Struct Mask 

pub struct Mask<'a> {
    data: &'a [u8],
    width: u32,
    height: u32,
    bits_per_pixel: u8,
    packed: bool,
}

A single channel coverage mask of 1, 2, 4 or 8 bits per pixel.

The data is kept in the table’s packing. The accessors decode it, so a caller does not need to know the bit depth or whether rows are padded.

Fields

data: &'a [u8]

width: u32

height: u32

bits_per_pixel: u8

packed: bool

Implementations

impl<'a> Mask<'a>

pub fn new( data: &'a [u8], width: u32, height: u32, bits_per_pixel: u8, packed: bool, ) -> Option<Mask<'a>>

Creates a view of data as width by height pixels of bits_per_pixel each.

In a packed mask, each row begins at the bit that follows the previous row. In an unpacked mask, each row is padded to a whole byte.

Returns None if the bit depth is not 1, 2, 4 or 8, or if data is too short.

pub fn width(&self) -> u32

Returns the width in pixels.

pub fn height(&self) -> u32

Returns the height in pixels.

pub fn bits_per_pixel(&self) -> u8

Returns the number of bits per pixel: 1, 2, 4 or 8.

pub fn is_packed(&self) -> bool

Returns true if rows are not padded to a whole byte.

pub fn data(&self) -> &'a [u8]

Returns the raw pixel data from the table.

pub fn decoded_len(&self) -> usize

Returns the size in bytes of the decoded mask, one byte per pixel.

This is the length decode_into writes.

pub fn is_empty(&self) -> bool

Returns true if there are no pixels.

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

Returns the coverage of the pixel at column x of row y.

The value ranges from 0 to 255 for any bit depth.

pub fn pixels(&self) -> impl Iterator<Item = u8> + 'a

Returns an iterator over the coverage of each pixel, row by row.

pub fn rows(&self) -> impl Iterator<Item = MaskRow<'a>> + 'a

Returns an iterator over the rows, from top to bottom.

pub fn decode_into(&self, dst: &mut [u8]) -> bool

Writes the coverage of each pixel to dst, row by row, one byte per pixel.

dst must hold at least decoded_len bytes, and any bytes past that are left as they were. Returns false, writing nothing, if dst is shorter.

Trait Implementations

impl<'a> Clone for Mask<'a>

fn clone(&self) -> Mask<'a>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Copy for Mask<'a>