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 "SkPath.h"
11#include "SkRandom.h"
12#include "SkScalar.h"
13#include "SkTArray.h"
14
15namespace skiagm {
16
17// This GM tests a grab-bag of convex and concave polygons. They are triangles,
18// trapezoid, diamond, polygons with lots of edges, several concave polygons...
19// But rectangles are excluded.
20class PolygonsGM: public GM {
21public:
22    PolygonsGM() {}
23
24protected:
25    virtual SkString onShortName() SK_OVERRIDE {
26        return SkString("polygons");
27    }
28
29    virtual SkISize onISize() SK_OVERRIDE {
30        size_t width = kNumPolygons * kCellSize + 40;
31        size_t height = (kNumJoins * kNumStrokeWidths + kNumExtraStyles) * kCellSize + 40;
32        return SkISize::Make(width, height);
33    }
34
35    // Construct all polygons
36    virtual void onOnceBeforeDraw() SK_OVERRIDE {
37        SkPoint p0[] = {{0, 0}, {60, 0}, {90, 40}};  // triangle
38        SkPoint p1[] = {{0, 0}, {0, 40}, {60, 40}, {40, 0}};  // trapezoid
39        SkPoint p2[] = {{0, 0}, {40, 40}, {80, 40}, {40, 0}};  // diamond
40        SkPoint p3[] = {{10, 0}, {50, 0}, {60, 10}, {60, 30}, {50, 40},
41                        {10, 40}, {0, 30}, {0, 10}};  // octagon
42        SkPoint p4[32];  // circle-like polygons with 32-edges.
43        SkPoint p5[] = {{0, 0}, {20, 20}, {0, 40}, {60, 20}};  // concave polygon with 4 edges
44        SkPoint p6[] = {{0, 40}, {0, 30}, {15, 30}, {15, 20}, {30, 20},
45                        {30, 10}, {45, 10}, {45, 0}, {60, 0}, {60, 40}};  // stairs-like polygon
46        SkPoint p7[] = {{0, 20}, {20, 20}, {30, 0}, {40, 20}, {60, 20},
47                        {45, 30}, {55, 50}, {30, 40}, {5, 50}, {15, 30}};  // five-point stars
48
49        for (size_t i = 0; i < SK_ARRAY_COUNT(p4); ++i) {
50            SkScalar angle = 2 * SK_ScalarPI * i / SK_ARRAY_COUNT(p4);
51            p4[i].set(20 * SkScalarCos(angle) + 20, 20 * SkScalarSin(angle) + 20);
52        }
53
54        struct Polygons {
55            SkPoint* fPoints;
56            size_t fPointNum;
57        } pgs[] = {
58            { p0, SK_ARRAY_COUNT(p0) },
59            { p1, SK_ARRAY_COUNT(p1) },
60            { p2, SK_ARRAY_COUNT(p2) },
61            { p3, SK_ARRAY_COUNT(p3) },
62            { p4, SK_ARRAY_COUNT(p4) },
63            { p5, SK_ARRAY_COUNT(p5) },
64            { p6, SK_ARRAY_COUNT(p6) },
65            { p7, SK_ARRAY_COUNT(p7) }
66        };
67
68        SkASSERT(SK_ARRAY_COUNT(pgs) == kNumPolygons);
69        for (size_t pgIndex = 0; pgIndex < SK_ARRAY_COUNT(pgs); ++pgIndex) {
70            fPolygons.push_back().moveTo(pgs[pgIndex].fPoints[0].fX,
71                                         pgs[pgIndex].fPoints[0].fY);
72            for (size_t ptIndex = 1; ptIndex < pgs[pgIndex].fPointNum; ++ptIndex) {
73                fPolygons.back().lineTo(pgs[pgIndex].fPoints[ptIndex].fX,
74                                        pgs[pgIndex].fPoints[ptIndex].fY);
75            }
76            fPolygons.back().close();
77        }
78    }
79
80    // Set the location for the current test on the canvas
81    static void SetLocation(SkCanvas* canvas, int counter, int lineNum) {
82        SkScalar x = SK_Scalar1 * kCellSize * (counter % lineNum) + 30 + SK_Scalar1 / 4;
83        SkScalar y = SK_Scalar1 * kCellSize * (counter / lineNum) + 30 + 3 * SK_Scalar1 / 4;
84        canvas->translate(x, y);
85    }
86
87    static void SetColorAndAlpha(SkPaint* paint, SkLCGRandom* rand) {
88        SkColor color = rand->nextU();
89        color |= 0xff000000;
90        paint->setColor(color);
91        if (40 == paint->getStrokeWidth()) {
92            paint->setAlpha(0xA0);
93        }
94    }
95
96    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
97        // Stroke widths are:
98        // 0(may use hairline rendering), 10(common case for stroke-style)
99        // 40(>= geometry width/height, make the contour filled in fact)
100        static const int kStrokeWidths[] = {0, 10, 40};
101        SkASSERT(kNumStrokeWidths == SK_ARRAY_COUNT(kStrokeWidths));
102
103        static const SkPaint::Join kJoins[] = {
104            SkPaint::kMiter_Join, SkPaint::kRound_Join, SkPaint::kBevel_Join
105        };
106        SkASSERT(kNumJoins == SK_ARRAY_COUNT(kJoins));
107
108        int counter = 0;
109        SkPaint paint;
110        paint.setAntiAlias(true);
111
112        SkLCGRandom rand;
113        // For stroke style painter
114        paint.setStyle(SkPaint::kStroke_Style);
115        for (int join = 0; join < kNumJoins; ++join) {
116            for (int width = 0; width < kNumStrokeWidths; ++width) {
117                for (int i = 0; i < fPolygons.count(); ++i) {
118                    canvas->save();
119                    SetLocation(canvas, counter, fPolygons.count());
120
121                    SetColorAndAlpha(&paint, &rand);
122                    paint.setStrokeJoin(kJoins[join]);
123                    paint.setStrokeWidth(SkIntToScalar(kStrokeWidths[width]));
124
125                    canvas->drawPath(fPolygons[i], paint);
126                    canvas->restore();
127                    ++counter;
128                }
129            }
130        }
131
132        // For stroke-and-fill style painter and fill style painter
133        static const SkPaint::Style kStyles[] = {
134            SkPaint::kStrokeAndFill_Style, SkPaint::kFill_Style
135        };
136        SkASSERT(kNumExtraStyles == SK_ARRAY_COUNT(kStyles));
137
138        paint.setStrokeJoin(SkPaint::kMiter_Join);
139        paint.setStrokeWidth(SkIntToScalar(20));
140        for (int style = 0; style < kNumExtraStyles; ++style) {
141            paint.setStyle(kStyles[style]);
142            for (int i = 0; i < fPolygons.count(); ++i) {
143                canvas->save();
144                SetLocation(canvas, counter, fPolygons.count());
145                SetColorAndAlpha(&paint, &rand);
146                canvas->drawPath(fPolygons[i], paint);
147                canvas->restore();
148                ++counter;
149            }
150        }
151    }
152
153private:
154    static const int kNumPolygons = 8;
155    static const int kCellSize = 100;
156    static const int kNumExtraStyles = 2;
157    static const int kNumStrokeWidths = 3;
158    static const int kNumJoins = 3;
159
160    SkTArray<SkPath> fPolygons;
161    typedef GM INHERITED;
162};
163
164//////////////////////////////////////////////////////////////////////////////
165
166DEF_GM(return new PolygonsGM;)
167
168}
169