summaryrefslogtreecommitdiff
path: root/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp
blob: 88f14b2ce454ddd1d63f57cedbef67ae99f23ce0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
// Copyright 2016 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com

#include "core/fpdfapi/edit/cpdf_pagecontentgenerator.h"

#include <map>
#include <memory>
#include <set>
#include <tuple>
#include <utility>

#include "core/fpdfapi/edit/cpdf_pagecontentmanager.h"
#include "core/fpdfapi/font/cpdf_font.h"
#include "core/fpdfapi/page/cpdf_docpagedata.h"
#include "core/fpdfapi/page/cpdf_image.h"
#include "core/fpdfapi/page/cpdf_imageobject.h"
#include "core/fpdfapi/page/cpdf_page.h"
#include "core/fpdfapi/page/cpdf_path.h"
#include "core/fpdfapi/page/cpdf_pathobject.h"
#include "core/fpdfapi/page/cpdf_textobject.h"
#include "core/fpdfapi/parser/cpdf_array.h"
#include "core/fpdfapi/parser/cpdf_dictionary.h"
#include "core/fpdfapi/parser/cpdf_document.h"
#include "core/fpdfapi/parser/cpdf_name.h"
#include "core/fpdfapi/parser/cpdf_number.h"
#include "core/fpdfapi/parser/cpdf_reference.h"
#include "core/fpdfapi/parser/cpdf_stream.h"
#include "core/fpdfapi/parser/fpdf_parser_decode.h"
#include "core/fpdfapi/parser/fpdf_parser_utility.h"
#include "third_party/base/stl_util.h"
#include "third_party/skia_shared/SkFloatToDecimal.h"

namespace {

std::ostream& operator<<(std::ostream& ar, const CFX_Matrix& matrix) {
  ar << matrix.a << " " << matrix.b << " " << matrix.c << " " << matrix.d << " "
     << matrix.e << " " << matrix.f;
  return ar;
}

bool GetColor(const CPDF_Color* pColor, float* rgb) {
  int intRGB[3];
  if (!pColor || !pColor->IsColorSpaceRGB() ||
      !pColor->GetRGB(&intRGB[0], &intRGB[1], &intRGB[2])) {
    return false;
  }
  rgb[0] = intRGB[0] / 255.0f;
  rgb[1] = intRGB[1] / 255.0f;
  rgb[2] = intRGB[2] / 255.0f;
  return true;
}

}  // namespace

CPDF_PageContentGenerator::CPDF_PageContentGenerator(
    CPDF_PageObjectHolder* pObjHolder)
    : m_pObjHolder(pObjHolder), m_pDocument(pObjHolder->GetDocument()) {
  for (const auto& pObj : *pObjHolder->GetPageObjectList()) {
    if (pObj)
      m_pageObjects.emplace_back(pObj.get());
  }
}

CPDF_PageContentGenerator::~CPDF_PageContentGenerator() {}

void CPDF_PageContentGenerator::GenerateContent() {
  ASSERT(m_pObjHolder->IsPage());

  std::map<int32_t, std::unique_ptr<std::ostringstream>> stream =
      GenerateModifiedStreams();

  UpdateContentStreams(&stream);
}

std::map<int32_t, std::unique_ptr<std::ostringstream>>
CPDF_PageContentGenerator::GenerateModifiedStreams() {
  // Make sure default graphics are created.
  GetOrCreateDefaultGraphics();

  // Figure out which streams are dirty.
  std::set<int32_t> all_dirty_streams;
  for (auto& pPageObj : m_pageObjects) {
    if (pPageObj->IsDirty())
      all_dirty_streams.insert(pPageObj->GetContentStream());
  }
  const std::set<int32_t>& marked_dirty_streams =
      m_pObjHolder->GetDirtyStreams();
  all_dirty_streams.insert(marked_dirty_streams.begin(),
                           marked_dirty_streams.end());

  // Start regenerating dirty streams.
  std::map<int32_t, std::unique_ptr<std::ostringstream>> streams;
  std::set<int32_t> empty_streams;

  for (int32_t dirty_stream : all_dirty_streams) {
    std::unique_ptr<std::ostringstream> buf =
        pdfium::MakeUnique<std::ostringstream>();

    // Set the default graphic state values
    *buf << "q\n";
    if (!m_pObjHolder->GetLastCTM().IsIdentity())
      *buf << m_pObjHolder->GetLastCTM().GetInverse() << " cm\n";

    ProcessDefaultGraphics(buf.get());

    streams[dirty_stream] = std::move(buf);
    empty_streams.insert(dirty_stream);
  }

  // Process the page objects, write into each dirty stream.
  for (auto& pPageObj : m_pageObjects) {
    int stream_index = pPageObj->GetContentStream();
    auto it = streams.find(stream_index);
    if (it == streams.end())
      continue;

    std::ostringstream* buf = it->second.get();
    empty_streams.erase(stream_index);
    ProcessPageObject(buf, pPageObj.Get());
  }

  // Finish dirty streams.
  for (int32_t dirty_stream : all_dirty_streams) {
    std::ostringstream* buf = streams[dirty_stream].get();
    if (pdfium::ContainsKey(empty_streams, dirty_stream)) {
      // Clear to show that this stream needs to be deleted.
      buf->str("");
    } else {
      // Return graphics to original state
      *buf << "Q\n";
    }
  }

  // Clear dirty streams in m_pObjHolder
  m_pObjHolder->ClearDirtyStreams();

  return streams;
}

void CPDF_PageContentGenerator::UpdateContentStreams(
    std::map<int32_t, std::unique_ptr<std::ostringstream>>* new_stream_data) {
  // If no streams were regenerated or removed, nothing to do here.
  if (new_stream_data->empty())
    return;

  CPDF_PageContentManager page_content_manager(m_pObjHolder.Get());

  for (auto& pair : *new_stream_data) {
    int32_t stream_index = pair.first;
    std::ostringstream* buf = pair.second.get();

    if (stream_index == CPDF_PageObject::kNoContentStream) {
      int new_stream_index = page_content_manager.AddStream(buf);
      UpdateStreamlessPageObjects(new_stream_index);
      continue;
    }

    CPDF_Stream* old_stream =
        page_content_manager.GetStreamByIndex(stream_index);
    ASSERT(old_stream);

    // If buf is now empty, remove the stream instead of setting the data.
    if (buf->tellp() <= 0)
      page_content_manager.ScheduleRemoveStreamByIndex(stream_index);
    else
      old_stream->SetData(buf);
  }

  page_content_manager.ExecuteScheduledRemovals();
}

ByteString CPDF_PageContentGenerator::RealizeResource(
    const CPDF_Object* pResource,
    const ByteString& bsType) const {
  ASSERT(pResource);
  if (!m_pObjHolder->m_pResources) {
    m_pObjHolder->m_pResources = m_pDocument->NewIndirect<CPDF_Dictionary>();
    m_pObjHolder->GetDict()->SetFor(
        "Resources",
        m_pObjHolder->m_pResources->MakeReference(m_pDocument.Get()));
  }
  CPDF_Dictionary* pResList = m_pObjHolder->m_pResources->GetDictFor(bsType);
  if (!pResList)
    pResList = m_pObjHolder->m_pResources->SetNewFor<CPDF_Dictionary>(bsType);

  ByteString name;
  int idnum = 1;
  while (1) {
    name = ByteString::Format("FX%c%d", bsType[0], idnum);
    if (!pResList->KeyExist(name))
      break;

    idnum++;
  }
  pResList->SetFor(name, pResource->MakeReference(m_pDocument.Get()));
  return name;
}

bool CPDF_PageContentGenerator::ProcessPageObjects(std::ostringstream* buf) {
  bool bDirty = false;
  for (auto& pPageObj : m_pageObjects) {
    if (m_pObjHolder->IsPage() && !pPageObj->IsDirty())
      continue;

    bDirty = true;
    ProcessPageObject(buf, pPageObj.Get());
  }
  return bDirty;
}

void CPDF_PageContentGenerator::UpdateStreamlessPageObjects(
    int new_content_stream_index) {
  for (auto& pPageObj : m_pageObjects) {
    if (pPageObj->GetContentStream() == CPDF_PageObject::kNoContentStream)
      pPageObj->SetContentStream(new_content_stream_index);
  }
}

void CPDF_PageContentGenerator::ProcessPageObject(std::ostringstream* buf,
                                                  CPDF_PageObject* pPageObj) {
  if (CPDF_ImageObject* pImageObject = pPageObj->AsImage())
    ProcessImage(buf, pImageObject);
  else if (CPDF_PathObject* pPathObj = pPageObj->AsPath())
    ProcessPath(buf, pPathObj);
  else if (CPDF_TextObject* pTextObj = pPageObj->AsText())
    ProcessText(buf, pTextObj);
  pPageObj->SetDirty(false);
}

void CPDF_PageContentGenerator::ProcessImage(std::ostringstream* buf,
                                             CPDF_ImageObject* pImageObj) {
  if ((pImageObj->matrix().a == 0 && pImageObj->matrix().b == 0) ||
      (pImageObj->matrix().c == 0 && pImageObj->matrix().d == 0)) {
    return;
  }
  *buf << "q " << pImageObj->matrix() << " cm ";

  RetainPtr<CPDF_Image> pImage = pImageObj->GetImage();
  if (pImage->IsInline())
    return;

  CPDF_Stream* pStream = pImage->GetStream();
  if (!pStream)
    return;

  bool bWasInline = pStream->IsInline();
  if (bWasInline)
    pImage->ConvertStreamToIndirectObject();

  ByteString name = RealizeResource(pStream, "XObject");
  if (bWasInline)
    pImageObj->SetImage(
        m_pDocument->GetPageData()->GetImage(pStream->GetObjNum()));

  *buf << "/" << PDF_NameEncode(name) << " Do Q\n";
}

// Processing path with operators from Tables 4.9 and 4.10 of PDF spec 1.7:
// "re" appends a rectangle (here, used only if the whole path is a rectangle)
// "m" moves current point to the given coordinates
// "l" creates a line from current point to the new point
// "c" adds a Bezier curve from current to last point, using the two other
// points as the Bezier control points
// Note: "l", "c" change the current point
// "h" closes the subpath (appends a line from current to starting point)
// Path painting operators: "S", "n", "B", "f", "B*", "f*", depending on
// the filling mode and whether we want stroking the path or not.
// "Q" restores the graphics state imposed by the ProcessGraphics method.
void CPDF_PageContentGenerator::ProcessPath(std::ostringstream* buf,
                                            CPDF_PathObject* pPathObj) {
  ProcessGraphics(buf, pPathObj);

  *buf << pPathObj->m_Matrix << " cm ";

  auto& pPoints = pPathObj->m_Path.GetPoints();
  if (pPathObj->m_Path.IsRect()) {
    CFX_PointF diff = pPoints[2].m_Point - pPoints[0].m_Point;
    *buf << pPoints[0].m_Point.x << " " << pPoints[0].m_Point.y << " " << diff.x
         << " " << diff.y << " re";
  } else {
    for (size_t i = 0; i < pPoints.size(); i++) {
      if (i > 0)
        *buf << " ";

      char buffer[pdfium::skia::kMaximumSkFloatToDecimalLength];
      unsigned size =
          pdfium::skia::SkFloatToDecimal(pPoints[i].m_Point.x, buffer);
      buf->write(buffer, size) << " ";
      size = pdfium::skia::SkFloatToDecimal(pPoints[i].m_Point.y, buffer);
      buf->write(buffer, size);

      FXPT_TYPE pointType = pPoints[i].m_Type;
      if (pointType == FXPT_TYPE::MoveTo) {
        *buf << " m";
      } else if (pointType == FXPT_TYPE::LineTo) {
        *buf << " l";
      } else if (pointType == FXPT_TYPE::BezierTo) {
        if (i + 2 >= pPoints.size() ||
            !pPoints[i].IsTypeAndOpen(FXPT_TYPE::BezierTo) ||
            !pPoints[i + 1].IsTypeAndOpen(FXPT_TYPE::BezierTo) ||
            pPoints[i + 2].m_Type != FXPT_TYPE::BezierTo) {
          // If format is not supported, close the path and paint
          *buf << " h";
          break;
        }
        *buf << " " << pPoints[i + 1].m_Point.x << " "
             << pPoints[i + 1].m_Point.y << " " << pPoints[i + 2].m_Point.x
             << " " << pPoints[i + 2].m_Point.y << " c";
        i += 2;
      }
      if (pPoints[i].m_CloseFigure)
        *buf << " h";
    }
  }
  if (pPathObj->m_FillType == 0)
    *buf << (pPathObj->m_bStroke ? " S" : " n");
  else if (pPathObj->m_FillType == FXFILL_WINDING)
    *buf << (pPathObj->m_bStroke ? " B" : " f");
  else if (pPathObj->m_FillType == FXFILL_ALTERNATE)
    *buf << (pPathObj->m_bStroke ? " B*" : " f*");
  *buf << " Q\n";
}

// This method supports color operators rg and RGB from Table 4.24 of PDF spec
// 1.7. A color will not be set if the colorspace is not DefaultRGB or the RGB
// values cannot be obtained. The method also adds an external graphics
// dictionary, as described in Section 4.3.4.
// "rg" sets the fill color, "RG" sets the stroke color (using DefaultRGB)
// "w" sets the stroke line width.
// "ca" sets the fill alpha, "CA" sets the stroke alpha.
// "q" saves the graphics state, so that the settings can later be reversed
void CPDF_PageContentGenerator::ProcessGraphics(std::ostringstream* buf,
                                                CPDF_PageObject* pPageObj) {
  *buf << "q ";
  float fillColor[3];
  if (GetColor(pPageObj->m_ColorState.GetFillColor(), fillColor)) {
    *buf << fillColor[0] << " " << fillColor[1] << " " << fillColor[2]
         << " rg ";
  }
  float strokeColor[3];
  if (GetColor(pPageObj->m_ColorState.GetStrokeColor(), strokeColor)) {
    *buf << strokeColor[0] << " " << strokeColor[1] << " " << strokeColor[2]
         << " RG ";
  }
  float lineWidth = pPageObj->m_GraphState.GetLineWidth();
  if (lineWidth != 1.0f)
    *buf << lineWidth << " w ";
  CFX_GraphStateData::LineCap lineCap = pPageObj->m_GraphState.GetLineCap();
  if (lineCap != CFX_GraphStateData::LineCapButt)
    *buf << static_cast<int>(lineCap) << " J ";
  CFX_GraphStateData::LineJoin lineJoin = pPageObj->m_GraphState.GetLineJoin();
  if (lineJoin != CFX_GraphStateData::LineJoinMiter)
    *buf << static_cast<int>(lineJoin) << " j ";

  GraphicsData graphD;
  graphD.fillAlpha = pPageObj->m_GeneralState.GetFillAlpha();
  graphD.strokeAlpha = pPageObj->m_GeneralState.GetStrokeAlpha();
  graphD.blendType = pPageObj->m_GeneralState.GetBlendType();
  if (graphD.fillAlpha == 1.0f && graphD.strokeAlpha == 1.0f &&
      (graphD.blendType == FXDIB_BLEND_UNSUPPORTED ||
       graphD.blendType == FXDIB_BLEND_NORMAL)) {
    return;
  }

  ByteString name;
  auto it = m_pObjHolder->m_GraphicsMap.find(graphD);
  if (it != m_pObjHolder->m_GraphicsMap.end()) {
    name = it->second;
  } else {
    auto gsDict = pdfium::MakeUnique<CPDF_Dictionary>();
    if (graphD.fillAlpha != 1.0f)
      gsDict->SetNewFor<CPDF_Number>("ca", graphD.fillAlpha);

    if (graphD.strokeAlpha != 1.0f)
      gsDict->SetNewFor<CPDF_Number>("CA", graphD.strokeAlpha);

    if (graphD.blendType != FXDIB_BLEND_UNSUPPORTED &&
        graphD.blendType != FXDIB_BLEND_NORMAL) {
      gsDict->SetNewFor<CPDF_Name>("BM",
                                   pPageObj->m_GeneralState.GetBlendMode());
    }
    CPDF_Object* pDict = m_pDocument->AddIndirectObject(std::move(gsDict));
    name = RealizeResource(pDict, "ExtGState");
    m_pObjHolder->m_GraphicsMap[graphD] = name;
  }
  *buf << "/" << PDF_NameEncode(name) << " gs ";
}

void CPDF_PageContentGenerator::ProcessDefaultGraphics(
    std::ostringstream* buf) {
  *buf << "0 0 0 RG 0 0 0 rg 1 w "
       << static_cast<int>(CFX_GraphStateData::LineCapButt) << " J "
       << static_cast<int>(CFX_GraphStateData::LineJoinMiter) << " j\n";
  ByteString name = GetOrCreateDefaultGraphics();
  *buf << "/" << PDF_NameEncode(name) << " gs ";
}

ByteString CPDF_PageContentGenerator::GetOrCreateDefaultGraphics() const {
  GraphicsData defaultGraphics;
  defaultGraphics.fillAlpha = 1.0f;
  defaultGraphics.strokeAlpha = 1.0f;
  defaultGraphics.blendType = FXDIB_BLEND_NORMAL;
  auto it = m_pObjHolder->m_GraphicsMap.find(defaultGraphics);

  // If default graphics already exists, return it.
  if (it != m_pObjHolder->m_GraphicsMap.end())
    return it->second;

  // Otherwise, create them.
  auto gsDict = pdfium::MakeUnique<CPDF_Dictionary>();
  gsDict->SetNewFor<CPDF_Number>("ca", defaultGraphics.fillAlpha);
  gsDict->SetNewFor<CPDF_Number>("CA", defaultGraphics.strokeAlpha);
  gsDict->SetNewFor<CPDF_Name>("BM", "Normal");
  CPDF_Object* pDict = m_pDocument->AddIndirectObject(std::move(gsDict));
  ByteString name = RealizeResource(pDict, "ExtGState");
  m_pObjHolder->m_GraphicsMap[defaultGraphics] = name;
  return name;
}

// This method adds text to the buffer, BT begins the text object, ET ends it.
// Tm sets the text matrix (allows positioning and transforming text).
// Tf sets the font name (from Font in Resources) and font size.
// Tj sets the actual text, <####...> is used when specifying charcodes.
void CPDF_PageContentGenerator::ProcessText(std::ostringstream* buf,
                                            CPDF_TextObject* pTextObj) {
  ProcessGraphics(buf, pTextObj);
  *buf << "BT " << pTextObj->GetTextMatrix() << " Tm ";
  CPDF_Font* pFont = pTextObj->GetFont();
  if (!pFont)
    pFont = CPDF_Font::GetStockFont(m_pDocument.Get(), "Helvetica");
  FontData fontD;
  if (pFont->IsType1Font())
    fontD.type = "Type1";
  else if (pFont->IsTrueTypeFont())
    fontD.type = "TrueType";
  else if (pFont->IsCIDFont())
    fontD.type = "Type0";
  else
    return;
  fontD.baseFont = pFont->GetBaseFont();
  auto it = m_pObjHolder->m_FontsMap.find(fontD);
  ByteString dictName;
  if (it != m_pObjHolder->m_FontsMap.end()) {
    dictName = it->second;
  } else {
    CPDF_Object* pIndirectFont = pFont->GetFontDict();
    if (pIndirectFont->IsInline()) {
      // In this case we assume it must be a standard font
      auto fontDict = pdfium::MakeUnique<CPDF_Dictionary>();
      fontDict->SetNewFor<CPDF_Name>("Type", "Font");
      fontDict->SetNewFor<CPDF_Name>("Subtype", fontD.type);
      fontDict->SetNewFor<CPDF_Name>("BaseFont", fontD.baseFont);
      pIndirectFont = m_pDocument->AddIndirectObject(std::move(fontDict));
    }
    dictName = RealizeResource(pIndirectFont, "Font");
    m_pObjHolder->m_FontsMap[fontD] = dictName;
  }
  *buf << "/" << PDF_NameEncode(dictName) << " " << pTextObj->GetFontSize()
       << " Tf ";
  ByteString text;
  for (uint32_t charcode : pTextObj->GetCharCodes()) {
    if (charcode != CPDF_Font::kInvalidCharCode)
      pFont->AppendChar(&text, charcode);
  }
  *buf << PDF_EncodeString(text, true) << " Tj ET";
  *buf << " Q\n";
}