Add SaveLayer-Draw-Restore optimization.

tests/RecordOptsTest.cpp

Index: tests/RecordOptsTest.cpp
diff --git a/tests/RecordOptsTest.cpp b/tests/RecordOptsTest.cpp
index 260b97b3e8535a48c4c517e88c66ec10a9edf46c..90347eda1f5836a64b7cfa6d21bb9f2fe5e2c3df 100644
--- a/tests/RecordOptsTest.cpp
+++ b/tests/RecordOptsTest.cpp
@@ -12,6 +12,8 @@
 #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.
@@ -151,3 +153,76 @@ DEF_TEST(RecordOpts_NoopSaveRestores, r) {
     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);
+}