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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
View File

@@ -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;

53
tests/graphics/bitmap.cpp
View File

@@ -126,6 +126,59 @@ TEST_CASE("BitmapTestCase::Mask", "[bitmap][mask]")
REQUIRE(bmp.GetMask() == mask2);
}
TEST_CASE("BitmapTestCase::ConvertToImageWithMask", "[bitmap][image][mask]")
{
wxBitmap color(32, 32, 24);
{
wxMemoryDC dc(color);
dc.SetPen(*wxYELLOW_PEN);
dc.SetBrush(*wxYELLOW_BRUSH);
dc.DrawRectangle(0, 0, color.GetWidth(), color.GetHeight());
}
{
wxBitmap bmask(color.GetWidth(), color.GetHeight(), 1);
{
wxMemoryDC dc(bmask);
#if wxUSE_GRAPHICS_CONTEXT
wxGraphicsContext* gc = dc.GetGraphicsContext();
if (gc)
{
gc->SetAntialiasMode(wxANTIALIAS_NONE);
}
#endif // wxUSE_GRAPHICS_CONTEXT
dc.SetBackground(*wxBLACK_BRUSH);
dc.Clear();
dc.SetPen(*wxWHITE_PEN);
dc.SetBrush(*wxWHITE_BRUSH);
dc.DrawRectangle(4, 4, 8, 8);
}
REQUIRE_FALSE(color.HasAlpha());
REQUIRE(color.GetMask() == NULL);
color.SetMask(new wxMask(bmask));
REQUIRE_FALSE(color.HasAlpha());
REQUIRE(color.GetMask() != NULL);
}
wxImage image = color.ConvertToImage();
wxNativePixelData dataColor(color);
wxNativePixelData::Iterator rowStartColor(dataColor);
wxBitmap mask = color.GetMask()->GetBitmap();
wxNativePixelData dataMask(mask);
wxNativePixelData::Iterator rowStartMask(dataMask);
for ( int y = 0; y < color.GetHeight(); ++y ) {
wxNativePixelData::Iterator iColor = rowStartColor;
wxNativePixelData::Iterator iMask = rowStartMask;
for ( int x = 0; x < color.GetWidth(); ++x, ++iColor, ++iMask ) {
CHECK((iMask.Red() == 255 && iMask.Green() == 255 && iMask.Blue() == 255 ? iColor.Red() : 1) == image.GetRed(x, y));
CHECK((iMask.Red() == 255 && iMask.Green() == 255 && iMask.Blue() == 255 ? iColor.Green() : 2) == image.GetGreen(x, y));
CHECK((iMask.Red() == 255 && iMask.Green() == 255 && iMask.Blue() == 255 ? iColor.Blue() : 3) == image.GetBlue(x, y));
}
rowStartColor.OffsetY(dataColor, 1);
rowStartMask.OffsetY(dataMask, 1);
}
}
TEST_CASE("BitmapTestCase::OverlappingBlit", "[bitmap][blit]")
{
wxBitmap bmp(10, 10);