Changed to a class based method in passing around the rendering method for render_pictures.

This is based on a comment for https://codereview.appspot.com/6427061/

Review URL: https://codereview.appspot.com/6405080

git-svn-id: http://skia.googlecode.com/svn/trunk@4786 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tools/PictureRenderer.cpp b/tools/PictureRenderer.cpp
new file mode 100644
index 0000000..762b49c
--- /dev/null
+++ b/tools/PictureRenderer.cpp
@@ -0,0 +1,101 @@
+#include "PictureRenderer.h"
+#include "SamplePipeControllers.h"
+#include "SkCanvas.h"
+#include "SkDevice.h"
+#include "SkGPipe.h"
+#include "SkPicture.h"
+#include "SkTDArray.h"
+#include "SkTypes.h"
+#include "picture_utils.h"
+
+namespace sk_tools {
+
+enum {
+    kDefaultTileWidth = 256,
+    kDefaultTileHeight = 256
+};
+
+void PipePictureRenderer::render(SkPicture* pict, SkCanvas* canvas) {
+    PipeController pipeController(canvas);
+    SkGPipeWriter writer;
+    SkCanvas* pipeCanvas = writer.startRecording(&pipeController);
+    pipeCanvas->drawPicture(*pict);
+    writer.endRecording();
+}
+
+void SimplePictureRenderer::render(SkPicture* pict, SkCanvas* canvas) {
+    canvas->drawPicture(*pict);
+}
+
+TiledPictureRenderer::TiledPictureRenderer()
+    : fTileWidth(kDefaultTileWidth)
+    , fTileHeight(kDefaultTileHeight) {}
+
+void TiledPictureRenderer::init(const SkPicture& pict) {
+    deleteTiles();
+    setupTiles(pict);
+}
+
+void TiledPictureRenderer::render(SkPicture* pict, SkCanvas* canvas) {
+    for (int i = 0; i < fTiles.count(); ++i) {
+        fTiles[i].fCanvas->drawPicture(*pict);
+    }
+
+    copyTilesToCanvas(*pict, canvas);
+}
+
+TiledPictureRenderer::~TiledPictureRenderer() {
+    deleteTiles();
+}
+
+void TiledPictureRenderer::clipTile(const SkPicture& picture, const TileInfo& tile) {
+    SkRect clip = SkRect::MakeWH(SkIntToScalar(picture.width()),
+                                 SkIntToScalar(picture.height()));
+    tile.fCanvas->clipRect(clip);
+}
+
+void TiledPictureRenderer::addTile(const SkPicture& picture, int tile_x_start, int tile_y_start) {
+    TileInfo* tile = fTiles.push();
+
+    tile->fBitmap = SkNEW(SkBitmap);
+    sk_tools::setup_bitmap(tile->fBitmap, fTileWidth, fTileHeight);
+
+    tile->fCanvas = SkNEW_ARGS(SkCanvas, (*(tile->fBitmap)));
+    tile->fCanvas->translate(SkIntToScalar(-tile_x_start), SkIntToScalar(-tile_y_start));
+    clipTile(picture, *tile);
+}
+
+void TiledPictureRenderer::setupTiles(const SkPicture& picture) {
+    for (int tile_y_start = 0; tile_y_start < picture.height();
+         tile_y_start += fTileHeight) {
+        for (int tile_x_start = 0; tile_x_start < picture.width();
+             tile_x_start += fTileWidth) {
+            addTile(picture, tile_x_start, tile_y_start);
+        }
+    }
+}
+
+void TiledPictureRenderer::deleteTiles() {
+    for (int i = 0; i < fTiles.count(); ++i) {
+        SkDELETE(fTiles[i].fCanvas);
+        SkDELETE(fTiles[i].fBitmap);
+    }
+
+    fTiles.reset();
+}
+
+void TiledPictureRenderer::copyTilesToCanvas(const SkPicture& pict, SkCanvas* destination) {
+    int tile_index = 0;
+    for (int tile_y_start = 0; tile_y_start < pict.height();
+         tile_y_start += fTileHeight) {
+        for (int tile_x_start = 0; tile_x_start < pict.width();
+             tile_x_start += fTileWidth) {
+            SkASSERT(tile_index < fTiles.count());
+            SkBitmap source = fTiles[tile_index].fCanvas->getDevice()->accessBitmap(false);
+            destination->drawBitmap(source, tile_x_start, tile_y_start);
+            ++tile_index;
+        }
+    }
+}
+
+}