetY(pixData, 1);
wxAlphaPixelData::Iterator p(pixData);
for (int y=0; y<m_height; y++)
{
wxAlphaPixelData::Iterator rowStart = p;
wxUint32* const rowStartDst = data;
for (int x=0; x<m_width; x++)
{
// Each pixel in CAIRO_FORMAT_ARGB32 is a 32-bit quantity,
// with alpha in the upper 8 bits, then red, then green, then
// blue. The 32-bit quantities are stored native-endian.
// Pre-multiplied alpha is used.
unsigned char alpha = (bufferFormat == CAIRO_FORMAT_ARGB32) ? p.Alpha() : 255;
#ifdef __WXMSW__
// MSW bitmap pixel bits are already premultiplied.
*data = (alpha << 24 | p.Red() << 16 | p.Green() << 8 | p.Blue());
#else // !__WXMSW__
if (alpha == 0)
*data = 0;
else
*data = (alpha << 24
| Premultiply(alpha, p.Red()) << 16
| Premultiply(alpha, p.Green()) << 8
| Premultiply(alpha, p.Blue()));
#endif // __WXMSW__ / !__WXMSW__
++data;
++p;
}
data = rowStartDst + stride / 4;
p = rowStart;
p.OffsetY(pixData, 1);
}
}
#if defined(__WXMSW__) || defined(__WXOSX__)
// Reset "has alpha" flag back.
// (wxBitmap::UseAlpha() is used only on wxMSW and wxOSX.)
bmpSource.UseAlpha(hasAlpha);
#endif // __WXMSW__ || __WXOSX__
}
else // no alpha
{