Fix handling of MaskFilter matrices

1) extend GrFPArgs to track pre/post local matrices, add helpers for
   creating pre/post wrapper args

2) add a SkShaderBase helper (totalLocalMatrix) to centralize the LM
   sandwich logic.

3) update call sites to use the above

4) rename SkMatrixFilter::makeWithLocalMatrix -> makeWithMatrix, to
   disambiguate vs. SkShader::makeWithLocalMatrix.

BUG=skia:7744

Change-Id: Ib2b7b007e6924979b00649dde7c94ef4b34771f1
Reviewed-on: https://skia-review.googlesource.com/119330
Commit-Queue: Florin Malita <fmalita@chromium.org>
Reviewed-by: Brian Salomon <bsalomon@google.com>

12 files changed, 88 insertions, 104 deletions

diff --git a/src/shaders/SkImageShader.cpp b/src/shaders/SkImageShader.cpp
index 265f7e6013..1838e9e498 100644
--- a/src/shaders/SkImageShader.cpp
+++ b/src/shaders/SkImageShader.cpp
@@ -213,19 +213,11 @@ static GrSamplerState::WrapMode tile_mode_to_wrap_mode(const SkShader::TileMode
 
 std::unique_ptr<GrFragmentProcessor> SkImageShader::asFragmentProcessor(
         const GrFPArgs& args) const {
-    SkMatrix lm = this->getLocalMatrix();
+    const auto lm = this->totalLocalMatrix(args.fPreLocalMatrix, args.fPostLocalMatrix);
     SkMatrix lmInverse;
-    if (!lm.invert(&lmInverse)) {
+    if (!lm->invert(&lmInverse)) {
         return nullptr;
     }
-    if (args.fLocalMatrix) {
-        SkMatrix inv;
-        if (!args.fLocalMatrix->invert(&inv)) {
-            return nullptr;
-        }
-        lmInverse.postConcat(inv);
-        lm.preConcat(*args.fLocalMatrix);
-    }
 
     GrSamplerState::WrapMode wrapModes[] = {tile_mode_to_wrap_mode(fTileModeX),
                                             tile_mode_to_wrap_mode(fTileModeY)};
@@ -236,7 +228,7 @@ std::unique_ptr<GrFragmentProcessor> SkImageShader::asFragmentProcessor(
     // are provided by the caller.
     bool doBicubic;
     GrSamplerState::Filter textureFilterMode = GrSkFilterQualityToGrFilterMode(
-            args.fFilterQuality, *args.fViewMatrix, lm,
+            args.fFilterQuality, *args.fViewMatrix, *lm,
             args.fContext->contextPriv().sharpenMipmappedTextures(), &doBicubic);
     GrSamplerState samplerState(wrapModes, textureFilterMode);
     sk_sp<SkColorSpace> texColorSpace;
diff --git a/src/shaders/SkLocalMatrixShader.cpp b/src/shaders/SkLocalMatrixShader.cpp
index ca99af1bef..78110f5821 100644
--- a/src/shaders/SkLocalMatrixShader.cpp
+++ b/src/shaders/SkLocalMatrixShader.cpp
@@ -15,13 +15,8 @@
 #if SK_SUPPORT_GPU
 std::unique_ptr<GrFragmentProcessor> SkLocalMatrixShader::asFragmentProcessor(
         const GrFPArgs& args) const {
-    SkMatrix tmp = this->getLocalMatrix();
-    if (args.fLocalMatrix) {
-        tmp.preConcat(*args.fLocalMatrix);
-    }
     return as_SB(fProxyShader)
-            ->asFragmentProcessor(GrFPArgs(args.fContext, args.fViewMatrix, &tmp,
-                                           args.fFilterQuality, args.fDstColorSpaceInfo));
+            ->asFragmentProcessor(args.makeWithPreLocalMatrix(this->getLocalMatrix()));
 }
 #endif
 
diff --git a/src/shaders/SkPerlinNoiseShader.cpp b/src/shaders/SkPerlinNoiseShader.cpp
index 6179da3d32..8f6c85a494 100644
--- a/src/shaders/SkPerlinNoiseShader.cpp
+++ b/src/shaders/SkPerlinNoiseShader.cpp
@@ -1394,13 +1394,8 @@ std::unique_ptr<GrFragmentProcessor> SkPerlinNoiseShaderImpl::asFragmentProcesso
         const GrFPArgs& args) const {
     SkASSERT(args.fContext);
 
-    SkMatrix localMatrix = this->getLocalMatrix();
-    if (args.fLocalMatrix) {
-        localMatrix.preConcat(*args.fLocalMatrix);
-    }
-
-    SkMatrix matrix = *args.fViewMatrix;
-    matrix.preConcat(localMatrix);
+    const auto localMatrix = this->totalLocalMatrix(args.fPreLocalMatrix, args.fPostLocalMatrix);
+    const auto matrix = SkMatrix::Concat(*args.fViewMatrix, *localMatrix);
 
     // Either we don't stitch tiles, either we have a valid tile size
     SkASSERT(!fStitchTiles || !fTileSize.isEmpty());
@@ -1413,8 +1408,8 @@ std::unique_ptr<GrFragmentProcessor> SkPerlinNoiseShaderImpl::asFragmentProcesso
                                                                   matrix);
 
     SkMatrix m = *args.fViewMatrix;
-    m.setTranslateX(-localMatrix.getTranslateX() + SK_Scalar1);
-    m.setTranslateY(-localMatrix.getTranslateY() + SK_Scalar1);
+    m.setTranslateX(-localMatrix->getTranslateX() + SK_Scalar1);
+    m.setTranslateY(-localMatrix->getTranslateY() + SK_Scalar1);
 
     auto proxyProvider = args.fContext->contextPriv().proxyProvider();
     if (fType == kImprovedNoise_Type) {
diff --git a/src/shaders/SkPictureShader.cpp b/src/shaders/SkPictureShader.cpp
index 1d19b04721..de642a7dda 100644
--- a/src/shaders/SkPictureShader.cpp
+++ b/src/shaders/SkPictureShader.cpp
@@ -175,24 +175,20 @@ void SkPictureShader::flatten(SkWriteBuffer& buffer) const {
 //
 // 1) a cached image shader, which wraps a single picture tile at the given CTM/local matrix
 //
-// 2) a "composite" local matrix, to be passed down when dispatching createContext(),
+// 2) a tile scale adjustment, to be applied downstream when dispatching createContext(),
 //    appendStages() and asFragmentProcessor() in callers
 //
 // The composite local matrix includes the actual local matrix, any inherited/outer local matrix
 // and a scale component (to mape the actual tile bitmap size -> fTile size).
 //
 sk_sp<SkShader> SkPictureShader::refBitmapShader(const SkMatrix& viewMatrix,
-                                                 const SkMatrix* outerLocalMatrix,
+                                                 const SkMatrix& localMatrix,
                                                  SkColorSpace* dstColorSpace,
-                                                 SkMatrix* compositeLocalMatrix,
+                                                 SkVector* scaleAdjust,
                                                  const int maxTextureSize) const {
     SkASSERT(fPicture && !fPicture->cullRect().isEmpty());
 
-    *compositeLocalMatrix = this->getLocalMatrix();
-    if (outerLocalMatrix) {
-        compositeLocalMatrix->preConcat(*outerLocalMatrix);
-    }
-    const SkMatrix m = SkMatrix::Concat(viewMatrix, *compositeLocalMatrix);
+    const SkMatrix m = SkMatrix::Concat(viewMatrix, localMatrix);
 
     // Use a rotation-invariant scale
     SkPoint scale;
@@ -274,37 +270,52 @@ sk_sp<SkShader> SkPictureShader::refBitmapShader(const SkMatrix& viewMatrix,
         fAddedToCache.store(true);
     }
 
-    compositeLocalMatrix->preScale(1 / tileScale.width(), 1 / tileScale.height());
+    scaleAdjust->set(1 / tileScale.width(), 1 / tileScale.height());
 
     return tileShader;
 }
 
 bool SkPictureShader::onAppendStages(const StageRec& rec) const {
+    auto lm = this->totalLocalMatrix(rec.fLocalM);
+    SkVector scaleAdjust;
+
     // Keep bitmapShader alive by using alloc instead of stack memory
     auto& bitmapShader = *rec.fAlloc->make<sk_sp<SkShader>>();
-    SkMatrix compositeLocalMatrix;
-    bitmapShader = this->refBitmapShader(rec.fCTM, rec.fLocalM, rec.fDstCS, &compositeLocalMatrix);
+    bitmapShader = this->refBitmapShader(rec.fCTM, *lm, rec.fDstCS, &scaleAdjust);
+
+    if (!bitmapShader) {
+        return false;
+    }
+
+    if (scaleAdjust != SkVector::Make(1, 1)) {
+        lm.writable()->preScale(scaleAdjust.fX, scaleAdjust.fY);
+    }
 
     StageRec localRec = rec;
-    localRec.fLocalM = compositeLocalMatrix.isIdentity() ? nullptr : &compositeLocalMatrix;
+    localRec.fLocalM = lm->isIdentity() ? nullptr : &(*lm);
 
-    return bitmapShader && as_SB(bitmapShader)->appendStages(localRec);
+    return as_SB(bitmapShader)->appendStages(localRec);
 }
 
 /////////////////////////////////////////////////////////////////////////////////////////
 SkShaderBase::Context* SkPictureShader::onMakeContext(const ContextRec& rec, SkArenaAlloc* alloc)
 const {
-    SkMatrix compositeLocalMatrix;
+    auto lm = this->totalLocalMatrix(rec.fLocalMatrix);
+    SkVector scaleAdjust;
     sk_sp<SkShader> bitmapShader = this->refBitmapShader(*rec.fMatrix,
-                                                         rec.fLocalMatrix,
+                                                         *lm,
                                                          rec.fDstColorSpace,
-                                                         &compositeLocalMatrix);
+                                                         &scaleAdjust);
     if (!bitmapShader) {
         return nullptr;
     }
 
+    if (scaleAdjust != SkVector::Make(1, 1)) {
+        lm.writable()->preScale(scaleAdjust.fX, scaleAdjust.fY);
+    }
+
     ContextRec localRec = rec;
-    localRec.fLocalMatrix = compositeLocalMatrix.isIdentity() ? nullptr : &compositeLocalMatrix;
+    localRec.fLocalMatrix = lm->isIdentity() ? nullptr : &(*lm);
 
     PictureShaderContext* ctx =
         alloc->make<PictureShaderContext>(*this, localRec, std::move(bitmapShader), alloc);
@@ -369,20 +380,22 @@ std::unique_ptr<GrFragmentProcessor> SkPictureShader::asFragmentProcessor(
     if (args.fContext) {
         maxTextureSize = args.fContext->caps()->maxTextureSize();
     }
-    SkMatrix compositeLocalMatrix;
-    sk_sp<SkShader> bitmapShader(this->refBitmapShader(*args.fViewMatrix, args.fLocalMatrix,
+
+    auto lm = this->totalLocalMatrix(args.fPreLocalMatrix, args.fPostLocalMatrix);
+    SkVector scaleAdjust;
+    sk_sp<SkShader> bitmapShader(this->refBitmapShader(*args.fViewMatrix,*lm,
                                                        args.fDstColorSpaceInfo->colorSpace(),
-                                                       &compositeLocalMatrix,
-                                                       maxTextureSize));
+                                                       &scaleAdjust, maxTextureSize));
     if (!bitmapShader) {
         return nullptr;
     }
 
-    return as_SB(bitmapShader)->asFragmentProcessor(
-        GrFPArgs(args.fContext,
-                 args.fViewMatrix,
-                 compositeLocalMatrix.isIdentity() ? nullptr : &compositeLocalMatrix,
-                 args.fFilterQuality,
-                 args.fDstColorSpaceInfo));
+    if (scaleAdjust != SkVector::Make(1, 1)) {
+        lm.writable()->preScale(scaleAdjust.fX, scaleAdjust.fY);
+    }
+
+    GrFPArgs newArgs(args.fContext, args.fViewMatrix, args.fFilterQuality, args.fDstColorSpaceInfo);
+
+    return as_SB(bitmapShader)->asFragmentProcessor(newArgs.makeWithPreLocalMatrix(*lm));
 }
 #endif
diff --git a/src/shaders/SkPictureShader.h b/src/shaders/SkPictureShader.h
index 4970dac81b..5f28b6074b 100644
--- a/src/shaders/SkPictureShader.h
+++ b/src/shaders/SkPictureShader.h
@@ -46,9 +46,9 @@ private:
     SkPictureShader(sk_sp<SkPicture>, TileMode, TileMode, const SkMatrix*, const SkRect*,
                     sk_sp<SkColorSpace>);
 
-    sk_sp<SkShader> refBitmapShader(const SkMatrix&, const SkMatrix* localMatrix,
+    sk_sp<SkShader> refBitmapShader(const SkMatrix&, const SkMatrix& localMatrix,
                                     SkColorSpace* dstColorSpace,
-                                    SkMatrix* compositeLocalMatrix,
+                                    SkVector* scaleAdjust,
                                     const int maxTextureSize = 0) const;
 
     class PictureShaderContext : public Context {
diff --git a/src/shaders/SkShader.cpp b/src/shaders/SkShader.cpp
index 265f22beaa..f3ffd26ef4 100644
--- a/src/shaders/SkShader.cpp
+++ b/src/shaders/SkShader.cpp
@@ -67,15 +67,26 @@ void SkShaderBase::flatten(SkWriteBuffer& buffer) const {
     }
 }
 
+SkTCopyOnFirstWrite<SkMatrix>
+SkShaderBase::totalLocalMatrix(const SkMatrix* preLocalMatrix,
+                               const SkMatrix* postLocalMatrix) const {
+    SkTCopyOnFirstWrite<SkMatrix> m(fLocalMatrix);
+
+    if (preLocalMatrix) {
+        m.writable()->preConcat(*preLocalMatrix);
+    }
+
+    if (postLocalMatrix) {
+        m.writable()->postConcat(*postLocalMatrix);
+    }
+
+    return m;
+}
+
 bool SkShaderBase::computeTotalInverse(const SkMatrix& ctm,
                                        const SkMatrix* outerLocalMatrix,
                                        SkMatrix* totalInverse) const {
-    SkMatrix total = SkMatrix::Concat(ctm, fLocalMatrix);
-    if (outerLocalMatrix) {
-        total.preConcat(*outerLocalMatrix);
-    }
-
-    return total.invert(totalInverse);
+    return SkMatrix::Concat(ctm, *this->totalLocalMatrix(outerLocalMatrix)).invert(totalInverse);
 }
 
 bool SkShaderBase::asLuminanceColor(SkColor* colorPtr) const {
diff --git a/src/shaders/SkShaderBase.h b/src/shaders/SkShaderBase.h
index 89674a6ebb..cddc5540ee 100644
--- a/src/shaders/SkShaderBase.h
+++ b/src/shaders/SkShaderBase.h
@@ -12,6 +12,7 @@
 #include "SkMask.h"
 #include "SkMatrix.h"
 #include "SkShader.h"
+#include "SkTLazy.h"
 
 #if SK_SUPPORT_GPU
 #include "GrFPArgs.h"
@@ -185,9 +186,16 @@ public:
     // If this returns false, then we draw nothing (do not fall back to shader context)
     bool appendStages(const StageRec&) const;
 
-    bool computeTotalInverse(const SkMatrix& ctm,
-                             const SkMatrix* outerLocalMatrix,
-                             SkMatrix* totalInverse) const;
+    bool SK_WARN_UNUSED_RESULT computeTotalInverse(const SkMatrix& ctm,
+                                                   const SkMatrix* outerLocalMatrix,
+                                                   SkMatrix* totalInverse) const;
+
+    // Returns the total local matrix for this shader:
+    //
+    //   M = postLocalMatrix x shaderLocalMatrix x preLocalMatrix
+    //
+    SkTCopyOnFirstWrite<SkMatrix> totalLocalMatrix(const SkMatrix* preLocalMatrix,
+                                                   const SkMatrix* postLocalMatrix = nullptr) const;
 
 #ifdef SK_SUPPORT_LEGACY_SHADER_ISABITMAP
     virtual bool onIsABitmap(SkBitmap*, SkMatrix*, TileMode[2]) const {
diff --git a/src/shaders/gradients/SkLinearGradient.cpp b/src/shaders/gradients/SkLinearGradient.cpp
index b6436ca801..a377442dc4 100644
--- a/src/shaders/gradients/SkLinearGradient.cpp
+++ b/src/shaders/gradients/SkLinearGradient.cpp
@@ -195,16 +195,9 @@ std::unique_ptr<GrFragmentProcessor> SkLinearGradient::asFragmentProcessor(
     SkASSERT(args.fContext);
 
     SkMatrix matrix;
-    if (!this->getLocalMatrix().invert(&matrix)) {
+    if (!this->totalLocalMatrix(args.fPreLocalMatrix, args.fPostLocalMatrix)->invert(&matrix)) {
         return nullptr;
     }
-    if (args.fLocalMatrix) {
-        SkMatrix inv;
-        if (!args.fLocalMatrix->invert(&inv)) {
-            return nullptr;
-        }
-        matrix.postConcat(inv);
-    }
     matrix.postConcat(fPtsToUnit);
 
     return GrLinearGradient::Make(GrGradientEffect::CreateArgs(
diff --git a/src/shaders/gradients/SkRadialGradient.cpp b/src/shaders/gradients/SkRadialGradient.cpp
index 3f71f38c1f..6d193615a4 100644
--- a/src/shaders/gradients/SkRadialGradient.cpp
+++ b/src/shaders/gradients/SkRadialGradient.cpp
@@ -162,19 +162,10 @@ void GrRadialGradient::GLSLRadialProcessor::emitCode(EmitArgs& args) {
 
 std::unique_ptr<GrFragmentProcessor> SkRadialGradient::asFragmentProcessor(
         const GrFPArgs& args) const {
-    SkASSERT(args.fContext);
-
     SkMatrix matrix;
-    if (!this->getLocalMatrix().invert(&matrix)) {
+    if (!this->totalLocalMatrix(args.fPreLocalMatrix, args.fPostLocalMatrix)->invert(&matrix)) {
         return nullptr;
     }
-    if (args.fLocalMatrix) {
-        SkMatrix inv;
-        if (!args.fLocalMatrix->invert(&inv)) {
-            return nullptr;
-        }
-        matrix.postConcat(inv);
-    }
     matrix.postConcat(fPtsToUnit);
 
     return GrRadialGradient::Make(GrGradientEffect::CreateArgs(
diff --git a/src/shaders/gradients/SkSweepGradient.cpp b/src/shaders/gradients/SkSweepGradient.cpp
index e9c4450b00..3f605d7761 100644
--- a/src/shaders/gradients/SkSweepGradient.cpp
+++ b/src/shaders/gradients/SkSweepGradient.cpp
@@ -216,16 +216,9 @@ void GrSweepGradient::GLSLSweepProcessor::emitCode(EmitArgs& args) {
 std::unique_ptr<GrFragmentProcessor> SkSweepGradient::asFragmentProcessor(
         const GrFPArgs& args) const {
     SkMatrix matrix;
-    if (!this->getLocalMatrix().invert(&matrix)) {
+    if (!this->totalLocalMatrix(args.fPreLocalMatrix, args.fPostLocalMatrix)->invert(&matrix)) {
         return nullptr;
     }
-    if (args.fLocalMatrix) {
-        SkMatrix inv;
-        if (!args.fLocalMatrix->invert(&inv)) {
-            return nullptr;
-        }
-        matrix.postConcat(inv);
-    }
     matrix.postConcat(fPtsToUnit);
 
     return GrSweepGradient::Make(
diff --git a/src/shaders/gradients/SkTwoPointConicalGradient.cpp b/src/shaders/gradients/SkTwoPointConicalGradient.cpp
index cce25d00b7..88f0f82245 100644
--- a/src/shaders/gradients/SkTwoPointConicalGradient.cpp
+++ b/src/shaders/gradients/SkTwoPointConicalGradient.cpp
@@ -175,9 +175,13 @@ void SkTwoPointConicalGradient::flatten(SkWriteBuffer& buffer) const {
 
 std::unique_ptr<GrFragmentProcessor> SkTwoPointConicalGradient::asFragmentProcessor(
         const GrFPArgs& args) const {
-    SkASSERT(args.fContext);
+    SkMatrix matrix;
+    if (!this->totalLocalMatrix(args.fPreLocalMatrix, args.fPostLocalMatrix)->invert(&matrix)) {
+        return nullptr;
+    }
+
     return Gr2PtConicalGradientEffect::Make(
-            GrGradientEffect::CreateArgs(args.fContext, this, args.fLocalMatrix, fTileMode,
+            GrGradientEffect::CreateArgs(args.fContext, this, &matrix, fTileMode,
                                          args.fDstColorSpaceInfo->colorSpace()));
 }
 
diff --git a/src/shaders/gradients/SkTwoPointConicalGradient_gpu.cpp b/src/shaders/gradients/SkTwoPointConicalGradient_gpu.cpp
index c242895f1c..9d447785ed 100644
--- a/src/shaders/gradients/SkTwoPointConicalGradient_gpu.cpp
+++ b/src/shaders/gradients/SkTwoPointConicalGradient_gpu.cpp
@@ -388,18 +388,7 @@ std::unique_ptr<GrFragmentProcessor> Gr2PtConicalGradientEffect::Make(
     const SkTwoPointConicalGradient& shader =
         *static_cast<const SkTwoPointConicalGradient*>(args.fShader);
 
-    SkMatrix matrix;
-    if (!shader.getLocalMatrix().invert(&matrix)) {
-        return nullptr;
-    }
-    if (args.fMatrix) {
-        SkMatrix inv;
-        if (!args.fMatrix->invert(&inv)) {
-            return nullptr;
-        }
-        matrix.postConcat(inv);
-    }
-
+    SkMatrix matrix = *args.fMatrix;
     GrGradientEffect::CreateArgs newArgs(args.fContext, args.fShader, &matrix, args.fWrapMode,
         args.fDstColorSpace);
     // Data and matrix has to be prepared before constructing TwoPointConicalEffect so its parent