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wxPdfDocument 1.2.0
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wxPdfDocument 1.2.0
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This section explains how to use TrueType or Type1 fonts so that you are not limited to the standard fonts any more. The other interest is that you can choose the font encoding, which allows you to use other languages than the Western ones (the standard fonts having too few available characters).
There are two ways to use a new font: embedding it in the PDF or not. When a font is not embedded, it is sought in the system. The advantage is that the PDF file is lighter; on the other hand, if it is not available, a substitution font is used. So it is preferable to ensure that the needed font is installed on the client systems. If the file is to be viewed by a large audience, it is better to embed the fonts.
Adding a new font requires three steps for TrueType fonts:
For Type1, the first one is theoretically not necessary because the AFM file is usually shipped with the font. In case you have only a metric file in PFM format, it must be converted to AFM first.
The first step for a TrueType font consists in generating the AFM file (or UFM file in case of a Unicode TrueType font). A utility exists to do this task: ttf2ufm - a special version of ttf2pt1 - allowing to create AFM and/or UFM files. ttf2ufm has been modified to generate AFM and UFM files containing all the information which is required by the utility program makefont. An archive containing the modified source code of ttf2ufm and a Windows executable can be downloaded from here. The command line to use is the following:
ttf2ufm -a font.ttf font
For example, for Comic Sans MS Regular:
ttf2ufm -a c:/windows/fonts/comic.ttf comic
Two files are created; the one we are interested in is comic.afm.
The second step consists in generating a wxPdfDocument font metrics XML file containing all the information needed by wxPdfDocument; in addition, the font file is compressed. To do this, a utility program, makefont, is provided.
makefont {-a font.afm | -u font.ufm | -i } [-f font.{ttf|pfb}] [-e encoding] [-p patch] [-t {ttf|otf|t1}] [-o outdir]
-a font.afm | AFM font metric file for TrueType or Type1 fonts |
-u font.ufm | UFM font metric file for TrueType Unicode or OpenType Unicode fonts |
-i | Extract font metrics directly from TrueType Unicode or OpenType Unicode fonts |
-f font.{ttf|otf|pfb} | font file (.ttf = TrueType, .otf = OpenType, .pfb = Type1). If you own a Type1 font in ASCII format ( .pfa), you can convert it to binary format with t1utils. If you don't want to embed the font, omit this parameter. In this case, type is given by the type parameter. |
-e encoding | font encoding, i.e. cp1252. Omit this parameter for a symbolic font.like Symbol or ZapfDingBats. The encoding defines the association between a code (from 0 to 255) and a character. The first 128 are fixed and correspond to ASCII; the following are variable. The encodings are stored in .map files. Those available are:
Of course, the font must contain the characters corresponding to the chosen encoding. The encodings which begin with cp are those used by Windows; Linux systems usually use ISO. Remark: the standard fonts use cp1252. Note: For TrueType Unicode and OpenType Unicode fonts this parameter is ignored. |
-p patch | patch file for individual encoding changes. Use the same format as the
Note: The Unicode character id will not be interpreted. For TrueType Unicode and OpenType Unicode fonts this parameter is ignored. |
-t {ttf|otf|t1} | font type (ttf = TrueType, otf = OpenType, t1 = Type1). Only needed if omitting the font file. |
-o outdir | the output directory for all generated files (default: current working directory) |
Note: in the case of a font with the same name as a standard one, for instance arial.ttf, it is mandatory to embed. If you don't, Acrobat will use its own font.
Executing makefont generates an .xml file, with the same name as the .afm file resp. .ufm file. You may rename it if you wish. In case of embedding the font file is compressed and gives a file with .z as extension. For Unicode TrueType fonts a file with extension .ctg.z is created containing the character to glyph mapping.You may rename these files, too, but in this case you have to alter the file name(s) in the file tag in the .xml file accordingly.
You have to copy the generated file(s) to the font directory.
The last step is the most simple. You just need to call the AddFont() method. For instance:
pdf.AddFont(wxS("Comic"),wxS(""),wxS("comic.xml"));
or simply:
pdf.AddFont(wxS("Comic"));
And the font is now available (in regular and underlined styles), usable like the others. If we had worked with Comic Sans MS Bold (comicbd.ttf), we would have put:
pdf.AddFont(wxS("Comic"),wxS("B"),wxS("comicbd.xml"));
Font files are often quite voluminous; this is due to the fact that they contain the characters corresponding to many encodings. zlib compression reduces them but they remain fairly big. A technique exists to reduce them further. It consists in converting the font to the Type1 format with ttf2pt1 by specifying the encoding you are interested in; all other characters will be discarded. For instance, the arial.ttf font shipped with Windows 98 is 267KB (it contains 1296 characters). After compression it gives 147. Let's convert it to Type1 by keeping only cp1250 characters:
ttf2ufm -b -L cp1250.map c:/windows/fonts/arial.ttf arial
The .map files are located in the makefont directory. The command produces arial.pfb and arial.afm. The arial.pfb file is only 35KB, and 30KB after compression.
It is possible to go even further. If you are interested only in a subset of the encoding (you probably don't need all 217 characters), you can open the .map file and remove the lines you are not interested in. This will reduce the file size accordingly.
Since wxPdfDocument version 0.8.0 automatic font subsetting is supported for TrueType und TrueType Unicode fonts. Since version 0.8.5 subsetting of OpenType Unicode fonts is supported as well. Note: The font license must allow embedding and subsetting.
1.10.0