Crate zenpng 

PNG encoding and decoding with zencodec trait integration.

Uses zenflate for both compression and decompression, typed pixel buffers (imgref + rgb), metadata roundtrip (ICC/EXIF/XMP), and optional palette quantization via zenquant.

Quick start

use zenpng::{decode, probe, encode_rgb8, EncodeConfig, PngDecodeConfig};
use enough::Unstoppable;
use imgref::ImgVec;
use rgb::Rgb;

// Decode
let data: &[u8] = &[]; // your PNG bytes
let output = decode(data, &PngDecodeConfig::default(), &Unstoppable)?;
println!("{}x{}", output.info.width, output.info.height);

// Encode
let pixels = ImgVec::new(vec![Rgb { r: 0u8, g: 0, b: 0 }; 64], 8, 8);
let encoded = encode_rgb8(pixels.as_ref(), None, &EncodeConfig::default(), &Unstoppable, &Unstoppable)?;

zencodec traits

PngEncoderConfig implements [zencodec::EncoderConfig] and PngDecoderConfig implements [zencodec::DecoderConfig] for use with multi-codec dispatchers. Note: PngDecodeConfig (used in the quick start) is the lower-level decode config; PngDecoderConfig wraps it for the zencodec trait interface.

Modules

detect

PNG source analysis, compression assessment, and re-encoding recommendations. PNG source analysis and re-encoding recommendations.

Structs

ApngDecodeOutput

APNG decode output containing fully composed frames.

ApngEncodeConfig

APNG encode configuration.

ApngEncodeParams

Bundled parameters for APNG encoding with any Quantizer backend.

ApngFrame

A single composed APNG frame (canvas-sized pixels).

ApngFrameInfo

Per-frame APNG timing metadata.

ApngFrameInput

A single frame for APNG encoding.

AutoEncodeResult

Result of encode_auto, indicating which encoding path was chosen.

EncodeConfig

PNG encode configuration.

MultiFrameOutput

Output of multi-frame quantization with a shared palette.

PngAnimationFrameDecoder

APNG frame-by-frame decoder implementing AnimationFrameDecoder.

PngAnimationFrameEncoder

APNG frame-by-frame encoder implementing AnimationFrameEncoder.

PngChromaticities

PNG chromaticity values (cHRM chunk).

PngDecodeConfig

Decode configuration for PNG operations.

PngDecodeJob

Per-operation PNG decode job.

PngDecodeOutput

PNG decode output.

PngDecoder

Single-image PNG decoder.

PngDecoderConfig

PNG decoder configuration implementing DecoderConfig.

PngEncodeJob

Per-operation PNG encode job.

PngEncoder

Single-image PNG encoder.

PngEncoderConfig

PNG encoder configuration implementing EncoderConfig.

PngInfo

PNG image metadata from probing.

PngTime

Last modification time from tIME chunk.

QuantizeOutput

Output of a single-image quantization.

TextChunk

A text chunk from tEXt or zTXt.

ZenquantQuantizer

zenquant quantizer — perceptual median-cut with dithering and quality metrics.

Enums

Compression

PNG compression effort.

Filter

PNG row filter strategy.

PhysUnit

Physical pixel dimensions unit (pHYs chunk).

PngBackground

Background color from bKGD chunk.

PngError

Errors from PNG encode/decode operations.

PngWarning

Non-fatal issues detected during PNG decoding.

QualityGate

Quality gate for auto-encode: indexed (smaller) vs truecolor (lossless).

SignificantBits

Significant bits per channel from sBIT chunk.

Traits

Quantizer

A color quantizer that reduces RGBA8 images to ≤256 indexed colors.

Functions

available_backends

List available quantizer backend names (based on enabled features).

decode

Decode PNG to pixels.

decode_apng

Decode APNG with full compositing, returning canvas-sized frames.

default_quantizer

Create a default quantizer (zenquant if available, else first enabled backend).

encode_apng

Encode canvas-sized RGBA8 frames into a truecolor APNG file.

encode_apng_auto

Encode APNG frames, auto-choosing indexed or truecolor, with any Quantizer.

encode_apng_indexed

Encode canvas-sized RGBA8 frames into an indexed APNG with any Quantizer.

encode_auto

Encode RGBA8 pixels, automatically choosing indexed or truecolor PNG.

encode_gray8

Encode Gray8 pixels to PNG.

encode_gray16

Encode Gray16 pixels to PNG.

encode_indexed

Encode RGBA8 pixels to indexed PNG using any Quantizer backend.

encode_rgb8

Encode RGB8 pixels to PNG.

encode_rgb16

Encode RGB16 pixels to PNG.

encode_rgba8

Encode RGBA8 pixels to PNG.

encode_rgba16

Encode RGBA16 pixels to PNG.

probe

Probe PNG metadata without decoding pixels.

quantizer_by_name

Create a quantizer by name at runtime.

Type Aliases

PngLimitsDeprecated

Deprecated: use PngDecodeConfig instead.