Struct AaBuf 

pub struct AaBuf {
    pub width: usize,
    pub height: usize,
    /* private fields */
}

Anti-aliasing scratch buffer: 4 rows × (bitmap_width × 4) columns, 1 bit/pixel.

Bit packing is MSB-first (matching SplashBitmap Mono1 layout and the renderAALine / clipAALine code in SplashXPathScanner.cc):

• Bit 7 of byte 0 is pixel 0 of the row.
• Left-edge mask for pixel x: 0xff >> (x & 7).
• Right-edge mask for pixel x1 (exclusive): (0xff00u16 >> (x1 & 7)) as u8.

height is always AA_SIZE (4). width is bitmap_width * AA_SIZE.

Fields

width: usize

Width in pixels (= bitmap_width × AA_SIZE).

height: usize

Always AA_SIZE (4).

Implementations

impl AaBuf

pub fn new(bitmap_width: usize) -> Self

Create a new zeroed AA buffer for a bitmap of the given pixel width.

pub const fn row_bytes(&self) -> usize

Bytes per row (= width.div_ceil(8)).

pub fn clear(&mut self)

Clear all bits to 0.

pub fn set_span(&mut self, row: usize, x0: usize, x1: usize)

Set pixels [x0, x1) to 1 in the given row.

x0 and x1 are clamped to [0, width]. No-op if x0 ≥ x1.

Panics

Panics if row >= height.

pub fn get_byte(&self, row: usize, byte_idx: usize) -> u8

Read one raw byte from the given row at byte index byte_idx.

Panics

Panics if row >= height or byte_idx >= row_bytes().

pub fn row_slice(&self, row: usize) -> &[u8]

Read-only access to a full row as a byte slice.

Panics

Panics if row >= height.