vcl/inc/skia/utils.hxx | 38 +++++++++++++++++++++++++++++++++++++-
vcl/skia/gdiimpl.cxx | 6 +++---
vcl/skia/salbmp.cxx | 13 ++++++++-----
3 files changed, 48 insertions(+), 9 deletions(-)
New commits:
commit 8043fe3e45c8999c8eaf475ba46d50b125e38b93
Author: Luboš Luňák <l.lu...@collabora.com>
AuthorDate: Thu Apr 8 22:20:53 2021 +0200
Commit: Luboš Luňák <l.lu...@collabora.com>
CommitDate: Mon Apr 12 15:05:49 2021 +0200
use Skia linear+mipmap for quality large downscaling (tdf#140129)
This is what https://bugs.chromium.org/p/skia/issues/detail?id=11810#c1
suggests (although I consider it to be an annoyance having to do this
explicitly).
Change-Id: I3df80374492c7b208ebaf819c0b4794ba535aa53
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/113979
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lu...@collabora.com>
diff --git a/vcl/inc/skia/utils.hxx b/vcl/inc/skia/utils.hxx
index 716bd3e2471c..e53a17c7d934 100644
--- a/vcl/inc/skia/utils.hxx
+++ b/vcl/inc/skia/utils.hxx
@@ -85,11 +85,42 @@ VCL_DLLPUBLIC const SkSurfaceProps* surfaceProps();
// Set pixel geometry to be used by SkSurfaceProps.
VCL_DLLPUBLIC void setPixelGeometry(SkPixelGeometry pixelGeometry);
-inline SkSamplingOptions makeSamplingOptions(BmpScaleFlag scaling)
+// Normal scaling algorithms have a poor quality when downscaling a lot.
+// https://bugs.chromium.org/p/skia/issues/detail?id=11810 suggests to use
mipmaps
+// in such a case, which is annoying to do explicitly instead of Skia deciding
which
+// algorithm would be the best, but now with Skia removing SkFilterQuality and
requiring
+// explicitly being told what algorithm to use this appears to be the best we
can do.
+// Anything scaled down at least this ratio will use linear+mipmaps.
+constexpr int downscaleRatioThreshold = 4;
+
+inline SkSamplingOptions makeSamplingOptions(BmpScaleFlag scaling, const
SkMatrix& matrix)
{
switch (scaling)
{
case BmpScaleFlag::BestQuality:
+ if (matrix.getScaleX() <= 1.0 / downscaleRatioThreshold
+ || matrix.getScaleY() <= 1.0 / downscaleRatioThreshold)
+ return SkSamplingOptions(SkFilterMode::kLinear,
SkMipmapMode::kLinear);
+ return SkSamplingOptions(SkCubicResampler::Mitchell());
+ case BmpScaleFlag::Default:
+ return SkSamplingOptions(SkFilterMode::kLinear,
SkMipmapMode::kNone);
+ case BmpScaleFlag::Fast:
+ return SkSamplingOptions(SkFilterMode::kNearest,
SkMipmapMode::kNone);
+ default:
+ assert(false);
+ return SkSamplingOptions();
+ }
+}
+
+inline SkSamplingOptions makeSamplingOptions(BmpScaleFlag scaling, const Size&
srcSize,
+ const Size& destSize)
+{
+ switch (scaling)
+ {
+ case BmpScaleFlag::BestQuality:
+ if (srcSize.Width() / destSize.Width() >= downscaleRatioThreshold
+ || srcSize.Height() / destSize.Height() >=
downscaleRatioThreshold)
+ return SkSamplingOptions(SkFilterMode::kLinear,
SkMipmapMode::kLinear);
return SkSamplingOptions(SkCubicResampler::Mitchell());
case BmpScaleFlag::Default:
return SkSamplingOptions(SkFilterMode::kLinear,
SkMipmapMode::kNone);
@@ -104,7 +135,12 @@ inline SkSamplingOptions makeSamplingOptions(BmpScaleFlag
scaling)
inline SkSamplingOptions makeSamplingOptions(const SalTwoRect& rPosAry)
{
if (rPosAry.mnSrcWidth != rPosAry.mnDestWidth || rPosAry.mnSrcHeight !=
rPosAry.mnDestHeight)
+ {
+ if (rPosAry.mnSrcWidth / rPosAry.mnDestWidth >= downscaleRatioThreshold
+ || rPosAry.mnSrcHeight / rPosAry.mnDestHeight >=
downscaleRatioThreshold)
+ return SkSamplingOptions(SkFilterMode::kLinear,
SkMipmapMode::kLinear);
return SkSamplingOptions(SkCubicResampler::Mitchell()); // best
+ }
return SkSamplingOptions(); // none
}
diff --git a/vcl/skia/gdiimpl.cxx b/vcl/skia/gdiimpl.cxx
index 828b7959244b..fd4f64e930cf 100644
--- a/vcl/skia/gdiimpl.cxx
+++ b/vcl/skia/gdiimpl.cxx
@@ -1652,7 +1652,7 @@ sk_sp<SkImage>
SkiaSalGraphicsImpl::mergeCacheBitmaps(const SkiaSalBitmap& bitma
matrix.set(SkMatrix::kMScaleX, 1.0 * targetSize.Width() /
bitmap.GetSize().Width());
matrix.set(SkMatrix::kMScaleY, 1.0 * targetSize.Height() /
bitmap.GetSize().Height());
canvas->concat(matrix);
- samplingOptions = makeSamplingOptions(BmpScaleFlag::BestQuality);
+ samplingOptions = makeSamplingOptions(BmpScaleFlag::BestQuality,
matrix);
}
if (alphaBitmap != nullptr)
{
@@ -1884,7 +1884,7 @@ bool SkiaSalGraphicsImpl::drawTransformedBitmap(const
basegfx::B2DPoint& rNull,
canvas->concat(matrix);
SkSamplingOptions samplingOptions;
if (matrixNeedsHighQuality(matrix))
- samplingOptions = makeSamplingOptions(BmpScaleFlag::BestQuality);
+ samplingOptions = makeSamplingOptions(BmpScaleFlag::BestQuality,
matrix);
if (fAlpha == 1.0)
canvas->drawImage(imageToDraw, 0, 0, samplingOptions);
else
@@ -1911,7 +1911,7 @@ bool SkiaSalGraphicsImpl::drawTransformedBitmap(const
basegfx::B2DPoint& rNull,
canvas->concat(matrix);
SkSamplingOptions samplingOptions;
if (matrixNeedsHighQuality(matrix))
- samplingOptions = makeSamplingOptions(BmpScaleFlag::BestQuality);
+ samplingOptions = makeSamplingOptions(BmpScaleFlag::BestQuality,
matrix);
if (pSkiaAlphaBitmap)
{
SkPaint paint;
diff --git a/vcl/skia/salbmp.cxx b/vcl/skia/salbmp.cxx
index 1302a3532afb..bb19f9118637 100644
--- a/vcl/skia/salbmp.cxx
+++ b/vcl/skia/salbmp.cxx
@@ -779,9 +779,9 @@ const sk_sp<SkImage>& SkiaSalBitmap::GetSkImage() const
assert(surface);
SkPaint paint;
paint.setBlendMode(SkBlendMode::kSrc); // set as is, including
alpha
- surface->getCanvas()->drawImageRect(mImage,
- SkRect::MakeWH(mSize.Width(),
mSize.Height()),
-
makeSamplingOptions(mScaleQuality), &paint);
+ surface->getCanvas()->drawImageRect(
+ mImage, SkRect::MakeWH(mSize.Width(), mSize.Height()),
+ makeSamplingOptions(mScaleQuality, imageSize(mImage), mSize),
&paint);
SAL_INFO("vcl.skia.trace", "getskimage(" << this << "): image
scaled "
<< Size(mImage->width(),
mImage->height())
<< "->" << mSize << ":"
@@ -893,7 +893,9 @@ const sk_sp<SkImage>& SkiaSalBitmap::GetAlphaSkImage() const
paint.setBlendMode(SkBlendMode::kSrc); // set as is, including alpha
surface->getCanvas()->drawImageRect(
mImage, SkRect::MakeWH(mSize.Width(), mSize.Height()),
- scaling ? makeSamplingOptions(mScaleQuality) :
SkSamplingOptions(), &paint);
+ scaling ? makeSamplingOptions(mScaleQuality, imageSize(mImage),
mSize)
+ : SkSamplingOptions(),
+ &paint);
if (scaling)
SAL_INFO("vcl.skia.trace", "getalphaskimage(" << this << "): image
scaled "
<<
Size(mImage->width(), mImage->height())
@@ -1147,7 +1149,8 @@ void SkiaSalBitmap::EnsureBitmapData()
if (imageSize(mImage) != mSize) // pending scaling?
{
canvas.drawImageRect(mImage, SkRect::MakeWH(mSize.getWidth(),
mSize.getHeight()),
- makeSamplingOptions(mScaleQuality), &paint);
+ makeSamplingOptions(mScaleQuality,
imageSize(mImage), mSize),
+ &paint);
SAL_INFO("vcl.skia.trace",
"ensurebitmapdata(" << this << "): image scaled " <<
imageSize(mImage) << "->"
<< mSize << ":" <<
static_cast<int>(mScaleQuality));
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