Features

• Decodes almost any image that the PNG standard allows, except for images that use a different color depth than 8 bits. This includes all standard color modes and all transparency, interlacing and filtering options.
• Encodes images supports all color modes (true color, grayscale and indexed) and transparency for all these color modes. The best color mode will be chosen automatically, based on the amount of used colors.
• R/W access to the image’s pixels.
• R/W access to all image metadata that is stored in chunks.
• Memory efficient (uses a Fixnum, i.e. 4 bytes of memory, per pixel)
• Reasonably fast for Ruby standards, by only using integer math and a highly optimized saving routine.
• Interoperability with RMagick.