allow imagefilter to manage CTM decomposition

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1908173006

Review URL: https://codereview.chromium.org/1908173006

3 files changed, 25 insertions, 2 deletions

diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index 89c3c9e006..f8731e9ad2 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -1217,8 +1217,7 @@ void SkCanvas::internalSaveLayer(const SaveLayerRec& rec, SaveLayerStrategy stra
      *  Perhaps in the future we could augment #5 to apply REMAINDER as part of the draw (no longer
      *  a sprite operation) to avoid the extra buffer/overhead of MatrixImageFilter.
      */
-    if (imageFilter &&
-        !stashedMatrix.isScaleTranslate() &&
+    if (imageFilter && !stashedMatrix.isScaleTranslate() && !imageFilter->canHandleAffine() &&
         stashedMatrix.decomposeScale(&scale, &remainder))
     {
         // We will restore the matrix (which we are overwriting here) in restore via fStashedMatrix
diff --git a/src/core/SkImageFilter.cpp b/src/core/SkImageFilter.cpp
index 4128ba6cc2..6c73be29b5 100644
--- a/src/core/SkImageFilter.cpp
+++ b/src/core/SkImageFilter.cpp
@@ -330,6 +330,24 @@ bool SkImageFilter::asAColorFilter(SkColorFilter** filterPtr) const {
     return true;
 }
 
+bool SkImageFilter::onCanHandleAffine() const {
+    bool hasInputs = false;
+
+    const int count = this->countInputs();
+    for (int i = 0; i < count; ++i) {
+        SkImageFilter* input = this->getInput(i);
+        if (input) {
+            if (!input->canHandleAffine()) {
+                return false;
+            }
+            hasInputs = true;
+        }
+    }
+    // We return true iff we had 1 or more inputs, and all of them can handle affine.
+    // If we have no inputs, or 1 or more of them do not handle affine, then we return false.
+    return hasInputs;
+}
+
 bool SkImageFilter::applyCropRect(const Context& ctx, const SkIRect& srcBounds,
                                   SkIRect* dstBounds) const {
     SkIRect temp = this->onFilterNodeBounds(srcBounds, ctx.ctm(), kForward_MapDirection);
diff --git a/src/effects/SkColorFilterImageFilter.cpp b/src/effects/SkColorFilterImageFilter.cpp
index 8d412cc2f5..7a2f4cc2ab 100644
--- a/src/effects/SkColorFilterImageFilter.cpp
+++ b/src/effects/SkColorFilterImageFilter.cpp
@@ -126,6 +126,12 @@ bool SkColorFilterImageFilter::onIsColorFilterNode(SkColorFilter** filter) const
     return false;
 }
 
+bool SkColorFilterImageFilter::onCanHandleAffine() const {
+    SkASSERT(1 == this->countInputs());
+    SkImageFilter* input = this->getInput(0);
+    return !input || input->canHandleAffine();
+}
+
 bool SkColorFilterImageFilter::affectsTransparentBlack() const {
     return fColorFilter->affectsTransparentBlack();
 }