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

class Font::FreeType::GlyphImage

Glyph images from font typefaces

Synopsis

use Font::FreeType;

my Font::FreeType $freetype .= new;
my $face = $freetype.face('Vera.ttf');
$face.set-char-size(24, 24, 100, 100);

for $face.glyph-images('ABC') {
    # Read vector outline.
    my $svg = .outline.svg;
    my $bitmap = .bitmap;
}

Description

This class represents individual glyph images (character image) loaded from a font.

set-bold(int strength)

Embolden the glyph. This needs to be done before calling either the bitmap() or outline() methods.

bitmap(:render-mode])

If the glyph is from a bitmap font, the bitmap image is returned. If it is from a vector font, then it is converted into a bitmap glyph. The outline is rendered into a bitmap at the face’s current size.

If anti-aliasing is used then shades of grey between 0 and 255 may occur. Anti-aliasing is performed by default, but can be turned off by passing the FT_RENDER_MODE_MONO option.

The size of the bitmap can be obtained as follows:

my $bitmap = $glyph-image.bitmap;
my $width =  $bitmap.width;
my $height = $bitmap.height;

The optional :render-mode argument can be any one of the following:

• FT_RENDER_MODE_NORMAL

  The default. Uses anti-aliasing.

• FT_RENDER_MODE_LIGHT

  Changes the hinting algorithm to make the glyph image closer to it’s real shape, but probably more fuzzy.

  Only available with Freetype version 2.1.4 or newer.

• FT_RENDER_MODE_MONO

  Render with anti-aliasing disabled. Each pixel will be either 0 or 255.

• FT_RENDER_MODE_LCD

  Render in colour for an LCD display, with three times as many pixels across the image as normal.

  Only available with Freetype version 2.1.3 or newer.

• FT_RENDER_MODE_LCD_V

  Render in colour for an LCD display, with three times as many rows down the image as normal.

  Only available with Freetype version 2.1.3 or newer.

bitmap_magick( :render-mode_) ** NYI **

A simple wrapper around the bitmap() method. Renders the bitmap as normal and returns it as an Image::Magick object, which can then be composited onto a larger bit-mapped image, or manipulated using any of the features available in Image::Magick.

The image is in the ‘gray’ format, with a depth of 8 bits.

The left and top distances in pixels are returned as well, in the same way as for the bitmap() method.

This method, particularly the use of the left and top offsets for correct positioning of the bitmap, is demonstrated in the magick.pl example program.

is-outline()

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

outline()

Returns an object of type Font::FreeType::Outline

See Also

• Font::FreeType

• Font::FreeType::Face

Authors

Geoff Richards qef@laxan.com

David Warring david.warring@gmail.com (Raku Port)

Copyright

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.