add drawPicture variant that takes a matrix and paint

gm/picture.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 "gm.h"
+#include "SkPaint.h"
+#include "SkPictureRecorder.h"
+
+static SkPicture* make_picture() {
+    SkPictureRecorder rec;
+    SkCanvas* canvas = rec.beginRecording(100, 100);
+
+    SkPaint paint;
+    paint.setAntiAlias(true);
+    SkPath path;
+
+    paint.setColor(0x800000FF);
+    canvas->drawRect(SkRect::MakeWH(100, 100), paint);
+
+    paint.setColor(0x80FF0000);
+    path.moveTo(0, 0); path.lineTo(100, 0); path.lineTo(100, 100);
+    canvas->drawPath(path, paint);
+    
+    paint.setColor(0x8000FF00);
+    path.reset(); path.moveTo(0, 0); path.lineTo(100, 0); path.lineTo(0, 100);
+    canvas->drawPath(path, paint);
+
+    paint.setColor(0x80FFFFFF);
+    paint.setXfermodeMode(SkXfermode::kPlus_Mode);
+    canvas->drawRect(SkRect::MakeXYWH(25, 25, 50, 50), paint);
+
+    return rec.endRecording();
+}
+
+// Exercise the optional arguments to drawPicture
+//
+class PictureGM : public skiagm::GM {
+public:
+    PictureGM() : fPicture(make_picture()) {}
+
+protected:
+    virtual SkString onShortName() SK_OVERRIDE {
+        return SkString("pictures");
+    }
+
+    virtual SkISize onISize() SK_OVERRIDE {
+        return SkISize::Make(450, 120);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+        canvas->translate(10, 10);
+
+        SkMatrix matrix;
+        SkPaint paint;
+
+        canvas->drawPicture(fPicture);
+        
+        matrix.setTranslate(110, 0);
+        canvas->drawPicture(fPicture, &matrix, NULL);
+        
+        matrix.postTranslate(110, 0);
+        canvas->drawPicture(fPicture, &matrix, &paint);
+
+        paint.setAlpha(0x80);
+        matrix.postTranslate(110, 0);
+        canvas->drawPicture(fPicture, &matrix, &paint);
+    }
+
+private:
+    SkAutoTUnref<SkPicture> fPicture;
+
+    typedef skiagm::GM INHERITED;
+};
+
+DEF_GM( return SkNEW(PictureGM); )