update bitmapshader to avoid potential rendering error for kA8_Config

gm/bitmapshader.cpp

 
 /*
  * Copyright 2013 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 "SkBitmap.h"
@@ skipping 17 matching lines @@
     SkPaint circlePaint;
     circlePaint.setColor(SK_ColorBLACK);
 
     bm->allocPixels(SkImageInfo::MakeA8(20, 20));
     bm->eraseColor(SK_ColorTRANSPARENT);
 
     SkCanvas canvas(*bm);
     canvas.drawCircle(10, 10, 10, circlePaint);
 }
 
-static void adopt_shader(SkPaint* paint, SkShader* shader) {
+static void adopt_shader(SkPaint* paint, SkShader* shader, SkMatrix s) {
+    shader->setLocalMatrix(s);
     paint->setShader(shader);
     SkSafeUnref(shader);
 }
 
 class BitmapShaderGM : public GM {
 public:
 
     BitmapShaderGM() {
         this->setBGColor(SK_ColorGRAY);
         draw_bm(&fBitmap);
         draw_mask(&fMask);
     }
 
 protected:
     virtual SkString onShortName() {
         return SkString("bitmapshaders");
     }
 
     virtual SkISize onISize() {
-        return SkISize::Make(75, 100);
+        return SkISize::Make(150, 100);
     }
 
     virtual void onDraw(SkCanvas* canvas) {
         SkPaint paint;
 
-        adopt_shader(&paint, SkShader::CreateBitmapShader(fBitmap, SkShader::kClamp_TileMode,
-                                                          SkShader::kClamp_TileMode));
+        for (int i = 0; i < 2; i++) {
+            SkMatrix s;
+            s.reset();
+            if (1 == i) {
+                s.setScale(1.5, 1.5);
+                s.postTranslate(2, 2);
+            }
 
-        // draw the shader with a bitmap mask
-        canvas->drawBitmap(fMask, 0, 0, &paint);
-        canvas->drawBitmap(fMask, 30, 0, &paint);
+            canvas->save();
+            adopt_shader(&paint, SkShader::CreateBitmapShader(fBitmap, SkShader::kClamp_TileMode,
+                                                              SkShader::kClamp_TileMode), s);
 
-        canvas->translate(0, 25);
+            // draw the shader with a bitmap mask
+            canvas->drawBitmap(fMask, 0, 0, &paint);
+            canvas->drawBitmap(fMask, 30, 0, &paint);
 
-        canvas->drawCircle(10, 10, 10, paint);
-        canvas->drawCircle(40, 10, 10, paint); // no blue circle expected
+            canvas->translate(0, 25);
 
-        canvas->translate(0, 25);
+            canvas->drawCircle(10, 10, 10, paint);
+            canvas->drawCircle(40, 10, 10, paint); // no blue circle expected
 
-        adopt_shader(&paint, SkShader::CreateBitmapShader(fMask, SkShader::kRepeat_TileMode,
-                                                          SkShader::kRepeat_TileMode));
-        paint.setColor(SK_ColorRED);
+            canvas->translate(0, 25);
 
-        // draw the mask using the shader and a color
-        canvas->drawRect(SkRect::MakeXYWH(0, 0, 20, 20), paint);
-        canvas->drawRect(SkRect::MakeXYWH(30, 0, 20, 20), paint);
+            // clear the shader, colorized by a solid color with a bitmap mask
+            paint.setShader(NULL);
+            paint.setColor(SK_ColorGREEN);
+            canvas->drawBitmap(fMask, 0, 0, &paint);
+            canvas->drawBitmap(fMask, 30, 0, &paint);
+
+            canvas->translate(0, 25);
+
+            adopt_shader(&paint, SkShader::CreateBitmapShader(fMask, SkShader::kRepeat_TileMode,
+                                                              SkShader::kRepeat_TileMode), s);
+            paint.setColor(SK_ColorRED);
+
+            // draw the mask using the shader and a color
+            canvas->drawRect(SkRect::MakeXYWH(0, 0, 20, 20), paint);
+            canvas->drawRect(SkRect::MakeXYWH(30, 0, 20, 20), paint);
+            canvas->restore();
+            canvas->translate(60, 0);
+        }
     }
 
 private:
     SkBitmap fBitmap;
     SkBitmap fMask;
 
     typedef GM INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static GM* MyFactory(void*) { return new BitmapShaderGM; }
 static GMRegistry reg(MyFactory);
 
 }