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> > The PDF format is extremely strict on this point. The string width, > > except for the base 14 fonts (which are standardised) comes from > > the PDF itself, in the Widths array (or similar for CID fonts). > > The Widths (or similar) data is (except as noted) compulsory, so > > to generate a PDF, you must in any case have this information. > > What does the viewer application do when it has to substitute > a font ? > Draw the string in the new font using the widthtable of the > old font ? Yes. Though Acrobat never "just" substitutes another font. Acrobat uses the width table, and the other attributes of the font (e.g. is it serif, what is the stroke width), to make a substitute that is similar in design, not just spacing, to the original font. This is then laid out using the predetermined widths. Another PDF viewer might do it differently, but it is one of the sacred trusts of PDF that text is laid out with the correct spacing, whatever font gets actually used. This actually seems enough to satisfy a lot of users, who don't care much about the length of a serif or even what it is, so I can't go along with the "everyone must always embed" philosphy. Substitution works, and must continue to work, for the existing body of files that won't go away. Of course, in pre-press and other strict design disciplines, embedded fonts (and hence, no substitution) are a must. Aandi To change your subscription: http://www.pdfzone.com/discussions/lists-pdfdev.html
