1Font::TTF::Glyph(3) User Contributed Perl Documentation Font::TTF::Glyph(3)
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6 Font::TTF::Glyph - Holds a information for a single glyph
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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 Variables for all glyphs:
19 The standard attributes each glyph has are:
20 numberOfContours
22 For simple glyphs this will be the count of contours. For compound
23 glyphs this will be -1.
24 xMin
26 yMin
27 xMax
28 yMax
29 These identify the bounding box of the glyph.
30 There are also other, derived, instance variables for each glyph which
32 are read when the whole glyph is read (via "read_dat"):
33 instLen
35 Number of bytes in the hinting instructions (Warning this variable
36 is deprecated, use "length($g-"{'hints'})> instead).
37 hints
39 The string containing the hinting code for the glyph
40 Variables for simple glyphs (numberOfContours >= 0):
42 endPoints
43 An array of endpoints for each contour in the glyph. There are
44 "numberOfContours" contours in a glyph. The number of points in a
45 glyph is equal to the highest endpoint of a contour.
46 numPoints
48 This is a generated value which contains the total number of points
49 for this simple glyph.
50 There are also a number of arrays indexed by point number:
52 flags
54 The flags associated with reading this point. The flags for a point
55 are recalculated for a point when it is "update"d. Thus the flags
56 are not very useful. The only important bit is bit 0 which
57 indicates whether the point is an 'on' curve point, or an 'off'
58 curve point.
59 x The absolute x co-ordinate of the point.
61 y The absolute y co-ordinate of the point
63 Variables for compound glyphs (numberOfContours == -1):
65 metric
66 This holds the component number (not its glyph number) of the
67 component from which the metrics for this glyph should be taken.
68 comps
70 This is an array of hashes for each component. Each hash has a
71 number of elements:
72 glyph
74 The glyph number of the glyph which comprises this component of
75 the composite. NOTE: In some badly generated fonts, "glyph"
76 may contain a numerical value but that glyph might not actually
77 exist in the font file. This could occur in any glyph, but is
78 particularly likely for glyphs that have no strokes, such as
79 SPACE, U+00A0 NO-BREAK SPACE, or U+200B ZERO WIDTH SPACE.
80 args
82 An array of two arguments which may be an x, y co-ordinate or
83 two attachment points (one on the base glyph the other on the
84 component). See flags for details.
85 flag
87 The flag for this component
88 scale
90 A 4 number array for component scaling. This allows stretching,
91 rotating, etc. Note that scaling applies to placement co-
92 ordinates (rather than attachment points) before locating
93 rather than after.
94 numPoints
96 This is a generated value which contains the number of components
97 read in for this compound glyph.
98 Private instance variables:
100 INFILE (P)
101 The input file form which to read any information
102 LOC (P)
104 Location relative to the start of the glyf table in the read file
105 BASE (P)
107 The location of the glyf table in the read file
108 LEN (P)
110 This is the number of bytes required by the glyph. It should be
111 kept up to date by calling the "update" method whenever any of the
112 glyph content changes.
113 OUTLOC (P)
115 Location relative to the start of the glyf table. This variable is
116 only active whilst the output process is going on. It is used to
117 inform the location table where the glyph is located, since the
118 glyf table is output before the loca table due to alphabetical
119 ordering.
120 OUTLEN (P)
122 This indicates the length of the glyph data when it is output. This
123 more accurately reflects the internal memory form than the "LEN"
124 variable which only reflects the read file length. The "OUTLEN"
125 variable is only set after calling "out" or "out_dat".
126 Editing
128 If you want to edit a glyph in some way, then you should read_dat the
129 glyph, then make your changes and then update the glyph or set the
130 $g->{' isDirty'} variable. The application must ensure that the
131 following instance variables are correct, from which update will
132 calculate the rest, including the bounding box information.
133 numPoints
135 numberOfContours
136 endPoints
137 x, y, flags (only flags bit 0)
138 instLen
139 hints
140 For components, the numPoints, x, y, endPoints & flags are not required
142 but the following information is required for each component.
143 flag (bits 2, 10, 11, 12)
145 glyph
146 args
147 scale
148 metric (glyph instance variable)
149
152 Creates a new glyph setting various instance variables
153 $g->read
155 Reads the header component of the glyph (numberOfContours and bounding
156 box) and also the glyph content, but into a data field rather than
157 breaking it down into its constituent structures. Use read_dat for
158 this.
159 $g->read_dat
161 Reads the contents of the glyph (components and curves, etc.) from the
162 memory store "DAT" into structures within the object.
163 $g->out($fh)
165 Writes the glyph data to outfile
166 $g->out_xml($context, $depth)
168 Outputs an XML description of the glyph
169 $g->dirty($val)
171 This sets the dirty flag to the given value or 1 if no given value. It
172 returns the value of the flag
173 $g->update
175 Generates a "$self-"{'DAT'}> from the internal structures, if the data
176 has been read into structures in the first place. If you are building a
177 glyph from scratch you will need to set the instance variable '
178 isDirty'.
179 $g->update_bbox
181 Updates the bounding box for this glyph according to the points in the
182 glyph
183 $g->maxInfo
185 Returns lots of information about a glyph so that the "maxp" table can
186 update itself. Returns array containing contributions of this glyph to
187 maxPoints, maxContours, maxCompositePoints, maxCompositeContours,
188 maxSizeOfInstructions, maxComponentElements, and maxComponentDepth.
189 $g->empty
191 Empties the glyph of all information to the level of not having been
192 read. Useful for saving memory in apps with many glyphs being read
193 $g->get_points
195 This method creates point information for a compound glyph. The
196 information is stored in the same place as if the glyph was not a
197 compound, but since numberOfContours is negative, the glyph is still
198 marked as being a compound
199 $g->get_refs
201 Returns an array of all the glyph ids that are used to make up this
202 glyph. That is all the compounds and their references and so on. If
203 this glyph is not a compound, then returns an empty array.
204 Please note the warning about bad fonts that reference nonexistent
206 glyphs under INSTANCE VARIABLES above. This function will not attempt
207 to filter out nonexistent glyph numbers.
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210 • The instance variables used here are somewhat clunky and
211 inconsistent with the other tables.
212 • "update" doesn't re-calculate the bounding box or
214 "numberOfContours".
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217 Martin Hosken <http://scripts.sil.org/FontUtils>.
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220 Copyright (c) 1998-2016, SIL International (http://www.sil.org)
221 This module is released under the terms of the Artistic License 2.0.
223 For details, see the full text of the license in the file LICENSE.
224perl v5.38.0 2023-07-20 Font::TTF::Glyph(3)