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