Struct Encoder 

pub struct Encoder<W, F> { /* private fields */ }

The main object, which does all of the encoding work.

Implementations

impl<W: Write, F> Encoder<W, F>

pub fn finish(&mut self) -> Result<()>

Finish encoding an image, writing any delayed data.

Examples found in repository

examples/flag.rs (line 37)

fn main() {
    let mut enc = Options::smallest(480, 360)
        .build(File::create("flag.png").unwrap())
        .unwrap();

    meta::text(
        &mut enc,
        meta::Keyword::Author,
        "Ram Kaniyur",
    ).unwrap();

    let mut row = [255; 480 * 4];

    for x in 0..480 {
        let i = x * 4;

        if x < 160 {
            row[i] = 0;
        } else if x < 320 {
            row[i + 1] = 0;
        } else {
            row[i + 2] = 0;
        }
    }

    for _y in 0..360 {
        enc.write(&row).unwrap();
    }

    enc.finish().unwrap();
}

pub fn chunk(&mut self, kind: &[u8; 4], data: &[u8]) -> Result<()>

Write a chunk with the given type and data.

pub fn writer(&mut self) -> &mut W

Get access to the writer that this was built with.

Be careful, because you can easily corrupt the image with this method.

impl<W: Write, F: Filter> Encoder<W, F>

pub fn new(opts: &Options, sink: W) -> Result<Self>

Make a new encoder, which writes to a given sink, with a custom filter.

This method also immediately writes the PNG headers to the sink.

pub fn write(&mut self, rows: &[u8]) -> Result<()>

Feed zero or more rows to the encoder.

Rows are specified in top-to-bottom and left-to-right order.

Panics

This method panics if you try to write data that doesn’t fit into a whole number of rows.

Examples found in repository

examples/flag.rs (line 34)

fn main() {
    let mut enc = Options::smallest(480, 360)
        .build(File::create("flag.png").unwrap())
        .unwrap();

    meta::text(
        &mut enc,
        meta::Keyword::Author,
        "Ram Kaniyur",
    ).unwrap();

    let mut row = [255; 480 * 4];

    for x in 0..480 {
        let i = x * 4;

        if x < 160 {
            row[i] = 0;
        } else if x < 320 {
            row[i + 1] = 0;
        } else {
            row[i + 2] = 0;
        }
    }

    for _y in 0..360 {
        enc.write(&row).unwrap();
    }

    enc.finish().unwrap();
}

pub fn reset(&mut self, opts: &Options) -> Result<()>

Reset the encoder to encode another image with the given options.

There’s a good chance that, before calling this method, you’ll want to call writer() to get a mutable reference to the writer, and swap that out with a different writer. This method also writes the headers of the new image to the sink.

Warning

This currently doesn’t change the compression level!