+#ifdef __WXMSW__
+ // if there is a mask, set the alpha bytes in the target buffer to
+ // fully transparent or fully opaque
+ if (bmpSource.GetMask())
+ {
+ wxBitmap bmpMask = bmpSource.GetMaskBitmap();
+ bufferFormat = CAIRO_FORMAT_ARGB32;
+ data = (wxUint32*)m_buffer;
+ wxNativePixelData
+ pixData(bmpMask, wxPoint(0, 0), wxSize(m_width, m_height));
+ wxCHECK_RET( pixData, wxT("Failed to gain raw access to mask data."));
+
+ wxNativePixelData::Iterator p(pixData);
+ for (int y=0; y<m_height; y++)
+ {
+ wxNativePixelData::Iterator rowStart = p;
+ wxUint32* const rowStartDst = data;
+ for (int x=0; x<m_width; x++)
+ {
+ if (p.Red()+p.Green()+p.Blue() == 0)
+ *data = 0;
+ else
+ *data = (wxALPHA_OPAQUE << 24) | (*data & 0x00FFFFFF);
+ ++data;
+ ++p;
+ }
+
+ data = rowStartDst + stride / 4;
+ p = rowStart;
+ p.OffsetY(pixData, 1);
+ }
+ }
+#endif
+
+ InitSurface(bufferFormat, stride);
+#endif // wxHAS_RAW_BITMAP
+}
+
+#if wxUSE_IMAGE
+
+// Helper functions for dealing with alpha pre-multiplication.
+namespace
+{
+
+inline unsigned char Premultiply(unsigned char alpha, unsigned char data)
+{
+ return alpha ? (data * alpha)/0xff : data;
+}
+
+inline unsigned char Unpremultiply(unsigned char alpha, unsigned char data)
+{
+ return alpha ? (data * 0xff)/alpha : data;
+}
+
+} // anonymous namespace
+
+wxCairoBitmapData::wxCairoBitmapData(wxGraphicsRenderer* renderer,
+ const wxImage& image)
+ : wxGraphicsObjectRefData(renderer)
+{
+ const cairo_format_t bufferFormat = image.HasAlpha()
+ ? CAIRO_FORMAT_ARGB32
+ : CAIRO_FORMAT_RGB24;
+
+ int stride = InitBuffer(image.GetWidth(), image.GetHeight(), bufferFormat);
+
+ // Copy wxImage data into the buffer. Notice that we work with wxUint32
+ // values and not bytes becase Cairo always works with buffers in native
+ // endianness.
+ wxUint32* dst = reinterpret_cast<wxUint32*>(m_buffer);
+ const unsigned char* src = image.GetData();
+
+ if ( bufferFormat == CAIRO_FORMAT_ARGB32 )
+ {
+ const unsigned char* alpha = image.GetAlpha();
+
+ for ( int y = 0; y < m_height; y++ )
+ {
+ wxUint32* const rowStartDst = dst;
+
+ for ( int x = 0; x < m_width; x++ )
+ {
+ const unsigned char a = *alpha++;
+
+ *dst++ = a << 24 |
+ Premultiply(a, src[0]) << 16 |
+ Premultiply(a, src[1]) << 8 |
+ Premultiply(a, src[2]);
+ src += 3;
+ }
+
+ dst = rowStartDst + stride / 4;
+ }
+ }
+ else // RGB
+ {
+ for ( int y = 0; y < m_height; y++ )
+ {
+ wxUint32* const rowStartDst = dst;
+
+ for ( int x = 0; x < m_width; x++ )
+ {
+ *dst++ = src[0] << 16 |
+ src[1] << 8 |
+ src[2];
+ src += 3;
+ }
+
+ dst = rowStartDst + stride / 4;
+ }
+ }
+
+ InitSurface(bufferFormat, stride);