Font::TTF::Glyph - phpMan

Che Dong
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.