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      1 
      2 /*
      3  * Copyright 2014 Google Inc.
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  */
      8 
      9 #include "gm.h"
     10 #include "SkGradientShader.h"
     11 #include "SkPatchUtils.h"
     12 
     13 static SkShader* make_shader() {
     14     const SkColor colors[] = {
     15         SK_ColorRED, SK_ColorCYAN, SK_ColorGREEN, SK_ColorWHITE, SK_ColorMAGENTA, SK_ColorBLUE,
     16         SK_ColorYELLOW,
     17     };
     18     const SkPoint pts[] = { { 100.f / 4.f, 0.f }, { 3.f * 100.f / 4.f, 100.f } };
     19 
     20     return SkGradientShader::CreateLinear(pts, colors, nullptr, SK_ARRAY_COUNT(colors),
     21                                           SkShader::kMirror_TileMode);
     22 }
     23 
     24 static void draw_control_points(SkCanvas* canvas, const SkPoint cubics[12]) {
     25     //draw control points
     26     SkPaint paint;
     27     SkPoint bottom[SkPatchUtils::kNumPtsCubic];
     28     SkPatchUtils::getBottomCubic(cubics, bottom);
     29     SkPoint top[SkPatchUtils::kNumPtsCubic];
     30     SkPatchUtils::getTopCubic(cubics, top);
     31     SkPoint left[SkPatchUtils::kNumPtsCubic];
     32     SkPatchUtils::getLeftCubic(cubics, left);
     33     SkPoint right[SkPatchUtils::kNumPtsCubic];
     34     SkPatchUtils::getRightCubic(cubics, right);
     35 
     36     paint.setColor(SK_ColorBLACK);
     37     paint.setStrokeWidth(0.5f);
     38     SkPoint corners[4] = { bottom[0], bottom[3], top[0], top[3] };
     39     canvas->drawPoints(SkCanvas::kLines_PointMode, 4, bottom, paint);
     40     canvas->drawPoints(SkCanvas::kLines_PointMode, 2, bottom + 1, paint);
     41     canvas->drawPoints(SkCanvas::kLines_PointMode, 4, top, paint);
     42     canvas->drawPoints(SkCanvas::kLines_PointMode, 4, left, paint);
     43     canvas->drawPoints(SkCanvas::kLines_PointMode, 4, right, paint);
     44 
     45     canvas->drawPoints(SkCanvas::kLines_PointMode, 2, top + 1, paint);
     46     canvas->drawPoints(SkCanvas::kLines_PointMode, 2, left + 1, paint);
     47     canvas->drawPoints(SkCanvas::kLines_PointMode, 2, right + 1, paint);
     48 
     49     paint.setStrokeWidth(2);
     50 
     51     paint.setColor(SK_ColorRED);
     52     canvas->drawPoints(SkCanvas::kPoints_PointMode, 4, corners, paint);
     53 
     54     paint.setColor(SK_ColorBLUE);
     55     canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, bottom + 1, paint);
     56 
     57     paint.setColor(SK_ColorCYAN);
     58     canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, top + 1, paint);
     59 
     60     paint.setColor(SK_ColorYELLOW);
     61     canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, left + 1, paint);
     62 
     63     paint.setColor(SK_ColorGREEN);
     64     canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, right + 1, paint);
     65 }
     66 
     67 DEF_SIMPLE_GM(patch_primitive, canvas, 800, 800) {
     68         SkPaint paint;
     69 
     70         // The order of the colors and points is clockwise starting at upper-left corner.
     71         const SkPoint cubics[SkPatchUtils::kNumCtrlPts] = {
     72             //top points
     73             {100,100},{150,50},{250,150}, {300,100},
     74             //right points
     75             {250, 150},{350,250},
     76             //bottom points
     77             {300,300},{250,250},{150,350},{100,300},
     78             //left points
     79             {50,250},{150,150}
     80         };
     81 
     82         const SkColor colors[SkPatchUtils::kNumCorners] = {
     83             SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorCYAN
     84         };
     85         const SkPoint texCoords[SkPatchUtils::kNumCorners] = {
     86             {0.0f, 0.0f}, {100.0f, 0.0f}, {100.0f,100.0f}, {0.0f, 100.0f}}
     87         ;
     88 
     89         const SkXfermode::Mode modes[] = {
     90             SkXfermode::kSrc_Mode,
     91             SkXfermode::kDst_Mode,
     92             SkXfermode::kModulate_Mode,
     93         };
     94 
     95         SkAutoTUnref<SkShader> shader(make_shader());
     96 
     97         canvas->save();
     98         for (int y = 0; y < 3; y++) {
     99             SkAutoTUnref<SkXfermode> xfer(SkXfermode::Create(modes[y]));
    100 
    101             for (int x = 0; x < 4; x++) {
    102                 canvas->save();
    103                 canvas->translate(x * 350.0f, y * 350.0f);
    104                 switch (x) {
    105                     case 0:
    106                         canvas->drawPatch(cubics, nullptr, nullptr, xfer, paint);
    107                         break;
    108                     case 1:
    109                         canvas->drawPatch(cubics, colors, nullptr, xfer, paint);
    110                         break;
    111                     case 2:
    112                         paint.setShader(shader);
    113                         canvas->drawPatch(cubics, nullptr, texCoords, xfer, paint);
    114                         paint.setShader(nullptr);
    115                         break;
    116                     case 3:
    117                         paint.setShader(shader);
    118                         canvas->drawPatch(cubics, colors, texCoords, xfer, paint);
    119                         paint.setShader(nullptr);
    120                         break;
    121                     default:
    122                         break;
    123                 }
    124 
    125                 draw_control_points(canvas, cubics);
    126                 canvas->restore();
    127             }
    128         }
    129         canvas->restore();
    130 }
    131