46png Module
46.1Overview
The png module provides measures to read/write image data in PNG format. To utilize it, import the png module using import function.
Below is an example to read a PNG file:
import(png)
img = image('foo.png')
46.2Exntension to Function's Capability
This module extends the capability of function image() and instance method image#write() so that they can read/write PNG files.
When function image() is provided with a stream that satisfies the following conditions, it would recognize the stream as a PNG file.
- The identifier of the stream ends with a suffix "
.png". - The stream data begins with a byte sequence "
\x89\x50\x4e\x47\x0d\x0a\x1a\x0a".
When instance method image#write() is provided with a stream that satisfies the following condition, it would write image data in PNG format.
- The identifier of the stream ends with a suffix "
.png".
46.3Module Function
46.4Extension to image Class
This module extends the image class with methods described here.
image#read@png(stream:stream:r):reduce
Reads a PNG image from a stream.
image#write@png(stream:stream:w):reduce
Writes a PNG image to a stream.
46.5Thanks
This module uses libpng library which is distributed in the following site: