Struct ListCache 

pub struct ListCache { /* private fields */ }

A list’s layout, kept from one frame to the next.

Measuring a line’s bubble — shaping its text to find where it wraps — is a function of (its text, the column’s width, the theme’s type). None of those change between the frames of a caret blink, a presence change or an arriving message, so neither does the measurement: it is kept here and reused, and the rows are kept whole until something they were placed from changes.

What invalidates what:

• a line whose text changed is measured again, alone;
• a width or text-scale change measures every line again, because every bubble is a different shape;
• a font or locale change (the renderer’s shaping epoch) drops every measurement too;
• a moved list, or a line whose instant, author or side changed, re-places the rows from the kept measurements without measuring anything.

Nothing here estimates. The height of the last message is the height it is painted at, so a scrollbar cannot disagree with where the conversation ends.

Implementations

impl ListCache

pub fn work(&self) -> ListWork

What the last layout and paint did.

Trait Implementations

impl Default for ListCache

fn default() -> ListCache

Returns the “default value” for a type.