1/*
2 * Copyright 2017 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#include "Test.h"
8#include "SkInsetConvexPolygon.h"
9
10static bool is_convex(const SkTDArray<SkPoint>& poly) {
11    if (poly.count() < 3) {
12        return false;
13    }
14
15    SkVector v0 = poly[0] - poly[poly.count() - 1];
16    SkVector v1 = poly[1] - poly[poly.count() - 1];
17    SkScalar winding = v0.cross(v1);
18
19    for (int i = 0; i < poly.count()-1; ++i) {
20        int j = i + 1;
21        int k = (i + 2) % poly.count();
22
23        SkVector v0 = poly[j] - poly[i];
24        SkVector v1 = poly[k] - poly[i];
25        SkScalar perpDot = v0.cross(v1);
26        int side = winding*perpDot;
27        if (side < 0) {
28            return false;
29        }
30    }
31
32    return true;
33}
34
35DEF_TEST(InsetConvexPoly, reporter) {
36    SkTDArray<SkPoint> rrectPoly;
37
38    // round rect
39    *rrectPoly.push() = SkPoint::Make(-100, 55);
40    *rrectPoly.push() = SkPoint::Make(100, 55);
41    *rrectPoly.push() = SkPoint::Make(100 + 2.5f, 50 + 4.330127f);
42    *rrectPoly.push() = SkPoint::Make(100 + 3.535534f, 50 + 3.535534f);
43    *rrectPoly.push() = SkPoint::Make(100 + 4.330127f, 50 + 2.5f);
44    *rrectPoly.push() = SkPoint::Make(105, 50);
45    *rrectPoly.push() = SkPoint::Make(105, -50);
46    *rrectPoly.push() = SkPoint::Make(100 + 4.330127f, -50 - 2.5f);
47    *rrectPoly.push() = SkPoint::Make(100 + 3.535534f, -50 - 3.535534f);
48    *rrectPoly.push() = SkPoint::Make(100 + 2.5f, -50 - 4.330127f);
49    *rrectPoly.push() = SkPoint::Make(100, -55);
50    *rrectPoly.push() = SkPoint::Make(-100, -55);
51    *rrectPoly.push() = SkPoint::Make(-100 - 2.5f, -50 - 4.330127f);
52    *rrectPoly.push() = SkPoint::Make(-100 - 3.535534f, -50 - 3.535534f);
53    *rrectPoly.push() = SkPoint::Make(-100 - 4.330127f, -50 - 2.5f);
54    *rrectPoly.push() = SkPoint::Make(-105, -50);
55    *rrectPoly.push() = SkPoint::Make(-105, 50);
56    *rrectPoly.push() = SkPoint::Make(-100 - 4.330127f, 50 + 2.5f);
57    *rrectPoly.push() = SkPoint::Make(-100 - 3.535534f, 50 + 3.535534f);
58    *rrectPoly.push() = SkPoint::Make(-100 - 2.5f, 50 + 4.330127f);
59    REPORTER_ASSERT(reporter, is_convex(rrectPoly));
60
61    // inset a little
62    SkTDArray<SkPoint> insetPoly;
63    bool result = SkInsetConvexPolygon(&rrectPoly[0], rrectPoly.count(), 3, &insetPoly);
64    REPORTER_ASSERT(reporter, result);
65    REPORTER_ASSERT(reporter, is_convex(insetPoly));
66
67    // inset to rect
68    result = SkInsetConvexPolygon(&rrectPoly[0], rrectPoly.count(), 10, &insetPoly);
69    REPORTER_ASSERT(reporter, result);
70    REPORTER_ASSERT(reporter, is_convex(insetPoly));
71    REPORTER_ASSERT(reporter, insetPoly.count() == 4);
72    if (insetPoly.count() == 4) {
73        REPORTER_ASSERT(reporter, insetPoly[0].equals(-95, 45));
74        REPORTER_ASSERT(reporter, insetPoly[1].equals(95, 45));
75        REPORTER_ASSERT(reporter, insetPoly[2].equals(95, -45));
76        REPORTER_ASSERT(reporter, insetPoly[3].equals(-95, -45));
77    }
78
79    // just to full inset
80    // fails, but outputs a line segment
81    result = SkInsetConvexPolygon(&rrectPoly[0], rrectPoly.count(), 55, &insetPoly);
82    REPORTER_ASSERT(reporter, !result);
83    REPORTER_ASSERT(reporter, !is_convex(insetPoly));
84    REPORTER_ASSERT(reporter, insetPoly.count() == 2);
85    if (insetPoly.count() == 2) {
86        REPORTER_ASSERT(reporter, insetPoly[0].equals(-50, 0));
87        REPORTER_ASSERT(reporter, insetPoly[1].equals(50, 0));
88    }
89
90    // past full inset
91    result = SkInsetConvexPolygon(&rrectPoly[0], rrectPoly.count(), 75, &insetPoly);
92    REPORTER_ASSERT(reporter, !result);
93    REPORTER_ASSERT(reporter, insetPoly.count() == 0);
94
95    // troublesome case
96    SkTDArray<SkPoint> clippedRRectPoly;
97    *clippedRRectPoly.push() = SkPoint::Make(335.928101f, 428.219055f);
98    *clippedRRectPoly.push() = SkPoint::Make(330.414459f, 423.034912f);
99    *clippedRRectPoly.push() = SkPoint::Make(325.749084f, 417.395508f);
100    *clippedRRectPoly.push() = SkPoint::Make(321.931946f, 411.300842f);
101    *clippedRRectPoly.push() = SkPoint::Make(318.963074f, 404.750977f);
102    *clippedRRectPoly.push() = SkPoint::Make(316.842468f, 397.745850f);
103    *clippedRRectPoly.push() = SkPoint::Make(315.570068f, 390.285522f);
104    *clippedRRectPoly.push() = SkPoint::Make(315.145966f, 382.369965f);
105    *clippedRRectPoly.push() = SkPoint::Make(315.570068f, 374.454346f);
106    *clippedRRectPoly.push() = SkPoint::Make(316.842468f, 366.994019f);
107    *clippedRRectPoly.push() = SkPoint::Make(318.963074f, 359.988892f);
108    *clippedRRectPoly.push() = SkPoint::Make(321.931946f, 353.439056f);
109    *clippedRRectPoly.push() = SkPoint::Make(325.749084f, 347.344421f);
110    *clippedRRectPoly.push() = SkPoint::Make(330.414459f, 341.705017f);
111    *clippedRRectPoly.push() = SkPoint::Make(335.928101f, 336.520813f);
112    *clippedRRectPoly.push() = SkPoint::Make(342.289948f, 331.791901f);
113    *clippedRRectPoly.push() = SkPoint::Make(377.312134f, 331.791901f);
114    *clippedRRectPoly.push() = SkPoint::Make(381.195313f, 332.532593f);
115    *clippedRRectPoly.push() = SkPoint::Make(384.464935f, 334.754700f);
116    *clippedRRectPoly.push() = SkPoint::Make(386.687042f, 338.024292f);
117    *clippedRRectPoly.push() = SkPoint::Make(387.427765f, 341.907532f);
118    *clippedRRectPoly.push() = SkPoint::Make(387.427765f, 422.832367f);
119    *clippedRRectPoly.push() = SkPoint::Make(386.687042f, 426.715576f);
120    *clippedRRectPoly.push() = SkPoint::Make(384.464935f, 429.985168f);
121    *clippedRRectPoly.push() = SkPoint::Make(381.195313f, 432.207275f);
122    *clippedRRectPoly.push() = SkPoint::Make(377.312134f, 432.947998f);
123    *clippedRRectPoly.push() = SkPoint::Make(342.289948f, 432.947998f);
124    REPORTER_ASSERT(reporter, is_convex(clippedRRectPoly));
125
126    result = SkInsetConvexPolygon(&clippedRRectPoly[0], clippedRRectPoly.count(), 32.3699417f,
127                                  &insetPoly);
128    REPORTER_ASSERT(reporter, result);
129    REPORTER_ASSERT(reporter, is_convex(insetPoly));
130}
131