Struct TextSystem 

pub struct TextSystem { /* private fields */ }

The font and layout contexts a thread lays text out with.

One system per thread keeps parley’s non-Send contexts out of shared state. The system is inert state: creating, replacing or dropping one touches nothing but this thread.

Implementations

impl TextSystem

pub fn bundled_only() -> TextSystem

Creates a system that sees only the bundled fonts.

Without the bundled-fonts feature the system starts empty and every glyph lays out as missing.

pub fn with_system_fonts() -> TextSystem

Creates a system that sees the system fonts plus the bundled ones as a fallback.

System fonts are discovered only when the system-fonts feature is enabled, which is impossible on wasm. Without it this behaves like TextSystem::bundled_only.

pub fn install(self)

Installs this system for the current thread, replacing whatever the thread owned before.

Panics

Panics if the thread’s system is in use, because a system cannot be replaced while a layout borrows it.

pub fn with<R>(f: impl FnOnce(&mut TextSystem) -> R) -> R

Runs f with the current thread’s system, creating one on first use: TextSystem::with_system_fonts on native targets and TextSystem::bundled_only on wasm.

Panics

Panics if called from inside another with call on the same thread, for example from a crate::TextLayout constructor, because a system cannot be handed out twice at once.