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      1 /*
      2  * Copyright 2018 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 "sk_tool_utils.h"
     10 #include "SkBitmap.h"
     11 #include "SkTextUtils.h"
     12 
     13 namespace skiagm {
     14 
     15 // This GM recreates the blend mode images from the Android documentation
     16 class AndroidBlendModesGM : public GM {
     17 public:
     18     AndroidBlendModesGM() {
     19         this->setBGColor(SK_ColorBLACK);
     20     }
     21 
     22 protected:
     23     SkString onShortName() override {
     24         return SkString("androidblendmodes");
     25     }
     26 
     27     SkISize onISize() override {
     28         return SkISize::Make(kNumCols * kBitmapSize, kNumRows * kBitmapSize);
     29     }
     30 
     31     void onOnceBeforeDraw() override {
     32         SkImageInfo ii = SkImageInfo::MakeN32Premul(kBitmapSize, kBitmapSize);
     33         {
     34             fCompositeSrc.allocPixels(ii);
     35             SkCanvas tmp(fCompositeSrc);
     36             tmp.clear(SK_ColorTRANSPARENT);
     37             SkPaint p;
     38             p.setAntiAlias(true);
     39             p.setColor(sk_tool_utils::color_to_565(kBlue));
     40             tmp.drawRect(SkRect::MakeLTRB(16, 96, 160, 240), p);
     41         }
     42 
     43         {
     44             fCompositeDst.allocPixels(ii);
     45             SkCanvas tmp(fCompositeDst);
     46             tmp.clear(SK_ColorTRANSPARENT);
     47             SkPaint p;
     48             p.setAntiAlias(true);
     49             p.setColor(sk_tool_utils::color_to_565(kRed));
     50             tmp.drawCircle(160, 95, 80, p);
     51         }
     52     }
     53 
     54     void drawTile(SkCanvas* canvas, int xOffset, int yOffset, SkBlendMode mode) {
     55         canvas->translate(xOffset, yOffset);
     56 
     57         canvas->clipRect(SkRect::MakeXYWH(0, 0, 256, 256));
     58 
     59         canvas->saveLayer(nullptr, nullptr);
     60 
     61         SkPaint p;
     62         canvas->drawBitmap(fCompositeDst, 0, 0, &p);
     63         p.setBlendMode(mode);
     64         canvas->drawBitmap(fCompositeSrc, 0, 0, &p);
     65     }
     66 
     67     void onDraw(SkCanvas* canvas) override {
     68         SkFont font(sk_tool_utils::create_portable_typeface());
     69 
     70         sk_tool_utils::draw_checkerboard(canvas,
     71                                          kWhite,
     72                                          kGrey,
     73                                          32);
     74 
     75         int xOffset = 0, yOffset = 0;
     76 
     77         // Android doesn't expose all the blend modes
     78         // Note that the Android documentation calls:
     79         //    Skia's kPlus,     add
     80         //    Skia's kModulate, multiply
     81         for (SkBlendMode mode : { SkBlendMode::kPlus /* add */, SkBlendMode::kClear,
     82                                   SkBlendMode::kDarken, SkBlendMode::kDst,
     83                                   SkBlendMode::kDstATop, SkBlendMode::kDstIn,
     84                                   SkBlendMode::kDstOut, SkBlendMode::kDstOver,
     85                                   SkBlendMode::kLighten, SkBlendMode::kModulate /* multiply */,
     86                                   SkBlendMode::kOverlay, SkBlendMode::kScreen,
     87                                   SkBlendMode::kSrc, SkBlendMode::kSrcATop,
     88                                   SkBlendMode::kSrcIn, SkBlendMode::kSrcOut,
     89                                   SkBlendMode::kSrcOver, SkBlendMode::kXor } ) {
     90 
     91             int saveCount = canvas->save();
     92             this->drawTile(canvas, xOffset, yOffset, mode);
     93             canvas->restoreToCount(saveCount);
     94 
     95             SkTextUtils::DrawString(canvas, SkBlendMode_Name(mode),
     96                                xOffset + kBitmapSize/2.0f,
     97                                yOffset + kBitmapSize,
     98                                font, SkPaint(), SkTextUtils::kCenter_Align);
     99 
    100             xOffset += 256;
    101             if (xOffset >= 1024) {
    102                 xOffset = 0;
    103                 yOffset += 256;
    104             }
    105         }
    106     }
    107 
    108 private:
    109     static const int kBitmapSize = 256;
    110     static const int kNumRows = 5;
    111     static const int kNumCols = 4;
    112 
    113     static const SkColor  kBlue  = SkColorSetARGB(255, 22, 150, 243);
    114     static const SkColor  kRed   = SkColorSetARGB(255, 233, 30, 99);
    115     static const SkColor  kWhite = SkColorSetARGB(255, 243, 243, 243);
    116     static const SkColor  kGrey  = SkColorSetARGB(255, 222, 222, 222);
    117 
    118     SkBitmap fCompositeSrc;
    119     SkBitmap fCompositeDst;
    120 
    121     typedef GM INHERITED;
    122 };
    123 
    124 //////////////////////////////////////////////////////////////////////////////
    125 
    126 DEF_GM(return new AndroidBlendModesGM;)
    127 }
    128