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 "sk_tool_utils.h"
  10 #include "SkBlendModePriv.h"
  11 #include "SkCanvas.h"
  12 #include "SkGradientShader.h"
  13 #include "SkLumaColorFilter.h"
  14
  15 static SkScalar kSize   = 80;
  16 static SkScalar kInset  = 10;
  17 static SkColor  kColor1 = SkColorSetARGB(0xff, 0xff, 0xff, 0);
  18 static SkColor  kColor2 = SkColorSetARGB(0xff, 0x82, 0xff, 0);
  19
  20 static void draw_label(SkCanvas* canvas, const char* label,
  21                        const SkPoint& offset) {
  22     SkPaint paint;
  23     sk_tool_utils::set_portable_typeface(&paint);
  24     size_t len = strlen(label);
  25
  26     SkScalar width = paint.measureText(label, len);
  27     canvas->drawText(label, len, offset.x() - width / 2, offset.y(),
  28                      paint);
  29 }
  30
  31 static void draw_scene(SkCanvas* canvas, const sk_sp<SkColorFilter>& filter, SkBlendMode mode,
  32                        const sk_sp<SkShader>& s1, const sk_sp<SkShader>& s2) {
  33     SkPaint paint;
  34     paint.setAntiAlias(true);
  35     SkRect r, c, bounds = SkRect::MakeWH(kSize, kSize);
  36
  37     c = bounds;
  38     c.fRight = bounds.centerX();
  39     paint.setARGB(0x20, 0, 0, 0xff);
  40     canvas->drawRect(bounds, paint);
  41
  42     canvas->saveLayer(&bounds, nullptr);
  43
  44     r = bounds;
  45     r.inset(kInset, 0);
  46     paint.setShader(s1);
  47     paint.setColor(s1 ? SK_ColorBLACK : SkColorSetA(kColor1, 0x80));
  48     canvas->drawOval(r, paint);
  49     if (!s1) {
  50         canvas->save();
  51         canvas->clipRect(c);
  52         paint.setColor(kColor1);
  53         canvas->drawOval(r, paint);
  54         canvas->restore();
  55     }
  56
  57     SkPaint xferPaint;
  58     xferPaint.setBlendMode(mode);
  59     canvas->saveLayer(&bounds, &xferPaint);
  60
  61     r = bounds;
  62     r.inset(0, kInset);
  63     paint.setShader(s2);
  64     paint.setColor(s2 ? SK_ColorBLACK : SkColorSetA(kColor2, 0x80));
  65     paint.setColorFilter(filter);
  66     canvas->drawOval(r, paint);
  67     if (!s2) {
  68         canvas->save();
  69         canvas->clipRect(c);
  70         paint.setColor(kColor2);
  71         canvas->drawOval(r, paint);
  72         canvas->restore();
  73     }
  74
  75     canvas->restore();
  76     canvas->restore();
  77 }
  78
  79 class LumaFilterGM : public skiagm::GM {
  80 public:
  81     LumaFilterGM() {
  82         SkColor  g1Colors[] = { kColor1, SkColorSetA(kColor1, 0x20) };
  83         SkColor  g2Colors[] = { kColor2, SkColorSetA(kColor2, 0x20) };
  84         SkPoint  g1Points[] = { { 0, 0 }, { 0,     100 } };
  85         SkPoint  g2Points[] = { { 0, 0 }, { kSize, 0   } };
  86         SkScalar pos[] = { 0.2f, 1.0f };
  87
  88         fFilter = SkLumaColorFilter::Make();
  89         fGr1 = SkGradientShader::MakeLinear(g1Points, g1Colors, pos, SK_ARRAY_COUNT(g1Colors),
  90                                             SkShader::kClamp_TileMode);
  91         fGr2 = SkGradientShader::MakeLinear(g2Points, g2Colors, pos, SK_ARRAY_COUNT(g2Colors),
  92                                             SkShader::kClamp_TileMode);
  93     }
  94
  95 protected:
  96
  97     SkString onShortName() override {
  98         return SkString("lumafilter");
  99     }
 100
 101     SkISize onISize() override {
 102         return SkISize::Make(600, 420);
 103     }
 104
 105     void onDraw(SkCanvas* canvas) override {
 106         SkBlendMode modes[] = {
 107             SkBlendMode::kSrcOver,
 108             SkBlendMode::kDstOver,
 109             SkBlendMode::kSrcATop,
 110             SkBlendMode::kDstATop,
 111             SkBlendMode::kSrcIn,
 112             SkBlendMode::kDstIn,
 113         };
 114         struct {
 115             const sk_sp<SkShader>& fShader1;
 116             const sk_sp<SkShader>& fShader2;
 117         } shaders[] = {
 118             { nullptr, nullptr },
 119             { nullptr, fGr2 },
 120             { fGr1, nullptr },
 121             { fGr1, fGr2 },
 122         };
 123
 124         SkScalar gridStep = kSize + 2 * kInset;
 125         for (size_t i = 0; i < SK_ARRAY_COUNT(modes); ++i) {
 126             draw_label(canvas, SkBlendMode_Name(modes[i]),
 127                        SkPoint::Make(gridStep * (0.5f + i), 20));
 128         }
 129
 130         for (size_t i = 0; i < SK_ARRAY_COUNT(shaders); ++i) {
 131             canvas->save();
 132             canvas->translate(kInset, gridStep * i + 30);
 133             for (size_t m = 0; m < SK_ARRAY_COUNT(modes); ++m) {
 134                 draw_scene(canvas, fFilter, modes[m], shaders[i].fShader1,
 135                            shaders[i].fShader2);
 136                 canvas->translate(gridStep, 0);
 137             }
 138             canvas->restore();
 139         }
 140     }
 141
 142 private:
 143     sk_sp<SkColorFilter>    fFilter;
 144     sk_sp<SkShader>         fGr1, fGr2;
 145
 146     typedef skiagm::GM INHERITED;
 147 };
 148
 149 //////////////////////////////////////////////////////////////////////////////
 150
 151 DEF_GM(return new LumaFilterGM;)