add SkRecordOptimize2 and an experimental API for more aggressive opts

src/core/SkRecordOpts.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkRecordOpts.h"
 
 #include "SkRecordPattern.h"
 #include "SkRecords.h"
 #include "SkTDArray.h"
 
 using namespace SkRecords;
 
-void SkRecordOptimize(SkRecord* record) {
-    // This might be useful  as a first pass in the future if we want to weed
-    // out junk for other optimization passes.  Right now, nothing needs it,
-    // and the bounding box hierarchy will do the work of skipping no-op
-    // Save-NoDraw-Restore sequences better than we can here.
-    //SkRecordNoopSaveRestores(record);
-
-    SkRecordNoopSaveLayerDrawRestores(record);
-    SkRecordMergeSvgOpacityAndFilterLayers(record);
-}
-
 // Most of the optimizations in this file are pattern-based.  These are all defined as structs with:
 //   - a Pattern typedef
 //   - a bool onMatch(SkRceord*, Pattern*, int begin, int end) method,
 //     which returns true if it made changes and false if not.
 
 // Run a pattern-based optimization once across the SkRecord, returning true if it made any changes.
 // It looks for spans which match Pass::Pattern, and when found calls onMatch() with the pattern,
 // record, and [begin,end) span of the commands that matched.
 template <typename Pass>
 static bool apply(Pass* pass, SkRecord* record) {
     typename Pass::Pattern pattern;
     bool changed = false;
     int begin, end = 0;
 
     while (pattern.search(record, &begin, &end)) {
         changed |= pass->onMatch(record, &pattern, begin, end);
     }
     return changed;
 }
 
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+static void multiple_set_matrices(SkRecord* record) {
+    struct {
+        typedef Pattern3<Is<SetMatrix>,

[mtklein, 2015/11/19 17:39:22]

Sorry, moved the goalposts.

This is now

typedef Pattern<Is<SetMatrix>,
                Greedy<Is<NoOp>>,
                Is<SetMatrix>>
    Match;

bool onMatch(SkRecord* record, Match*, int begin, int) {
    record->replace<NoOp>(begin);  // first SetMatrix
    return true;
}

+                         Star<Is<NoOp>>,
+                         Is<SetMatrix> >
+            Pattern;
+
+        bool onMatch(SkRecord* record, Pattern* pattern, int begin, int end) {
+            record->replace<NoOp>(begin);  // first SetMatrix
+            return true;
+        }
+    } pass;
+    // No need to loop, as we never "open up" opportunities for more of this type of optimization.

[mtklein, 2015/11/19 17:39:22]

I do think this is still true that a single pass gets everything.  E.g.,

   [SetMatrix      NoOp   SetMatrix] SetMatrix  ...
->       NoOp      NoOp   SetMatrix  SetMatrix  ...
->       NoOp      NoOp  [SetMatrix  SetMatrix] ...
->       NoOp      NoOp      NoOp    SetMatrix  ...

But it probably does not hurt to wrap it in a while(...) anyway.
If nothing else, it means we don't have trust we've thought this through
correctly.

+    apply(&pass, record);
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+#if 0   // experimental, but needs knowledge of previous matrix to operate correctly
+static void apply_matrix_to_draw_params(SkRecord* record) {
+    struct {
+        typedef Pattern3<Is<SetMatrix>,
+                         Is<DrawBitmapRect>,
+                         Is<Restore> >
+            Pattern;
+
+        bool onMatch(SkRecord* record, Pattern* pattern, int begin, int end) {
+            const SkMatrix& m = pattern->first<SetMatrix>()->matrix;
+            if (m.getType() > (SkMatrix::kScale_Mask | SkMatrix::kTranslate_Mask)) {
+                SkDebugf("too complex\n");
+                return false;   // can't handle rotation or perspective
+            }
+            if (m.getScaleX() < 0 || m.getScaleY() < 0) {
+                SkDebugf("negative\n");
+                return false;   // can't represent a flip in a rect
+            }
+            DrawBitmapRect* dbr = pattern->second<DrawBitmapRect>();
+            m.dump();
+            // wack the rect, and eliminate the matrix
+            m.mapRect(&dbr->dst);
+            record->replace<NoOp>(begin);
+            return true;
+        }
+    } pass;
+    apply(&pass, record);
+}
+#endif
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
 // Turns the logical NoOp Save and Restore in Save-Draw*-Restore patterns into actual NoOps.
 struct SaveOnlyDrawsRestoreNooper {
     typedef Pattern3<Is<Save>,
                      Star<Or<Is<NoOp>, IsDraw> >,
                      Is<Restore> >
         Pattern;
 
     bool onMatch(SkRecord* record, Pattern* pattern, int begin, int end) {
         record->replace<NoOp>(begin);  // Save
         record->replace<NoOp>(end-1);  // Restore
@@ skipping 166 matching lines @@
         record->replace<NoOp>(saveLayerIndex);     // SaveLayer
         record->replace<NoOp>(saveLayerIndex + 6); // Restore
         return true;
     }
 };
 
 void SkRecordMergeSvgOpacityAndFilterLayers(SkRecord* record) {
     SvgOpacityAndFilterLayerMergePass pass;
     apply(&pass, record);
 }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+void SkRecordOptimize(SkRecord* record) {
+    // This might be useful  as a first pass in the future if we want to weed
+    // out junk for other optimization passes.  Right now, nothing needs it,
+    // and the bounding box hierarchy will do the work of skipping no-op
+    // Save-NoDraw-Restore sequences better than we can here.
+    //SkRecordNoopSaveRestores(record);
+
+    SkRecordNoopSaveLayerDrawRestores(record);
+    SkRecordMergeSvgOpacityAndFilterLayers(record);
+}
+
+void SkRecordOptimize2(SkRecord* record) {
+    multiple_set_matrices(record);
+
+    SkRecordNoopSaveRestores(record);
+
+    SkRecordNoopSaveLayerDrawRestores(record);
+    SkRecordMergeSvgOpacityAndFilterLayers(record);
+}
+