egui/egui_web/src/backend.rs
2021-12-25 19:32:25 +01:00

284 lines
9.1 KiB
Rust

use crate::*;
pub use egui::{pos2, Color32};
// ----------------------------------------------------------------------------
fn create_painter(canvas_id: &str) -> Result<Box<dyn Painter>, JsValue> {
#[cfg(feature = "glow")]
return Ok(Box::new(crate::glow_wrapping::WrappedGlowPainter::new(
canvas_id,
)));
#[cfg(not(feature = "glow"))]
if let Ok(webgl2_painter) = webgl2::WebGl2Painter::new(canvas_id) {
console_log("Using WebGL2 backend");
Ok(Box::new(webgl2_painter))
} else {
console_log("Falling back to WebGL1 backend");
let webgl1_painter = webgl1::WebGlPainter::new(canvas_id)?;
Ok(Box::new(webgl1_painter))
}
}
// ----------------------------------------------------------------------------
/// Data gathered between frames.
#[derive(Default)]
pub struct WebInput {
/// Required because we don't get a position on touched
pub latest_touch_pos: Option<egui::Pos2>,
/// Required to maintain a stable touch position for multi-touch gestures.
pub latest_touch_pos_id: Option<egui::TouchId>,
pub raw: egui::RawInput,
}
impl WebInput {
pub fn new_frame(&mut self, canvas_size: egui::Vec2) -> egui::RawInput {
egui::RawInput {
screen_rect: Some(egui::Rect::from_min_size(Default::default(), canvas_size)),
pixels_per_point: Some(native_pixels_per_point()), // We ALWAYS use the native pixels-per-point
time: Some(now_sec()),
..self.raw.take()
}
}
}
// ----------------------------------------------------------------------------
use std::sync::atomic::Ordering::SeqCst;
pub struct NeedRepaint(std::sync::atomic::AtomicBool);
impl Default for NeedRepaint {
fn default() -> Self {
Self(true.into())
}
}
impl NeedRepaint {
pub fn fetch_and_clear(&self) -> bool {
self.0.swap(false, SeqCst)
}
pub fn set_true(&self) {
self.0.store(true, SeqCst);
}
}
impl epi::RepaintSignal for NeedRepaint {
fn request_repaint(&self) {
self.0.store(true, SeqCst);
}
}
// ----------------------------------------------------------------------------
pub struct AppRunner {
egui_ctx: egui::CtxRef,
painter: Box<dyn Painter>,
previous_frame_time: Option<f32>,
pub(crate) input: WebInput,
app: Box<dyn epi::App>,
pub(crate) needs_repaint: std::sync::Arc<NeedRepaint>,
storage: LocalStorage,
prefer_dark_mode: Option<bool>,
last_save_time: f64,
screen_reader: crate::screen_reader::ScreenReader,
pub(crate) text_cursor_pos: Option<egui::Pos2>,
pub(crate) mutable_text_under_cursor: bool,
}
impl AppRunner {
pub fn new(canvas_id: &str, app: Box<dyn epi::App>) -> Result<Self, JsValue> {
let egui_ctx = egui::CtxRef::default();
load_memory(&egui_ctx);
let prefer_dark_mode = crate::prefer_dark_mode();
if prefer_dark_mode == Some(true) {
egui_ctx.set_visuals(egui::Visuals::dark());
} else {
egui_ctx.set_visuals(egui::Visuals::light());
}
let storage = LocalStorage::default();
let mut runner = Self {
egui_ctx,
painter: create_painter(canvas_id)?,
previous_frame_time: None,
input: Default::default(),
app,
needs_repaint: Default::default(),
storage,
prefer_dark_mode,
last_save_time: now_sec(),
screen_reader: Default::default(),
text_cursor_pos: None,
mutable_text_under_cursor: false,
};
{
let mut app_output = epi::backend::AppOutput::default();
let mut frame = epi::backend::FrameBuilder {
info: runner.integration_info(),
tex_allocator: runner.painter.as_tex_allocator(),
output: &mut app_output,
repaint_signal: runner.needs_repaint.clone(),
}
.build();
runner
.app
.setup(&runner.egui_ctx, &mut frame, Some(&runner.storage));
}
Ok(runner)
}
pub fn egui_ctx(&self) -> &egui::CtxRef {
&self.egui_ctx
}
pub fn auto_save(&mut self) {
let now = now_sec();
let time_since_last_save = now - self.last_save_time;
if time_since_last_save > self.app.auto_save_interval().as_secs_f64() {
if self.app.persist_egui_memory() {
save_memory(&self.egui_ctx);
}
self.app.save(&mut self.storage);
self.last_save_time = now;
}
}
pub fn canvas_id(&self) -> &str {
self.painter.canvas_id()
}
pub fn warm_up(&mut self) -> Result<(), JsValue> {
if self.app.warm_up_enabled() {
let saved_memory = self.egui_ctx.memory().clone();
self.egui_ctx.memory().set_everything_is_visible(true);
self.logic()?;
*self.egui_ctx.memory() = saved_memory; // We don't want to remember that windows were huge.
self.egui_ctx.clear_animations();
}
Ok(())
}
fn integration_info(&self) -> epi::IntegrationInfo {
epi::IntegrationInfo {
name: self.painter.name(),
web_info: Some(epi::WebInfo {
web_location_hash: location_hash().unwrap_or_default(),
}),
prefer_dark_mode: self.prefer_dark_mode,
cpu_usage: self.previous_frame_time,
native_pixels_per_point: Some(native_pixels_per_point()),
}
}
pub fn logic(&mut self) -> Result<(egui::Output, Vec<egui::ClippedMesh>), JsValue> {
let frame_start = now_sec();
resize_canvas_to_screen_size(self.canvas_id(), self.app.max_size_points());
let canvas_size = canvas_size_in_points(self.canvas_id());
let raw_input = self.input.new_frame(canvas_size);
let mut app_output = epi::backend::AppOutput::default();
let mut frame = epi::backend::FrameBuilder {
info: self.integration_info(),
tex_allocator: self.painter.as_tex_allocator(),
output: &mut app_output,
repaint_signal: self.needs_repaint.clone(),
}
.build();
let (egui_output, shapes) = self.egui_ctx.run(raw_input, |egui_ctx| {
self.app.update(egui_ctx, &mut frame);
});
let clipped_meshes = self.egui_ctx.tessellate(shapes);
self.handle_egui_output(&egui_output);
{
let epi::backend::AppOutput {
quit: _, // Can't quit a web page
window_size: _, // Can't resize a web page
window_title: _, // TODO: change title of window
decorated: _, // Can't toggle decorations
drag_window: _, // Can't be dragged
} = app_output;
}
self.previous_frame_time = Some((now_sec() - frame_start) as f32);
Ok((egui_output, clipped_meshes))
}
pub fn paint(&mut self, clipped_meshes: Vec<egui::ClippedMesh>) -> Result<(), JsValue> {
self.painter.upload_egui_texture(&self.egui_ctx.texture());
self.painter.clear(self.app.clear_color());
self.painter
.paint_meshes(clipped_meshes, self.egui_ctx.pixels_per_point())
}
fn handle_egui_output(&mut self, output: &egui::Output) {
if self.egui_ctx.memory().options.screen_reader {
self.screen_reader.speak(&output.events_description());
}
let egui::Output {
cursor_icon,
open_url,
copied_text,
needs_repaint: _, // handled elsewhere
events: _, // already handled
mutable_text_under_cursor,
text_cursor_pos,
} = output;
set_cursor_icon(*cursor_icon);
if let Some(open) = open_url {
crate::open_url(&open.url, open.new_tab);
}
#[cfg(web_sys_unstable_apis)]
if !copied_text.is_empty() {
set_clipboard_text(copied_text);
}
#[cfg(not(web_sys_unstable_apis))]
let _ = copied_text;
self.mutable_text_under_cursor = *mutable_text_under_cursor;
if &self.text_cursor_pos != text_cursor_pos {
move_text_cursor(text_cursor_pos, self.canvas_id());
self.text_cursor_pos = *text_cursor_pos;
}
}
}
/// Install event listeners to register different input events
/// and start running the given app.
pub fn start(canvas_id: &str, app: Box<dyn epi::App>) -> Result<AppRunnerRef, JsValue> {
let mut runner = AppRunner::new(canvas_id, app)?;
runner.warm_up()?;
start_runner(runner)
}
/// Install event listeners to register different input events
/// and starts running the given `AppRunner`.
fn start_runner(app_runner: AppRunner) -> Result<AppRunnerRef, JsValue> {
let runner_ref = AppRunnerRef(Arc::new(Mutex::new(app_runner)));
install_canvas_events(&runner_ref)?;
install_document_events(&runner_ref)?;
install_text_agent(&runner_ref)?;
repaint_every_ms(&runner_ref, 1000)?; // just in case. TODO: make it a parameter
paint_and_schedule(runner_ref.clone())?;
Ok(runner_ref)
}