Struct GrayImage 

pub struct GrayImage { /* private fields */ }

Available on crate feature scan only.

An 8-bit greyscale image: what a scanner actually works on.

Colour carries no information a barcode reader wants, so every input is reduced to luminance on the way in. Transparent pixels are composited over white first, because a barcode rendered with Color::TRANSPARENT as its background is black ink on nothing, and “nothing” prints as paper.

Implementations

impl GrayImage

pub fn from_luma(width: u32, height: u32, luma: Vec<u8>) -> Result<Self>

Wrap an existing 8-bit luminance buffer, one byte per pixel.

Errors

Returns Error::InvalidImage if either dimension is zero, if the buffer length is not exactly width * height, or if the image is larger than the crate’s pixel-count limit.

pub fn from_rgb8(width: u32, height: u32, rgb: &[u8]) -> Result<Self>

Convert a packed 8-bit RGB buffer, three bytes per pixel.

Errors

As from_luma, for a buffer of width * height * 3.

pub fn from_rgba8(width: u32, height: u32, rgba: &[u8]) -> Result<Self>

Convert a packed 8-bit RGBA buffer, four bytes per pixel, compositing over a white background.

Errors

As from_luma, for a buffer of width * height * 4.

pub fn from_png(bytes: &[u8]) -> Result<Self>

Available on crate feature png only.

Decode a PNG image.

Handles every colour type and bit depth the png crate can normalise to 8 bits, including palettes and greyscale.

Errors

Returns Error::InvalidImage if the bytes are not a PNG this crate can read, or if the image exceeds the pixel-count limit.

pub fn from_png_file(path: impl AsRef<Path>) -> Result<Self>

Available on crate features png and std only.

Read a PNG file from disk.

Errors

Returns Error::Io if the file cannot be read, or whatever from_png reports.

pub fn width(&self) -> u32

Width in pixels.

pub fn height(&self) -> u32

Height in pixels.

pub fn luma(&self) -> &[u8]

The luminance buffer, row-major, one byte per pixel.

pub fn pixel(&self, x: u32, y: u32) -> u8

Luminance at (x, y). Out-of-bounds reads as white, matching the way BitMatrix::get tolerates out-of-bounds coordinates.

Trait Implementations

impl Clone for GrayImage

fn clone(&self) -> GrayImage

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for GrayImage

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

Formats the value using the given formatter.

impl Eq for GrayImage

impl PartialEq for GrayImage

fn eq(&self, other: &GrayImage) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for GrayImage