vcl/skia/salbmp.cxx | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
New commits:
commit 3769d01791e54be0fbfc6d706596283213700ad0
Author: Luboš Luňák <l.lu...@centrum.cz>
AuthorDate: Tue Jul 7 12:15:20 2020 +0000
Commit: Luboš Luňák <l.lu...@collabora.com>
CommitDate: Wed Jul 8 09:31:12 2020 +0200
prevent SkiaSalBitmap::Scale() from breaking indexed bitmaps (tdf#134574)
Since the actual scaling is done later at some unknown time,
the palette mustn't change, but scaling can change colors.
Change-Id: Ie254c8b31993d9d509c32a730dd8c8b5d3cb2256
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/98258
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lu...@collabora.com>
diff --git a/vcl/skia/salbmp.cxx b/vcl/skia/salbmp.cxx
index 8cd1a158dc2f..6373eeea405a 100644
--- a/vcl/skia/salbmp.cxx
+++ b/vcl/skia/salbmp.cxx
@@ -296,8 +296,8 @@ bool SkiaSalBitmap::Scale(const double& rScaleX, const
double& rScaleY, BmpScale
if (mSize == newSize)
return true;
- SAL_INFO("vcl.skia.trace", "scale(" << this << "): " << mSize << "->" <<
newSize << ":"
- << static_cast<int>(nScaleFlag));
+ SAL_INFO("vcl.skia.trace", "scale(" << this << "): " << mSize << "/" <<
mBitCount << "->"
+ << newSize << ":" <<
static_cast<int>(nScaleFlag));
// The idea here is that the actual scaling will be delayed until the
result
// is actually needed. Usually the scaled bitmap will be drawn somewhere,
@@ -319,8 +319,18 @@ bool SkiaSalBitmap::Scale(const double& rScaleX, const
double& rScaleY, BmpScale
currentQuality = kHigh_SkFilterQuality;
break;
default:
+ SAL_INFO("vcl.skia.trace", "scale(" << this << "): unsupported
scale algorithm");
return false;
}
+ if (mBitCount < 24 && !mPalette.IsGreyPalette8Bit())
+ {
+ // Scaling can introduce additional colors not present in the original
+ // bitmap (e.g. when smoothing). If the bitmap is indexed (has
non-trivial palette),
+ // this would break the bitmap, because the actual scaling is done
only somewhen later.
+ // Linear 8bit palette (grey) is ok, since there we use directly the
values as colors.
+ SAL_INFO("vcl.skia.trace", "scale(" << this << "): indexed bitmap");
+ return false;
+ }
// if there is already one scale() pending, use the lowest quality of all
requested
static_assert(kMedium_SkFilterQuality < kHigh_SkFilterQuality);
mScaleQuality = std::min(mScaleQuality, currentQuality);
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