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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, 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     virtual uint32_t onGetFlags() const SK_OVERRIDE {
    102         return kSkipTiled_Flag;
    103     }
    104 
    105     virtual SkString onShortName() SK_OVERRIDE {
    106         return SkString("lumafilter");
    107     }
    108 
    109     virtual SkISize onISize() SK_OVERRIDE {
    110         return SkISize::Make(600, 420);
    111     }
    112 
    113     virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
    114         SkXfermode::Mode modes[] = { SkXfermode::kSrcOver_Mode,
    115                                      SkXfermode::kDstOver_Mode,
    116                                      SkXfermode::kSrcATop_Mode,
    117                                      SkXfermode::kDstATop_Mode,
    118                                      SkXfermode::kSrcIn_Mode,
    119                                      SkXfermode::kDstIn_Mode,
    120                                    };
    121         struct {
    122             SkShader*   fShader1;
    123             SkShader*   fShader2;
    124         } shaders[] = {
    125             { NULL, NULL },
    126             { NULL, fGr2 },
    127             { fGr1, NULL },
    128             { fGr1, fGr2 },
    129         };
    130 
    131         SkScalar gridStep = kSize + 2 * kInset;
    132         for (size_t i = 0; i < SK_ARRAY_COUNT(modes); ++i) {
    133             draw_label(canvas, SkXfermode::ModeName(modes[i]),
    134                        SkPoint::Make(gridStep * (0.5f + i), 20));
    135         }
    136 
    137         for (size_t i = 0; i < SK_ARRAY_COUNT(shaders); ++i) {
    138             canvas->save();
    139             canvas->translate(kInset, gridStep * i + 30);
    140             for (size_t m = 0; m < SK_ARRAY_COUNT(modes); ++m) {
    141                 draw_scene(canvas, fFilter, modes[m], shaders[i].fShader1,
    142                            shaders[i].fShader2);
    143                 canvas->translate(gridStep, 0);
    144             }
    145             canvas->restore();
    146         }
    147     }
    148 
    149 private:
    150     SkAutoTUnref<SkColorFilter> fFilter;
    151     SkAutoTUnref<SkShader>      fGr1, fGr2;
    152 
    153     typedef skiagm::GM INHERITED;
    154 };
    155 
    156 //////////////////////////////////////////////////////////////////////////////
    157 
    158 DEF_GM( return SkNEW(LumaFilterGM); )
    159