add deferred config to DM

dm/DMSrcSink.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "DMSrcSink.h"
 #include "SamplePipeControllers.h"
 #include "SkCommonFlags.h"
 #include "SkCodec.h"
 #include "SkData.h"
+#include "SkDeferredCanvas.h"
 #include "SkDocument.h"
 #include "SkError.h"
 #include "SkImageGenerator.h"
 #include "SkMultiPictureDraw.h"
 #include "SkNullCanvas.h"
 #include "SkOSFile.h"
 #include "SkPictureData.h"
 #include "SkPictureRecorder.h"
 #include "SkRandom.h"
 #include "SkScanlineDecoder.h"
@@ skipping 560 matching lines @@
             const uint32_t kFlags = 0; // We mirror SkDeferredCanvas, which doesn't use any flags.
             return fSrc.draw(pipe.startRecording(&controller, kFlags, size.width(), size.height()));
         }
         SkISize size() const override { return fSrc.size(); }
         Name name() const override { sk_throw(); return ""; }  // No one should be calling this.
     } proxy(src);
     return fSink->draw(proxy, bitmap, stream, log);
 }
 
 /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
+    
+ViaDeferred::ViaDeferred(Sink* sink) : fSink(sink) {}
+
+Error ViaDeferred::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream, SkString* log) const {

[robertphillips, 2015/05/05 14:45:42]

update comment

[reed1, 2015/05/05 14:55:25]

Done.

+    // We turn ourselves into another Src that draws our argument into bitmap/stream via pipe.

[mtklein, 2015/05/05 14:45:30]

update / delete?

[reed1, 2015/05/05 14:55:25]

Done.

+    struct ProxySrc : public Src {
+        const Src& fSrc;
+        ProxySrc(const Src& src) : fSrc(src) {}
+
+        Error draw(SkCanvas* canvas) const override {
+            SkISize size = this->size();
+            SkImageInfo info = SkImageInfo::MakeN32Premul(size.width(), size.height());

[mtklein, 2015/05/05 14:45:30]

Is it useful to have the deferred canvas match the color type of the ultimate
destination, or is this N32-is-good-enough-for-anyone?

[reed1, 2015/05/05 14:55:25]

Good point, I think I can use the same "info"

+            SkAutoTUnref<SkSurface> surface(canvas->newSurface(info));
+            if (!surface.get()) {
+                return Error("can make surface for deferred canvas");

[mtklein, 2015/05/05 14:45:30]

can -> can't?

[reed1, 2015/05/05 14:55:25]

Done.

+            }
+            SkAutoTDelete<SkDeferredCanvas> defcan(SkDeferredCanvas::Create(surface));
+            Error err = fSrc.draw(defcan);
+            if (err.isEmpty()) {

[mtklein, 2015/05/05 14:45:30]

Seems like you're swallowing the error when it's not empty?

Error err = fSrc.draw(defcan);
if (!err.isEmpty()) {
  return err;
}
...
return "";

[reed1, 2015/05/05 14:55:25]

Done.

+                SkAutoTUnref<SkImage> image(defcan->newImageSnapshot());
+                if (image) {
+                    canvas->drawImage(image, 0, 0, NULL);
+                } else {
+                    return Error("failed to create deferred image snapshot");

[mtklein, 2015/05/05 14:45:30]

FYI, you can just write
  return "Failed to create deferred image snapshot.";

[reed1, 2015/05/05 14:55:25]

Acknowledged.

+                }
+            }
+            return "";
+        }
+        SkISize size() const override { return fSrc.size(); }
+        Name name() const override { sk_throw(); return ""; }  // No one should be calling this.
+    } proxy(src);
+    return fSink->draw(proxy, bitmap, stream, log);
+}
+    
+/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
 ViaSerialization::ViaSerialization(Sink* sink) : fSink(sink) {}
 
 Error ViaSerialization::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream, SkString* log)
     const {
     // Record our Src into a picture.
     SkSize size;
     size = src.size();
     SkPictureRecorder recorder;
     Error err = src.draw(recorder.beginRecording(size.width(), size.height()));
@@ skipping 117 matching lines @@
             canvas->drawPicture(pic);
             return "";
         }
         SkISize size() const override { return fSrc.size(); }
         Name name() const override { sk_throw(); return ""; }  // No one should be calling this.
     } proxy(src);
     return fSink->draw(proxy, bitmap, stream, log);
 }
 
 }  // namespace DM