Crate edgefirst_image 

EdgeFirst HAL - Image Converter

The edgefirst_image crate is part of the EdgeFirst Hardware Abstraction Layer (HAL) and provides functionality for converting images between different formats and sizes. The crate is designed to work with hardware acceleration when available, but also provides a CPU-based fallback for environments where hardware acceleration is not present or not suitable.

The main features of the edgefirst_image crate include:

• Support for various image formats, including YUYV, RGB, RGBA, and GREY.
• Support for source crop, destination crop, rotation, and flipping.
• Image conversion using hardware acceleration (G2D, OpenGL) when available.
• CPU-based image conversion as a fallback option.

The crate defines a TensorImage struct that represents an image as a tensor, along with its format information. It also provides an ImageProcessor struct that manages the conversion process, selecting the appropriate conversion method based on the available hardware.

Examples

let image = include_bytes!("../../../testdata/zidane.jpg");
let img = TensorImage::load(image, Some(RGBA), None)?;
let mut converter = ImageProcessor::new()?;
let mut dst = TensorImage::new(640, 480, RGB, None)?;
converter.convert(&img, &mut dst, Rotation::None, Flip::None, Crop::default())?;

Environment Variables

The behavior of the edgefirst_image::ImageProcessor struct can be influenced by the following environment variables:

• EDGEFIRST_FORCE_BACKEND: When set to cpu, g2d, or opengl (case-insensitive), only that single backend is initialized and no fallback chain is used. If the forced backend fails to initialize, an error is returned immediately. This is useful for benchmarking individual backends in isolation. When this variable is set, the EDGEFIRST_DISABLE_* variables are ignored.
• EDGEFIRST_DISABLE_GL: If set to 1, disables the use of OpenGL for image conversion, forcing the use of CPU or other available hardware methods.
• EDGEFIRST_DISABLE_G2D: If set to 1, disables the use of G2D for image conversion, forcing the use of CPU or other available hardware methods.
• EDGEFIRST_DISABLE_CPU: If set to 1, disables the use of CPU for image conversion, forcing the use of hardware acceleration methods. If no hardware acceleration methods are available, an error will be returned when attempting to create an ImageProcessor.

Additionally the TensorMemory used by default allocations can be controlled using the EDGEFIRST_TENSOR_FORCE_MEM environment variable. If set to 1, default tensor memory uses system memory. This will disable the use of specialized memory regions for tensors and hardware acceleration. However, this will increase the performance of the CPU converter.

Structs

CPUProcessor

CPUConverter implements the ImageProcessor trait using the fallback CPU implementation for image processing.

Crop

ImageProcessor

Image converter that uses available hardware acceleration or CPU as a fallback.

ImageProcessorConfig

Configuration for ImageProcessor construction.

MaskRegion

Region metadata for a single detection within a compact mask atlas.

Rect

TensorImage

An image represented as a tensor with associated format information.

TensorImageRef

A borrowed view of an image tensor for zero-copy preprocessing.

Enums

Error

Flip

Rotation

Constants

BGRA

8 bit BGRA (byte order: B, G, R, A). Used by Cairo/Wayland (ARGB32 on little-endian).

GREY

8 bit grayscale, full range

NV12

8 bit planar YUV420, limited range

NV16

8 bit planar YUV422, limited range

PLANAR_RGB

PLANAR_RGBA

PLANAR_RGB_INT8

Planar RGB (channels-first) with uint8→int8 XOR 0x80 reinterpretation. The underlying bytes are uint8 with MSB flipped; when cast to i8, values map correctly: uint8 0 → int8 -128, uint8 128 → int8 0, uint8 255 → int8 127. Tensor shape is [3, H, W] (channels-first).

RGB

8 bit RGB

RGBA

8 bit RGBA

RGB_INT8

Packed RGB with uint8→int8 XOR 0x80 reinterpretation. The underlying bytes are uint8 with MSB flipped; when cast to i8, values map correctly: uint8 0 → int8 -128, uint8 128 → int8 0, uint8 255 → int8 127.

VYUY

8 bit interleaved YUV422 (VYUY byte order), limited range

YUYV

8 bit interleaved YUV422, limited range

Traits

ImageProcessorTrait

TensorImageDst

Trait for types that can be used as destination images for conversion.

Type Aliases

Result