1Font::TTF::Glyph(3) User Contributed Perl Documentation Font::TTF::Glyph(3)
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6 Font::TTF::Glyph - Holds a single glyph's information
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9 This is a single glyph description as held in a TT font. On creation
10 only its header is read. Thus you can get the bounding box of each
11 glyph without having to read all the other information.
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14 In addition to the named variables in a glyph header ("xMin" etc.),
15 there are also all capital instance variables for holding working
16 information, mostly from the location table.
17 The standard attributes each glyph has are:
19 numberOfContours
21 xMin
22 yMin
23 xMax
24 yMax
25 There are also other, derived, instance variables for each glyph which
27 are read when the whole glyph is read (via "read_dat"):
28 instLen
30 Number of bytes in the hinting instructions (Warning this variable
31 is deprecated, use "length($g-"{'hints'})> instead).
32 hints
34 The string containing the hinting code for the glyph
35 In addition there are other attribute like instance variables for sim‐
37 ple glyphs:
38 For each contour there is:
40 endPoints
42 An array of endpoints for each contour in the glyph. There are
43 "numberOfContours" contours in a glyph. The number of points in
44 a glyph is equal to the highest endpoint of a contour.
45 There are also a number of arrays indexed by point number
47 flags
49 The flags associated with reading this point. The flags for a
50 point are recalculated for a point when it is "update"d. Thus
51 the flags are not very useful. The only important bit is bit 0
52 which indicates whether the point is an 'on' curve point, or an
53 'off' curve point.
54 x The absolute x co-ordinate of the point.
56 y The absolute y co-ordinate of the point
58 For composite glyphs there are other variables
60 metric
62 This holds the component number (not its glyph number) of the com‐
63 ponent from which the metrics for this glyph should be taken.
64 comps
66 This is an array of hashes for each component. Each hash has a num‐
67 ber of elements:
68 glyph
70 The glyph number of the glyph which comprises this component of
71 the composite.
72 args
74 An array of two arguments which may be an x, y co-ordinate or
75 two attachment points (one on the base glyph the other on the
76 component). See flags for details.
77 flag
79 The flag for this component
80 scale
82 A 4 number array for component scaling. This allows stretching,
83 rotating, etc. Note that scaling applies to placement co-ordi‐
84 nates (rather than attachment points) before locating rather
85 than after.
86 numPoints
88 This is a generated value which contains the number of components
89 read in for this compound glyph.
90 The private instance variables are:
92 INFILE (P)
94 The input file form which to read any information
95 LOC (P)
97 Location relative to the start of the glyf table in the read file
98 BASE (P)
100 The location of the glyf table in the read file
101 LEN (P)
103 This is the number of bytes required by the glyph. It should be
104 kept up to date by calling the "update" method whenever any of the
105 glyph content changes.
106 OUTLOC (P)
108 Location relative to the start of the glyf table. This variable is
109 only active whilst the output process is going on. It is used to
110 inform the location table where the glyph's location is, since the
111 glyf table is output before the loca table due to alphabetical
112 ordering.
113 OUTLEN (P)
115 This indicates the length of the glyph data when it is output. This
116 more accurately reflects the internal memory form than the "LEN"
117 variable which only reflects the read file length. The "OUTLEN"
118 variable is only set after calling "out" or "out_dat".
119 Editing
121 If you want to edit a glyph in some way, then you should read_dat the
123 glyph, then make your changes and then update the glyph or set the
124 $g->{' isdirty'} variable. It is the application's duty to ensure that
125 the following instance variables are correct, from which update will
126 calculate the rest, including the bounding box information.
127 numPoints
129 numberOfContours
130 endPoints
131 x, y, flags (only flags bit 0)
132 instLen
133 hints
134 For components, the numPoints, x, y, endPoints & flags are not required
136 but the following information is required for each component.
137 flag (bits 2, 10, 11, 12)
139 glyph
140 args
141 scale
142 metric (glyph instance variable)
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146 Creates a new glyph setting various instance variables
147 $g->read
149 Reads the header component of the glyph (bounding box, etc.) and also
151 the glyph content, but into a data field rather than breaking it down
152 into its constituent structures. Use read_dat for this.
153 $g->read_dat
155 Reads the contents of the glyph (components and curves, etc.) from the
157 memory store "DAT" into structures within the object. Then, to indicate
158 where the master form of the data is, it deletes the "DAT" instance
159 variable.
160 $g->out($fh)
162 Writes the glyph data to outfile
164 $g->out_xml($context, $depth)
166 Outputs an XML description of the glyph
168 $g->update
170 Generates a "$self-"{'DAT'}> from the internal structures, if the data
172 has been read into structures in the first place. If you are building a
173 glyph from scratch you will need to set the instance variable ' read'
174 to 2 (or something > 1) for the update to work.
175 $g->update_bbox
177 Updates the bounding box for this glyph according to the points in the
179 glyph
180 $g->maxInfo
182 Returns lots of information about a glyph so that the "maxp" table can
184 update itself.
185 $g->empty
187 Empties the glyph of all information to the level of not having been
189 read. Useful for saving memory in apps with many glyphs being read
190 $g->get_points
192 This method creates point information for a compound glyph. The infor‐
194 mation is stored in the same place as if the glyph was not a compound,
195 but since numberOfContours is negative, the glyph is still marked as
196 being a compound
197 $g->get_refs
199 Returns an array of all the glyph ids that are used to make up this
201 glyph. That is all the compounds and their references and so on. If
202 this glyph is not a compound, then returns an empty array
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205 · The instance variables used here are somewhat clunky and inconsis‐
206 tent with the other tables.
207 · "update" doesn't re-calculate the bounding box or "numberOfCon‐
209 tours".
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212 Martin Hosken Martin_Hosken@sil.org. See Font::TTF::Font for copyright
213 and licensing.
214perl v5.8.8 2005-06-14 Font::TTF::Glyph(3)