Shrink saveLayer device bounds when it supplies an explicit bounds and has a complex paint

src/core/SkRecordDraw.cpp

Index: src/core/SkRecordDraw.cpp
diff --git a/src/core/SkRecordDraw.cpp b/src/core/SkRecordDraw.cpp
index ad1327016b82de3351ba410b4c4238a34218f452..95bad046e34d76ab001efa5dd92c798cc554e814 100644
--- a/src/core/SkRecordDraw.cpp
+++ b/src/core/SkRecordDraw.cpp
@@ -144,11 +144,12 @@ static const SkRect kUnbounded = { -2e9f, -2e9f, 2e9f, 2e9f };
 // in for all the control ops we stashed away.
 class FillBounds : SkNoncopyable {
 public:
-    FillBounds(const SkRecord& record, SkBBoxHierarchy* bbh) : fBounds(record.count()) {
+    FillBounds(const SkRect& cullRect, const SkRecord& record, SkBBoxHierarchy* bbh) 
+        : fBounds(record.count()) {
         // Calculate bounds for all ops.  This won't go quite in order, so we'll need
         // to store the bounds separately then feed them in to the BBH later in order.
         fCTM = &SkMatrix::I();
-        fCurrentClipBounds = kUnbounded;
+        fCurrentClipBounds = cullRect;

[mtklein, 2014/10/31 18:21:01]

This seems an orthogonal change.  Might stick to kUnbounded for now and we
exploit the cull rect separately?  If we're going to use it, we might as well
use it everywhere we use kUnbounded.

I'm not sure we want to use the cull like this until we have an API that lets
the users pass it as a full rect instead of a width/height.  We're disabling the
(perhaps unintentional) feature of being able to draw in negative space if we
do.

         for (fCurrentOp = 0; fCurrentOp < record.count(); fCurrentOp++) {
             record.visit<void>(fCurrentOp, *this);
         }
@@ -253,7 +254,14 @@ private:
 
     void pushSaveBlock(const SkPaint* paint) {
         // Starting a new Save block.  Push a new entry to represent that.
-        SaveBounds sb = { 0, Bounds::MakeEmpty(), paint };
+        SaveBounds sb;
+        sb.controlOps = 0;
+        // If the paint affects transparent black, the bound shouldn't be smaller
+        // then the current clip bounds.	
+        sb.bounds =
+            PaintMayAffectTransparentBlack(paint) ? fCurrentClipBounds : Bounds::MakeEmpty();
+        sb.paint = paint;
+
         fSaveStack.push(sb);
         this->pushControl();
     }
@@ -303,19 +311,15 @@ private:
         SaveBounds sb;
         fSaveStack.pop(&sb);
 
-        // If the paint affects transparent black, we can't trust any of our calculated bounds.
-        const Bounds& bounds =
-            PaintMayAffectTransparentBlack(sb.paint) ? fCurrentClipBounds : sb.bounds;
-
         while (sb.controlOps --> 0) {
-            this->popControl(bounds);
+            this->popControl(sb.bounds);
         }
 
         // This whole Save block may be part another Save block.
-        this->updateSaveBounds(bounds);
+        this->updateSaveBounds(sb.bounds);
 
         // If called from a real Restore (not a phony one for balance), it'll need the bounds.
-        return bounds;
+        return sb.bounds;
     }
 
     void pushControl() {
@@ -554,6 +558,6 @@ private:
 
 }  // namespace SkRecords
 
-void SkRecordFillBounds(const SkRecord& record, SkBBoxHierarchy* bbh) {
-    SkRecords::FillBounds(record, bbh);
+void SkRecordFillBounds(const SkRect& cullRect, const SkRecord& record, SkBBoxHierarchy* bbh) {
+    SkRecords::FillBounds(cullRect, record, bbh);
 }