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      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, 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, nullptr);
     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             { nullptr, nullptr },
    123             { nullptr, fGr2 },
    124             { fGr1, nullptr },
    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 new LumaFilterGM;)
    156