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Font-FreeType-raku

Read font files and render glyphs using FreeType2

[Raku PDF Project] / [Font-FreeType Module] / Font::FreeType :: Glyph

class Font::FreeType::Glyph

iterator for font typeface glyphs

Synopsis

use Font::FreeType;
use Font::FreeType::Glyph;

my Font::FreeType $freetype .= new;
my $face = $freetype.face('t/fonts/Vera.ttf');
$face.set-char-size(24, 24, 100, 100);

# Do some stuff with glyphs
$face.for-glyphs: 'ABC', -> Font::FreeType::Glyph $g {
    say "glyph {$g.name} has size {$g.width} X {$g.height}";
    # dump the glyph's bitmap to a binary PGM file
    my $g-image = $g.glyph-image;
    ($g.name() ~ '.pgm').IO.open(:w, :bin).write: $g-image.bitmap.pgm;
}

Description

This is an iterator class that represents individual glyphs loaded from a font.

See Font::FreeType::Face for how to obtain glyph objects, in particular the for-glyph-slots method.

For a detailed description of the meaning of glyph metrics, and the structure of vectorial outlines, see http://freetype.sourceforge.net/freetype2/docs/glyphs/

Methods

Unless otherwise stated, all methods will die if there is an error, and the metrics are scaled to the size of the font face.

char-code()

The character code (in Unicode) of the glyph. Could potentially return codes in other character sets if the font doesn’t have a Unicode character mapping, but most modern fonts do.

index()

The index number of the glyph in the font face.

is-outline()

True if the glyph has a vector outline, in which case it is safe to call outline_decompose(). Otherwise, the glyph only has a bitmap image.

height()

The height of the glyph.

horizontal-advance()

The distance from the origin of this glyph to the place where the next glyph’s origin should be. Only applies to horizontal layouts. Always positive, so for right-to-left text (such as Hebrew) it should be subtracted from the current glyph’s position.

glyph-image()

Return a Font::FreeType::GlyphImage object for the glyph. This can then be used to obtain bitmaps and outlines.

left-bearing()

The left side bearing, which is the distance from the origin to the left of the glyph image. Usually positive for horizontal layouts and negative for vertical ones.

name()

The name of the glyph, if the font format supports glyph names, otherwise undef.

right-bearing()

The distance from the right edge of the glyph image to the place where the origin of the next character should be (i.e., the end of the advance width). Only applies to horizontal layouts. Usually positive.

vertical-advance()

The distance from the origin of the current glyph to the place where the next glyph’s origin should be, moving down the page. Only applies to vertical layouts. Always positive.

width()

The width of the glyph. This is the distance from the left side to the right side, not the amount you should move along before placing the next glyph when typesetting. For that, see the horizontal_advance() method.

Str()

The Unicode character represented by the glyph.

See Also

Copyright 2004, Geoff Richards.

Ported from Perl to Raku by David Warring david.warring@gmail.com Copyright 2017.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.