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, 0x82, 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, const sk_sp<SkColorFilter>& filter, SkBlendMode mode,
  30                        const sk_sp<SkShader>& s1, const sk_sp<SkShader>& s2) {
  31     SkPaint paint;
  32     paint.setAntiAlias(true);
  33     SkRect r, c, bounds = SkRect::MakeWH(kSize, kSize);
  34
  35     c = bounds;
  36     c.fRight = bounds.centerX();
  37     paint.setARGB(0x20, 0, 0, 0xff);
  38     canvas->drawRect(bounds, paint);
  39
  40     canvas->saveLayer(&bounds, nullptr);
  41
  42     r = bounds;
  43     r.inset(kInset, 0);
  44     paint.setShader(s1);
  45     paint.setColor(s1 ? SK_ColorBLACK : SkColorSetA(kColor1, 0x80));
  46     canvas->drawOval(r, paint);
  47     if (!s1) {
  48         canvas->save();
  49         canvas->clipRect(c);
  50         paint.setColor(kColor1);
  51         canvas->drawOval(r, paint);
  52         canvas->restore();
  53     }
  54
  55     SkPaint xferPaint;
  56     xferPaint.setBlendMode(mode);
  57     canvas->saveLayer(&bounds, &xferPaint);
  58
  59     r = bounds;
  60     r.inset(0, kInset);
  61     paint.setShader(s2);
  62     paint.setColor(s2 ? SK_ColorBLACK : SkColorSetA(kColor2, 0x80));
  63     paint.setColorFilter(filter);
  64     canvas->drawOval(r, paint);
  65     if (!s2) {
  66         canvas->save();
  67         canvas->clipRect(c);
  68         paint.setColor(kColor2);
  69         canvas->drawOval(r, paint);
  70         canvas->restore();
  71     }
  72
  73     canvas->restore();
  74     canvas->restore();
  75 }
  76
  77 class LumaFilterGM : public skiagm::GM {
  78 public:
  79     LumaFilterGM() {
  80         SkColor  g1Colors[] = { kColor1, SkColorSetA(kColor1, 0x20) };
  81         SkColor  g2Colors[] = { kColor2, SkColorSetA(kColor2, 0x20) };
  82         SkPoint  g1Points[] = { { 0, 0 }, { 0,     100 } };
  83         SkPoint  g2Points[] = { { 0, 0 }, { kSize, 0   } };
  84         SkScalar pos[] = { 0.2f, 1.0f };
  85
  86         fFilter = SkLumaColorFilter::Make();
  87         fGr1 = SkGradientShader::MakeLinear(g1Points, g1Colors, pos, SK_ARRAY_COUNT(g1Colors),
  88                                             SkShader::kClamp_TileMode);
  89         fGr2 = SkGradientShader::MakeLinear(g2Points, g2Colors, pos, SK_ARRAY_COUNT(g2Colors),
  90                                             SkShader::kClamp_TileMode);
  91     }
  92
  93 protected:
  94
  95     SkString onShortName() override {
  96         return SkString("lumafilter");
  97     }
  98
  99     SkISize onISize() override {
 100         return SkISize::Make(600, 420);
 101     }
 102
 103     void onDraw(SkCanvas* canvas) override {
 104         SkBlendMode modes[] = {
 105             SkBlendMode::kSrcOver,
 106             SkBlendMode::kDstOver,
 107             SkBlendMode::kSrcATop,
 108             SkBlendMode::kDstATop,
 109             SkBlendMode::kSrcIn,
 110             SkBlendMode::kDstIn,
 111         };
 112         struct {
 113             const sk_sp<SkShader>& fShader1;
 114             const sk_sp<SkShader>& fShader2;
 115         } shaders[] = {
 116             { nullptr, nullptr },
 117             { nullptr, fGr2 },
 118             { fGr1, nullptr },
 119             { fGr1, fGr2 },
 120         };
 121
 122         SkScalar gridStep = kSize + 2 * kInset;
 123         for (size_t i = 0; i < SK_ARRAY_COUNT(modes); ++i) {
 124             draw_label(canvas, SkXfermode::ModeName(modes[i]),
 125                        SkPoint::Make(gridStep * (0.5f + i), 20));
 126         }
 127
 128         for (size_t i = 0; i < SK_ARRAY_COUNT(shaders); ++i) {
 129             canvas->save();
 130             canvas->translate(kInset, gridStep * i + 30);
 131             for (size_t m = 0; m < SK_ARRAY_COUNT(modes); ++m) {
 132                 draw_scene(canvas, fFilter, modes[m], shaders[i].fShader1,
 133                            shaders[i].fShader2);
 134                 canvas->translate(gridStep, 0);
 135             }
 136             canvas->restore();
 137         }
 138     }
 139
 140 private:
 141     sk_sp<SkColorFilter>    fFilter;
 142     sk_sp<SkShader>         fGr1, fGr2;
 143
 144     typedef skiagm::GM INHERITED;
 145 };
 146
 147 //////////////////////////////////////////////////////////////////////////////
 148
 149 DEF_GM(return new LumaFilterGM;)