Add layer counting to SkPictureRecord

This will be used for a SkPicture::suitableForOptimization entry point.

R=bsalomon@google.com

Author: robertphillips@google.com

Review URL: https://codereview.chromium.org/464433002

5 files changed, 122 insertions, 5 deletions

diff --git a/src/core/SkPictureContentInfo.cpp b/src/core/SkPictureContentInfo.cpp
index 8185d850b8..1d19f352f4 100644
--- a/src/core/SkPictureContentInfo.cpp
+++ b/src/core/SkPictureContentInfo.cpp
@@ -71,6 +71,62 @@ void SkPictureContentInfo::onAddPaintPtr(const SkPaint* paint) {
     }
 }
 
+void SkPictureContentInfo::onSaveLayer() {
+    *fSaveStack.append() = kSaveLayer_Flag;
+}
+
+void SkPictureContentInfo::onSave() {
+    *fSaveStack.append() = kSave_Flag;
+}
+
+void SkPictureContentInfo::onRestore() {
+    SkASSERT(fSaveStack.count() > 0);
+
+    bool containedSaveLayer = fSaveStack.top() & kContainedSaveLayer_Flag;
+
+    if (fSaveStack.top() & kSaveLayer_Flag) {
+        ++fNumLayers;
+        if (containedSaveLayer) {
+            ++fNumInteriorLayers;
+        } else {
+            ++fNumLeafLayers;
+        }
+        containedSaveLayer = true;
+    }
+
+    fSaveStack.pop();
+
+    if (containedSaveLayer && fSaveStack.count() > 0) {
+        fSaveStack.top() |= kContainedSaveLayer_Flag;
+    }
+}
+
+void SkPictureContentInfo::rescindLastSave() {
+    SkASSERT(fSaveStack.count() > 0);
+    SkASSERT(fSaveStack.top() & kSave_Flag);
+
+    bool containedSaveLayer = fSaveStack.top() & kContainedSaveLayer_Flag;
+
+    fSaveStack.pop();
+
+    if (containedSaveLayer && fSaveStack.count() > 0) {
+        fSaveStack.top() |= kContainedSaveLayer_Flag;
+    }
+}
+
+void SkPictureContentInfo::rescindLastSaveLayer() {
+    SkASSERT(fSaveStack.count() > 0);
+    SkASSERT(fSaveStack.top() & kSaveLayer_Flag);
+
+    bool containedSaveLayer = fSaveStack.top() & kContainedSaveLayer_Flag;
+
+    fSaveStack.pop();
+
+    if (containedSaveLayer && fSaveStack.count() > 0) {
+        fSaveStack.top() |= kContainedSaveLayer_Flag;
+    }
+}
+
 void SkPictureContentInfo::set(const SkPictureContentInfo& src) {
     fNumOperations = src.fNumOperations;
     fNumTexts = src.fNumTexts;
@@ -78,6 +134,10 @@ void SkPictureContentInfo::set(const SkPictureContentInfo& src) {
     fNumFastPathDashEffects = src.fNumFastPathDashEffects;
     fNumAAConcavePaths = src.fNumAAConcavePaths;
     fNumAAHairlineConcavePaths = src.fNumAAHairlineConcavePaths;
+    fNumLayers = src.fNumLayers;
+    fNumInteriorLayers = src.fNumInteriorLayers;
+    fNumLeafLayers = src.fNumLeafLayers;
+    fSaveStack = src.fSaveStack;
 }
 
 void SkPictureContentInfo::reset() {
@@ -87,6 +147,10 @@ void SkPictureContentInfo::reset() {
     fNumFastPathDashEffects = 0;
     fNumAAConcavePaths = 0;
     fNumAAHairlineConcavePaths = 0;
+    fNumLayers = 0;
+    fNumInteriorLayers = 0;
+    fNumLeafLayers = 0;
+    fSaveStack.rewind();
 }
 
 void SkPictureContentInfo::swap(SkPictureContentInfo* other) {
@@ -96,4 +160,8 @@ void SkPictureContentInfo::swap(SkPictureContentInfo* other) {
     SkTSwap(fNumFastPathDashEffects, other->fNumFastPathDashEffects);
     SkTSwap(fNumAAConcavePaths, other->fNumAAConcavePaths);
     SkTSwap(fNumAAHairlineConcavePaths, other->fNumAAHairlineConcavePaths);
+    SkTSwap(fNumLayers, other->fNumLayers);
+    SkTSwap(fNumInteriorLayers, other->fNumInteriorLayers);
+    SkTSwap(fNumLeafLayers, other->fNumLeafLayers);
+    fSaveStack.swap(other->fSaveStack);
 }
diff --git a/src/core/SkPictureContentInfo.h b/src/core/SkPictureContentInfo.h
index cfeedcf483..d4d1d4fc5f 100644
--- a/src/core/SkPictureContentInfo.h
+++ b/src/core/SkPictureContentInfo.h
@@ -17,6 +17,11 @@ public:
 
     int numOperations() const { return fNumOperations; }
     bool hasText() const { return fNumTexts > 0; }
+
+    int numLayers() const { return fNumLayers; }
+    int numInteriorLayers() const { return fNumInteriorLayers; }
+    int numLeafLayers() const { return fNumLeafLayers; }
+
     bool suitableForGpuRasterization(GrContext* context, const char **reason,
                                      int sampleCount) const;
 
@@ -27,6 +32,12 @@ public:
     void onAddPaintPtr(const SkPaint* paint);
     void onDrawText() { ++fNumTexts; }
 
+    void onSaveLayer();
+    void onSave();
+    void onRestore();
+    void rescindLastSave();
+    void rescindLastSaveLayer();
+
     void set(const SkPictureContentInfo& src);
     void reset();
     void swap(SkPictureContentInfo* other);
@@ -49,6 +60,25 @@ private:
     // This field is incremented every time a drawPath call is
     // issued for a hairline stroked concave path.
     int fNumAAHairlineConcavePaths;
+    // These fields track the different layer flavors. fNumLayers is just
+    // a count of all saveLayers, fNumInteriorLayers is the number of layers
+    // with a layer inside them, fNumLeafLayers is the number of layers with
+    // no layer inside them.
+    int fNumLayers;
+    int fNumInteriorLayers;
+    int fNumLeafLayers;
+
+    enum Flags {
+        kSave_Flag      = 0x1,
+        kSaveLayer_Flag = 0x2,
+
+        // Did the current save or saveLayer contain another saveLayer.
+        // Percolated back down the save stack.
+        kContainedSaveLayer_Flag = 0x4
+    };
+
+    // Stack of save vs saveLayer information to track nesting
+    SkTDArray<uint32_t> fSaveStack;
 };
 
 #endif
diff --git a/src/core/SkPictureData.cpp b/src/core/SkPictureData.cpp
index 140ca88b34..ea9da79aa3 100644
--- a/src/core/SkPictureData.cpp
+++ b/src/core/SkPictureData.cpp
@@ -617,6 +617,9 @@ bool SkPictureData::suitableForGpuRasterization(GrContext* context, const char *
     }
 }
 
+bool SkPictureData::suitableForLayerOptimization() const {
+    return fContentInfo.numLayers() > 0;
+}
 #endif
 ///////////////////////////////////////////////////////////////////////////////
 
diff --git a/src/core/SkPictureData.h b/src/core/SkPictureData.h
index e3f3d020e6..3e3ab59a44 100644
--- a/src/core/SkPictureData.h
+++ b/src/core/SkPictureData.h
@@ -150,6 +150,8 @@ public:
      */
     bool suitableForGpuRasterization(GrContext* context, const char **reason,
                                      GrPixelConfig config, SkScalar dpi) const;
+
+    bool suitableForLayerOptimization() const;
 #endif
 
 private:
diff --git a/src/core/SkPictureRecord.cpp b/src/core/SkPictureRecord.cpp
index d9239ddcca..fc0b291912 100644
--- a/src/core/SkPictureRecord.cpp
+++ b/src/core/SkPictureRecord.cpp
@@ -151,6 +151,8 @@ void SkPictureRecord::willSave() {
 }
 
 void SkPictureRecord::recordSave() {
+    fContentInfo.onSave();
+
     // op only
     size_t size = kSaveSize;
     size_t initialOffset = this->addDraw(SAVE, &size);
@@ -179,6 +181,8 @@ SkCanvas::SaveLayerStrategy SkPictureRecord::willSaveLayer(const SkRect* bounds,
 
 void SkPictureRecord::recordSaveLayer(const SkRect* bounds, const SkPaint* paint,
                                       SaveFlags flags) {
+    fContentInfo.onSaveLayer();
+
     // op + bool for 'bounds'
     size_t size = 2 * kUInt32Size;
     if (NULL != bounds) {
@@ -508,8 +512,10 @@ enum PictureRecordOptType {
 };
 
 enum PictureRecordOptFlags {
-    kSkipIfBBoxHierarchy_Flag = 0x1,  // Optimization should be skipped if the
-                                      // SkPicture has a bounding box hierarchy.
+    kSkipIfBBoxHierarchy_Flag  = 0x1,  // Optimization should be skipped if the
+                                       // SkPicture has a bounding box hierarchy.
+    kRescindLastSave_Flag      = 0x2,
+    kRescindLastSaveLayer_Flag = 0x4,
 };
 
 struct PictureRecordOpt {
@@ -528,9 +534,10 @@ static const PictureRecordOpt gPictureRecordOpts[] = {
     // SkPictureStateTree, and applying the optimization introduces significant
     // record time overhead because it requires rewinding contents that were
     // recorded into the BBoxHierarchy.
-    { collapse_save_clip_restore, kRewind_OptType, kSkipIfBBoxHierarchy_Flag },
-    { remove_save_layer1,         kCollapseSaveLayer_OptType, 0 },
-    { remove_save_layer2,         kCollapseSaveLayer_OptType, 0 }
+    { collapse_save_clip_restore, kRewind_OptType, 
+                                                kSkipIfBBoxHierarchy_Flag|kRescindLastSave_Flag },
+    { remove_save_layer1,         kCollapseSaveLayer_OptType, kRescindLastSaveLayer_Flag },
+    { remove_save_layer2,         kCollapseSaveLayer_OptType, kRescindLastSaveLayer_Flag }
 };
 
 // This is called after an optimization has been applied to the command stream
@@ -585,6 +592,11 @@ void SkPictureRecord::willRestore() {
                 // Some optimization fired so don't add the RESTORE
                 apply_optimization_to_bbh(gPictureRecordOpts[opt].fType,
                                           fStateTree, fBoundingHierarchy);
+                if (gPictureRecordOpts[opt].fFlags & kRescindLastSave_Flag) {
+                    fContentInfo.rescindLastSave();
+                } else if (gPictureRecordOpts[opt].fFlags & kRescindLastSaveLayer_Flag) {
+                    fContentInfo.rescindLastSaveLayer();
+                } 
                 break;
             }
         }
@@ -601,6 +613,8 @@ void SkPictureRecord::willRestore() {
 }
 
 void SkPictureRecord::recordRestore(bool fillInSkips) {
+    fContentInfo.onRestore();
+
     if (fillInSkips) {
         this->fillRestoreOffsetPlaceholdersForCurrentStackLevel((uint32_t)fWriter.bytesWritten());
     }