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1 /* libs/graphics/effects/SkCullPoints.cpp | |
2 ** | |
3 ** Copyright 2006, The Android Open Source Project | |
4 ** | |
5 ** Licensed under the Apache License, Version 2.0 (the "License"); | |
6 ** you may not use this file except in compliance with the License. | |
7 ** You may obtain a copy of the License at | |
8 ** | |
9 ** http://www.apache.org/licenses/LICENSE-2.0 | |
10 ** | |
11 ** Unless required by applicable law or agreed to in writing, software | |
12 ** distributed under the License is distributed on an "AS IS" BASIS, | |
13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
14 ** See the License for the specific language governing permissions and | |
15 ** limitations under the License. | |
16 */ | |
17 | |
18 #include "SkCullPoints.h" | |
19 #include "Sk64.h" | |
20 | |
21 static bool cross_product_is_neg(const SkIPoint& v, int dx, int dy) | |
22 { | |
23 #if 0 | |
24 return v.fX * dy - v.fY * dx < 0; | |
25 #else | |
26 Sk64 tmp0, tmp1; | |
27 | |
28 tmp0.setMul(v.fX, dy); | |
29 tmp1.setMul(dx, v.fY); | |
30 tmp0.sub(tmp1); | |
31 return tmp0.isNeg(); | |
32 #endif | |
33 } | |
34 | |
35 bool SkCullPoints::sect_test(int x0, int y0, int x1, int y1) const | |
36 { | |
37 const SkIRect& r = fR; | |
38 | |
39 if ((x0 < r.fLeft && x1 < r.fLeft) || | |
40 (x0 > r.fRight && x1 > r.fRight) || | |
41 (y0 < r.fTop && y1 < r.fTop) || | |
42 (y0 > r.fBottom && y1 > r.fBottom)) | |
43 return false; | |
44 | |
45 // since the crossprod test is a little expensive, check for easy-in cases f
irst | |
46 if (r.contains(x0, y0) || r.contains(x1, y1)) | |
47 return true; | |
48 | |
49 // At this point we're not sure, so we do a crossprod test | |
50 SkIPoint vec; | |
51 const SkIPoint* rAsQuad = fAsQuad; | |
52 | |
53 vec.set(x1 - x0, y1 - y0); | |
54 bool isNeg = cross_product_is_neg(vec, x0 - rAsQuad[0].fX, y0 - rAsQuad[0].f
Y); | |
55 for (int i = 1; i < 4; i++) { | |
56 if (cross_product_is_neg(vec, x0 - rAsQuad[i].fX, y0 - rAsQuad[i].fY) !=
isNeg) | |
57 { | |
58 return true; | |
59 } | |
60 } | |
61 return false; // we didn't intersect | |
62 } | |
63 | |
64 static void toQuad(const SkIRect& r, SkIPoint quad[4]) | |
65 { | |
66 SkASSERT(quad); | |
67 | |
68 quad[0].set(r.fLeft, r.fTop); | |
69 quad[1].set(r.fRight, r.fTop); | |
70 quad[2].set(r.fRight, r.fBottom); | |
71 quad[3].set(r.fLeft, r.fBottom); | |
72 } | |
73 | |
74 SkCullPoints::SkCullPoints() | |
75 { | |
76 SkIRect r; | |
77 r.setEmpty(); | |
78 this->reset(r); | |
79 } | |
80 | |
81 SkCullPoints::SkCullPoints(const SkIRect& r) | |
82 { | |
83 this->reset(r); | |
84 } | |
85 | |
86 void SkCullPoints::reset(const SkIRect& r) | |
87 { | |
88 fR = r; | |
89 toQuad(fR, fAsQuad); | |
90 fPrevPt.set(0, 0); | |
91 fPrevResult = kNo_Result; | |
92 } | |
93 | |
94 void SkCullPoints::moveTo(int x, int y) | |
95 { | |
96 fPrevPt.set(x, y); | |
97 fPrevResult = kNo_Result; // so we trigger a movetolineto later | |
98 } | |
99 | |
100 SkCullPoints::LineToResult SkCullPoints::lineTo(int x, int y, SkIPoint line[]) | |
101 { | |
102 SkASSERT(line != NULL); | |
103 | |
104 LineToResult result = kNo_Result; | |
105 int x0 = fPrevPt.fX; | |
106 int y0 = fPrevPt.fY; | |
107 | |
108 // need to upgrade sect_test to chop the result | |
109 // and to correctly return kLineTo_Result when the result is connected | |
110 // to the previous call-out | |
111 if (this->sect_test(x0, y0, x, y)) | |
112 { | |
113 line[0].set(x0, y0); | |
114 line[1].set(x, y); | |
115 | |
116 if (fPrevResult != kNo_Result && fPrevPt.equals(x0, y0)) | |
117 result = kLineTo_Result; | |
118 else | |
119 result = kMoveToLineTo_Result; | |
120 } | |
121 | |
122 fPrevPt.set(x, y); | |
123 fPrevResult = result; | |
124 | |
125 return result; | |
126 } | |
127 | |
128 ////////////////////////////////////////////////////////////////////////////////
///////////////// | |
129 | |
130 #include "SkPath.h" | |
131 | |
132 SkCullPointsPath::SkCullPointsPath() | |
133 : fCP(), fPath(NULL) | |
134 { | |
135 } | |
136 | |
137 SkCullPointsPath::SkCullPointsPath(const SkIRect& r, SkPath* dst) | |
138 : fCP(r), fPath(dst) | |
139 { | |
140 } | |
141 | |
142 void SkCullPointsPath::reset(const SkIRect& r, SkPath* dst) | |
143 { | |
144 fCP.reset(r); | |
145 fPath = dst; | |
146 } | |
147 | |
148 void SkCullPointsPath::moveTo(int x, int y) | |
149 { | |
150 fCP.moveTo(x, y); | |
151 } | |
152 | |
153 void SkCullPointsPath::lineTo(int x, int y) | |
154 { | |
155 SkIPoint pts[2]; | |
156 | |
157 switch (fCP.lineTo(x, y, pts)) { | |
158 case SkCullPoints::kMoveToLineTo_Result: | |
159 fPath->moveTo(SkIntToScalar(pts[0].fX), SkIntToScalar(pts[0].fY)); | |
160 // fall through to the lineto case | |
161 case SkCullPoints::kLineTo_Result: | |
162 fPath->lineTo(SkIntToScalar(pts[1].fX), SkIntToScalar(pts[1].fY)); | |
163 break; | |
164 default: | |
165 break; | |
166 } | |
167 } | |
168 | |
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