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      1 #include "gm.h"
      2 #include "SkGradientShader.h"
      3 
      4 namespace skiagm {
      5 
      6 struct GradData {
      7     int             fCount;
      8     const SkColor*  fColors;
      9     const SkScalar* fPos;
     10 };
     11 
     12 static const SkColor gColors[] = {
     13     SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorWHITE, SK_ColorBLACK
     14 };
     15 static const SkScalar gPos0[] = { 0, SK_Scalar1 };
     16 static const SkScalar gPos1[] = { SK_Scalar1/4, SK_Scalar1*3/4 };
     17 static const SkScalar gPos2[] = {
     18     0, SK_Scalar1/8, SK_Scalar1/2, SK_Scalar1*7/8, SK_Scalar1
     19 };
     20 
     21 static const GradData gGradData[] = {
     22     { 2, gColors, NULL },
     23     { 2, gColors, gPos0 },
     24     { 2, gColors, gPos1 },
     25     { 5, gColors, NULL },
     26     { 5, gColors, gPos2 }
     27 };
     28 
     29 static SkShader* MakeLinear(const SkPoint pts[2], const GradData& data,
     30                             SkShader::TileMode tm, SkUnitMapper* mapper) {
     31     return SkGradientShader::CreateLinear(pts, data.fColors, data.fPos,
     32                                           data.fCount, tm, mapper);
     33 }
     34 
     35 static SkShader* MakeRadial(const SkPoint pts[2], const GradData& data,
     36                             SkShader::TileMode tm, SkUnitMapper* mapper) {
     37     SkPoint center;
     38     center.set(SkScalarAve(pts[0].fX, pts[1].fX),
     39                SkScalarAve(pts[0].fY, pts[1].fY));
     40     return SkGradientShader::CreateRadial(center, center.fX, data.fColors,
     41                                           data.fPos, data.fCount, tm, mapper);
     42 }
     43 
     44 static SkShader* MakeSweep(const SkPoint pts[2], const GradData& data,
     45                            SkShader::TileMode tm, SkUnitMapper* mapper) {
     46     SkPoint center;
     47     center.set(SkScalarAve(pts[0].fX, pts[1].fX),
     48                SkScalarAve(pts[0].fY, pts[1].fY));
     49     return SkGradientShader::CreateSweep(center.fX, center.fY, data.fColors,
     50                                          data.fPos, data.fCount, mapper);
     51 }
     52 
     53 static SkShader* Make2Radial(const SkPoint pts[2], const GradData& data,
     54                              SkShader::TileMode tm, SkUnitMapper* mapper) {
     55     SkPoint center0, center1;
     56     center0.set(SkScalarAve(pts[0].fX, pts[1].fX),
     57                 SkScalarAve(pts[0].fY, pts[1].fY));
     58     center1.set(SkScalarInterp(pts[0].fX, pts[1].fX, SkIntToScalar(3)/5),
     59                 SkScalarInterp(pts[0].fY, pts[1].fY, SkIntToScalar(1)/4));
     60     return SkGradientShader::CreateTwoPointRadial(
     61                                                   center1, (pts[1].fX - pts[0].fX) / 7,
     62                                                   center0, (pts[1].fX - pts[0].fX) / 2,
     63                                                   data.fColors, data.fPos, data.fCount, tm, mapper);
     64 }
     65 
     66 typedef SkShader* (*GradMaker)(const SkPoint pts[2], const GradData& data,
     67                                SkShader::TileMode tm, SkUnitMapper* mapper);
     68 static const GradMaker gGradMakers[] = {
     69     MakeLinear, MakeRadial, MakeSweep, Make2Radial
     70 };
     71 
     72 ///////////////////////////////////////////////////////////////////////////////
     73 
     74 class GradientsGM : public GM {
     75 public:
     76 	GradientsGM() {}
     77 
     78 protected:
     79     SkString onShortName() {
     80         return SkString("gradients");
     81     }
     82 
     83 	SkISize onISize() { return make_isize(640, 510); }
     84 
     85     void drawBG(SkCanvas* canvas) {
     86         canvas->drawColor(0xFFDDDDDD);
     87     }
     88 
     89     virtual void onDraw(SkCanvas* canvas) {
     90         this->drawBG(canvas);
     91 
     92         SkPoint pts[2] = {
     93             { 0, 0 },
     94             { SkIntToScalar(100), SkIntToScalar(100) }
     95         };
     96         SkShader::TileMode tm = SkShader::kClamp_TileMode;
     97         SkRect r = { 0, 0, SkIntToScalar(100), SkIntToScalar(100) };
     98         SkPaint paint;
     99         paint.setAntiAlias(true);
    100 
    101         canvas->translate(SkIntToScalar(20), SkIntToScalar(20));
    102         for (size_t i = 0; i < SK_ARRAY_COUNT(gGradData); i++) {
    103             canvas->save();
    104             for (size_t j = 0; j < SK_ARRAY_COUNT(gGradMakers); j++) {
    105                 SkShader* shader = gGradMakers[j](pts, gGradData[i], tm, NULL);
    106                 paint.setShader(shader);
    107                 canvas->drawRect(r, paint);
    108                 shader->unref();
    109                 canvas->translate(0, SkIntToScalar(120));
    110             }
    111             canvas->restore();
    112             canvas->translate(SkIntToScalar(120), 0);
    113         }
    114     }
    115 
    116 private:
    117     typedef GM INHERITED;
    118 };
    119 
    120 ///////////////////////////////////////////////////////////////////////////////
    121 
    122 static GM* MyFactory(void*) { return new GradientsGM; }
    123 static GMRegistry reg(MyFactory);
    124 
    125 }
    126 
    127