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103 lines
3.5 KiB
Rust
103 lines
3.5 KiB
Rust
// Copyright © SixtyFPS GmbH <info@sixtyfps.io>
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// SPDX-License-Identifier: (GPL-3.0-only OR LicenseRef-SixtyFPS-commercial)
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/*!
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The backend is the abstraction for crates that need to do the actual drawing and event loop
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*/
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use alloc::boxed::Box;
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use alloc::rc::Rc;
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use alloc::string::String;
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use crate::graphics::{Image, IntSize};
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use crate::window::Window;
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#[cfg(feature = "std")]
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use once_cell::sync::OnceCell;
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#[cfg(all(not(feature = "std"), feature = "unsafe_single_core"))]
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use crate::unsafe_single_core::OnceCell;
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#[derive(Copy, Clone)]
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/// Behavior describing how the event loop should terminate.
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pub enum EventLoopQuitBehavior {
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/// Terminate the event loop when the last window was closed.
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QuitOnLastWindowClosed,
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/// Keep the event loop running until [`Backend::quit_event_loop()`] is called.
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QuitOnlyExplicitly,
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}
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/// Interface implemented by back-ends
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pub trait Backend: Send + Sync {
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/// Instantiate a window for a component.
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/// FIXME: should return a Box<dyn PlatformWindow>
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fn create_window(&'static self) -> Rc<Window>;
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/// Spins an event loop and renders the visible windows.
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fn run_event_loop(&'static self, behavior: EventLoopQuitBehavior);
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/// Exits the event loop.
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fn quit_event_loop(&'static self);
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#[cfg(feature = "std")] // FIXME: just because of the Error
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/// This function can be used to register a custom TrueType font with SixtyFPS,
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/// for use with the `font-family` property. The provided slice must be a valid TrueType
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/// font.
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fn register_font_from_memory(
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&'static self,
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data: &'static [u8],
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) -> Result<(), Box<dyn std::error::Error>>;
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#[cfg(feature = "std")]
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/// This function can be used to register a custom TrueType font with SixtyFPS,
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/// for use with the `font-family` property. The provided path must refer to a valid TrueType
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/// font.
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fn register_font_from_path(
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&'static self,
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path: &std::path::Path,
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) -> Result<(), Box<dyn std::error::Error>>;
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fn set_clipboard_text(&'static self, text: String);
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fn clipboard_text(&'static self) -> Option<String>;
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/// Send an user event to from another thread that should be run in the GUI event loop
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fn post_event(&'static self, event: Box<dyn FnOnce() + Send>);
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fn image_size(&'static self, image: &Image) -> IntSize;
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fn duration_since_start(&'static self) -> core::time::Duration {
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#[cfg(feature = "std")]
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{
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let the_beginning = *INITIAL_INSTANT.get_or_init(instant::Instant::now);
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instant::Instant::now() - the_beginning
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}
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#[cfg(not(feature = "std"))]
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core::time::Duration::ZERO
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}
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}
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#[cfg(feature = "std")]
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static INITIAL_INSTANT: once_cell::sync::OnceCell<instant::Instant> =
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once_cell::sync::OnceCell::new();
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#[cfg(feature = "std")]
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impl std::convert::From<crate::animations::Instant> for instant::Instant {
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fn from(our_instant: crate::animations::Instant) -> Self {
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let the_beginning = *INITIAL_INSTANT.get_or_init(instant::Instant::now);
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the_beginning + core::time::Duration::from_millis(our_instant.0)
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}
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}
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static PRIVATE_BACKEND_INSTANCE: OnceCell<Box<dyn Backend + 'static>> = OnceCell::new();
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pub fn instance() -> Option<&'static dyn Backend> {
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use core::ops::Deref;
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PRIVATE_BACKEND_INSTANCE.get().map(|backend_box| backend_box.deref())
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}
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pub fn instance_or_init(
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factory_fn: impl FnOnce() -> Box<dyn Backend + 'static>,
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) -> &'static dyn Backend {
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use core::ops::Deref;
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PRIVATE_BACKEND_INSTANCE.get_or_init(factory_fn).deref()
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}
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