Struct PngEncoder 

pub struct PngEncoder { /* private fields */ }

Encodes a PNG stream.

Implementations

impl PngEncoder

pub const fn new() -> PngEncoder

An encoder at the default compression level.

pub const fn with_level(level: Level) -> PngEncoder

An encoder at an explicit DEFLATE level.

pub fn with_palette( self, colours: usize, dither: f32, ) -> Result<PngEncoder, PixelsError>

This encoder writing a palette image of at most colours entries, diffusing dither (0..=1) of the quantization error.

Errors

Returns PixelsError::InvalidArgument for colours outside 2..=256 or dither outside 0..=1.

pub fn from_options(options: &EncodeOptions) -> PngEncoder

An encoder configured from generic encode options.

EncodeOptions::compression_level is the DEFLATE level. Without one, EncodeOptions::quality, which cannot trade fidelity for size in a lossless format, is read as compression effort, mapping 1..=100 onto levels 1..=9.

EncodeOptions::wants_palette selects palette output, of EncodeOptions::colours entries (256 by default) dithered by EncodeOptions::dither (1 by default).

Trait Implementations

impl Debug for PngEncoder

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for PngEncoder

fn default() -> PngEncoder

Returns the “default value” for a type.

impl Encoder for PngEncoder

fn set_icc_profile(&mut self, profile: Option<&[u8]>) -> Result<(), PixelsError>

Embed profile as the image’s ICC colour profile, or write none.

fn set_exif(&mut self, exif: Option<&[u8]>) -> Result<(), PixelsError>

Embed exif (TIFF-structured bytes, as Decoder::exif gives them) as the image’s EXIF block, or write none.

fn set_xmp(&mut self, xmp: Option<&[u8]>) -> Result<(), PixelsError>

Embed xmp, an XMP packet as Decoder::xmp gives it, or write none.

fn set_density(&mut self, density: Option<Density>) -> Result<(), PixelsError>

Record density as the image’s resolution, or write the format’s default.

fn write_header( &mut self, desc: &ImageDescriptor, sink: &mut dyn Sink, ) -> Result<(), PixelsError>

Begin an image, writing any container header.

fn write_row( &mut self, row: &[u8], _sink: &mut dyn Sink, ) -> Result<(), PixelsError>

Write the next row, top to bottom.

fn finish(&mut self, sink: &mut dyn Sink) -> Result<(), PixelsError>

Finish the image, writing any trailer and flushing the sink.