1 /*
2 * Copyright 2011 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 "SkParse.h"
8 #include "SkParsePath.h"
9
is_between(int c,int min,int max)10 static inline bool is_between(int c, int min, int max) {
11 return (unsigned)(c - min) <= (unsigned)(max - min);
12 }
13
is_ws(int c)14 static inline bool is_ws(int c) {
15 return is_between(c, 1, 32);
16 }
17
is_digit(int c)18 static inline bool is_digit(int c) {
19 return is_between(c, '0', '9');
20 }
21
is_sep(int c)22 static inline bool is_sep(int c) {
23 return is_ws(c) || c == ',';
24 }
25
is_lower(int c)26 static inline bool is_lower(int c) {
27 return is_between(c, 'a', 'z');
28 }
29
to_upper(int c)30 static inline int to_upper(int c) {
31 return c - 'a' + 'A';
32 }
33
skip_ws(const char str[])34 static const char* skip_ws(const char str[]) {
35 SkASSERT(str);
36 while (is_ws(*str))
37 str++;
38 return str;
39 }
40
skip_sep(const char str[])41 static const char* skip_sep(const char str[]) {
42 if (!str) {
43 return nullptr;
44 }
45 while (is_sep(*str))
46 str++;
47 return str;
48 }
49
find_points(const char str[],SkPoint value[],int count,bool isRelative,SkPoint * relative)50 static const char* find_points(const char str[], SkPoint value[], int count,
51 bool isRelative, SkPoint* relative) {
52 str = SkParse::FindScalars(str, &value[0].fX, count * 2);
53 if (isRelative) {
54 for (int index = 0; index < count; index++) {
55 value[index].fX += relative->fX;
56 value[index].fY += relative->fY;
57 }
58 }
59 return str;
60 }
61
find_scalar(const char str[],SkScalar * value,bool isRelative,SkScalar relative)62 static const char* find_scalar(const char str[], SkScalar* value,
63 bool isRelative, SkScalar relative) {
64 str = SkParse::FindScalar(str, value);
65 if (!str) {
66 return nullptr;
67 }
68 if (isRelative) {
69 *value += relative;
70 }
71 str = skip_sep(str);
72 return str;
73 }
74
FromSVGString(const char data[],SkPath * result)75 bool SkParsePath::FromSVGString(const char data[], SkPath* result) {
76 SkPath path;
77 SkPoint first = {0, 0};
78 SkPoint c = {0, 0};
79 SkPoint lastc = {0, 0};
80 SkPoint points[3];
81 char op = '\0';
82 char previousOp = '\0';
83 bool relative = false;
84 for (;;) {
85 if (!data) {
86 // Truncated data
87 return false;
88 }
89 data = skip_ws(data);
90 if (data[0] == '\0') {
91 break;
92 }
93 char ch = data[0];
94 if (is_digit(ch) || ch == '-' || ch == '+' || ch == '.') {
95 if (op == '\0') {
96 return false;
97 }
98 } else if (is_sep(ch)) {
99 data = skip_sep(data);
100 } else {
101 op = ch;
102 relative = false;
103 if (is_lower(op)) {
104 op = (char) to_upper(op);
105 relative = true;
106 }
107 data++;
108 data = skip_sep(data);
109 }
110 switch (op) {
111 case 'M':
112 data = find_points(data, points, 1, relative, &c);
113 path.moveTo(points[0]);
114 previousOp = '\0';
115 op = 'L';
116 c = points[0];
117 break;
118 case 'L':
119 data = find_points(data, points, 1, relative, &c);
120 path.lineTo(points[0]);
121 c = points[0];
122 break;
123 case 'H': {
124 SkScalar x;
125 data = find_scalar(data, &x, relative, c.fX);
126 path.lineTo(x, c.fY);
127 c.fX = x;
128 } break;
129 case 'V': {
130 SkScalar y;
131 data = find_scalar(data, &y, relative, c.fY);
132 path.lineTo(c.fX, y);
133 c.fY = y;
134 } break;
135 case 'C':
136 data = find_points(data, points, 3, relative, &c);
137 goto cubicCommon;
138 case 'S':
139 data = find_points(data, &points[1], 2, relative, &c);
140 points[0] = c;
141 if (previousOp == 'C' || previousOp == 'S') {
142 points[0].fX -= lastc.fX - c.fX;
143 points[0].fY -= lastc.fY - c.fY;
144 }
145 cubicCommon:
146 path.cubicTo(points[0], points[1], points[2]);
147 lastc = points[1];
148 c = points[2];
149 break;
150 case 'Q': // Quadratic Bezier Curve
151 data = find_points(data, points, 2, relative, &c);
152 goto quadraticCommon;
153 case 'T':
154 data = find_points(data, &points[1], 1, relative, &c);
155 points[0] = c;
156 if (previousOp == 'Q' || previousOp == 'T') {
157 points[0].fX -= lastc.fX - c.fX;
158 points[0].fY -= lastc.fY - c.fY;
159 }
160 quadraticCommon:
161 path.quadTo(points[0], points[1]);
162 lastc = points[0];
163 c = points[1];
164 break;
165 case 'A': {
166 SkPoint radii;
167 SkScalar angle, largeArc, sweep;
168 if ((data = find_points(data, &radii, 1, false, nullptr))
169 && (data = skip_sep(data))
170 && (data = find_scalar(data, &angle, false, 0))
171 && (data = skip_sep(data))
172 && (data = find_scalar(data, &largeArc, false, 0))
173 && (data = skip_sep(data))
174 && (data = find_scalar(data, &sweep, false, 0))
175 && (data = skip_sep(data))
176 && (data = find_points(data, &points[0], 1, relative, &c))) {
177 path.arcTo(radii, angle, (SkPath::ArcSize) SkToBool(largeArc),
178 (SkPath::Direction) !SkToBool(sweep), points[0]);
179 path.getLastPt(&c);
180 }
181 } break;
182 case 'Z':
183 path.close();
184 c = first;
185 break;
186 case '~': {
187 SkPoint args[2];
188 data = find_points(data, args, 2, false, nullptr);
189 path.moveTo(args[0].fX, args[0].fY);
190 path.lineTo(args[1].fX, args[1].fY);
191 } break;
192 default:
193 return false;
194 }
195 if (previousOp == 0) {
196 first = c;
197 }
198 previousOp = op;
199 }
200 // we're good, go ahead and swap in the result
201 result->swap(path);
202 return true;
203 }
204
205 ///////////////////////////////////////////////////////////////////////////////
206
207 #include "SkGeometry.h"
208 #include "SkString.h"
209 #include "SkStream.h"
210
write_scalar(SkWStream * stream,SkScalar value)211 static void write_scalar(SkWStream* stream, SkScalar value) {
212 char buffer[64];
213 #ifdef SK_BUILD_FOR_WIN32
214 int len = _snprintf(buffer, sizeof(buffer), "%g", value);
215 #else
216 int len = snprintf(buffer, sizeof(buffer), "%g", value);
217 #endif
218 char* stop = buffer + len;
219 stream->write(buffer, stop - buffer);
220 }
221
append_scalars(SkWStream * stream,char verb,const SkScalar data[],int count)222 static void append_scalars(SkWStream* stream, char verb, const SkScalar data[],
223 int count) {
224 stream->write(&verb, 1);
225 write_scalar(stream, data[0]);
226 for (int i = 1; i < count; i++) {
227 stream->write(" ", 1);
228 write_scalar(stream, data[i]);
229 }
230 }
231
ToSVGString(const SkPath & path,SkString * str)232 void SkParsePath::ToSVGString(const SkPath& path, SkString* str) {
233 SkDynamicMemoryWStream stream;
234
235 SkPath::Iter iter(path, false);
236 SkPoint pts[4];
237
238 for (;;) {
239 switch (iter.next(pts, false)) {
240 case SkPath::kConic_Verb: {
241 const SkScalar tol = SK_Scalar1 / 1024; // how close to a quad
242 SkAutoConicToQuads quadder;
243 const SkPoint* quadPts = quadder.computeQuads(pts, iter.conicWeight(), tol);
244 for (int i = 0; i < quadder.countQuads(); ++i) {
245 append_scalars(&stream, 'Q', &quadPts[i*2 + 1].fX, 4);
246 }
247 } break;
248 case SkPath::kMove_Verb:
249 append_scalars(&stream, 'M', &pts[0].fX, 2);
250 break;
251 case SkPath::kLine_Verb:
252 append_scalars(&stream, 'L', &pts[1].fX, 2);
253 break;
254 case SkPath::kQuad_Verb:
255 append_scalars(&stream, 'Q', &pts[1].fX, 4);
256 break;
257 case SkPath::kCubic_Verb:
258 append_scalars(&stream, 'C', &pts[1].fX, 6);
259 break;
260 case SkPath::kClose_Verb:
261 stream.write("Z", 1);
262 break;
263 case SkPath::kDone_Verb:
264 str->resize(stream.bytesWritten());
265 stream.copyTo(str->writable_str());
266 return;
267 }
268 }
269 }
270