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      CHAPTER 5                                                                          Text



      Note: This classification of nonsymbolic and symbolic fonts is peculiar to PDF. A
      font may contain additional characters that are used in Latin writing systems but
      are outside the Adobe standard Latin character set; PDF considers such a font to be
      symbolic. The use of two flags to represent a single binary choice is a historical acci-
      dent.

      The ForceBold flag (bit 19) determines whether bold glyphs are painted with
      extra pixels even at very small text sizes. Typically, when glyphs are painted at
      small sizes on very low-resolution devices such as display screens, features of bold
      glyphs may appear only 1 pixel wide. Because this is the minimum feature width
      on a pixel-based device, ordinary (nonbold) glyphs also appear with 1-pixel-wide
      features and therefore cannot be distinguished from bold glyphs. If the ForceBold
      flag is set, features of bold glyphs may be thickened at small text sizes.

      Example 5.12 illustrates a font descriptor whose Flags entry has the Serif,
      Nonsymbolic, and ForceBold flags (bits 2, 6, and 19) set.

      Example 5.12

         7 0 obj
            << /Type /FontDescriptor
                /FontName /AGaramond−Semibold
                /Flags 262178                             % Bits 2, 6, and 19
                /FontBBox [ −177 −269 1123 866 ]
                /MissingWidth 255
                /StemV 105
                /StemH 45
                /CapHeight 660
                /XHeight 394
                /Ascent 720
                /Descent −270
                /Leading 83
                /MaxWidth 1212
                /AvgWidth 478
                /ItalicAngle 0
            >>
         endobj


5.7.2 Font Descriptors for CIDFonts

      In addition to the entries in Table 5.19 on page 456, the FontDescriptor dictionar-
      ies of CIDFonts may contain the entries listed in Table 5.21.

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