Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
Font::TTF::Glyph(3)   User Contributed Perl Documentation  Font::TTF::Glyph(3)

NAME
       Font::TTF::Glyph	- Holds	a information for a single glyph

DESCRIPTION
       This is a single	glyph description as held in a TT font.	On creation
       only its	header is read.	Thus you can get the bounding box of each
       glyph without having to read all	the other information.

INSTANCE VARIABLES
       In addition to the named	variables in a glyph header ("xMin" etc.),
       there are also all capital instance variables for holding working
       information, mostly from	the location table.

   Variables for all glyphs:
       The standard attributes each glyph has are:

       numberOfContours
	   For simple glyphs this will be the count of contours. For compound
	   glyphs this will be -1.

       xMin
       yMin
       xMax
       yMax
	   These identify the bounding box of the glyph.

       There are also other, derived, instance variables for each glyph	which
       are read	when the whole glyph is	read (via "read_dat"):

       instLen
	   Number of bytes in the hinting instructions (Warning	this variable
	   is deprecated, use "length($g-"{'hints'})> instead).

       hints
	   The string containing the hinting code for the glyph

   Variables for simple	glyphs (numberOfContours >= 0):
       endPoints
	   An array of endpoints for each contour in the glyph.	There are
	   "numberOfContours" contours in a glyph. The number of points	in a
	   glyph is equal to the highest endpoint of a contour.

       numPoints
	   This	is a generated value which contains the	total number of	points
	   for this simple glyph.

       There are also a	number of arrays indexed by point number:

       flags
	   The flags associated	with reading this point. The flags for a point
	   are recalculated for	a point	when it	is "update"d. Thus the flags
	   are not very	useful.	The only important bit is bit 0	which
	   indicates whether the point is an 'on' curve	point, or an 'off'
	   curve point.

       x   The absolute	x co-ordinate of the point.

       y   The absolute	y co-ordinate of the point

   Variables for compound glyphs (numberOfContours == -1):
       metric
	   This	holds the component number (not	its glyph number) of the
	   component from which	the metrics for	this glyph should be taken.

       comps
	   This	is an array of hashes for each component. Each hash has	a
	   number of elements:

	   glyph
	       The glyph number	of the glyph which comprises this component of
	       the composite.  NOTE: In	some badly generated fonts, "glyph"
	       may contain a numerical value but that glyph might not actually
	       exist in	the font file.	This could occur in any	glyph, but is
	       particularly likely for glyphs that have	no strokes, such as
	       SPACE, U+00A0 NO-BREAK SPACE, or	U+200B ZERO WIDTH SPACE.

	   args
	       An array	of two arguments which may be an x, y co-ordinate or
	       two attachment points (one on the base glyph the	other on the
	       component). See flags for details.

	   flag
	       The flag	for this component

	   scale
	       A 4 number array	for component scaling. This allows stretching,
	       rotating, etc.  Note that scaling applies to placement co-
	       ordinates (rather than attachment points) before	locating
	       rather than after.

       numPoints
	   This	is a generated value which contains the	number of components
	   read	in for this compound glyph.

   Private instance variables:
       INFILE (P)
	   The input file form which to	read any information

       LOC (P)
	   Location relative to	the start of the glyf table in the read	file

       BASE (P)
	   The location	of the glyf table in the read file

       LEN (P)
	   This	is the number of bytes required	by the glyph. It should	be
	   kept	up to date by calling the "update" method whenever any of the
	   glyph content changes.

       OUTLOC (P)
	   Location relative to	the start of the glyf table. This variable is
	   only	active whilst the output process is going on. It is used to
	   inform the location table where the glyph is	located, since the
	   glyf	table is output	before the loca	table due to alphabetical
	   ordering.

       OUTLEN (P)
	   This	indicates the length of	the glyph data when it is output. This
	   more	accurately reflects the	internal memory	form than the "LEN"
	   variable which only reflects	the read file length. The "OUTLEN"
	   variable is only set	after calling "out" or "out_dat".

   Editing
       If you want to edit a glyph in some way,	then you should	read_dat the
       glyph, then make	your changes and then update the glyph or set the
       $g->{' isDirty'}	variable.  The application must	ensure that the
       following instance variables are	correct, from which update will
       calculate the rest, including the bounding box information.

	   numPoints
	   numberOfContours
	   endPoints
	   x, y, flags	       (only flags bit 0)
	   instLen
	   hints

       For components, the numPoints, x, y, endPoints &	flags are not required
       but the following information is	required for each component.

	   flag		       (bits 2,	10, 11,	12)
	   glyph
	   args
	   scale
	   metric	       (glyph instance variable)

METHODS
Font::TTF::Glyph->new(%parms)
       Creates a new glyph setting various instance variables

   $g->read
       Reads the header	component of the glyph (numberOfContours and bounding
       box) and	also the glyph content,	but into a data	field rather than
       breaking	it down	into its constituent structures. Use read_dat for
       this.

   $g->read_dat
       Reads the contents of the glyph (components and curves, etc.) from the
       memory store "DAT" into structures within the object.

   $g->out($fh)
       Writes the glyph	data to	outfile

   $g->out_xml($context, $depth)
       Outputs an XML description of the glyph

   $g->dirty($val)
       This sets the dirty flag	to the given value or 1	if no given value. It
       returns the value of the	flag

   $g->update
       Generates a "$self-"{'DAT'}> from the internal structures, if the data
       has been	read into structures in	the first place. If you	are building a
       glyph from scratch you will need	to set the instance variable '
       isDirty'.

   $g->update_bbox
       Updates the bounding box	for this glyph according to the	points in the
       glyph

   $g->maxInfo
       Returns lots of information about a glyph so that the "maxp" table can
       update itself. Returns array containing contributions of	this glyph to
       maxPoints, maxContours, maxCompositePoints, maxCompositeContours,
       maxSizeOfInstructions, maxComponentElements, and	maxComponentDepth.

   $g->empty
       Empties the glyph of all	information to the level of not	having been
       read.  Useful for saving	memory in apps with many glyphs	being read

   $g->get_points
       This method creates point information for a compound glyph. The
       information is stored in	the same place as if the glyph was not a
       compound, but since numberOfContours is negative, the glyph is still
       marked as being a compound

   $g->get_refs
       Returns an array	of all the glyph ids that are used to make up this
       glyph. That is all the compounds	and their references and so on.	If
       this glyph is not a compound, then returns an empty array.

       Please note the warning about bad fonts that reference nonexistent
       glyphs under INSTANCE VARIABLES above.  This function will not attempt
       to filter out nonexistent glyph numbers.

BUGS
       o   The instance	variables used here are	somewhat clunky	and
	   inconsistent	with the other tables.

       o   "update" doesn't re-calculate the bounding box or
	   "numberOfContours".

AUTHOR
       Martin Hosken <http://scripts.sil.org/FontUtils>.

LICENSING
       Copyright (c) 1998-2016,	SIL International (http://www.sil.org)

       This module is released under the terms of the Artistic License 2.0.
       For details, see	the full text of the license in	the file LICENSE.

perl v5.32.0			  2016-08-03		   Font::TTF::Glyph(3)

NAME | DESCRIPTION | INSTANCE VARIABLES | METHODS | Font::TTF::Glyph->new(%parms) | BUGS | AUTHOR | LICENSING

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=Font::TTF::Glyph&sektion=3&manpath=FreeBSD+12.1-RELEASE+and+Ports>

home | help