phpman > man > Font::TTF::Glyph(3pm)

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

    *   "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.