First version of bitmap use tracking in SkPictureRecord

src/core/SkPicturePlayback.cpp

Index: src/core/SkPicturePlayback.cpp
===================================================================
--- src/core/SkPicturePlayback.cpp	(revision 13686)
+++ src/core/SkPicturePlayback.cpp	(working copy)
@@ -5,15 +5,16 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
+#include <new>
+#include "SkBBoxHierarchy.h"
+#include "SkOffsetTable.h"
 #include "SkPicturePlayback.h"
 #include "SkPictureRecord.h"
+#include "SkPictureStateTree.h"
+#include "SkReadBuffer.h"
 #include "SkTypeface.h"
-#include "SkReadBuffer.h"
+#include "SkTSort.h"
 #include "SkWriteBuffer.h"
-#include <new>
-#include "SkBBoxHierarchy.h"
-#include "SkPictureStateTree.h"
-#include "SkTSort.h"
 
 template <typename T> int SafeCount(const T* obj) {
     return obj ? obj->count() : 0;
@@ -101,6 +102,8 @@
     fBitmapHeap.reset(SkSafeRef(record.fBitmapHeap));
     fPathHeap.reset(SkSafeRef(record.fPathHeap));
 
+    fBitmapUseOffsets.reset(SkSafeRef(record.fBitmapUseOffsets.get()));
+
     // ensure that the paths bounds are pre-computed
     if (fPathHeap.get()) {
         for (int i = 0; i < fPathHeap->count(); i++) {
@@ -718,6 +721,50 @@
     return (DrawType) op;
 }
 
+// The activeOps parameter is actually "const SkTDArray<SkPictureStateTree::Draw*>&".
+// It represents the operations about to be drawn, as generated by some spatial
+// subdivision helper class. It should already be in 'fOffset' sorted order.
+void SkPicturePlayback::preLoadBitmaps(const SkTDArray<void*>& activeOps) {
+    if (0 == activeOps.count() || NULL == fBitmapUseOffsets) {
+        return;
+    }
+
+    SkTDArray<int> active;
+
+    SkAutoTDeleteArray<bool> needToCheck(new bool[fBitmapUseOffsets->numIDs()]);
+    for (int i = 0; i < fBitmapUseOffsets->numIDs(); ++i) {
+        needToCheck.get()[i] = true;
+    }
+
+    uint32_t max = ((SkPictureStateTree::Draw*)activeOps[activeOps.count()-1])->fOffset;
+
+    for (int i = 0; i < activeOps.count(); ++i) {
+        SkPictureStateTree::Draw* draw = (SkPictureStateTree::Draw*) activeOps[i];
+
+        for (int j = 0; j < fBitmapUseOffsets->numIDs(); ++j) {
+            if (!needToCheck.get()[j]) {
+                continue;
+            }
+
+            if (!fBitmapUseOffsets->overlap(j, draw->fOffset, max)) {
+                needToCheck.get()[j] = false;
+                continue;
+            }
+
+            if (!fBitmapUseOffsets->includes(j, draw->fOffset)) {
+                continue;
+            }
+
+            *active.append() = j;
+            needToCheck.get()[j] = false;
+        }
+    }
+
+    for (int i = 0; i < active.count(); ++i) {
+        SkDebugf("preload texture %d\n", active[i]);
+    }
+}
+
 void SkPicturePlayback::draw(SkCanvas& canvas, SkDrawPictureCallback* callback) {
 #ifdef ENABLE_TIME_DRAW
     SkAutoTime  at("SkPicture::draw", 50);
@@ -738,26 +785,26 @@
 
     SkReader32 reader(fOpData->bytes(), fOpData->size());
     TextContainer text;
-    SkTDArray<void*> results;
+    SkTDArray<void*> activeOps;
 
     if (NULL != fStateTree && NULL != fBoundingHierarchy) {
         SkRect clipBounds;
         if (canvas.getClipBounds(&clipBounds)) {
             SkIRect query;
             clipBounds.roundOut(&query);
-            fBoundingHierarchy->search(query, &results);
-            if (results.count() == 0) {
+            fBoundingHierarchy->search(query, &activeOps);
+            if (activeOps.count() == 0) {
                 return;
             }
             SkTQSort<SkPictureStateTree::Draw>(
-                reinterpret_cast<SkPictureStateTree::Draw**>(results.begin()),
-                reinterpret_cast<SkPictureStateTree::Draw**>(results.end()-1));
+                reinterpret_cast<SkPictureStateTree::Draw**>(activeOps.begin()),
+                reinterpret_cast<SkPictureStateTree::Draw**>(activeOps.end()-1));
         }
     }
 
     SkPictureStateTree::Iterator it = (NULL == fStateTree) ?
         SkPictureStateTree::Iterator() :
-        fStateTree->getIterator(results, &canvas);
+        fStateTree->getIterator(activeOps, &canvas);
 
     if (it.isValid()) {
         uint32_t skipTo = it.draw();
@@ -767,6 +814,8 @@
         reader.setOffset(skipTo);
     }
 
+    this->preLoadBitmaps(activeOps);
+
     // Record this, so we can concat w/ it if we encounter a setMatrix()
     SkMatrix initialMatrix = canvas.getTotalMatrix();
     int originalSaveCount = canvas.getSaveCount();