Fix SkLocalMatrixShader::isAImage() to respect local matrix and image local matrix

Fixes cts tests.

b/37161109
b/37237678

Bug: skia:
Change-Id: Ida9ac5e4261e8a6b22e8cdc0e585e0e7929dbbfd
Reviewed-on: https://skia-review.googlesource.com/13249
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>

2 files changed, 12 insertions, 3 deletions

diff --git a/src/core/SkLocalMatrixShader.cpp b/src/core/SkLocalMatrixShader.cpp
index 9d9e109fcb..22eb0fec93 100644
--- a/src/core/SkLocalMatrixShader.cpp
+++ b/src/core/SkLocalMatrixShader.cpp
@@ -51,6 +51,17 @@ SkShader::Context* SkLocalMatrixShader::onMakeContext(
     return fProxyShader->makeContext(newRec, alloc);
 }
 
+SkImage* SkLocalMatrixShader::onIsAImage(SkMatrix* outMatrix, enum TileMode* mode) const {
+    SkMatrix imageMatrix;
+    SkImage* image = fProxyShader->isAImage(&imageMatrix, mode);
+    if (outMatrix) {
+        // Local matrix must be applied first so it is on the right side of the concat.
+        *outMatrix = SkMatrix::Concat(imageMatrix, this->getLocalMatrix());
+    }
+
+    return image;
+}
+
 bool SkLocalMatrixShader::onAppendStages(SkRasterPipeline* p,
                                          SkColorSpace* dst,
                                          SkArenaAlloc* scratch,
diff --git a/src/core/SkLocalMatrixShader.h b/src/core/SkLocalMatrixShader.h
index 5c0424053b..cba140906b 100644
--- a/src/core/SkLocalMatrixShader.h
+++ b/src/core/SkLocalMatrixShader.h
@@ -45,9 +45,7 @@ protected:
 
     Context* onMakeContext(const ContextRec&, SkArenaAlloc*) const override;
 
-    SkImage* onIsAImage(SkMatrix* matrix, TileMode* mode) const override {
-        return fProxyShader->isAImage(matrix, mode);
-    }
+    SkImage* onIsAImage(SkMatrix* matrix, TileMode* mode) const override;
 
     bool onAppendStages(SkRasterPipeline*, SkColorSpace*, SkArenaAlloc*,
                         const SkMatrix&, const SkPaint&, const SkMatrix*) const override;