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      1 /*
      2  * Copyright 2011 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 "SampleCode.h"
      9 #include "SkView.h"
     10 #include "SkCanvas.h"
     11 #include "SkDevice.h"
     12 #include "SkColorPriv.h"
     13 #include "SkShader.h"
     14 
     15 static const struct {
     16     SkXfermode::Mode  fMode;
     17     const char*         fLabel;
     18 } gModes[] = {
     19     { SkXfermode::kClear_Mode,    "Clear"     },
     20     { SkXfermode::kSrc_Mode,      "Src"       },
     21     { SkXfermode::kDst_Mode,      "Dst"       },
     22     { SkXfermode::kSrcOver_Mode,  "SrcOver"   },
     23     { SkXfermode::kDstOver_Mode,  "DstOver"   },
     24     { SkXfermode::kSrcIn_Mode,    "SrcIn"     },
     25     { SkXfermode::kDstIn_Mode,    "DstIn"     },
     26     { SkXfermode::kSrcOut_Mode,   "SrcOut"    },
     27     { SkXfermode::kDstOut_Mode,   "DstOut"    },
     28     { SkXfermode::kSrcATop_Mode,  "SrcATop"   },
     29     { SkXfermode::kDstATop_Mode,  "DstATop"   },
     30     { SkXfermode::kXor_Mode,      "Xor"       },
     31 };
     32 
     33 const int gWidth = 64;
     34 const int gHeight = 64;
     35 const SkScalar W = SkIntToScalar(gWidth);
     36 const SkScalar H = SkIntToScalar(gHeight);
     37 
     38 static SkScalar drawCell(SkCanvas* canvas, SkXfermode* mode, SkAlpha a0, SkAlpha a1) {
     39 
     40     SkPaint paint;
     41     paint.setAntiAlias(true);
     42 
     43     SkRect r = SkRect::MakeWH(W, H);
     44     r.inset(W/10, H/10);
     45 
     46     paint.setColor(SK_ColorBLUE);
     47     paint.setAlpha(a0);
     48     canvas->drawOval(r, paint);
     49 
     50     paint.setColor(SK_ColorRED);
     51     paint.setAlpha(a1);
     52     paint.setXfermode(mode);
     53     for (int angle = 0; angle < 24; ++angle) {
     54         SkScalar x = SkScalarCos(SkIntToScalar(angle) * (SK_ScalarPI * 2) / 24) * gWidth;
     55         SkScalar y = SkScalarSin(SkIntToScalar(angle) * (SK_ScalarPI * 2) / 24) * gHeight;
     56         paint.setStrokeWidth(SK_Scalar1 * angle * 2 / 24);
     57         canvas->drawLine(W/2, H/2, W/2 + x, H/2 + y, paint);
     58     }
     59 
     60     return H;
     61 }
     62 
     63 static SkShader* make_bg_shader() {
     64     SkBitmap bm;
     65     bm.allocN32Pixels(2, 2);
     66     *bm.getAddr32(0, 0) = *bm.getAddr32(1, 1) = 0xFFFFFFFF;
     67     *bm.getAddr32(1, 0) = *bm.getAddr32(0, 1) = SkPackARGB32(0xFF, 0xCC, 0xCC, 0xCC);
     68 
     69     SkMatrix m;
     70     m.setScale(SkIntToScalar(6), SkIntToScalar(6));
     71 
     72     return SkShader::CreateBitmapShader(bm,
     73                                         SkShader::kRepeat_TileMode,
     74                                         SkShader::kRepeat_TileMode,
     75                                         &m);
     76 }
     77 
     78 class HairModesView : public SampleView {
     79     SkPaint fBGPaint;
     80 public:
     81     HairModesView() {
     82         fBGPaint.setShader(make_bg_shader())->unref();
     83     }
     84 
     85 protected:
     86     // overrides from SkEventSink
     87     virtual bool onQuery(SkEvent* evt) {
     88         if (SampleCode::TitleQ(*evt)) {
     89             SampleCode::TitleR(evt, "HairlineModes");
     90             return true;
     91         }
     92         return this->INHERITED::onQuery(evt);
     93     }
     94 
     95     virtual void onDrawContent(SkCanvas* canvas) {
     96         const SkRect bounds = SkRect::MakeWH(W, H);
     97         static const SkAlpha gAlphaValue[] = { 0xFF, 0x88, 0x88 };
     98 
     99         canvas->translate(SkIntToScalar(4), SkIntToScalar(4));
    100 
    101         for (int alpha = 0; alpha < 4; ++alpha) {
    102             canvas->save();
    103             canvas->save();
    104             for (size_t i = 0; i < SK_ARRAY_COUNT(gModes); ++i) {
    105                 if (6 == i) {
    106                     canvas->restore();
    107                     canvas->translate(W * 5, 0);
    108                     canvas->save();
    109                 }
    110                 SkXfermode* mode = SkXfermode::Create(gModes[i].fMode);
    111 
    112                 canvas->drawRect(bounds, fBGPaint);
    113                 canvas->saveLayer(&bounds, nullptr);
    114                 SkScalar dy = drawCell(canvas, mode,
    115                                        gAlphaValue[alpha & 1],
    116                                        gAlphaValue[alpha & 2]);
    117                 canvas->restore();
    118 
    119                 canvas->translate(0, dy * 5 / 4);
    120                 SkSafeUnref(mode);
    121             }
    122             canvas->restore();
    123             canvas->restore();
    124             canvas->translate(W * 5 / 4, 0);
    125         }
    126     }
    127 
    128 private:
    129     typedef SampleView INHERITED;
    130 };
    131 
    132 ///////////////////////////////////////////////////////////////////////////////
    133 
    134 static SkView* MyFactory() { return new HairModesView; }
    135 static SkViewRegister reg(MyFactory);
    136