Add SaveLayer-Draw-Restore optimization.

tests/RecordOptsTest.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 "Test.h"
 
 #include "SkRecord.h"
 #include "SkRecordOpts.h"
 #include "SkRecorder.h"
 #include "SkRecords.h"
 
+#include "SkXfermode.h"
+
 static const int W = 1920, H = 1080;
 
 // If the command we're reading is a U, set ptr to it, otherwise set it to NULL.
 template <typename U>
 struct ReadAs {
     explicit ReadAs(const U** ptr) : ptr(ptr), type(SkRecords::Type(~0)) {}
 
     const U** ptr;
     SkRecords::Type type;
 
@@ skipping 119 matching lines @@
 
     SkRecordNoopSaveRestores(&record);
 
     for (unsigned index = 0; index < 8; index++) {
         assert_type<SkRecords::NoOp>(r, record, index);
     }
     assert_type<SkRecords::Save>(r, record, 8);
     assert_type<SkRecords::DrawRect>(r, record, 9);
     assert_type<SkRecords::Restore>(r, record, 10);
 }
+
+static void assert_savelayer_restore(skiatest::Reporter* r,
+                                     SkRecord* record,
+                                     unsigned i,
+                                     bool shouldBeNoOped) {
+    SkRecordNoopSaveLayerDrawRestores(record);
+    if (shouldBeNoOped) {
+        assert_type<SkRecords::NoOp>(r, *record, i);
+        assert_type<SkRecords::NoOp>(r, *record, i+2);
+    } else {
+        assert_type<SkRecords::SaveLayer>(r, *record, i);
+        assert_type<SkRecords::Restore>(r, *record, i+2);
+    }
+}
+

[robertphillips, 2014/05/07 14:28:15]

Not for this CL but, at some point we should render before and after tiles and
compare the colors.

[mtklein, 2014/05/07 14:38:14]

Yup, I think we're already covered.  We run SkRecord with and without
optimization in DM, comparing that both are identical to the direct raster
bitmap (and thus, to each other).  This pattern seems to be tested pretty
thoroughly by gm/optimizations, so we get all those before/after tests for free
here too.

I'm planning to also add a SKP-as-GM mode to DM so we can just toss in tricky
SKPs as an quick way to extend the tested set.

+DEF_TEST(RecordOpts_NoopSaveLayerDrawRestore, r) {
+    SkRecord record;
+    SkRecorder recorder(SkRecorder::kWriteOnly_Mode, &record, W, H);
+
+    SkRect bounds = SkRect::MakeWH(100, 200);
+    SkRect   draw = SkRect::MakeWH(50, 60);
+
+    SkPaint goodLayerPaint, badLayerPaint, worseLayerPaint;
+    goodLayerPaint.setColor(0x03000000);  // Only alpha.
+    badLayerPaint.setColor( 0x03040506);  // Not only alpha.
+    worseLayerPaint.setXfermodeMode(SkXfermode::kDstIn_Mode);  // Any effect will do.
+
+    SkPaint goodDrawPaint, badDrawPaint;
+    goodDrawPaint.setColor(0xFF020202);  // Opaque.
+    badDrawPaint.setColor( 0x0F020202);  // Not opaque.
+
+    // No change: optimization can't handle bounds.
+    recorder.saveLayer(&bounds, NULL);
+        recorder.drawRect(draw, goodDrawPaint);
+    recorder.restore();
+    assert_savelayer_restore(r, &record, 0, false);
+
+    // SaveLayer/Restore removed: no bounds + no paint = no point.
+    recorder.saveLayer(NULL, NULL);
+        recorder.drawRect(draw, goodDrawPaint);
+    recorder.restore();
+    assert_savelayer_restore(r, &record, 3, true);
+
+    // TODO(mtklein): test case with null draw paint
+
+    // No change: layer paint isn't alpha-only.
+    recorder.saveLayer(NULL, &badLayerPaint);
+        recorder.drawRect(draw, goodDrawPaint);
+    recorder.restore();
+    assert_savelayer_restore(r, &record, 6, false);
+
+    // No change: layer paint has an effect.
+    recorder.saveLayer(NULL, &worseLayerPaint);
+        recorder.drawRect(draw, goodDrawPaint);
+    recorder.restore();
+    assert_savelayer_restore(r, &record, 9, false);
+
+    // No change: draw paint isn't opaque.
+    recorder.saveLayer(NULL, &goodLayerPaint);
+        recorder.drawRect(draw, badDrawPaint);
+    recorder.restore();
+    assert_savelayer_restore(r, &record, 12, false);
+
+    // SaveLayer/Restore removed: we can fold in the alpha!
+    recorder.saveLayer(NULL, &goodLayerPaint);
+        recorder.drawRect(draw, goodDrawPaint);
+    recorder.restore();
+    assert_savelayer_restore(r, &record, 15, true);
+
+    const SkRecords::DrawRect* drawRect = assert_type<SkRecords::DrawRect>(r, record, 16);
+    REPORTER_ASSERT(r, drawRect != NULL);
+    REPORTER_ASSERT(r, drawRect->paint.getColor() == 0x03020202);
+}