NAME

Image::PNG::Portable - portable PNG output for Raku

SYNOPSIS

use Image::PNG::Portable;
my $o = Image::PNG::Portable.new: :width(16), :height(16);
$o.set: 8,8, 255,255,255;
$o.set-text-meta('Author', 'Apogee');
$o.write: 'image.png';

my $o2 = Image::PNG::Portable.new;
$o2.read: 'image.png';
$o2.get: 0, 0; # Pixel color value at x,y of 0,0 => (0, 0, 0, 255)
$o2.get-text-meta('Author');

STATUS

This module is currently useful for reading & outputting 8-bit-per-channel truecolor images with tExt metadata. Writing precompression filters, palettes, grayscale, non-8-bit channels, and ancillary features like gamma correction, and color profiles are all NYI.

DESCRIPTION

This is an almost-pure Raku PNG module.

USAGE

The following types are used internally and in this documentation. They are here for brevity, not exported in the public API.

subset UInt8 of Int where 0 <= * <= 255; # unsigned 8-bit
subset PInt  of Int where * > 0;         # positive

METHODS

.new(PInt :height!, Bool $alpha = True)

Creates a new Image::PNG::Portable object, initialized to black. If the alpha channel is enabled, it is initialized to transparent.

.set(UInt y, UInt8 green, UInt8 alpha = 255)

Sets the color of a pixel in the image.

.set-all(UInt8 green, UInt8 alpha = 255)

Sets the color of all pixels in the image.

.get(UInt y)

Gets the color of a pixel in the image as an array of channel values.

.write($file)

Writes the contents of the image to the specified file.

.read(metadata-only = False)

Reads the PNG file to the Image object. If $metadata-only is set to True, will not read pixel data.

.get(y)

Get the color information at pixel y (zero-indexed).

.set-text-meta(value)

Set tExt metadata for value.

.set-text-meta(%pairs)

Set tExt metadata from %pairs.

.text-meta-keys()

Get all tExt metadata keys.

.get-text-meta($key)

Get tExt metadata for given key $key.

.clear-text-metadata()

Clear tExt metadata.

.text-metadata()

Get the tExt metadata as a Hash.

AUTHORs

• raydiak

• Matt Doughty

COPYRIGHT AND LICENSE

Copyright 2015 - 2021 raydiak

Copyright 2025 Raku Community

This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.