gm/lumafilter.cpp

   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 "SkCanvas.h"
  10 #include "SkGradientShader.h"
  11 #include "SkLumaColorFilter.h"
  12
  13 static SkScalar kSize   = 80;
  14 static SkScalar kInset  = 10;
  15 static SkColor  kColor1 = SkColorSetARGB(0xff, 0xff, 0xff, 0);
  16 static SkColor  kColor2 = SkColorSetARGB(0xff, 0x80, 0xff, 0);
  17
  18 static void draw_label(SkCanvas* canvas, const char* label,
  19                        const SkPoint& offset) {
  20     SkPaint paint;
  21     sk_tool_utils::set_portable_typeface(&paint);
  22     size_t len = strlen(label);
  23
  24     SkScalar width = paint.measureText(label, len);
  25     canvas->drawText(label, len, offset.x() - width / 2, offset.y(),
  26                      paint);
  27 }
  28
  29 static void draw_scene(SkCanvas* canvas, SkColorFilter* filter,
  30                        SkXfermode::Mode mode, SkShader* s1,
  31                        SkShader* s2) {
  32     SkPaint paint;
  33     paint.setAntiAlias(true);
  34     SkRect r, c, bounds = SkRect::MakeWH(kSize, kSize);
  35
  36     c = bounds;
  37     c.fRight = bounds.centerX();
  38     paint.setARGB(0x20, 0, 0, 0xff);
  39     canvas->drawRect(bounds, paint);
  40
  41     canvas->saveLayer(&bounds, NULL);
  42
  43     r = bounds;
  44     r.inset(kInset, 0);
  45     paint.setShader(s1);
  46     paint.setColor(s1 ? SK_ColorBLACK : SkColorSetA(kColor1, 0x80));
  47     canvas->drawOval(r, paint);
  48     if (!s1) {
  49         canvas->save();
  50         canvas->clipRect(c);
  51         paint.setColor(kColor1);
  52         canvas->drawOval(r, paint);
  53         canvas->restore();
  54     }
  55
  56     SkPaint xferPaint;
  57     xferPaint.setXfermodeMode(mode);
  58     canvas->saveLayer(&bounds, &xferPaint);
  59
  60     r = bounds;
  61     r.inset(0, kInset);
  62     paint.setShader(s2);
  63     paint.setColor(s2 ? SK_ColorBLACK : SkColorSetA(kColor2, 0x80));
  64     paint.setColorFilter(filter);
  65     canvas->drawOval(r, paint);
  66     if (!s2) {
  67         canvas->save();
  68         canvas->clipRect(c);
  69         paint.setColor(kColor2);
  70         canvas->drawOval(r, paint);
  71         canvas->restore();
  72     }
  73
  74     canvas->restore();
  75     canvas->restore();
  76 }
  77
  78 class LumaFilterGM : public skiagm::GM {
  79 public:
  80     LumaFilterGM() {
  81         SkColor  g1Colors[] = { kColor1, SkColorSetA(kColor1, 0x20) };
  82         SkColor  g2Colors[] = { kColor2, SkColorSetA(kColor2, 0x20) };
  83         SkPoint  g1Points[] = { { 0, 0 }, { 0,     100 } };
  84         SkPoint  g2Points[] = { { 0, 0 }, { kSize, 0   } };
  85         SkScalar pos[] = { 0.2f, 1.0f };
  86
  87         fFilter.reset(SkLumaColorFilter::Create());
  88         fGr1.reset(SkGradientShader::CreateLinear(g1Points,
  89                                                   g1Colors,
  90                                                   pos,
  91                                                   SK_ARRAY_COUNT(g1Colors),
  92                                                   SkShader::kClamp_TileMode));
  93         fGr2.reset(SkGradientShader::CreateLinear(g2Points,
  94                                                   g2Colors,
  95                                                   pos,
  96                                                   SK_ARRAY_COUNT(g2Colors),
  97                                                   SkShader::kClamp_TileMode));
  98     }
  99
 100 protected:
 101
 102     SkString onShortName() override {
 103         return SkString("lumafilter");
 104     }
 105
 106     SkISize onISize() override {
 107         return SkISize::Make(600, 420);
 108     }
 109
 110     void onDraw(SkCanvas* canvas) override {
 111         SkXfermode::Mode modes[] = { SkXfermode::kSrcOver_Mode,
 112                                      SkXfermode::kDstOver_Mode,
 113                                      SkXfermode::kSrcATop_Mode,
 114                                      SkXfermode::kDstATop_Mode,
 115                                      SkXfermode::kSrcIn_Mode,
 116                                      SkXfermode::kDstIn_Mode,
 117                                    };
 118         struct {
 119             SkShader*   fShader1;
 120             SkShader*   fShader2;
 121         } shaders[] = {
 122             { NULL, NULL },
 123             { NULL, fGr2 },
 124             { fGr1, NULL },
 125             { fGr1, fGr2 },
 126         };
 127
 128         SkScalar gridStep = kSize + 2 * kInset;
 129         for (size_t i = 0; i < SK_ARRAY_COUNT(modes); ++i) {
 130             draw_label(canvas, SkXfermode::ModeName(modes[i]),
 131                        SkPoint::Make(gridStep * (0.5f + i), 20));
 132         }
 133
 134         for (size_t i = 0; i < SK_ARRAY_COUNT(shaders); ++i) {
 135             canvas->save();
 136             canvas->translate(kInset, gridStep * i + 30);
 137             for (size_t m = 0; m < SK_ARRAY_COUNT(modes); ++m) {
 138                 draw_scene(canvas, fFilter, modes[m], shaders[i].fShader1,
 139                            shaders[i].fShader2);
 140                 canvas->translate(gridStep, 0);
 141             }
 142             canvas->restore();
 143         }
 144     }
 145
 146 private:
 147     SkAutoTUnref<SkColorFilter> fFilter;
 148     SkAutoTUnref<SkShader>      fGr1, fGr2;
 149
 150     typedef skiagm::GM INHERITED;
 151 };
 152
 153 //////////////////////////////////////////////////////////////////////////////
 154
 155 DEF_GM( return SkNEW(LumaFilterGM); )