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      1 /*
      2  * Copyright 2013 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #include "gm.h"
      9 #include "SkBitmap.h"
     10 #include "SkCanvas.h"
     11 #include "SkColorData.h"
     12 
     13 /**
     14  * This GM checks that bitmap pixels are unpremultiplied before being exported
     15  * to other formats. If unpremultiplication is implemented properly, this
     16  * GM should come out completely white. If not, this GM looks like a row of two
     17  * greyscale gradients above a row of grey lines.
     18  * This tests both the ARGB4444 and ARGB8888 bitmap configurations.
     19  */
     20 
     21 constexpr int SLIDE_SIZE = 256;
     22 
     23 static void init_bitmap(SkColorType ct, SkBitmap* bitmap) {
     24     bitmap->allocPixels(SkImageInfo::Make(SLIDE_SIZE, SLIDE_SIZE, ct,
     25                                           kPremul_SkAlphaType));
     26     bitmap->eraseColor(SK_ColorWHITE);
     27 }
     28 
     29 static SkBitmap make_argb8888_gradient() {
     30     SkBitmap bitmap;
     31     init_bitmap(kN32_SkColorType, &bitmap);
     32     for (int y = 0; y < SLIDE_SIZE; y++) {
     33         uint32_t* dst = bitmap.getAddr32(0, y);
     34         for (int x = 0; x < SLIDE_SIZE; x++) {
     35             dst[x] = SkPackARGB32(y, y, y, y);
     36         }
     37     }
     38     return bitmap;
     39 }
     40 
     41 static SkBitmap make_argb4444_gradient() {
     42     SkBitmap bitmap;
     43     init_bitmap(kARGB_4444_SkColorType, &bitmap);
     44     // Using draw rather than readPixels to suppress dither
     45     SkPaint paint;
     46     paint.setBlendMode(SkBlendMode::kSrc);
     47     SkCanvas{ bitmap }.drawBitmap(make_argb8888_gradient(), 0, 0, &paint);
     48     return bitmap;
     49 }
     50 
     51 static SkBitmap make_argb8888_stripes() {
     52     SkBitmap bitmap;
     53     init_bitmap(kN32_SkColorType, &bitmap);
     54     uint8_t rowColor = 0;
     55     for (int y = 0; y < SLIDE_SIZE; y++) {
     56         uint32_t* dst = bitmap.getAddr32(0, y);
     57         for (int x = 0; x < SLIDE_SIZE; x++) {
     58             dst[x] = SkPackARGB32(rowColor, rowColor,
     59                                   rowColor, rowColor);
     60         }
     61         if (rowColor == 0) {
     62             rowColor = 255;
     63         } else {
     64             rowColor = 0;
     65         }
     66     }
     67     return bitmap;
     68 }
     69 
     70 static SkBitmap make_argb4444_stripes() {
     71     SkBitmap bitmap;
     72     init_bitmap(kARGB_4444_SkColorType, &bitmap);
     73     // Using draw rather than readPixels to suppress dither
     74     SkPaint paint;
     75     paint.setBlendMode(SkBlendMode::kSrc);
     76     SkCanvas{ bitmap }.drawBitmap(make_argb8888_stripes(), 0, 0, &paint);
     77     return bitmap;
     78 }
     79 
     80 namespace skiagm {
     81 
     82 class BitmapPremulGM : public GM {
     83 public:
     84     BitmapPremulGM() {
     85         this->setBGColor(SK_ColorWHITE);
     86     }
     87 
     88 protected:
     89     SkString onShortName() override {
     90         return SkString("bitmap_premul");
     91     }
     92 
     93     SkISize onISize() override {
     94         return SkISize::Make(SLIDE_SIZE * 2, SLIDE_SIZE * 2);
     95     }
     96 
     97     void onDraw(SkCanvas* canvas) override {
     98         SkScalar slideSize = SkIntToScalar(SLIDE_SIZE);
     99         canvas->drawBitmap(make_argb8888_gradient(), 0, 0);
    100         canvas->drawBitmap(make_argb4444_gradient(), slideSize, 0);
    101         canvas->drawBitmap(make_argb8888_stripes(), 0, slideSize);
    102         canvas->drawBitmap(make_argb4444_stripes(), slideSize, slideSize);
    103     }
    104 
    105 private:
    106     typedef GM INHERITED;
    107 };
    108 
    109 DEF_GM( return new BitmapPremulGM; )
    110 }
    111