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Fix handling of mask in wxBitmap::ConvertToImage()

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Handling mask when converting wxBitmap to wxImage was accidentally
broken by 7e9afad53a (Add real support for monochrome bitmaps to wxMSW,
2020-10-19). Fix this now and reuse the new wxMonoPixelData to make the
code simpler and more readable.

This commit is best viewed ignoring whitespace-only changes, as it
unindents a large block of code.

Closes https://github.com/wxWidgets/wxWidgets/pull/2125

Closes #18974, #18975.
This commit is contained in:
Bill Su
2020-11-21 01:49:55 -05:00
committed by Vadim Zeitlin
parent b27aefacef
commit 47078992c6
2 changed files with 96 additions and 52 deletions
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95
src/msw/bitmap.cpp
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@@ -968,67 +968,58 @@ wxImage wxBitmap::ConvertToImage() const
return wxNullImage;
}
// now do the same for the mask, if we have any
HBITMAP hbmpMask = GetMask() ? (HBITMAP) GetMask()->GetMaskBitmap() : NULL;
if ( hbmpMask )
// now handle the mask, if we have any
if ( GetMask() )
{
wxDIB dibMask(hbmpMask);
if ( dibMask.IsOk() )
// we hard code the mask colour for now but we could also make an
// effort (and waste time) to choose a colour not present in the
// image already to avoid having to fudge the pixels below --
// whether it's worth to do it is unclear however
static const int MASK_RED = 1;
static const int MASK_GREEN = 2;
static const int MASK_BLUE = 3;
static const int MASK_BLUE_REPLACEMENT = 2;
wxBitmap bmpMask(GetMask()->GetBitmap());
wxMonoPixelData dataMask(bmpMask);
const int h = dataMask.GetHeight();
const int w = dataMask.GetWidth();
unsigned char* data = image.GetData();
wxMonoPixelData::Iterator rowStart(dataMask);
for ( int y = 0; y < h; ++y )
{
// TODO: use wxRawBitmap to iterate over DIB
// we hard code the mask colour for now but we could also make an
// effort (and waste time) to choose a colour not present in the
// image already to avoid having to fudge the pixels below --
// whether it's worth to do it is unclear however
static const int MASK_RED = 1;
static const int MASK_GREEN = 2;
static const int MASK_BLUE = 3;
static const int MASK_BLUE_REPLACEMENT = 2;
const int h = dibMask.GetHeight();
const int w = dibMask.GetWidth();
const int bpp = dibMask.GetDepth();
const int maskBytesPerPixel = bpp >> 3;
const int maskBytesPerLine = wxDIB::GetLineSize(w, bpp);
unsigned char *data = image.GetData();
// remember that DIBs are stored in bottom to top order
unsigned char *
maskLineStart = dibMask.GetData() + ((h - 1) * maskBytesPerLine);
for ( int y = 0; y < h; y++, maskLineStart -= maskBytesPerLine )
// traverse one mask line
wxMonoPixelData::Iterator p = rowStart;
for ( int x = 0; x < w; ++x )
{
// traverse one mask DIB line
unsigned char *mask = maskLineStart;
for ( int x = 0; x < w; x++, mask += maskBytesPerPixel )
// should this pixel be transparent?
if ( p.Pixel() )
{
// should this pixel be transparent?
if ( *mask )
// no, check that it isn't transparent by accident
if ( (data[0] == MASK_RED) &&
(data[1] == MASK_GREEN) &&
(data[2] == MASK_BLUE) )
{
// no, check that it isn't transparent by accident
if ( (data[0] == MASK_RED) &&
(data[1] == MASK_GREEN) &&
(data[2] == MASK_BLUE) )
{
// we have to fudge the colour a bit to prevent
// this pixel from appearing transparent
data[2] = MASK_BLUE_REPLACEMENT;
}
// we have to fudge the colour a bit to prevent
// this pixel from appearing transparent
data[2] = MASK_BLUE_REPLACEMENT;
}
data += 3;
}
else // yes, transparent pixel
{
*data++ = MASK_RED;
*data++ = MASK_GREEN;
*data++ = MASK_BLUE;
}
data += 3;
}
else // yes, transparent pixel
{
*data++ = MASK_RED;
*data++ = MASK_GREEN;
*data++ = MASK_BLUE;
}
++p;
}
image.SetMaskColour(MASK_RED, MASK_GREEN, MASK_BLUE);
rowStart.OffsetY(dataMask, 1);
}
image.SetMaskColour(MASK_RED, MASK_GREEN, MASK_BLUE);
}
return image;