Chunky PNG

This library can read and write PNG files. It is written in pure Ruby for maximum portability. Let me rephrase: it does NOT require RMagick or any other memory leaking image library.

Source code

github.com/wvanbergen/chunky_png/tree

RDoc

rdoc.info/gems/chunky_png/frames

Wiki

github.com/wvanbergen/chunky_png/wiki

Issue tracker

github.com/wvanbergen/chunky_png/issues

Features

Also, have a look at OilyPNG at github.com/wvanbergen/oily_png. OilyPNG is a mixin module that implements some of the ChunkyPNG algorithms in C, which provides a massive speed boost to encoding and decoding.

Usage

require 'chunky_png'

# Creating an image from scratch, save as an interlaced PNG
png = ChunkyPNG::Image.new(16, 16, ChunkyPNG::Color::TRANSPARENT)
png[1,1] = ChunkyPNG::Color.rgba(10, 20, 30, 128)
png[2,1] = ChunkyPNG::Color('black @ 0.5')
png.save('filename.png', :interlace => true)

# Compose images using alpha blending.
avatar = ChunkyPNG::Image.from_file('avatar.png')
badge  = ChunkyPNG::Image.from_file('no_ie_badge.png')
avatar.compose!(badge, 10, 10)
avatar.save('composited.png', :fast_rgba) # Force the fast saving routine.

# Accessing metadata
image = ChunkyPNG::Image.from_file('with_metadata.png')
puts image.metadata['Title']
image.metadata['Author'] = 'Willem van Bergen'
image.save('with_metadata.png') # Overwrite file

# Low level access to PNG chunks
png_stream = ChunkyPNG::Datastream.from_file('filename.png')
png_stream.each_chunk { |chunk| p chunk.type }

For more information, see the project wiki on github.com/wvanbergen/chunky_png/wiki or the RDOC documentation on rdoc.info/gems/chunky_png/frames

About

The library is written by Willem van Bergen for Floorplanner.com, and released under the MIT license (see LICENSE). Please contact me for questions or remarks. Patches are greatly appreciated!

Please check out the changelog on github.com/wvanbergen/chunky_png/wiki/Changelog to see what changed in all versions.

P.S.: The name of this library is intentionally similar to Chunky Bacon and Chunky GIF. Use Google if you want to know _why. :-)

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