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      1 // Copyright 2016 PDFium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
      6 
      7 #include "core/fpdfapi/font/cpdf_simplefont.h"
      8 
      9 #include "core/fpdfapi/parser/cpdf_array.h"
     10 #include "core/fpdfapi/parser/cpdf_dictionary.h"
     11 #include "core/fxge/fx_freetype.h"
     12 #include "third_party/base/numerics/safe_math.h"
     13 
     14 CPDF_SimpleFont::CPDF_SimpleFont() : m_BaseEncoding(PDFFONT_ENCODING_BUILTIN) {
     15   memset(m_CharWidth, 0xff, sizeof(m_CharWidth));
     16   memset(m_GlyphIndex, 0xff, sizeof(m_GlyphIndex));
     17   memset(m_ExtGID, 0xff, sizeof(m_ExtGID));
     18   for (size_t i = 0; i < FX_ArraySize(m_CharBBox); ++i)
     19     m_CharBBox[i] = FX_RECT(-1, -1, -1, -1);
     20 }
     21 
     22 CPDF_SimpleFont::~CPDF_SimpleFont() {}
     23 
     24 int CPDF_SimpleFont::GlyphFromCharCode(uint32_t charcode, bool* pVertGlyph) {
     25   if (pVertGlyph)
     26     *pVertGlyph = false;
     27 
     28   if (charcode > 0xff)
     29     return -1;
     30 
     31   int index = m_GlyphIndex[charcode];
     32   if (index == 0xffff || (index == 0 && IsTrueTypeFont()))
     33     return -1;
     34 
     35   return index;
     36 }
     37 
     38 void CPDF_SimpleFont::LoadCharMetrics(int charcode) {
     39   if (!m_Font.GetFace())
     40     return;
     41 
     42   if (charcode < 0 || charcode > 0xff) {
     43     return;
     44   }
     45   int glyph_index = m_GlyphIndex[charcode];
     46   if (glyph_index == 0xffff) {
     47     if (!m_pFontFile && charcode != 32) {
     48       LoadCharMetrics(32);
     49       m_CharBBox[charcode] = m_CharBBox[32];
     50       if (m_bUseFontWidth) {
     51         m_CharWidth[charcode] = m_CharWidth[32];
     52       }
     53     }
     54     return;
     55   }
     56   FXFT_Face face = m_Font.GetFace();
     57   int err = FXFT_Load_Glyph(
     58       face, glyph_index,
     59       FXFT_LOAD_NO_SCALE | FXFT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH);
     60   if (err)
     61     return;
     62 
     63   int iHoriBearingX = FXFT_Get_Glyph_HoriBearingX(face);
     64   int iHoriBearingY = FXFT_Get_Glyph_HoriBearingY(face);
     65   m_CharBBox[charcode] =
     66       FX_RECT(TT2PDF(iHoriBearingX, face), TT2PDF(iHoriBearingY, face),
     67               TT2PDF(iHoriBearingX + FXFT_Get_Glyph_Width(face), face),
     68               TT2PDF(iHoriBearingY - FXFT_Get_Glyph_Height(face), face));
     69 
     70   if (m_bUseFontWidth) {
     71     int TT_Width = TT2PDF(FXFT_Get_Glyph_HoriAdvance(face), face);
     72     if (m_CharWidth[charcode] == 0xffff) {
     73       m_CharWidth[charcode] = TT_Width;
     74     } else if (TT_Width && !IsEmbedded()) {
     75       m_CharBBox[charcode].right =
     76           m_CharBBox[charcode].right * m_CharWidth[charcode] / TT_Width;
     77       m_CharBBox[charcode].left =
     78           m_CharBBox[charcode].left * m_CharWidth[charcode] / TT_Width;
     79     }
     80   }
     81 }
     82 
     83 int CPDF_SimpleFont::GetCharWidthF(uint32_t charcode) {
     84   if (charcode > 0xff)
     85     charcode = 0;
     86 
     87   if (m_CharWidth[charcode] == 0xffff) {
     88     LoadCharMetrics(charcode);
     89     if (m_CharWidth[charcode] == 0xffff) {
     90       m_CharWidth[charcode] = 0;
     91     }
     92   }
     93   return m_CharWidth[charcode];
     94 }
     95 
     96 FX_RECT CPDF_SimpleFont::GetCharBBox(uint32_t charcode) {
     97   if (charcode > 0xff)
     98     charcode = 0;
     99 
    100   if (m_CharBBox[charcode].left == -1)
    101     LoadCharMetrics(charcode);
    102 
    103   return m_CharBBox[charcode];
    104 }
    105 
    106 bool CPDF_SimpleFont::LoadCommon() {
    107   CPDF_Dictionary* pFontDesc = m_pFontDict->GetDictFor("FontDescriptor");
    108   if (pFontDesc) {
    109     LoadFontDescriptor(pFontDesc);
    110   }
    111   CPDF_Array* pWidthArray = m_pFontDict->GetArrayFor("Widths");
    112   m_bUseFontWidth = !pWidthArray;
    113   if (pWidthArray) {
    114     if (pFontDesc && pFontDesc->KeyExist("MissingWidth")) {
    115       int MissingWidth = pFontDesc->GetIntegerFor("MissingWidth");
    116       for (int i = 0; i < 256; i++) {
    117         m_CharWidth[i] = MissingWidth;
    118       }
    119     }
    120     size_t width_start = m_pFontDict->GetIntegerFor("FirstChar", 0);
    121     size_t width_end = m_pFontDict->GetIntegerFor("LastChar", 0);
    122     if (width_start <= 255) {
    123       if (width_end == 0 || width_end >= width_start + pWidthArray->GetCount())
    124         width_end = width_start + pWidthArray->GetCount() - 1;
    125       if (width_end > 255)
    126         width_end = 255;
    127       for (size_t i = width_start; i <= width_end; i++)
    128         m_CharWidth[i] = pWidthArray->GetIntegerAt(i - width_start);
    129     }
    130   }
    131   if (m_pFontFile) {
    132     if (m_BaseFont.GetLength() > 8 && m_BaseFont[7] == '+')
    133       m_BaseFont = m_BaseFont.Right(m_BaseFont.GetLength() - 8);
    134   } else {
    135     LoadSubstFont();
    136   }
    137   if (!FontStyleIsSymbolic(m_Flags))
    138     m_BaseEncoding = PDFFONT_ENCODING_STANDARD;
    139   CPDF_Object* pEncoding = m_pFontDict->GetDirectObjectFor("Encoding");
    140   LoadPDFEncoding(pEncoding, m_BaseEncoding, &m_CharNames, !!m_pFontFile,
    141                   m_Font.IsTTFont());
    142   LoadGlyphMap();
    143   m_CharNames.clear();
    144   if (!m_Font.GetFace())
    145     return true;
    146 
    147   if (FontStyleIsAllCaps(m_Flags)) {
    148     unsigned char kLowercases[][2] = {{'a', 'z'}, {0xe0, 0xf6}, {0xf8, 0xfd}};
    149     for (size_t range = 0; range < FX_ArraySize(kLowercases); ++range) {
    150       const auto& lower = kLowercases[range];
    151       for (int i = lower[0]; i <= lower[1]; ++i) {
    152         if (m_GlyphIndex[i] != 0xffff && m_pFontFile)
    153           continue;
    154 
    155         int j = i - 32;
    156         m_GlyphIndex[i] = m_GlyphIndex[j];
    157         if (m_CharWidth[j]) {
    158           m_CharWidth[i] = m_CharWidth[j];
    159           m_CharBBox[i] = m_CharBBox[j];
    160         }
    161       }
    162     }
    163   }
    164   CheckFontMetrics();
    165   return true;
    166 }
    167 
    168 void CPDF_SimpleFont::LoadSubstFont() {
    169   if (!m_bUseFontWidth && !FontStyleIsFixedPitch(m_Flags)) {
    170     int width = 0, i;
    171     for (i = 0; i < 256; i++) {
    172       if (m_CharWidth[i] == 0 || m_CharWidth[i] == 0xffff)
    173         continue;
    174 
    175       if (width == 0)
    176         width = m_CharWidth[i];
    177       else if (width != m_CharWidth[i])
    178         break;
    179     }
    180     if (i == 256 && width)
    181       m_Flags |= FXFONT_FIXED_PITCH;
    182   }
    183   pdfium::base::CheckedNumeric<int> safeStemV(m_StemV);
    184   if (m_StemV < 140)
    185     safeStemV *= 5;
    186   else
    187     safeStemV = safeStemV * 4 + 140;
    188   m_Font.LoadSubst(m_BaseFont, IsTrueTypeFont(), m_Flags,
    189                    safeStemV.ValueOrDefault(FXFONT_FW_NORMAL), m_ItalicAngle, 0,
    190                    false);
    191 }
    192 
    193 bool CPDF_SimpleFont::IsUnicodeCompatible() const {
    194   return m_BaseEncoding != PDFFONT_ENCODING_BUILTIN &&
    195          m_BaseEncoding != PDFFONT_ENCODING_ADOBE_SYMBOL &&
    196          m_BaseEncoding != PDFFONT_ENCODING_ZAPFDINGBATS;
    197 }
    198 
    199 WideString CPDF_SimpleFont::UnicodeFromCharCode(uint32_t charcode) const {
    200   WideString unicode = CPDF_Font::UnicodeFromCharCode(charcode);
    201   if (!unicode.IsEmpty())
    202     return unicode;
    203   wchar_t ret = m_Encoding.UnicodeFromCharCode((uint8_t)charcode);
    204   if (ret == 0)
    205     return WideString();
    206   return ret;
    207 }
    208 
    209 uint32_t CPDF_SimpleFont::CharCodeFromUnicode(wchar_t unicode) const {
    210   uint32_t ret = CPDF_Font::CharCodeFromUnicode(unicode);
    211   if (ret)
    212     return ret;
    213   return m_Encoding.CharCodeFromUnicode(unicode);
    214 }
    215 
    216 bool CPDF_SimpleFont::HasFontWidths() const {
    217   return !m_bUseFontWidth;
    218 }
    219