Add fallback fonts in pdfium

core/fpdfapi/fpdf_font/cpdf_font.cpp

 // 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/fpdf_font/include/cpdf_font.h"
 
 #include <memory>
 #include <vector>
@@ skipping 433 matching lines @@
   }
 
   if (!charnames.empty() && !charnames[charcode].IsEmpty())
     return charnames[charcode].c_str();
 
   const FX_CHAR* name = nullptr;
   if (iBaseEncoding)
     name = PDF_CharNameFromPredefinedCharSet(iBaseEncoding, charcode);
   return name && name[0] ? name : nullptr;
 }
+
+uint32_t CPDF_Font::FallbackFontFromCharcode(uint32_t charcode,

[dsinclair, 2016/08/23 19:41:18]

This only ever returns 1, can the return value just be removed?

[npm, 2016/08/23 20:36:57]

The intention is that the return value may be different once we use more than
one fallback font.

+                                             bool* pVertGlyph) {
+  if (m_FontPlusFallbacks.size() < 2) {
+    m_FontPlusFallbacks.push_back(new CFX_Font());

[dsinclair, 2016/08/23 19:41:18]

This font is going to end up leaking. The other font your adding is owned by
someone else. I think we need to work out the ownership here so that either, a)
this font is created elsewhere and added to the map, or b) the other font is
owned by this vector.

[npm, 2016/08/23 20:36:57]

Ok, a vector of unique pointers using only the fallbacks works.

+    m_FontPlusFallbacks[1]->LoadSubst("Arial", IsTrueTypeFont(), m_Flags,
+                                      m_StemV * 5, m_ItalicAngle, 0,
+                                      IsVertWriting());
+  }
+  return 1;
+}
+
+int CPDF_Font::FallbackGlyphFromCharcode(int fallbackFont,
+                                         uint32_t charcode,
+                                         bool* pVertGlyph) {
+  int glyph = FXFT_Get_Char_Index(m_FontPlusFallbacks[fallbackFont]->GetFace(),
+                                  charcode);
+  if (glyph == 0 || glyph == 0xffff)
+    return -1;
+  return glyph;
+}