diff options
Diffstat (limited to 'vcl/skia/gdiimpl.cxx')
| -rw-r--r-- | vcl/skia/gdiimpl.cxx | 31 |
1 files changed, 15 insertions, 16 deletions
diff --git a/vcl/skia/gdiimpl.cxx b/vcl/skia/gdiimpl.cxx index 40341bba85f7..e6c373c2f86b 100644 --- a/vcl/skia/gdiimpl.cxx +++ b/vcl/skia/gdiimpl.cxx @@ -1272,23 +1272,19 @@ bool SkiaSalGraphicsImpl::blendBitmap(const SalTwoRect& rPosAry, const SalBitmap assert(dynamic_cast<const SkiaSalBitmap*>(&rBitmap)); const SkiaSalBitmap& rSkiaBitmap = static_cast<const SkiaSalBitmap&>(rBitmap); - // This is used by VirtualDevice in the alpha mode for the "alpha" layer which - // is actually one-minus-alpha (opacity). Therefore white=0xff=transparent, - // black=0x00=opaque. So the result is transparent only if both the inputs - // are transparent. Since for blending operations white=1.0 and black=0.0, - // kMultiply should handle exactly that (transparent*transparent=transparent, - // opaque*transparent=opaque). And guessing from the "floor" in TYPE_BLEND in opengl's - // combinedTextureFragmentShader.glsl, the layer is not even alpha values but - // simply yes-or-no mask. + // This is used by VirtualDevice in the alpha mode for the "alpha" layer + // So the result is transparent only if both the inputs + // are transparent. Which seems to be what SkBlendMode::kModulate does, + // so use that. // See also blendAlphaBitmap(). if (rSkiaBitmap.IsFullyOpaqueAsAlpha()) { - // Optimization. If the bitmap means fully opaque, it's all zero's. In CPU + // Optimization. If the bitmap means fully opaque, it's all one's. In CPU // mode it should be faster to just copy instead of SkBlendMode::kMultiply. drawBitmap(rPosAry, rSkiaBitmap); } else - drawBitmap(rPosAry, rSkiaBitmap, SkBlendMode::kMultiply); + drawBitmap(rPosAry, rSkiaBitmap, SkBlendMode::kModulate); return true; } @@ -1337,10 +1333,10 @@ bool SkiaSalGraphicsImpl::blendAlphaBitmap(const SalTwoRect& rPosAry, // First do the "( 1 - alpha ) * mask" // (no idea how to do "floor", but hopefully not needed in practice). sk_sp<SkShader> shaderAlpha - = SkShaders::Blend(SkBlendMode::kDstOut, rSkiaMaskBitmap.GetAlphaSkShader(samplingOptions), + = SkShaders::Blend(SkBlendMode::kDstIn, rSkiaMaskBitmap.GetAlphaSkShader(samplingOptions), rSkiaAlphaBitmap.GetAlphaSkShader(samplingOptions)); // And now draw the bitmap with "1 - x", where x is the "( 1 - alpha ) * mask". - sk_sp<SkShader> shader = SkShaders::Blend(SkBlendMode::kSrcOut, shaderAlpha, + sk_sp<SkShader> shader = SkShaders::Blend(SkBlendMode::kSrcIn, shaderAlpha, rSkiaSourceBitmap.GetSkShader(samplingOptions)); drawShader(rPosAry, shader); return true; @@ -1368,9 +1364,12 @@ void SkiaSalGraphicsImpl::drawMask(const SalTwoRect& rPosAry, const SalBitmap& r { assert(dynamic_cast<const SkiaSalBitmap*>(&rSalBitmap)); const SkiaSalBitmap& skiaBitmap = static_cast<const SkiaSalBitmap&>(rSalBitmap); + // SkBlendMode::kDstOut must be used instead of SkBlendMode::kDstIn because + // the alpha channel of what is drawn appears to get inverted at some point + // after it is drawn drawShader( rPosAry, - SkShaders::Blend(SkBlendMode::kDstOut, // VCL alpha is one-minus-alpha. + SkShaders::Blend(SkBlendMode::kDstOut, // VCL alpha is alpha. SkShaders::Color(toSkColor(nMaskColor)), skiaBitmap.GetAlphaSkShader(makeSamplingOptions(rPosAry, mScaling)))); } @@ -1680,7 +1679,7 @@ sk_sp<SkImage> SkiaSalGraphicsImpl::mergeCacheBitmaps(const SkiaSalBitmap& bitma { canvas->clear(SK_ColorTRANSPARENT); paint.setShader( - SkShaders::Blend(SkBlendMode::kDstOut, bitmap.GetSkShader(samplingOptions, bitmapType), + SkShaders::Blend(SkBlendMode::kDstIn, bitmap.GetSkShader(samplingOptions, bitmapType), alphaBitmap->GetAlphaSkShader(samplingOptions, alphaBitmapType))); canvas->drawPaint(paint); } @@ -1742,7 +1741,7 @@ bool SkiaSalGraphicsImpl::drawAlphaBitmap(const SalTwoRect& rPosAry, const SalBi else drawShader(rPosAry, SkShaders::Blend( - SkBlendMode::kDstOut, // VCL alpha is one-minus-alpha. + SkBlendMode::kDstIn, rSkiaSourceBitmap.GetSkShader(makeSamplingOptions(rPosAry, mScaling)), rSkiaAlphaBitmap.GetAlphaSkShader(makeSamplingOptions(rPosAry, mScaling)))); return true; @@ -1965,7 +1964,7 @@ bool SkiaSalGraphicsImpl::drawTransformedBitmap(const basegfx::B2DPoint& rNull, if (pSkiaAlphaBitmap) { SkPaint paint = makeBitmapPaint(); - paint.setShader(SkShaders::Blend(SkBlendMode::kDstOut, // VCL alpha is one-minus-alpha. + paint.setShader(SkShaders::Blend(SkBlendMode::kDstIn, rSkiaBitmap.GetSkShader(samplingOptions), pSkiaAlphaBitmap->GetAlphaSkShader(samplingOptions))); if (fAlpha != 1.0) |