Struct Tile 

#[repr(C)]
pub struct Tile {
    pub packed_winding_line_idx: u32,
    pub x: u16,
    pub y: u16,
}

A tile represents an aligned area on the pixmap, used to subdivide the viewport into sub-areas (currently 4x4) and analyze line intersections inside each such area.

Keep in mind that it is possible to have multiple tiles with the same index, namely if we have multiple lines crossing the same 4x4 area!

Note

This struct is #[repr(C)], but the byte order of its fields is dependent on the endianness of the compilation target.

Fields

packed_winding_line_idx: u32

The index of the line this tile belongs to into the line buffer, intersection data, and winding data packed together.

The layout is:

• Bits 0-4 (5 bits): Intersection and Winding Mask (W | R | L | B | T).
  • Bit 0 (mask 0b00001): Intersects top edge (T)
  • Bit 1 (mask 0b00010): Intersects bottom edge (B)
  • Bit 2 (mask 0b00100): Intersects left edge (L)
  • Bit 3 (mask 0b01000): Intersects right edge (R)
  • Bit 4 (mask 0b10000): Winding (W) - 1 if crosses top edge.
• Bits 5-31 (27 bits): The line index (line_idx).

Sorting Note: The line_idx occupies the higher bits to ensure that when sorting tiles with the same (x, y) coordinates, they are sorted by their line index first, and then by their intersection mask.

x: u16

The index of the tile in the x direction.

y: u16

The index of the tile in the y direction.

Implementations

impl Tile

pub const WIDTH: u16 = 4

The width of a tile in pixels.

pub const HEIGHT: u16 = 4

The height of a tile in pixels.

pub const SENTINEL: Self

A special tile used to signal the end of a tile stream during rendering.

pub fn new_clamped( x: u16, y: u16, line_idx: u32, intersection_mask: u32, ) -> Self

Create a new tile. x and y will be clamped to the largest possible coordinate if they are too large.

line_idx must be smaller than MAX_LINES_PER_PATH.

pub const fn new(x: u16, y: u16, line_idx: u32, intersection_mask: u32) -> Self

The base tile constructor

Unlike Self::new_clamped, this constructor stores x and y exactly as provided. Callers must ensure these coordinates do not exceed the limits required by downstream processing (typically u16::MAX / WIDTH and u16::MAX / HEIGHT).

pub const fn same_loc(&self, other: &Self) -> bool

Check whether two tiles are at the same location.

pub const fn prev_loc(&self, other: &Self) -> bool

Check whether self is adjacent to the left of other.

pub const fn same_row(&self, other: &Self) -> bool

Check whether two tiles are on the same row.

pub const fn line_idx(&self) -> u32

The index of the line this tile belongs to into the line buffer.

Returns the high 27 bits.

pub const fn winding(&self) -> bool

Whether the line crosses the top edge of the tile.

Lines making this crossing increment or decrement the coarse tile winding, depending on the line direction.

Checks Bit 4 (Winding).

pub const fn intersection_mask(&self) -> u32

The 5 bits of intersection and winding data.

pub const fn intersects_top(&self) -> bool

Whether the line intersects the top edge of the tile.

pub const fn intersects_bottom(&self) -> bool

Whether the line intersects the bottom edge of the tile.

pub const fn intersects_left(&self) -> bool

Whether the line intersects the left edge of the tile.

pub const fn intersects_right(&self) -> bool

Whether the line intersects the right edge of the tile.

const fn to_bits(self) -> u64

Return the u64 representation of this tile.

This is the u64 interpretation of (y, x, packed_winding_line_idx) where y is the most-significant part of the number and packed_winding_line_idx the least significant.

pub const fn is_sentinel(&self) -> bool

Whether a tile is a sentinel tile

Trait Implementations

impl Clone for Tile

fn clone(&self) -> Tile

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Tile

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

Formats the value using the given formatter.

impl Ord for Tile

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Tile

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Tile

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for Tile

impl Eq for Tile