Ubuntu Manpage: Font::FreeType - read font files and render glyphs from Perl using FreeType2

Provided by: libfont-freetype-perl_0.07-1build1_amd64

NAME

       Font::FreeType - read font files and render glyphs from Perl using FreeType2

SYNOPSIS

           use Font::FreeType;

           my $freetype = Font::FreeType->new;
           my $face = $freetype->face('Vera.ttf');

           $face->set_char_size(24, 24, 100, 100);
           my $glyph = $face->glyph_from_char('A');

DESCRIPTION

This module allows Perl programs to conveniently read information from font files. All
the font access is done through the FreeType2 library, which supports many formats. It
can render images of characters with high-quality hinting and antialiasing, extract
metrics information, and extract the outlines of characters in scalable formats like
TrueType.

Warning: this module is currently in 'beta' stage. It'll be another release or two before
it stabilizes. The API may change in ways that break programs based on it, but I don't
think it will change much. Some of the values returned may be wrong, or not scaled
correctly. See the TODO file to get a handle on how far along this work is.
Contributions welcome, particularly if you know more than I do (which isn't much) about
fonts and the FreeType2 library.

The Font::FreeType API is not intended to replicate the C API of the FreeType library --
it offers a much more Perl-friendly interface.

The quickest way to get started with this library is to look at the examples in the
examples directory of the distribution. Full details of the API are contained in this
documentation, and (more importantly) the documentation for the Font::FreeType::Face and
Font::FreeType::Glyph classes.

To use the library, first create a Font::FreeType object. This can be used to load faces
from files, for example:

my $freetype = Font::FreeType->new;
my $face = $freetype->face('Vera.ttf');

If your font is scalable (i.e., not a bitmapped font) then set the size and resolution you
want to see it at, for example 24pt at 100dpi:

$face->set_char_size(24, 24, 100, 100);

Then load a particular glyph (an image of a character), either by character code (in
Unicode) or the actual character:

my $glyph = $face->glyph_from_char_code(65);
my $glyph = $face->glyph_from_char('A');

Glyphs can be rendered to bitmap images, among other things:

my $bitmap = $glyph->bitmap;

See the documentation for Font::FreeType::Glyph for details of the format of the bitmap
array reference that returns, and for other ways to get information about a glyph.

METHODS

Unless otherwise stated, all methods will die if there is an error.

new()
Create a new 'instance' of the freetype library and return the object. This is a
class method, which doesn't take any arguments. If you only want to load one face,
then it's probably not even worth saving the object to a variable:

my $face = Font::FreeType->new->face('Vera.ttf');

face(filename, %options)
Return a Font::FreeType::Face object representing a font face from the specified file.

The "index" option specifies which face to load from the file. It defaults to 0, and
since most fonts only contain one face it rarely needs to be provided.

The "load_flags" option takes various flags which alter the way glyphs are loaded.
The default is usually OK for rendering fonts to bitmap images. When extracting
outlines from fonts, be sure to set the FT_LOAD_NO_HINTING flag.

The following load flags are available. They can be combined with the bitwise OR
operator ("|"). The symbols are exported by the module and so will be available once
you do "use Font::FreeType".

FT_LOAD_DEFAULT
The same as doing nothing special.

FT_LOAD_CROP_BITMAP
Remove extraneous black bits round the edges of bitmaps when loading embedded
bitmaps.

FT_LOAD_FORCE_AUTOHINT
Use FreeType's own automatic hinting algorithm rather than the normal TrueType
one. Probably only useful for testing the FreeType library.

FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH
Probably only useful for loading fonts with wrong metrics.

FT_LOAD_IGNORE_TRANSFORM
Don't transform glyphs. This module doesn't yet have support for transformations.

FT_LOAD_LINEAR_DESIGN
Don't scale the metrics.

FT_LOAD_NO_AUTOHINT
Don't use the FreeType autohinting algorithm. Hinting with other algorithms (such
as the TrueType one) will still be done if possible. Apparently some fonts look
worse with the autohinter than without any hinting.

This option is only available with FreeType 2.1.3 or newer.

FT_LOAD_NO_BITMAP
Don't load embedded bitmaps provided with scalable fonts. Bitmap fonts are still
loaded normally. This probably doesn't make much difference in the current
version of this module, as embedded bitmaps aren't deliberately used.

FT_LOAD_NO_HINTING
Prevents the coordinates of the outline from being adjusted ('grid fitted') to the
current size. Hinting should be turned on when rendering bitmap images of glyphs,
and off when extracting the outline information if you don't know at what
resolution it will be rendered. For example, when converting glyphs to PostScript
or PDF, use this to turn the hinting off.

FT_LOAD_NO_SCALE
Don't scale the font's outline or metrics to the right size. This will currently
generate bad numbers. To be fixed in a later version.

FT_LOAD_PEDANTIC
Raise errors when a font file is broken, rather than trying to work around it.

FT_LOAD_VERTICAL_LAYOUT
Return metrics and glyphs suitable for vertical layout. This module doesn't yet
provide any intentional support for vertical layout, so this probably won't be
much use.

version()
Returns the version number of the underlying FreeType library being used. If called
in scalar context returns a string containing three numbers in the format
"major.minor.patch". In list context returns the three numbers as separate values.

AUTHOR

       Geoff Richards <qef@laxan.com>

COPYRIGHT