Struct ImageDecoder 

pub struct ImageDecoder { /* private fields */ }

Reusable image decoder with internal scratch buffers.

Create one ImageDecoder at program initialisation and pass it to ImageLoad::load_image in the hot loop. The scratch buffers grow to the high-water mark and are reused across calls — no per-frame allocations after the first few frames.

The decoder always produces the source’s native format and configures the destination tensor’s dimensions + pixel format accordingly (JPEG → Nv12/Grey, PNG → Rgb/Rgba/Grey). It never colour-converts or rotates; use ImageProcessor::convert() for that.

Example

use edgefirst_codec::{ImageDecoder, ImageLoad};
use edgefirst_tensor::{Tensor, TensorTrait, TensorMemory, PixelFormat};

let mut decoder = ImageDecoder::new();
// Allocate a buffer large enough for the biggest expected image.
let mut tensor = Tensor::<u8>::image(1920, 1080, PixelFormat::Nv12, Some(TensorMemory::Mem))
    .expect("alloc");

for _ in 0..100 {
    let frame = std::fs::read("frame.jpg").unwrap();
    let _info = tensor.load_image(&mut decoder, &frame);
}

Implementations

impl ImageDecoder

pub fn new() -> Self

Create a new decoder with empty scratch buffers.

pub fn decode_into<T: ImagePixel>( &mut self, data: &[u8], dst: &mut Tensor<T>, ) -> Result<ImageInfo>

Decode image data into a typed tensor, configuring its dimensions and pixel format to the decoded native format.

Detects the image format (JPEG or PNG) from magic bytes.

Errors

• CodecError::InsufficientCapacity if the image is larger than the tensor’s allocation
• CodecError::UnsupportedDtype if T is not valid for the native format (JPEG NV12/GREY require u8)
• CodecError::InvalidData if the data is not a valid JPEG or PNG

pub fn decode_into_dyn( &mut self, data: &[u8], dst: &mut TensorDyn, ) -> Result<ImageInfo>

Decode image data into a type-erased tensor.

pub fn decode_from_reader<T: ImagePixel, R: Read>( &mut self, reader: R, dst: &mut Tensor<T>, ) -> Result<ImageInfo>

Read all bytes from a Read source into the internal input buffer, then decode. The input buffer is reused across calls.

pub fn decode_from_reader_dyn<R: Read>( &mut self, reader: R, dst: &mut TensorDyn, ) -> Result<ImageInfo>

Read all bytes from a Read source, then decode into a type-erased tensor.

Trait Implementations

impl Default for ImageDecoder

fn default() -> Self

Returns the “default value” for a type.