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
8
9 #include "SkData.h"
10 #include "SkGeometry.h"
11 #include "SkPaint.h"
12 #include "SkPath.h"
13 #include "SkPDFResourceDict.h"
14 #include "SkPDFUtils.h"
15 #include "SkStream.h"
16 #include "SkString.h"
17 #include "SkPDFTypes.h"
18
19 //static
RectToArray(const SkRect & rect)20 SkPDFArray* SkPDFUtils::RectToArray(const SkRect& rect) {
21 SkPDFArray* result = new SkPDFArray();
22 result->reserve(4);
23 result->appendScalar(rect.fLeft);
24 result->appendScalar(rect.fTop);
25 result->appendScalar(rect.fRight);
26 result->appendScalar(rect.fBottom);
27 return result;
28 }
29
30 // static
MatrixToArray(const SkMatrix & matrix)31 SkPDFArray* SkPDFUtils::MatrixToArray(const SkMatrix& matrix) {
32 SkScalar values[6];
33 if (!matrix.asAffine(values)) {
34 SkMatrix::SetAffineIdentity(values);
35 }
36
37 SkPDFArray* result = new SkPDFArray;
38 result->reserve(6);
39 for (size_t i = 0; i < SK_ARRAY_COUNT(values); i++) {
40 result->appendScalar(values[i]);
41 }
42 return result;
43 }
44
45 // static
AppendTransform(const SkMatrix & matrix,SkWStream * content)46 void SkPDFUtils::AppendTransform(const SkMatrix& matrix, SkWStream* content) {
47 SkScalar values[6];
48 if (!matrix.asAffine(values)) {
49 SkMatrix::SetAffineIdentity(values);
50 }
51 for (size_t i = 0; i < SK_ARRAY_COUNT(values); i++) {
52 SkPDFUtils::AppendScalar(values[i], content);
53 content->writeText(" ");
54 }
55 content->writeText("cm\n");
56 }
57
58 // static
MoveTo(SkScalar x,SkScalar y,SkWStream * content)59 void SkPDFUtils::MoveTo(SkScalar x, SkScalar y, SkWStream* content) {
60 SkPDFUtils::AppendScalar(x, content);
61 content->writeText(" ");
62 SkPDFUtils::AppendScalar(y, content);
63 content->writeText(" m\n");
64 }
65
66 // static
AppendLine(SkScalar x,SkScalar y,SkWStream * content)67 void SkPDFUtils::AppendLine(SkScalar x, SkScalar y, SkWStream* content) {
68 SkPDFUtils::AppendScalar(x, content);
69 content->writeText(" ");
70 SkPDFUtils::AppendScalar(y, content);
71 content->writeText(" l\n");
72 }
73
74 // static
AppendCubic(SkScalar ctl1X,SkScalar ctl1Y,SkScalar ctl2X,SkScalar ctl2Y,SkScalar dstX,SkScalar dstY,SkWStream * content)75 void SkPDFUtils::AppendCubic(SkScalar ctl1X, SkScalar ctl1Y,
76 SkScalar ctl2X, SkScalar ctl2Y,
77 SkScalar dstX, SkScalar dstY, SkWStream* content) {
78 SkString cmd("y\n");
79 SkPDFUtils::AppendScalar(ctl1X, content);
80 content->writeText(" ");
81 SkPDFUtils::AppendScalar(ctl1Y, content);
82 content->writeText(" ");
83 if (ctl2X != dstX || ctl2Y != dstY) {
84 cmd.set("c\n");
85 SkPDFUtils::AppendScalar(ctl2X, content);
86 content->writeText(" ");
87 SkPDFUtils::AppendScalar(ctl2Y, content);
88 content->writeText(" ");
89 }
90 SkPDFUtils::AppendScalar(dstX, content);
91 content->writeText(" ");
92 SkPDFUtils::AppendScalar(dstY, content);
93 content->writeText(" ");
94 content->writeText(cmd.c_str());
95 }
96
append_quad(const SkPoint quad[],SkWStream * content)97 static void append_quad(const SkPoint quad[], SkWStream* content) {
98 SkPoint cubic[4];
99 SkConvertQuadToCubic(quad, cubic);
100 SkPDFUtils::AppendCubic(cubic[1].fX, cubic[1].fY, cubic[2].fX, cubic[2].fY,
101 cubic[3].fX, cubic[3].fY, content);
102 }
103
104 // static
AppendRectangle(const SkRect & rect,SkWStream * content)105 void SkPDFUtils::AppendRectangle(const SkRect& rect, SkWStream* content) {
106 // Skia has 0,0 at top left, pdf at bottom left. Do the right thing.
107 SkScalar bottom = SkMinScalar(rect.fBottom, rect.fTop);
108
109 SkPDFUtils::AppendScalar(rect.fLeft, content);
110 content->writeText(" ");
111 SkPDFUtils::AppendScalar(bottom, content);
112 content->writeText(" ");
113 SkPDFUtils::AppendScalar(rect.width(), content);
114 content->writeText(" ");
115 SkPDFUtils::AppendScalar(rect.height(), content);
116 content->writeText(" re\n");
117 }
118
119 // static
EmitPath(const SkPath & path,SkPaint::Style paintStyle,SkWStream * content)120 void SkPDFUtils::EmitPath(const SkPath& path, SkPaint::Style paintStyle,
121 SkWStream* content) {
122 // Filling a path with no area results in a drawing in PDF renderers but
123 // Chrome expects to be able to draw some such entities with no visible
124 // result, so we detect those cases and discard the drawing for them.
125 // Specifically: moveTo(X), lineTo(Y) and moveTo(X), lineTo(X), lineTo(Y).
126 enum SkipFillState {
127 kEmpty_SkipFillState = 0,
128 kSingleLine_SkipFillState = 1,
129 kNonSingleLine_SkipFillState = 2,
130 };
131 SkipFillState fillState = kEmpty_SkipFillState;
132 if (paintStyle != SkPaint::kFill_Style) {
133 fillState = kNonSingleLine_SkipFillState;
134 }
135 SkPoint lastMovePt = SkPoint::Make(0,0);
136 SkDynamicMemoryWStream currentSegment;
137 SkPoint args[4];
138 SkPath::Iter iter(path, false);
139 for (SkPath::Verb verb = iter.next(args); verb != SkPath::kDone_Verb; verb = iter.next(args)) {
140 // args gets all the points, even the implicit first point.
141 switch (verb) {
142 case SkPath::kMove_Verb:
143 MoveTo(args[0].fX, args[0].fY, ¤tSegment);
144 lastMovePt = args[0];
145 fillState = kEmpty_SkipFillState;
146 break;
147 case SkPath::kLine_Verb:
148 AppendLine(args[1].fX, args[1].fY, ¤tSegment);
149 if (fillState == kEmpty_SkipFillState) {
150 if (args[0] != lastMovePt) {
151 fillState = kSingleLine_SkipFillState;
152 }
153 } else if (fillState == kSingleLine_SkipFillState) {
154 fillState = kNonSingleLine_SkipFillState;
155 }
156 break;
157 case SkPath::kQuad_Verb:
158 append_quad(args, ¤tSegment);
159 fillState = kNonSingleLine_SkipFillState;
160 break;
161 case SkPath::kConic_Verb: {
162 const SkScalar tol = SK_Scalar1 / 4;
163 SkAutoConicToQuads converter;
164 const SkPoint* quads = converter.computeQuads(args, iter.conicWeight(), tol);
165 for (int i = 0; i < converter.countQuads(); ++i) {
166 append_quad(&quads[i * 2], ¤tSegment);
167 }
168 } break;
169 case SkPath::kCubic_Verb:
170 AppendCubic(args[1].fX, args[1].fY, args[2].fX, args[2].fY,
171 args[3].fX, args[3].fY, ¤tSegment);
172 fillState = kNonSingleLine_SkipFillState;
173 break;
174 case SkPath::kClose_Verb:
175 if (fillState != kSingleLine_SkipFillState) {
176 ClosePath(¤tSegment);
177 currentSegment.writeToStream(content);
178 }
179 currentSegment.reset();
180 break;
181 default:
182 SkASSERT(false);
183 break;
184 }
185 }
186 if (currentSegment.bytesWritten() > 0) {
187 currentSegment.writeToStream(content);
188 }
189 }
190
191 // static
ClosePath(SkWStream * content)192 void SkPDFUtils::ClosePath(SkWStream* content) {
193 content->writeText("h\n");
194 }
195
196 // static
PaintPath(SkPaint::Style style,SkPath::FillType fill,SkWStream * content)197 void SkPDFUtils::PaintPath(SkPaint::Style style, SkPath::FillType fill,
198 SkWStream* content) {
199 if (style == SkPaint::kFill_Style) {
200 content->writeText("f");
201 } else if (style == SkPaint::kStrokeAndFill_Style) {
202 content->writeText("B");
203 } else if (style == SkPaint::kStroke_Style) {
204 content->writeText("S");
205 }
206
207 if (style != SkPaint::kStroke_Style) {
208 NOT_IMPLEMENTED(fill == SkPath::kInverseEvenOdd_FillType, false);
209 NOT_IMPLEMENTED(fill == SkPath::kInverseWinding_FillType, false);
210 if (fill == SkPath::kEvenOdd_FillType) {
211 content->writeText("*");
212 }
213 }
214 content->writeText("\n");
215 }
216
217 // static
StrokePath(SkWStream * content)218 void SkPDFUtils::StrokePath(SkWStream* content) {
219 SkPDFUtils::PaintPath(
220 SkPaint::kStroke_Style, SkPath::kWinding_FillType, content);
221 }
222
223 // static
DrawFormXObject(int objectIndex,SkWStream * content)224 void SkPDFUtils::DrawFormXObject(int objectIndex, SkWStream* content) {
225 content->writeText("/");
226 content->writeText(SkPDFResourceDict::getResourceName(
227 SkPDFResourceDict::kXObject_ResourceType,
228 objectIndex).c_str());
229 content->writeText(" Do\n");
230 }
231
232 // static
ApplyGraphicState(int objectIndex,SkWStream * content)233 void SkPDFUtils::ApplyGraphicState(int objectIndex, SkWStream* content) {
234 content->writeText("/");
235 content->writeText(SkPDFResourceDict::getResourceName(
236 SkPDFResourceDict::kExtGState_ResourceType,
237 objectIndex).c_str());
238 content->writeText(" gs\n");
239 }
240
241 // static
ApplyPattern(int objectIndex,SkWStream * content)242 void SkPDFUtils::ApplyPattern(int objectIndex, SkWStream* content) {
243 // Select Pattern color space (CS, cs) and set pattern object as current
244 // color (SCN, scn)
245 SkString resourceName = SkPDFResourceDict::getResourceName(
246 SkPDFResourceDict::kPattern_ResourceType,
247 objectIndex);
248 content->writeText("/Pattern CS/Pattern cs/");
249 content->writeText(resourceName.c_str());
250 content->writeText(" SCN/");
251 content->writeText(resourceName.c_str());
252 content->writeText(" scn\n");
253 }
254
AppendScalar(SkScalar value,SkWStream * stream)255 void SkPDFUtils::AppendScalar(SkScalar value, SkWStream* stream) {
256 // The range of reals in PDF/A is the same as SkFixed: +/- 32,767 and
257 // +/- 1/65,536 (though integers can range from 2^31 - 1 to -2^31).
258 // When using floats that are outside the whole value range, we can use
259 // integers instead.
260
261 #if !defined(SK_ALLOW_LARGE_PDF_SCALARS)
262 if (value > 32767 || value < -32767) {
263 stream->writeDecAsText(SkScalarRoundToInt(value));
264 return;
265 }
266
267 char buffer[SkStrAppendScalar_MaxSize];
268 char* end = SkStrAppendFixed(buffer, SkScalarToFixed(value));
269 stream->write(buffer, end - buffer);
270 return;
271 #endif // !SK_ALLOW_LARGE_PDF_SCALARS
272
273 #if defined(SK_ALLOW_LARGE_PDF_SCALARS)
274 // Floats have 24bits of significance, so anything outside that range is
275 // no more precise than an int. (Plus PDF doesn't support scientific
276 // notation, so this clamps to SK_Max/MinS32).
277 if (value > (1 << 24) || value < -(1 << 24)) {
278 stream->writeDecAsText(value);
279 return;
280 }
281 // Continue to enforce the PDF limits for small floats.
282 if (value < 1.0f/65536 && value > -1.0f/65536) {
283 stream->writeDecAsText(0);
284 return;
285 }
286 // SkStrAppendFloat might still use scientific notation, so use snprintf
287 // directly..
288 static const int kFloat_MaxSize = 19;
289 char buffer[kFloat_MaxSize];
290 int len = SNPRINTF(buffer, kFloat_MaxSize, "%#.8f", value);
291 // %f always prints trailing 0s, so strip them.
292 for (; buffer[len - 1] == '0' && len > 0; len--) {
293 buffer[len - 1] = '\0';
294 }
295 if (buffer[len - 1] == '.') {
296 buffer[len - 1] = '\0';
297 }
298 stream->writeText(buffer);
299 return;
300 #endif // SK_ALLOW_LARGE_PDF_SCALARS
301 }
302
FormatString(const char * cin,size_t len)303 SkString SkPDFUtils::FormatString(const char* cin, size_t len) {
304 SkDEBUGCODE(static const size_t kMaxLen = 65535;)
305 SkASSERT(len <= kMaxLen);
306
307 // 7-bit clean is a heuristic to decide what string format to use;
308 // a 7-bit clean string should require little escaping.
309 bool sevenBitClean = true;
310 size_t characterCount = 2 + len;
311 for (size_t i = 0; i < len; i++) {
312 if (cin[i] > '~' || cin[i] < ' ') {
313 sevenBitClean = false;
314 break;
315 }
316 if (cin[i] == '\\' || cin[i] == '(' || cin[i] == ')') {
317 ++characterCount;
318 }
319 }
320 SkString result;
321 if (sevenBitClean) {
322 result.resize(characterCount);
323 char* str = result.writable_str();
324 *str++ = '(';
325 for (size_t i = 0; i < len; i++) {
326 if (cin[i] == '\\' || cin[i] == '(' || cin[i] == ')') {
327 *str++ = '\\';
328 }
329 *str++ = cin[i];
330 }
331 *str++ = ')';
332 } else {
333 result.resize(2 * len + 2);
334 char* str = result.writable_str();
335 *str++ = '<';
336 for (size_t i = 0; i < len; i++) {
337 uint8_t c = static_cast<uint8_t>(cin[i]);
338 static const char gHex[] = "0123456789ABCDEF";
339 *str++ = gHex[(c >> 4) & 0xF];
340 *str++ = gHex[(c ) & 0xF];
341 }
342 *str++ = '>';
343 }
344 return result;
345 }
346