DM: add --tileGrid

dm/DMTileGridTask.cpp

Index: dm/DMTileGridTask.cpp
diff --git a/dm/DMTileGridTask.cpp b/dm/DMTileGridTask.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..67cbbd924af25f7938ffeafd28702515d9c81504
--- /dev/null
+++ b/dm/DMTileGridTask.cpp
@@ -0,0 +1,77 @@
+#include "DMTileGridTask.h"
+#include "DMWriteTask.h"
+#include "DMUtil.h"
+
+#include "SkCommandLineFlags.h"
+#include "SkPicture.h"
+#include "SkTileGridPicture.h"
+
+// TODO(mtklein): Tile grid tests are currently failing.  (Skia issue 1198).  When fixed, -> true.
+DEFINE_bool(tileGrid, false, "If true, run picture replay tests with a tile grid.");
+
+namespace DM {
+
+TileGridTask::TileGridTask(const Task& parent, skiagm::GM* gm, SkBitmap reference, SkISize tileSize)
+    : Task(parent)
+    , fName(UnderJoin(parent.name().c_str(), "tilegrid"))
+    , fGM(gm)
+    , fReference(reference)
+    , fTileSize(tileSize)
+    {}
+
+static int tiles_needed(int fullDimension, int tileDimension) {
+    return (fullDimension + tileDimension - 1) / tileDimension;
+}
+
+void TileGridTask::draw() {
+    const SkTileGridPicture::TileGridInfo info = {
+        fTileSize,
+        SkISize::Make(0,0),   // Overlap between adjacent tiles.
+        SkIPoint::Make(0,0),  // Offset.
+    };
+    const SkISize size = fGM->getISize();
+    SkTileGridPicture recorded(size.width(), size.height(), info);
+    RecordPicture(fGM.get(), &recorded, SkPicture::kUsePathBoundsForClip_RecordingFlag);
+
+    SkBitmap full;
+    SetupBitmap(fReference.config(), fGM.get(), &full);
+    SkCanvas fullCanvas(full);
+
+    SkBitmap tile;
+    tile.setConfig(fReference.config(), fTileSize.width(), fTileSize.height());
+    tile.allocPixels();
+    SkCanvas tileCanvas(tile);
+
+    SkPaint paint;
+    paint.setXfermodeMode(SkXfermode::kSrc_Mode);
+
+    for (int y = 0; y < tiles_needed(full.height(), tile.height()); y++) {
+        for (int x = 0; x < tiles_needed(full.width(), tile.width()); x++) {
+            SkAutoCanvasRestore ar(&tileCanvas, true/*also save now*/);
+
+            const SkScalar xOffset = x * tile.width(),
+                           yOffset = y * tile.height();
+            SkMatrix matrix = tileCanvas.getTotalMatrix();
+            matrix.postTranslate(-xOffset, -yOffset);
+            tileCanvas.setMatrix(matrix);
+
+            recorded.draw(&tileCanvas);
+            tileCanvas.flush();
+            fullCanvas.drawBitmap(tile, xOffset, yOffset, &paint);
+        }
+    }
+
+    if (!BitmapsEqual(full, fReference)) {
+        this->fail();
+        this->spawnChild(SkNEW_ARGS(WriteTask, (*this, full)));
+    }
+}
+
+bool TileGridTask::shouldSkip() const {
+    if (fGM->getFlags() & skiagm::GM::kSkipPicture_Flag) {
+        return true;
+    }
+    return !FLAGS_tileGrid;
+}
+
+}  // namespace DM