vcl/skia/salbmp.cxx | 34 +++++++++++++++++++++++++++++++---
1 file changed, 31 insertions(+), 3 deletions(-)
New commits:
commit eec512887d01ba9958f3e427ae0b1a2916564f46
Author: Luboš Luňák <l.lu...@collabora.com>
AuthorDate: Fri Apr 3 17:52:57 2020 +0200
Commit: Luboš Luňák <l.lu...@collabora.com>
CommitDate: Tue Apr 7 11:53:13 2020 +0200
optimize SkiaSalBitmap::ConvertToGreyscale()
Normally VCL can handle the pixel buffer operations, but this is often
called by the separate-alpha-outdev hack, where we get only the SkImage.
So optimize to avoid the SkImage->buffer->SkImage conversion.
Change-Id: I9d2c11d102adc89aac41ff55f11553dbcee9cd97
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/91770
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lu...@collabora.com>
diff --git a/vcl/skia/salbmp.cxx b/vcl/skia/salbmp.cxx
index 7c3d183a54d9..f9fae9dd83e8 100644
--- a/vcl/skia/salbmp.cxx
+++ b/vcl/skia/salbmp.cxx
@@ -33,6 +33,8 @@
#include <SkPixelRef.h>
#include <SkSurface.h>
#include <SkSwizzle.h>
+#include <SkColorFilter.h>
+#include <SkColorMatrix.h>
#include <skia/utils.hxx>
#include <skia/zone.hxx>
@@ -347,9 +349,35 @@ bool SkiaSalBitmap::ConvertToGreyscale()
#ifdef DBG_UTIL
assert(mWriteAccessCount == 0);
#endif
- // Skia can convert color SkBitmap to a greyscale one (draw using
SkCanvas),
- // but it uses different coefficients for the color->grey conversion than
VCL.
- // So just let VCL do it.
+ // Normally this would need to convert contents of mBuffer for all
possible formats,
+ // so just let the VCL algorithm do it.
+ // The exception is when this bitmap contains only SkImage, which most
probably
+ // comes from SkiaSalGraphicsImpl::GetBitmap(). That is often used by the
horrible
+ // separate-alpha-outdev hack, and followed by a later call to
GetAlphaSkBitmap().
+ // Avoid the costly SkImage->buffer->SkImage conversion.
+ if (!mBuffer && mImage)
+ {
+ if (mBitCount == 8 && mPalette == Bitmap::GetGreyPalette(256))
+ return true;
+ sk_sp<SkSurface> surface = SkiaHelper::createSkSurface(mPixelsSize);
+ SkPaint paint;
+ paint.setBlendMode(SkBlendMode::kSrc); // set as is, including alpha
+ // VCL uses different coefficients for conversion to gray than Skia,
so use the VCL
+ // values from Bitmap::ImplMakeGreyscales(). Do not use
kGray_8_SkColorType,
+ // Skia would use its gray conversion formula.
+ // NOTE: The matrix is 4x5 organized as columns (i.e. each line is a
column, not a row).
+ constexpr SkColorMatrix toGray(77 / 256.0, 151 / 256.0, 28 / 256.0, 0,
0, // R column
+ 77 / 256.0, 151 / 256.0, 28 / 256.0, 0,
0, // G column
+ 77 / 256.0, 151 / 256.0, 28 / 256.0, 0,
0, // B column
+ 0, 0, 0, 1, 0); // don't modify alpha
+ paint.setColorFilter(SkColorFilters::Matrix(toGray));
+ surface->getCanvas()->drawImage(mImage, 0, 0, &paint);
+ mBitCount = 8;
+ mPalette = Bitmap::GetGreyPalette(256);
+ ResetToSkImage(surface->makeImageSnapshot());
+ SAL_INFO("vcl.skia.trace", "converttogreyscale(" << this << ")");
+ return true;
+ }
return false;
}
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