Crate png[−][src]

Expand description

PNG encoder and decoder

This crate contains a PNG encoder and decoder. It supports reading of single lines or whole frames.

The most important types for decoding purposes are Decoder and Reader. They both wrap a std::io::Read. Decoder serves as a builder for Reader. Calling Decoder::read_info reads from the Read until the image data is reached.

Using the decoder

use std::fs::File;

// The decoder is a build for reader and can be used to set various decoding options
// via `Transformations`. The default output transformation is `Transformations::EXPAND
// | Transformations::STRIP_ALPHA`.
let decoder = png::Decoder::new(File::open("tests/pngsuite/basi0g01.png").unwrap());
let (info, mut reader) = decoder.read_info().unwrap();
// Allocate the output buffer.
let mut buf = vec![0; info.buffer_size()];
// Read the next frame. An APNG might contain multiple frames.
reader.next_frame(&mut buf).unwrap();
// Inspect more details of the last read frame.
let in_animation = reader.info().frame_control.is_some();

Encoder

Using the encoder

// For reading and opening files
use std::path::Path;
use std::fs::File;
use std::io::BufWriter;

let path = Path::new(r"/path/to/image.png");
let file = File::create(path).unwrap();
let ref mut w = BufWriter::new(file);

let mut encoder = png::Encoder::new(w, 2, 1); // Width is 2 pixels and height is 1.
encoder.set_color(png::ColorType::RGBA);
encoder.set_depth(png::BitDepth::Eight);
let mut writer = encoder.write_header().unwrap();

let data = [255, 0, 0, 255, 0, 0, 0, 255]; // An array containing a RGBA sequence. First pixel is red and second pixel is black.
writer.write_image_data(&data).unwrap(); // Save