-
Notifications
You must be signed in to change notification settings - Fork 1.5k
/
context.rs
1430 lines (1253 loc) · 52.8 KB
/
context.rs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
// #![warn(missing_docs)]
use std::sync::Arc;
use crate::{
animation_manager::AnimationManager, data::output::PlatformOutput, frame_state::FrameState,
input_state::*, layers::GraphicLayers, memory::Options, os::OperatingSystem,
output::FullOutput, TextureHandle, *,
};
use epaint::{mutex::*, stats::*, text::Fonts, textures::TextureFilter, TessellationOptions, *};
// ----------------------------------------------------------------------------
struct WrappedTextureManager(Arc<RwLock<epaint::TextureManager>>);
impl Default for WrappedTextureManager {
fn default() -> Self {
let mut tex_mngr = epaint::textures::TextureManager::default();
// Will be filled in later
let font_id = tex_mngr.alloc(
"egui_font_texture".into(),
epaint::FontImage::new([0, 0]).into(),
Default::default(),
);
assert_eq!(font_id, TextureId::default());
Self(Arc::new(RwLock::new(tex_mngr)))
}
}
// ----------------------------------------------------------------------------
#[derive(Default)]
struct ContextImpl {
/// `None` until the start of the first frame.
fonts: Option<Fonts>,
memory: Memory,
animation_manager: AnimationManager,
tex_manager: WrappedTextureManager,
os: OperatingSystem,
input: InputState,
/// State that is collected during a frame and then cleared
frame_state: FrameState,
// The output of a frame:
graphics: GraphicLayers,
output: PlatformOutput,
paint_stats: PaintStats,
/// the duration backend will poll for new events, before forcing another egui update
/// even if there's no new events.
repaint_after: std::time::Duration,
/// While positive, keep requesting repaints. Decrement at the end of each frame.
repaint_requests: u32,
request_repaint_callback: Option<Box<dyn Fn() + Send + Sync>>,
/// used to suppress multiple calls to [`Self::request_repaint_callback`] during the same frame.
has_requested_repaint_this_frame: bool,
requested_repaint_last_frame: bool,
}
impl ContextImpl {
fn begin_frame_mut(&mut self, new_raw_input: RawInput) {
self.has_requested_repaint_this_frame = false; // allow new calls during the frame
self.memory.begin_frame(&self.input, &new_raw_input);
self.input = std::mem::take(&mut self.input)
.begin_frame(new_raw_input, self.requested_repaint_last_frame);
if let Some(new_pixels_per_point) = self.memory.new_pixels_per_point.take() {
self.input.pixels_per_point = new_pixels_per_point;
}
self.frame_state.begin_frame(&self.input);
self.update_fonts_mut();
// Ensure we register the background area so panels and background ui can catch clicks:
let screen_rect = self.input.screen_rect();
self.memory.areas.set_state(
LayerId::background(),
containers::area::State {
pos: screen_rect.min,
size: screen_rect.size(),
interactable: true,
},
);
}
/// Load fonts unless already loaded.
fn update_fonts_mut(&mut self) {
let pixels_per_point = self.input.pixels_per_point();
let max_texture_side = self.input.max_texture_side;
if let Some(font_definitions) = self.memory.new_font_definitions.take() {
let fonts = Fonts::new(pixels_per_point, max_texture_side, font_definitions);
self.fonts = Some(fonts);
}
let fonts = self.fonts.get_or_insert_with(|| {
let font_definitions = FontDefinitions::default();
Fonts::new(pixels_per_point, max_texture_side, font_definitions)
});
fonts.begin_frame(pixels_per_point, max_texture_side);
if self.memory.options.preload_font_glyphs {
// Preload the most common characters for the most common fonts.
// This is not very important to do, but may a few GPU operations.
for font_id in self.memory.options.style.text_styles.values() {
fonts.lock().fonts.font(font_id).preload_common_characters();
}
}
}
}
// ----------------------------------------------------------------------------
/// Your handle to egui.
///
/// This is the first thing you need when working with egui.
/// Contains the [`InputState`], [`Memory`], [`PlatformOutput`], and more.
///
/// [`Context`] is cheap to clone, and any clones refers to the same mutable data
/// ([`Context`] uses refcounting internally).
///
/// All methods are marked `&self`; [`Context`] has interior mutability (protected by a mutex).
///
///
/// You can store
///
/// # Example:
///
/// ``` no_run
/// # fn handle_platform_output(_: egui::PlatformOutput) {}
/// # fn paint(textures_detla: egui::TexturesDelta, _: Vec<egui::ClippedPrimitive>) {}
/// let mut ctx = egui::Context::default();
///
/// // Game loop:
/// loop {
/// let raw_input = egui::RawInput::default();
/// let full_output = ctx.run(raw_input, |ctx| {
/// egui::CentralPanel::default().show(&ctx, |ui| {
/// ui.label("Hello world!");
/// if ui.button("Click me").clicked() {
/// // take some action here
/// }
/// });
/// });
/// handle_platform_output(full_output.platform_output);
/// let clipped_primitives = ctx.tessellate(full_output.shapes); // create triangles to paint
/// paint(full_output.textures_delta, clipped_primitives);
/// }
/// ```
#[derive(Clone)]
pub struct Context(Arc<RwLock<ContextImpl>>);
impl std::cmp::PartialEq for Context {
fn eq(&self, other: &Context) -> bool {
Arc::ptr_eq(&self.0, &other.0)
}
}
impl Default for Context {
fn default() -> Self {
Self(Arc::new(RwLock::new(ContextImpl {
// Start with painting an extra frame to compensate for some widgets
// that take two frames before they "settle":
repaint_requests: 1,
..ContextImpl::default()
})))
}
}
impl Context {
fn read(&self) -> RwLockReadGuard<'_, ContextImpl> {
self.0.read()
}
fn write(&self) -> RwLockWriteGuard<'_, ContextImpl> {
self.0.write()
}
/// Run the ui code for one frame.
///
/// Put your widgets into a [`SidePanel`], [`TopBottomPanel`], [`CentralPanel`], [`Window`] or [`Area`].
///
/// This will modify the internal reference to point to a new generation of [`Context`].
/// Any old clones of this [`Context`] will refer to the old [`Context`], which will not get new input.
///
/// You can alternatively run [`Self::begin_frame`] and [`Context::end_frame`].
///
/// ```
/// // One egui context that you keep reusing:
/// let mut ctx = egui::Context::default();
///
/// // Each frame:
/// let input = egui::RawInput::default();
/// let full_output = ctx.run(input, |ctx| {
/// egui::CentralPanel::default().show(&ctx, |ui| {
/// ui.label("Hello egui!");
/// });
/// });
/// // handle full_output
/// ```
#[must_use]
pub fn run(&self, new_input: RawInput, run_ui: impl FnOnce(&Context)) -> FullOutput {
self.begin_frame(new_input);
run_ui(self);
self.end_frame()
}
/// An alternative to calling [`Self::run`].
///
/// ```
/// // One egui context that you keep reusing:
/// let mut ctx = egui::Context::default();
///
/// // Each frame:
/// let input = egui::RawInput::default();
/// ctx.begin_frame(input);
///
/// egui::CentralPanel::default().show(&ctx, |ui| {
/// ui.label("Hello egui!");
/// });
///
/// let full_output = ctx.end_frame();
/// // handle full_output
/// ```
pub fn begin_frame(&self, new_input: RawInput) {
self.write().begin_frame_mut(new_input);
}
// ---------------------------------------------------------------------
/// If the given [`Id`] has been used previously the same frame at at different position,
/// then an error will be printed on screen.
///
/// This function is already called for all widgets that do any interaction,
/// but you can call this from widgets that store state but that does not interact.
///
/// The given [`Rect`] should be approximately where the widget will be.
/// The most important thing is that [`Rect::min`] is approximately correct,
/// because that's where the warning will be painted. If you don't know what size to pick, just pick [`Vec2::ZERO`].
pub fn check_for_id_clash(&self, id: Id, new_rect: Rect, what: &str) {
let prev_rect = self.frame_state().used_ids.insert(id, new_rect);
if let Some(prev_rect) = prev_rect {
// it is ok to reuse the same ID for e.g. a frame around a widget,
// or to check for interaction with the same widget twice:
if prev_rect.expand(0.1).contains_rect(new_rect)
|| new_rect.expand(0.1).contains_rect(prev_rect)
{
return;
}
let show_error = |pos: Pos2, text: String| {
let painter = self.debug_painter();
let rect = painter.error(pos, text);
if let Some(pointer_pos) = self.pointer_hover_pos() {
if rect.contains(pointer_pos) {
painter.error(
rect.left_bottom() + vec2(2.0, 4.0),
"ID clashes happens when things like Windows or CollapsingHeaders share names,\n\
or when things like Plot and Grid:s aren't given unique id_source:s.\n\n\
Sometimes the solution is to use ui.push_id.",
);
}
}
};
let id_str = id.short_debug_format();
if prev_rect.min.distance(new_rect.min) < 4.0 {
show_error(
new_rect.min,
format!("Double use of {} ID {}", what, id_str),
);
} else {
show_error(
prev_rect.min,
format!("First use of {} ID {}", what, id_str),
);
show_error(
new_rect.min,
format!("Second use of {} ID {}", what, id_str),
);
}
}
}
// ---------------------------------------------------------------------
/// Use `ui.interact` instead
#[allow(clippy::too_many_arguments)]
pub(crate) fn interact(
&self,
clip_rect: Rect,
item_spacing: Vec2,
layer_id: LayerId,
id: Id,
rect: Rect,
sense: Sense,
enabled: bool,
) -> Response {
let gap = 0.5; // Just to make sure we don't accidentally hover two things at once (a small eps should be sufficient).
// Make it easier to click things:
let interact_rect = rect.expand2(
(0.5 * item_spacing - Vec2::splat(gap))
.at_least(Vec2::splat(0.0))
.at_most(Vec2::splat(5.0)),
); // make it easier to click
let hovered = self.rect_contains_pointer(layer_id, clip_rect.intersect(interact_rect));
self.interact_with_hovered(layer_id, id, rect, sense, enabled, hovered)
}
/// You specify if a thing is hovered, and the function gives a [`Response`].
pub(crate) fn interact_with_hovered(
&self,
layer_id: LayerId,
id: Id,
rect: Rect,
sense: Sense,
enabled: bool,
hovered: bool,
) -> Response {
let hovered = hovered && enabled; // can't even hover disabled widgets
let mut response = Response {
ctx: self.clone(),
layer_id,
id,
rect,
sense,
enabled,
hovered,
clicked: Default::default(),
double_clicked: Default::default(),
triple_clicked: Default::default(),
dragged: false,
drag_released: false,
is_pointer_button_down_on: false,
interact_pointer_pos: None,
changed: false, // must be set by the widget itself
};
if !enabled || !sense.focusable || !layer_id.allow_interaction() {
// Not interested or allowed input:
self.memory().surrender_focus(id);
return response;
}
self.check_for_id_clash(id, rect, "widget");
let clicked_elsewhere = response.clicked_elsewhere();
let ctx_impl = &mut *self.write();
let memory = &mut ctx_impl.memory;
let input = &mut ctx_impl.input;
// We only want to focus labels if the screen reader is on.
let interested_in_focus =
sense.interactive() || sense.focusable && memory.options.screen_reader;
if interested_in_focus {
memory.interested_in_focus(id);
}
if sense.click
&& memory.has_focus(response.id)
&& (input.key_pressed(Key::Space) || input.key_pressed(Key::Enter))
{
// Space/enter works like a primary click for e.g. selected buttons
response.clicked[PointerButton::Primary as usize] = true;
}
if sense.click || sense.drag {
memory.interaction.click_interest |= hovered && sense.click;
memory.interaction.drag_interest |= hovered && sense.drag;
response.dragged = memory.interaction.drag_id == Some(id);
response.is_pointer_button_down_on =
memory.interaction.click_id == Some(id) || response.dragged;
for pointer_event in &input.pointer.pointer_events {
match pointer_event {
PointerEvent::Moved(_) => {}
PointerEvent::Pressed { .. } => {
if hovered {
if sense.click && memory.interaction.click_id.is_none() {
// potential start of a click
memory.interaction.click_id = Some(id);
response.is_pointer_button_down_on = true;
}
// HACK: windows have low priority on dragging.
// This is so that if you drag a slider in a window,
// the slider will steal the drag away from the window.
// This is needed because we do window interaction first (to prevent frame delay),
// and then do content layout.
if sense.drag
&& (memory.interaction.drag_id.is_none()
|| memory.interaction.drag_is_window)
{
// potential start of a drag
memory.interaction.drag_id = Some(id);
memory.interaction.drag_is_window = false;
memory.window_interaction = None; // HACK: stop moving windows (if any)
response.is_pointer_button_down_on = true;
response.dragged = true;
}
}
}
PointerEvent::Released(click) => {
response.drag_released = response.dragged;
response.dragged = false;
if hovered && response.is_pointer_button_down_on {
if let Some(click) = click {
let clicked = hovered && response.is_pointer_button_down_on;
response.clicked[click.button as usize] = clicked;
response.double_clicked[click.button as usize] =
clicked && click.is_double();
response.triple_clicked[click.button as usize] =
clicked && click.is_triple();
}
}
}
}
}
}
if response.is_pointer_button_down_on {
response.interact_pointer_pos = input.pointer.interact_pos();
}
if input.pointer.any_down() {
response.hovered &= response.is_pointer_button_down_on; // we don't hover widgets while interacting with *other* widgets
}
if memory.has_focus(response.id) && clicked_elsewhere {
memory.surrender_focus(id);
}
if response.dragged() && !memory.has_focus(response.id) {
// e.g.: remove focus from a widget when you drag something else
memory.stop_text_input();
}
response
}
/// Get a full-screen painter for a new or existing layer
pub fn layer_painter(&self, layer_id: LayerId) -> Painter {
let screen_rect = self.input().screen_rect();
Painter::new(self.clone(), layer_id, screen_rect)
}
/// Paint on top of everything else
pub fn debug_painter(&self) -> Painter {
Self::layer_painter(self, LayerId::debug())
}
/// How much space is still available after panels has been added.
/// This is the "background" area, what egui doesn't cover with panels (but may cover with windows).
/// This is also the area to which windows are constrained.
pub fn available_rect(&self) -> Rect {
self.frame_state().available_rect()
}
}
/// ## Borrows parts of [`Context`]
impl Context {
/// Stores all the egui state.
///
/// If you want to store/restore egui, serialize this.
#[inline]
pub fn memory(&self) -> RwLockWriteGuard<'_, Memory> {
RwLockWriteGuard::map(self.write(), |c| &mut c.memory)
}
/// Stores superficial widget state.
#[inline]
pub fn data(&self) -> RwLockWriteGuard<'_, crate::util::IdTypeMap> {
RwLockWriteGuard::map(self.write(), |c| &mut c.memory.data)
}
#[inline]
pub(crate) fn graphics(&self) -> RwLockWriteGuard<'_, GraphicLayers> {
RwLockWriteGuard::map(self.write(), |c| &mut c.graphics)
}
/// What egui outputs each frame.
///
/// ```
/// # let mut ctx = egui::Context::default();
/// ctx.output().cursor_icon = egui::CursorIcon::Progress;
/// ```
#[inline]
pub fn output(&self) -> RwLockWriteGuard<'_, PlatformOutput> {
RwLockWriteGuard::map(self.write(), |c| &mut c.output)
}
#[inline]
pub(crate) fn frame_state(&self) -> RwLockWriteGuard<'_, FrameState> {
RwLockWriteGuard::map(self.write(), |c| &mut c.frame_state)
}
/// Access the [`InputState`].
///
/// Note that this locks the [`Context`], so be careful with if-let bindings:
///
/// ```
/// # let mut ctx = egui::Context::default();
/// if let Some(pos) = ctx.input().pointer.hover_pos() {
/// // ⚠️ Using `ctx` again here will lead to a dead-lock!
/// }
///
/// if let Some(pos) = { ctx.input().pointer.hover_pos() } {
/// // This is fine!
/// }
///
/// let pos = ctx.input().pointer.hover_pos();
/// if let Some(pos) = pos {
/// // This is fine!
/// }
/// ```
#[inline]
pub fn input(&self) -> RwLockReadGuard<'_, InputState> {
RwLockReadGuard::map(self.read(), |c| &c.input)
}
#[inline]
pub fn input_mut(&self) -> RwLockWriteGuard<'_, InputState> {
RwLockWriteGuard::map(self.write(), |c| &mut c.input)
}
/// Not valid until first call to [`Context::run()`].
/// That's because since we don't know the proper `pixels_per_point` until then.
#[inline]
pub fn fonts(&self) -> RwLockReadGuard<'_, Fonts> {
RwLockReadGuard::map(self.read(), |c| {
c.fonts
.as_ref()
.expect("No fonts available until first call to Context::run()")
})
}
#[inline]
fn fonts_mut(&self) -> RwLockWriteGuard<'_, Option<Fonts>> {
RwLockWriteGuard::map(self.write(), |c| &mut c.fonts)
}
#[inline]
pub fn options(&self) -> RwLockWriteGuard<'_, Options> {
RwLockWriteGuard::map(self.write(), |c| &mut c.memory.options)
}
/// Change the options used by the tessellator.
#[inline]
pub fn tessellation_options(&self) -> RwLockWriteGuard<'_, TessellationOptions> {
RwLockWriteGuard::map(self.write(), |c| &mut c.memory.options.tessellation_options)
}
/// What operating system are we running on?
///
/// When compiling natively, this is
/// figured out from the `target_os`.
///
/// For web, this can be figured out from the user-agent,
/// and is done so by [`eframe`](https://github.com/emilk/egui/tree/master/crates/eframe).
pub fn os(&self) -> OperatingSystem {
self.read().os
}
/// Set the operating system we are running on.
///
/// If you are writing wasm-based integration for egui you
/// may want to set this based on e.g. the user-agent.
pub fn set_os(&self, os: OperatingSystem) {
self.write().os = os;
}
/// Format the given shortcut in a human-readable way (e.g. `Ctrl+Shift+X`).
///
/// Can be used to get the text for [`Button::shortcut_text`].
pub fn format_shortcut(&self, shortcut: &KeyboardShortcut) -> String {
let os = self.os();
let is_mac = matches!(os, OperatingSystem::Mac | OperatingSystem::IOS);
let can_show_symbols = || {
let ModifierNames {
alt,
ctrl,
shift,
mac_cmd,
..
} = ModifierNames::SYMBOLS;
let font_id = TextStyle::Body.resolve(&self.style());
let fonts = self.fonts();
let mut fonts = fonts.lock();
let font = fonts.fonts.font(&font_id);
font.has_glyphs(alt)
&& font.has_glyphs(ctrl)
&& font.has_glyphs(shift)
&& font.has_glyphs(mac_cmd)
};
if is_mac && can_show_symbols() {
shortcut.format(&ModifierNames::SYMBOLS, is_mac)
} else {
shortcut.format(&ModifierNames::NAMES, is_mac)
}
}
}
impl Context {
/// Call this if there is need to repaint the UI, i.e. if you are showing an animation.
///
/// If this is called at least once in a frame, then there will be another frame right after this.
/// Call as many times as you wish, only one repaint will be issued.
///
/// If called from outside the UI thread, the UI thread will wake up and run,
/// provided the egui integration has set that up via [`Self::set_request_repaint_callback`]
/// (this will work on `eframe`).
pub fn request_repaint(&self) {
// request two frames of repaint, just to cover some corner cases (frame delays):
let mut ctx = self.write();
ctx.repaint_requests = 2;
if let Some(callback) = &ctx.request_repaint_callback {
if !ctx.has_requested_repaint_this_frame {
(callback)();
ctx.has_requested_repaint_this_frame = true;
}
}
}
/// Request repaint after the specified duration elapses in the case of no new input
/// events being received.
///
/// The function can be multiple times, but only the *smallest* duration will be considered.
/// So, if the function is called two times with `1 second` and `2 seconds`, egui will repaint
/// after `1 second`
///
/// This is primarily useful for applications who would like to save battery by avoiding wasted
/// redraws when the app is not in focus. But sometimes the GUI of the app might become stale
/// and outdated if it is not updated for too long.
///
/// Lets say, something like a stop watch widget that displays the time in seconds. You would waste
/// resources repainting multiple times within the same second (when you have no input),
/// just calculate the difference of duration between current time and next second change,
/// and call this function, to make sure that you are displaying the latest updated time, but
/// not wasting resources on needless repaints within the same second.
///
/// NOTE: only works if called before `Context::end_frame()`. to force egui to update,
/// use `Context::request_repaint()` instead.
///
/// ### Quirk:
/// Duration begins at the next frame. lets say for example that its a very inefficient app
/// and takes 500 milliseconds per frame at 2 fps. The widget / user might want a repaint in
/// next 500 milliseconds. Now, app takes 1000 ms per frame (1 fps) because the backend event
/// timeout takes 500 milli seconds AFTER the vsync swap buffer.
/// So, its not that we are requesting repaint within X duration. We are rather timing out
/// during app idle time where we are not receiving any new input events.
pub fn request_repaint_after(&self, duration: std::time::Duration) {
// Maybe we can check if duration is ZERO, and call self.request_repaint()?
let mut ctx = self.write();
ctx.repaint_after = ctx.repaint_after.min(duration);
}
/// For integrations: this callback will be called when an egui user calls [`Self::request_repaint`].
///
/// This lets you wake up a sleeping UI thread.
///
/// Note that only one callback can be set. Any new call overrides the previous callback.
pub fn set_request_repaint_callback(&self, callback: impl Fn() + Send + Sync + 'static) {
let callback = Box::new(callback);
self.write().request_repaint_callback = Some(callback);
}
/// Tell `egui` which fonts to use.
///
/// The default `egui` fonts only support latin and cyrillic alphabets,
/// but you can call this to install additional fonts that support e.g. korean characters.
///
/// The new fonts will become active at the start of the next frame.
pub fn set_fonts(&self, font_definitions: FontDefinitions) {
if let Some(current_fonts) = &*self.fonts_mut() {
// NOTE: this comparison is expensive since it checks TTF data for equality
if current_fonts.lock().fonts.definitions() == &font_definitions {
return; // no change - save us from reloading font textures
}
}
self.memory().new_font_definitions = Some(font_definitions);
}
/// The [`Style`] used by all subsequent windows, panels etc.
pub fn style(&self) -> Arc<Style> {
self.options().style.clone()
}
/// The [`Style`] used by all new windows, panels etc.
///
/// You can also use [`Ui::style_mut`] to change the style of a single [`Ui`].
///
/// Example:
/// ```
/// # let mut ctx = egui::Context::default();
/// let mut style: egui::Style = (*ctx.style()).clone();
/// style.spacing.item_spacing = egui::vec2(10.0, 20.0);
/// ctx.set_style(style);
/// ```
pub fn set_style(&self, style: impl Into<Arc<Style>>) {
self.options().style = style.into();
}
/// The [`Visuals`] used by all subsequent windows, panels etc.
///
/// You can also use [`Ui::visuals_mut`] to change the visuals of a single [`Ui`].
///
/// Example:
/// ```
/// # let mut ctx = egui::Context::default();
/// ctx.set_visuals(egui::Visuals::light()); // Switch to light mode
/// ```
pub fn set_visuals(&self, visuals: crate::Visuals) {
std::sync::Arc::make_mut(&mut self.options().style).visuals = visuals;
}
/// The number of physical pixels for each logical point.
#[inline(always)]
pub fn pixels_per_point(&self) -> f32 {
self.input().pixels_per_point()
}
/// Set the number of physical pixels for each logical point.
/// Will become active at the start of the next frame.
///
/// Note that this may be overwritten by input from the integration via [`RawInput::pixels_per_point`].
/// For instance, when using `eframe` on web, the browsers native zoom level will always be used.
pub fn set_pixels_per_point(&self, pixels_per_point: f32) {
if pixels_per_point != self.pixels_per_point() {
self.request_repaint();
}
self.memory().new_pixels_per_point = Some(pixels_per_point);
}
/// Useful for pixel-perfect rendering
pub(crate) fn round_to_pixel(&self, point: f32) -> f32 {
let pixels_per_point = self.pixels_per_point();
(point * pixels_per_point).round() / pixels_per_point
}
/// Useful for pixel-perfect rendering
pub(crate) fn round_pos_to_pixels(&self, pos: Pos2) -> Pos2 {
pos2(self.round_to_pixel(pos.x), self.round_to_pixel(pos.y))
}
/// Useful for pixel-perfect rendering
pub(crate) fn round_vec_to_pixels(&self, vec: Vec2) -> Vec2 {
vec2(self.round_to_pixel(vec.x), self.round_to_pixel(vec.y))
}
/// Useful for pixel-perfect rendering
pub(crate) fn round_rect_to_pixels(&self, rect: Rect) -> Rect {
Rect {
min: self.round_pos_to_pixels(rect.min),
max: self.round_pos_to_pixels(rect.max),
}
}
/// Allocate a texture.
///
/// In order to display an image you must convert it to a texture using this function.
///
/// Make sure to only call this once for each image, i.e. NOT in your main GUI code.
///
/// The given name can be useful for later debugging, and will be visible if you call [`Self::texture_ui`].
///
/// For how to load an image, see [`ImageData`] and [`ColorImage::from_rgba_unmultiplied`].
///
/// ```
/// struct MyImage {
/// texture: Option<egui::TextureHandle>,
/// }
///
/// impl MyImage {
/// fn ui(&mut self, ui: &mut egui::Ui) {
/// let texture: &egui::TextureHandle = self.texture.get_or_insert_with(|| {
/// // Load the texture only once.
/// ui.ctx().load_texture(
/// "my-image",
/// egui::ColorImage::example(),
/// egui::TextureFilter::Linear
/// )
/// });
///
/// // Show the image:
/// ui.image(texture, texture.size_vec2());
/// }
/// }
/// ```
///
/// Se also [`crate::ImageData`], [`crate::Ui::image`] and [`crate::ImageButton`].
pub fn load_texture(
&self,
name: impl Into<String>,
image: impl Into<ImageData>,
filter: TextureFilter,
) -> TextureHandle {
let name = name.into();
let image = image.into();
let max_texture_side = self.input().max_texture_side;
crate::egui_assert!(
image.width() <= max_texture_side && image.height() <= max_texture_side,
"Texture {:?} has size {}x{}, but the maximum texture side is {}",
name,
image.width(),
image.height(),
max_texture_side
);
let tex_mngr = self.tex_manager();
let tex_id = tex_mngr.write().alloc(name, image, filter);
TextureHandle::new(tex_mngr, tex_id)
}
/// Low-level texture manager.
///
/// In general it is easier to use [`Self::load_texture`] and [`TextureHandle`].
///
/// You can show stats about the allocated textures using [`Self::texture_ui`].
pub fn tex_manager(&self) -> Arc<RwLock<epaint::textures::TextureManager>> {
self.read().tex_manager.0.clone()
}
// ---------------------------------------------------------------------
/// Constrain the position of a window/area so it fits within the provided boundary.
///
/// If area is `None`, will constrain to [`Self::available_rect`].
pub(crate) fn constrain_window_rect_to_area(&self, window: Rect, area: Option<Rect>) -> Rect {
let mut area = area.unwrap_or_else(|| self.available_rect());
if window.width() > area.width() {
// Allow overlapping side bars.
// This is important for small screens, e.g. mobiles running the web demo.
area.max.x = self.input().screen_rect().max.x;
area.min.x = self.input().screen_rect().min.x;
}
if window.height() > area.height() {
// Allow overlapping top/bottom bars:
area.max.y = self.input().screen_rect().max.y;
area.min.y = self.input().screen_rect().min.y;
}
let mut pos = window.min;
// Constrain to screen, unless window is too large to fit:
let margin_x = (window.width() - area.width()).at_least(0.0);
let margin_y = (window.height() - area.height()).at_least(0.0);
pos.x = pos.x.at_most(area.right() + margin_x - window.width()); // move left if needed
pos.x = pos.x.at_least(area.left() - margin_x); // move right if needed
pos.y = pos.y.at_most(area.bottom() + margin_y - window.height()); // move right if needed
pos.y = pos.y.at_least(area.top() - margin_y); // move down if needed
pos = self.round_pos_to_pixels(pos);
Rect::from_min_size(pos, window.size())
}
}
impl Context {
/// Call at the end of each frame.
#[must_use]
pub fn end_frame(&self) -> FullOutput {
if self.input().wants_repaint() {
self.request_repaint();
}
let textures_delta;
{
let ctx_impl = &mut *self.write();
ctx_impl
.memory
.end_frame(&ctx_impl.input, &ctx_impl.frame_state.used_ids);
let font_image_delta = ctx_impl.fonts.as_ref().unwrap().font_image_delta();
if let Some(font_image_delta) = font_image_delta {
ctx_impl
.tex_manager
.0
.write()
.set(TextureId::default(), font_image_delta);
}
textures_delta = ctx_impl.tex_manager.0.write().take_delta();
};
let platform_output: PlatformOutput = std::mem::take(&mut self.output());
// if repaint_requests is greater than zero. just set the duration to zero for immediate
// repaint. if there's no repaint requests, then we can use the actual repaint_after instead.
let repaint_after = if self.read().repaint_requests > 0 {
self.write().repaint_requests -= 1;
std::time::Duration::ZERO
} else {
self.read().repaint_after
};
{
let ctx_impl = &mut *self.write();
ctx_impl.requested_repaint_last_frame = repaint_after.is_zero();
ctx_impl.has_requested_repaint_this_frame = false; // allow new calls between frames
// make sure we reset the repaint_after duration.
// otherwise, if repaint_after is low, then any widget setting repaint_after next frame,
// will fail to overwrite the previous lower value. and thus, repaints will never
// go back to higher values.
ctx_impl.repaint_after = std::time::Duration::MAX;
}
let shapes = self.drain_paint_lists();
FullOutput {
platform_output,
repaint_after,
textures_delta,
shapes,
}
}
fn drain_paint_lists(&self) -> Vec<ClippedShape> {
let ctx_impl = &mut *self.write();
ctx_impl
.graphics
.drain(ctx_impl.memory.areas.order())
.collect()
}
/// Tessellate the given shapes into triangle meshes.
pub fn tessellate(&self, shapes: Vec<ClippedShape>) -> Vec<ClippedPrimitive> {
// A tempting optimization is to reuse the tessellation from last frame if the
// shapes are the same, but just comparing the shapes takes about 50% of the time
// it takes to tessellate them, so it is not a worth optimization.
let pixels_per_point = self.pixels_per_point();
let tessellation_options = *self.tessellation_options();
let texture_atlas = self.fonts().texture_atlas();
let font_tex_size = texture_atlas.lock().size();
let prepared_discs = texture_atlas.lock().prepared_discs();
let paint_stats = PaintStats::from_shapes(&shapes);
let clipped_primitives = tessellator::tessellate_shapes(
pixels_per_point,
tessellation_options,
font_tex_size,
prepared_discs,
shapes,
);
self.write().paint_stats = paint_stats.with_clipped_primitives(&clipped_primitives);
clipped_primitives
}
// ---------------------------------------------------------------------
/// How much space is used by panels and windows.
pub fn used_rect(&self) -> Rect {
let mut used = self.frame_state().used_by_panels;
for window in self.memory().areas.visible_windows() {
used = used.union(window.rect());
}
used
}
/// How much space is used by panels and windows.
/// You can shrink your egui area to this size and still fit all egui components.
pub fn used_size(&self) -> Vec2 {
self.used_rect().max - Pos2::ZERO
}
// ---------------------------------------------------------------------
/// Is the pointer (mouse/touch) over any egui area?
pub fn is_pointer_over_area(&self) -> bool {
let pointer_pos = self.input().pointer.interact_pos();
if let Some(pointer_pos) = pointer_pos {
if let Some(layer) = self.layer_id_at(pointer_pos) {
if layer.order == Order::Background {
!self.frame_state().unused_rect.contains(pointer_pos)
} else {