src/third_party/skia/gm/arithmode.cpp

   1 /*
   2  * Copyright 2011 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 "SkCanvas.h"
  10 #include "SkColorPriv.h"
  11 #include "SkShader.h"
  12
  13 #include "SkArithmeticMode.h"
  14 #include "SkGradientShader.h"
  15 #define WW  100
  16 #define HH  32
  17
  18 static SkBitmap make_bm() {
  19     SkBitmap bm;
  20     bm.allocN32Pixels(WW, HH);
  21     bm.eraseColor(SK_ColorTRANSPARENT);
  22     return bm;
  23 }
  24
  25 static SkBitmap make_src() {
  26     SkBitmap bm = make_bm();
  27     SkCanvas canvas(bm);
  28     SkPaint paint;
  29     SkPoint pts[] = { {0, 0}, {SkIntToScalar(WW), SkIntToScalar(HH)} };
  30     SkColor colors[] = {
  31         SK_ColorTRANSPARENT, SK_ColorGREEN, SK_ColorCYAN,
  32         SK_ColorRED, SK_ColorMAGENTA, SK_ColorWHITE,
  33     };
  34     SkShader* s = SkGradientShader::CreateLinear(pts, colors, NULL, SK_ARRAY_COUNT(colors),
  35                                                  SkShader::kClamp_TileMode);
  36     paint.setShader(s)->unref();
  37     canvas.drawPaint(paint);
  38     return bm;
  39 }
  40
  41 static SkBitmap make_dst() {
  42     SkBitmap bm = make_bm();
  43     SkCanvas canvas(bm);
  44     SkPaint paint;
  45     SkPoint pts[] = { {0, SkIntToScalar(HH)}, {SkIntToScalar(WW), 0} };
  46     SkColor colors[] = {
  47         SK_ColorBLUE, SK_ColorYELLOW, SK_ColorBLACK, SK_ColorGREEN, SK_ColorGRAY
  48     };
  49     SkShader* s = SkGradientShader::CreateLinear(pts, colors, NULL, SK_ARRAY_COUNT(colors),
  50                                                  SkShader::kClamp_TileMode);
  51     paint.setShader(s)->unref();
  52     canvas.drawPaint(paint);
  53     return bm;
  54 }
  55
  56 static void show_k_text(SkCanvas* canvas, SkScalar x, SkScalar y, const SkScalar k[]) {
  57     SkPaint paint;
  58     paint.setTextSize(SkIntToScalar(24));
  59     paint.setAntiAlias(true);
  60     sk_tool_utils::set_portable_typeface(&paint);
  61     for (int i = 0; i < 4; ++i) {
  62         SkString str;
  63         str.appendScalar(k[i]);
  64         SkScalar width = paint.measureText(str.c_str(), str.size());
  65         canvas->drawText(str.c_str(), str.size(), x, y + paint.getTextSize(), paint);
  66         x += width + SkIntToScalar(10);
  67     }
  68 }
  69
  70 class ArithmodeGM : public skiagm::GM {
  71 public:
  72     ArithmodeGM () {}
  73
  74 protected:
  75
  76     virtual SkString onShortName() {
  77         return SkString("arithmode");
  78     }
  79
  80     virtual SkISize onISize() { return SkISize::Make(640, 480); }
  81
  82     virtual void onDraw(SkCanvas* canvas) {
  83         SkBitmap src = make_src();
  84         SkBitmap dst = make_dst();
  85
  86         const SkScalar one = SK_Scalar1;
  87         static const SkScalar K[] = {
  88             0, 0, 0, 0,
  89             0, 0, 0, one,
  90             0, one, 0, 0,
  91             0, 0, one, 0,
  92             0, one, one, 0,
  93             0, one, -one, 0,
  94             0, one/2, one/2, 0,
  95             0, one/2, one/2, one/4,
  96             0, one/2, one/2, -one/4,
  97             one/4, one/2, one/2, 0,
  98             -one/4, one/2, one/2, 0,
  99         };
 100
 101         const SkScalar* k = K;
 102         const SkScalar* stop = k + SK_ARRAY_COUNT(K);
 103         SkScalar y = 0;
 104         SkScalar gap = SkIntToScalar(src.width() + 20);
 105         while (k < stop) {
 106             SkScalar x = 0;
 107             canvas->drawBitmap(src, x, y, NULL);
 108             x += gap;
 109             canvas->drawBitmap(dst, x, y, NULL);
 110             x += gap;
 111             SkRect rect = SkRect::MakeXYWH(x, y, SkIntToScalar(WW), SkIntToScalar(HH));
 112             canvas->saveLayer(&rect, NULL);
 113             canvas->drawBitmap(dst, x, y, NULL);
 114             SkXfermode* xfer = SkArithmeticMode::Create(k[0], k[1], k[2], k[3]);
 115             SkPaint paint;
 116             paint.setXfermode(xfer)->unref();
 117             canvas->drawBitmap(src, x, y, &paint);
 118             canvas->restore();
 119             x += gap;
 120             show_k_text(canvas, x, y, k);
 121             k += 4;
 122             y += SkIntToScalar(src.height() + 12);
 123         }
 124     }
 125
 126 private:
 127     typedef GM INHERITED;
 128 };
 129
 130 ///////////////////////////////////////////////////////////////////////////////
 131
 132 static skiagm::GM* MyFactory(void*) { return new ArithmodeGM; }
 133 static skiagm::GMRegistry reg(MyFactory);