Struct DisplayList 

pub struct DisplayList { /* private fields */ }

A flat list of display items in paint order, ready for a renderer to replay.

The list is rebuilt from the widget tree whenever a node paints. Clips are nested, so every DisplayItem::PushClip needs a later DisplayItem::PopClip, which DisplayList::finish checks in debug builds. Offsets nest the same way with DisplayItem::PushOffset and DisplayItem::PopOffset.

Implementations

impl DisplayList

pub fn new() -> DisplayList

Creates an empty list.

use smudge_core::geometry::{Color, Corners, Rect};
use smudge_core::paint::{DisplayList, PaintOp};

let mut list = DisplayList::new();
list.push_op(PaintOp::FillRect {
    rect: Rect::new(0.0, 0.0, 8.0, 8.0),
    radius: Corners::ZERO,
    color: Color::BLACK,
});
list.finish();
assert_eq!(list.len(), 1);

pub fn clear(&mut self)

Removes every item, leaving the list empty and ready for a new build.

pub fn push_op(&mut self, op: PaintOp)

Appends one drawing operation.

pub fn extend_ops(&mut self, ops: &[PaintOp])

Appends several drawing operations in order.

pub fn push_clip(&mut self, rect: Rect)

Starts a clip to rect, which applies to every following item until the matching DisplayList::pop_clip.

pub fn pop_clip(&mut self)

Ends the most recent clip.

Callers must pair every call with an earlier DisplayList::push_clip. DisplayList::finish reports an imbalance in debug builds.

pub fn push_offset(&mut self, offset: Point)

Starts an offset scope, which translates every following item by offset until the matching DisplayList::pop_offset.

Scopes nest with clips and with each other. A clip pushed inside a scope holds its rectangle in the scope’s coordinates, so it moves with the scope.

pub fn pop_offset(&mut self)

Ends the most recent offset scope.

Callers must pair every call with an earlier DisplayList::push_offset. DisplayList::finish reports an imbalance in debug builds.

pub fn items(&self) -> &[DisplayItem]

Returns the items in paint order.

pub fn len(&self) -> usize

Returns the number of items, counting clips.

pub fn is_empty(&self) -> bool

Returns true when the list holds no item.

pub fn finish(&mut self)

Completes a build of the list.

The frame calls this once after rebuilding the list and before handing it to a renderer. In release builds it does nothing, because an unbalanced list is an internal invariant violation rather than input from outside the library.

Panics

Panics in debug builds when a DisplayItem::PushClip has no matching DisplayItem::PopClip, when a PopClip appears with no clip open, or when an offset scope is unbalanced the same way.

Trait Implementations

impl Clone for DisplayList

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DisplayList

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

Formats the value using the given formatter.

impl Default for DisplayList

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for DisplayList

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for DisplayList