Trait LuminanceSource 

pub trait LuminanceSource {
    const SUPPORTS_ROTATION: bool = false;
    const SUPPORTS_CROP: bool = false;

    // Required methods
    fn get_row(&self, y: usize) -> Option<Cow<'_, [u8]>>;
    fn get_column(&self, x: usize) -> Vec<u8> ;
    fn get_matrix(&self) -> Vec<u8> ;
    fn get_width(&self) -> usize;
    fn get_height(&self) -> usize;
    fn invert(&mut self);
    fn get_luma8_point(&self, x: usize, y: usize) -> u8;

    // Provided methods
    fn is_crop_supported(&self) -> bool { ... }
    fn is_rotate_supported(&self) -> bool { ... }
    fn crop(
        &self,
        _left: usize,
        _top: usize,
        _width: usize,
        _height: usize,
    ) -> Result<Self>
       where Self: Sized { ... }
    fn rotate_counter_clockwise(&self) -> Result<Self>
       where Self: Sized { ... }
    fn rotate_counter_clockwise_45(&self) -> Result<Self>
       where Self: Sized { ... }
    fn invert_block_of_bytes(&self, vec_to_invert: Vec<u8>) -> Vec<u8>  { ... }
}

The purpose of this class hierarchy is to abstract different bitmap implementations across platforms into a standard interface for requesting greyscale luminance values. The interface only provides immutable methods; therefore crop and rotation create copies. This is to ensure that one Reader does not modify the original luminance source and leave it in an unknown state for other Readers in the chain.

@author dswitkin@google.com (Daniel Switkin)

Provided Associated Constants

const SUPPORTS_ROTATION: bool = false

const SUPPORTS_CROP: bool = false

Required Methods

fn get_row(&self, y: usize) -> Option<Cow<'_, [u8]>>

Fetches one row of luminance data from the underlying platform’s bitmap. Values range from 0 (black) to 255 (white). Because Java does not have an unsigned byte type, callers will have to bitwise and with 0xff for each value. It is preferable for implementations of this method to only fetch this row rather than the whole image, since no 2D Readers may be installed and getMatrix() may never be called.

@param y The row to fetch, which must be in [0,getHeight()) @param row An optional preallocated array. If null or too small, it will be ignored. Always use the returned object, and ignore the .length of the array. @return An array containing the luminance data.

fn get_column(&self, x: usize) -> Vec<u8>

Get a column of of the image

fn get_matrix(&self) -> Vec<u8>

Fetches luminance data for the underlying bitmap. Values should be fetched using: {@code int luminance = array[y * width + x] & 0xff}

@return A row-major 2D array of luminance values. Do not use result.length as it may be larger than width * height bytes on some platforms. Do not modify the contents of the result.

fn get_width(&self) -> usize

@return The width of the bitmap.

fn get_height(&self) -> usize

@return The height of the bitmap.

fn invert(&mut self)

@return a wrapper of this {@code LuminanceSource} which inverts the luminances it returns – black becomes white and vice versa, and each value becomes (255-value).

fn get_luma8_point(&self, x: usize, y: usize) -> u8

Provided Methods

fn is_crop_supported(&self) -> bool

@return Whether this subclass supports cropping.

fn is_rotate_supported(&self) -> bool

@return Whether this subclass supports counter-clockwise rotation.

fn crop( &self, _left: usize, _top: usize, _width: usize, _height: usize, ) -> Result<Self>

where Self: Sized,

Returns a new object with cropped image data. Implementations may keep a reference to the original data rather than a copy. Only callable if isCropSupported() is true.

@param left The left coordinate, which must be in [0,getWidth()) @param top The top coordinate, which must be in [0,getHeight()) @param width The width of the rectangle to crop. @param height The height of the rectangle to crop. @return A cropped version of this object.

fn rotate_counter_clockwise(&self) -> Result<Self>

where Self: Sized,

Returns a new object with rotated image data by 90 degrees counterclockwise. Only callable if {@link #isRotateSupported()} is true.

@return A rotated version of this object.

fn rotate_counter_clockwise_45(&self) -> Result<Self>

where Self: Sized,

Returns a new object with rotated image data by 45 degrees counterclockwise. Only callable if {@link #isRotateSupported()} is true.

@return A rotated version of this object.

fn invert_block_of_bytes(&self, vec_to_invert: Vec<u8>) -> Vec<u8>

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl LuminanceSource for BufferedImageLuminanceSource

const SUPPORTS_CROP: bool = true

const SUPPORTS_ROTATION: bool = true

impl LuminanceSource for Luma8LuminanceSource

const SUPPORTS_CROP: bool = true

const SUPPORTS_ROTATION: bool = true

impl LuminanceSource for PlanarYUVLuminanceSource

const SUPPORTS_CROP: bool = true

const SUPPORTS_ROTATION: bool = false

impl LuminanceSource for RGBLuminanceSource

const SUPPORTS_CROP: bool = true