1
2 /*
3 * Copyright 2011 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8 #include "SkParse.h"
9 #include "SkParsePath.h"
10
is_between(int c,int min,int max)11 static inline bool is_between(int c, int min, int max) {
12 return (unsigned)(c - min) <= (unsigned)(max - min);
13 }
14
is_ws(int c)15 static inline bool is_ws(int c) {
16 return is_between(c, 1, 32);
17 }
18
is_digit(int c)19 static inline bool is_digit(int c) {
20 return is_between(c, '0', '9');
21 }
22
is_sep(int c)23 static inline bool is_sep(int c) {
24 return is_ws(c) || c == ',';
25 }
26
is_lower(int c)27 static inline bool is_lower(int c) {
28 return is_between(c, 'a', 'z');
29 }
30
to_upper(int c)31 static inline int to_upper(int c) {
32 return c - 'a' + 'A';
33 }
34
skip_ws(const char str[])35 static const char* skip_ws(const char str[]) {
36 SkASSERT(str);
37 while (is_ws(*str))
38 str++;
39 return str;
40 }
41
skip_sep(const char str[])42 static const char* skip_sep(const char str[]) {
43 SkASSERT(str);
44 while (is_sep(*str))
45 str++;
46 return str;
47 }
48
find_points(const char str[],SkPoint value[],int count,bool isRelative,SkPoint * relative)49 static const char* find_points(const char str[], SkPoint value[], int count,
50 bool isRelative, SkPoint* relative) {
51 str = SkParse::FindScalars(str, &value[0].fX, count * 2);
52 if (isRelative) {
53 for (int index = 0; index < count; index++) {
54 value[index].fX += relative->fX;
55 value[index].fY += relative->fY;
56 }
57 }
58 return str;
59 }
60
find_scalar(const char str[],SkScalar * value,bool isRelative,SkScalar relative)61 static const char* find_scalar(const char str[], SkScalar* value,
62 bool isRelative, SkScalar relative) {
63 str = SkParse::FindScalar(str, value);
64 if (isRelative) {
65 *value += relative;
66 }
67 return str;
68 }
69
FromSVGString(const char data[],SkPath * result)70 bool SkParsePath::FromSVGString(const char data[], SkPath* result) {
71 SkPath path;
72 SkPoint f = {0, 0};
73 SkPoint c = {0, 0};
74 SkPoint lastc = {0, 0};
75 SkPoint points[3];
76 char op = '\0';
77 char previousOp = '\0';
78 bool relative = false;
79 for (;;) {
80 data = skip_ws(data);
81 if (data[0] == '\0') {
82 break;
83 }
84 char ch = data[0];
85 if (is_digit(ch) || ch == '-' || ch == '+') {
86 if (op == '\0') {
87 return false;
88 }
89 } else {
90 op = ch;
91 relative = false;
92 if (is_lower(op)) {
93 op = (char) to_upper(op);
94 relative = true;
95 }
96 data++;
97 data = skip_sep(data);
98 }
99 switch (op) {
100 case 'M':
101 data = find_points(data, points, 1, relative, &c);
102 path.moveTo(points[0]);
103 op = 'L';
104 c = points[0];
105 break;
106 case 'L':
107 data = find_points(data, points, 1, relative, &c);
108 path.lineTo(points[0]);
109 c = points[0];
110 break;
111 case 'H': {
112 SkScalar x;
113 data = find_scalar(data, &x, relative, c.fX);
114 path.lineTo(x, c.fY);
115 c.fX = x;
116 } break;
117 case 'V': {
118 SkScalar y;
119 data = find_scalar(data, &y, relative, c.fY);
120 path.lineTo(c.fX, y);
121 c.fY = y;
122 } break;
123 case 'C':
124 data = find_points(data, points, 3, relative, &c);
125 goto cubicCommon;
126 case 'S':
127 data = find_points(data, &points[1], 2, relative, &c);
128 points[0] = c;
129 if (previousOp == 'C' || previousOp == 'S') {
130 points[0].fX -= lastc.fX - c.fX;
131 points[0].fY -= lastc.fY - c.fY;
132 }
133 cubicCommon:
134 path.cubicTo(points[0], points[1], points[2]);
135 lastc = points[1];
136 c = points[2];
137 break;
138 case 'Q': // Quadratic Bezier Curve
139 data = find_points(data, points, 2, relative, &c);
140 goto quadraticCommon;
141 case 'T':
142 data = find_points(data, &points[1], 1, relative, &c);
143 points[0] = points[1];
144 if (previousOp == 'Q' || previousOp == 'T') {
145 points[0].fX = c.fX * 2 - lastc.fX;
146 points[0].fY = c.fY * 2 - lastc.fY;
147 }
148 quadraticCommon:
149 path.quadTo(points[0], points[1]);
150 lastc = points[0];
151 c = points[1];
152 break;
153 case 'Z':
154 path.close();
155 #if 0 // !!! still a bug?
156 if (fPath.isEmpty() && (f.fX != 0 || f.fY != 0)) {
157 c.fX -= SkScalar.Epsilon; // !!! enough?
158 fPath.moveTo(c);
159 fPath.lineTo(f);
160 fPath.close();
161 }
162 #endif
163 c = f;
164 op = '\0';
165 break;
166 case '~': {
167 SkPoint args[2];
168 data = find_points(data, args, 2, false, NULL);
169 path.moveTo(args[0].fX, args[0].fY);
170 path.lineTo(args[1].fX, args[1].fY);
171 } break;
172 default:
173 return false;
174 }
175 if (previousOp == 0) {
176 f = c;
177 }
178 previousOp = op;
179 }
180 // we're good, go ahead and swap in the result
181 result->swap(path);
182 return true;
183 }
184
185 ///////////////////////////////////////////////////////////////////////////////
186
187 #include "SkString.h"
188 #include "SkStream.h"
189
write_scalar(SkWStream * stream,SkScalar value)190 static void write_scalar(SkWStream* stream, SkScalar value) {
191 #ifdef SK_SCALAR_IS_FLOAT
192 char buffer[64];
193 #ifdef SK_BUILD_FOR_WIN32
194 int len = _snprintf(buffer, sizeof(buffer), "%g", value);
195 #else
196 int len = snprintf(buffer, sizeof(buffer), "%g", value);
197 #endif
198 char* stop = buffer + len;
199 #else
200 char buffer[SkStrAppendScalar_MaxSize];
201 char* stop = SkStrAppendScalar(buffer, value);
202 #endif
203 stream->write(buffer, stop - buffer);
204 }
205
append_scalars(SkWStream * stream,char verb,const SkScalar data[],int count)206 static void append_scalars(SkWStream* stream, char verb, const SkScalar data[],
207 int count) {
208 stream->write(&verb, 1);
209 write_scalar(stream, data[0]);
210 for (int i = 1; i < count; i++) {
211 stream->write(" ", 1);
212 write_scalar(stream, data[i]);
213 }
214 }
215
ToSVGString(const SkPath & path,SkString * str)216 void SkParsePath::ToSVGString(const SkPath& path, SkString* str) {
217 SkDynamicMemoryWStream stream;
218
219 SkPath::Iter iter(path, false);
220 SkPoint pts[4];
221
222 for (;;) {
223 switch (iter.next(pts)) {
224 case SkPath::kMove_Verb:
225 append_scalars(&stream, 'M', &pts[0].fX, 2);
226 break;
227 case SkPath::kLine_Verb:
228 append_scalars(&stream, 'L', &pts[1].fX, 2);
229 break;
230 case SkPath::kQuad_Verb:
231 append_scalars(&stream, 'Q', &pts[1].fX, 4);
232 break;
233 case SkPath::kCubic_Verb:
234 append_scalars(&stream, 'C', &pts[1].fX, 6);
235 break;
236 case SkPath::kClose_Verb:
237 stream.write("Z", 1);
238 break;
239 case SkPath::kDone_Verb:
240 str->resize(stream.getOffset());
241 stream.copyTo(str->writable_str());
242 return;
243 }
244 }
245 }
246
247