1
2 //----------------------------------------------------------------------------
3 // Anti-Grain Geometry - Version 2.3
4 // Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
5 //
6 // Permission to copy, use, modify, sell and distribute this software
7 // is granted provided this copyright notice appears in all copies.
8 // This software is provided "as is" without express or implied
9 // warranty, and with no claim as to its suitability for any purpose.
10 //
11 //----------------------------------------------------------------------------
12 // Contact: [email protected]
13 // [email protected]
14 // http://www.antigrain.com
15 //----------------------------------------------------------------------------
16 //
17 // Liang-Barsky clipping
18 //
19 //----------------------------------------------------------------------------
20 #ifndef AGG_CLIP_LIANG_BARSKY_INCLUDED
21 #define AGG_CLIP_LIANG_BARSKY_INCLUDED
22 #include "agg_basics.h"
23 #include "third_party/base/numerics/safe_math.h"
24 namespace pdfium
25 {
26 namespace agg
27 {
28 template<class T>
clipping_flags(T x,T y,const rect_base<T> & clip_box)29 inline unsigned clipping_flags(T x, T y, const rect_base<T>& clip_box)
30 {
31 return (x > clip_box.x2) |
32 ((y > clip_box.y2) << 1) |
33 ((x < clip_box.x1) << 2) |
34 ((y < clip_box.y1) << 3);
35 }
36 template<class T>
clip_liang_barsky(T x1,T y1,T x2,T y2,const rect_base<T> & clip_box,T * x,T * y)37 inline unsigned clip_liang_barsky(T x1, T y1, T x2, T y2,
38 const rect_base<T>& clip_box,
39 T* x, T* y)
40 {
41 const float nearzero = 1e-30f;
42
43 pdfium::base::CheckedNumeric<float> width = x2;
44 width -= x1;
45 if (!width.IsValid())
46 return 0;
47 pdfium::base::CheckedNumeric<float> height = y2;
48 height -= y1;
49 if (!height.IsValid())
50 return 0;
51
52 float deltax = width.ValueOrDefault(0);
53 float deltay = height.ValueOrDefault(0);
54 unsigned np = 0;
55 if(deltax == 0) {
56 deltax = (x1 > clip_box.x1) ? -nearzero : nearzero;
57 }
58 float xin, xout;
59 if(deltax > 0) {
60 xin = (float)clip_box.x1;
61 xout = (float)clip_box.x2;
62 } else {
63 xin = (float)clip_box.x2;
64 xout = (float)clip_box.x1;
65 }
66 float tinx = (xin - x1) / deltax;
67 if(deltay == 0) {
68 deltay = (y1 > clip_box.y1) ? -nearzero : nearzero;
69 }
70 float yin, yout;
71 if(deltay > 0) {
72 yin = (float)clip_box.y1;
73 yout = (float)clip_box.y2;
74 } else {
75 yin = (float)clip_box.y2;
76 yout = (float)clip_box.y1;
77 }
78 float tiny = (yin - y1) / deltay;
79 float tin1, tin2;
80 if (tinx < tiny) {
81 tin1 = tinx;
82 tin2 = tiny;
83 } else {
84 tin1 = tiny;
85 tin2 = tinx;
86 }
87 if(tin1 <= 1.0f) {
88 if(0 < tin1) {
89 *x++ = (T)xin;
90 *y++ = (T)yin;
91 ++np;
92 }
93 if(tin2 <= 1.0f) {
94 float toutx = (xout - x1) / deltax;
95 float touty = (yout - y1) / deltay;
96 float tout1 = (toutx < touty) ? toutx : touty;
97 if (tin2 > 0 || tout1 > 0) {
98 if(tin2 <= tout1) {
99 if(tin2 > 0) {
100 if(tinx > tiny) {
101 *x++ = (T)xin;
102 *y++ = (T)(y1 + (deltay * tinx));
103 } else {
104 *x++ = (T)(x1 + (deltax * tiny));
105 *y++ = (T)yin;
106 }
107 ++np;
108 }
109 if(tout1 < 1.0f) {
110 if(toutx < touty) {
111 *x++ = (T)xout;
112 *y++ = (T)(y1 + (deltay * toutx));
113 } else {
114 *x++ = (T)(x1 + (deltax * touty));
115 *y++ = (T)yout;
116 }
117 } else {
118 *x++ = x2;
119 *y++ = y2;
120 }
121 ++np;
122 } else {
123 if(tinx > tiny) {
124 *x++ = (T)xin;
125 *y++ = (T)yout;
126 } else {
127 *x++ = (T)xout;
128 *y++ = (T)yin;
129 }
130 ++np;
131 }
132 }
133 }
134 }
135 return np;
136 }
137 }
138 } // namespace pdfium
139 #endif
140