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Merged
emilk merged 2 commits into from
Mar 30, 2025
Merged

Rename should_propagate_event & add should_prevent_default #5779

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146f5bf
eframe/web: allow customization of `prevent_default` behavior
th0rex Mar 11, 2025
5f4e48d
eframe/web: rename should_propagate_event to should_stop_propagation
th0rex Mar 25, 2025
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15 changes: 11 additions & 4 deletions crates/eframe/src/epi.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -499,10 +499,16 @@ pub struct WebOptions {
/// If the web event corresponding to an egui event should be propagated
/// to the rest of the web page.
///
/// The default is `false`, meaning
/// The default is `true`, meaning
/// [`stopPropagation`](https://developer.mozilla.org/en-US/docs/Web/API/Event/stopPropagation)
/// is called on every event.
pub should_propagate_event: Box<dyn Fn(&egui::Event) -> bool>,
/// is called on every event, and the event is not propagated to the rest of the web page.
pub should_stop_propagation: Box<dyn Fn(&egui::Event) -> bool>,

/// Whether the web event corresponding to an egui event should have `prevent_default` called
/// on it or not.
///
/// Defaults to true.
pub should_prevent_default: Box<dyn Fn(&egui::Event) -> bool>,
}

#[cfg(target_arch = "wasm32")]
Expand All @@ -519,7 +525,8 @@ impl Default for WebOptions {

dithering: true,

should_propagate_event: Box::new(|_| false),
should_stop_propagation: Box::new(|_| true),
should_prevent_default: Box::new(|_| true),
}
}
}
Expand Down
141 changes: 97 additions & 44 deletions crates/eframe/src/web/events.rs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -139,15 +139,20 @@ fn install_keydown(runner_ref: &WebRunner, target: &EventTarget) -> Result<(), J
{
if let Some(text) = text_from_keyboard_event(&event) {
let egui_event = egui::Event::Text(text);
let should_propagate = (runner.web_options.should_propagate_event)(&egui_event);
let should_stop_propagation =
(runner.web_options.should_stop_propagation)(&egui_event);
let should_prevent_default =
(runner.web_options.should_prevent_default)(&egui_event);
runner.input.raw.events.push(egui_event);
runner.needs_repaint.repaint_asap();

// If this is indeed text, then prevent any other action.
event.prevent_default();
if should_prevent_default {
event.prevent_default();
}

// Use web options to tell if the event should be propagated to parent elements.
if !should_propagate {
if should_stop_propagation {
event.stop_propagation();
}
}
Expand Down Expand Up @@ -184,7 +189,7 @@ pub(crate) fn on_keydown(event: web_sys::KeyboardEvent, runner: &mut AppRunner)
repeat: false, // egui will fill this in for us!
modifiers,
};
let should_propagate = (runner.web_options.should_propagate_event)(&egui_event);
let should_stop_propagation = (runner.web_options.should_stop_propagation)(&egui_event);
runner.input.raw.events.push(egui_event);
runner.needs_repaint.repaint_asap();

Expand All @@ -201,7 +206,7 @@ pub(crate) fn on_keydown(event: web_sys::KeyboardEvent, runner: &mut AppRunner)
}

// Use web options to tell if the web event should be propagated to parent elements based on the egui event.
if !should_propagate {
if should_stop_propagation {
event.stop_propagation();
}
}
Expand Down Expand Up @@ -261,7 +266,7 @@ pub(crate) fn on_keyup(event: web_sys::KeyboardEvent, runner: &mut AppRunner) {
let modifiers = modifiers_from_kb_event(&event);
runner.input.raw.modifiers = modifiers;

let mut propagate_event = false;
let mut should_stop_propagation = true;

if let Some(key) = translate_key(&event.key()) {
let egui_event = egui::Event::Key {
Expand All @@ -271,7 +276,7 @@ pub(crate) fn on_keyup(event: web_sys::KeyboardEvent, runner: &mut AppRunner) {
repeat: false,
modifiers,
};
propagate_event |= (runner.web_options.should_propagate_event)(&egui_event);
should_stop_propagation &= (runner.web_options.should_stop_propagation)(&egui_event);
runner.input.raw.events.push(egui_event);
}

Expand All @@ -290,7 +295,7 @@ pub(crate) fn on_keyup(event: web_sys::KeyboardEvent, runner: &mut AppRunner) {
repeat: false,
modifiers,
};
propagate_event |= (runner.web_options.should_propagate_event)(&egui_event);
should_stop_propagation &= (runner.web_options.should_stop_propagation)(&egui_event);
runner.input.raw.events.push(egui_event);
}
}
Expand All @@ -299,7 +304,7 @@ pub(crate) fn on_keyup(event: web_sys::KeyboardEvent, runner: &mut AppRunner) {

// Use web options to tell if the web event should be propagated to parent elements based on the egui event.
let has_focus = runner.input.raw.focused;
if has_focus && !propagate_event {
if has_focus && should_stop_propagation {
event.stop_propagation();
}
}
Expand All @@ -310,19 +315,26 @@ fn install_copy_cut_paste(runner_ref: &WebRunner, target: &EventTarget) -> Resul
if let Ok(text) = data.get_data("text") {
let text = text.replace("\r\n", "\n");

let mut should_propagate = false;
let mut should_stop_propagation = true;
let mut should_prevent_default = true;
if !text.is_empty() && runner.input.raw.focused {
let egui_event = egui::Event::Paste(text);
should_propagate = (runner.web_options.should_propagate_event)(&egui_event);
should_stop_propagation =
(runner.web_options.should_stop_propagation)(&egui_event);
should_prevent_default =
(runner.web_options.should_prevent_default)(&egui_event);
runner.input.raw.events.push(egui_event);
runner.needs_repaint.repaint_asap();
}

// Use web options to tell if the web event should be propagated to parent elements based on the egui event.
if !should_propagate {
if should_stop_propagation {
event.stop_propagation();
}
event.prevent_default();

if should_prevent_default {
event.prevent_default();
}
}
}
})?;
Expand All @@ -340,10 +352,13 @@ fn install_copy_cut_paste(runner_ref: &WebRunner, target: &EventTarget) -> Resul
}

// Use web options to tell if the web event should be propagated to parent elements based on the egui event.
if !(runner.web_options.should_propagate_event)(&egui::Event::Cut) {
if (runner.web_options.should_stop_propagation)(&egui::Event::Cut) {
event.stop_propagation();
}
event.prevent_default();

if (runner.web_options.should_prevent_default)(&egui::Event::Cut) {
event.prevent_default();
}
})?;

runner_ref.add_event_listener(target, "copy", |event: web_sys::ClipboardEvent, runner| {
Expand All @@ -359,10 +374,13 @@ fn install_copy_cut_paste(runner_ref: &WebRunner, target: &EventTarget) -> Resul
}

// Use web options to tell if the web event should be propagated to parent elements based on the egui event.
if !(runner.web_options.should_propagate_event)(&egui::Event::Copy) {
if (runner.web_options.should_stop_propagation)(&egui::Event::Copy) {
event.stop_propagation();
}
event.prevent_default();

if (runner.web_options.should_prevent_default)(&egui::Event::Copy) {
event.prevent_default();
}
})?;

Ok(())
Expand Down Expand Up @@ -484,7 +502,7 @@ fn install_pointerdown(runner_ref: &WebRunner, target: &EventTarget) -> Result<(
|event: web_sys::PointerEvent, runner: &mut AppRunner| {
let modifiers = modifiers_from_mouse_event(&event);
runner.input.raw.modifiers = modifiers;
let mut should_propagate = false;
let mut should_stop_propagation = true;
if let Some(button) = button_from_mouse_event(&event) {
let pos = pos_from_mouse_event(runner.canvas(), &event, runner.egui_ctx());
let modifiers = runner.input.raw.modifiers;
Expand All @@ -494,7 +512,7 @@ fn install_pointerdown(runner_ref: &WebRunner, target: &EventTarget) -> Result<(
pressed: true,
modifiers,
};
should_propagate = (runner.web_options.should_propagate_event)(&egui_event);
should_stop_propagation = (runner.web_options.should_stop_propagation)(&egui_event);
runner.input.raw.events.push(egui_event);

// In Safari we are only allowed to write to the clipboard during the
Expand All @@ -506,7 +524,7 @@ fn install_pointerdown(runner_ref: &WebRunner, target: &EventTarget) -> Result<(
}

// Use web options to tell if the web event should be propagated to parent elements based on the egui event.
if !should_propagate {
if should_stop_propagation {
event.stop_propagation();
}
// Note: prevent_default breaks VSCode tab focusing, hence why we don't call it here.
Expand Down Expand Up @@ -536,7 +554,10 @@ fn install_pointerup(runner_ref: &WebRunner, target: &EventTarget) -> Result<(),
pressed: false,
modifiers,
};
let should_propagate = (runner.web_options.should_propagate_event)(&egui_event);
let should_stop_propagation =
(runner.web_options.should_stop_propagation)(&egui_event);
let should_prevent_default =
(runner.web_options.should_prevent_default)(&egui_event);
runner.input.raw.events.push(egui_event);

// Previously on iOS, the canvas would not receive focus on
Expand All @@ -555,10 +576,12 @@ fn install_pointerup(runner_ref: &WebRunner, target: &EventTarget) -> Result<(),
// Make sure we paint the output of the above logic call asap:
runner.needs_repaint.repaint_asap();

event.prevent_default();
if should_prevent_default {
event.prevent_default();
}

// Use web options to tell if the web event should be propagated to parent elements based on the egui event.
if !should_propagate {
if should_stop_propagation {
event.stop_propagation();
}
}
Expand Down Expand Up @@ -600,15 +623,19 @@ fn install_mousemove(runner_ref: &WebRunner, target: &EventTarget) -> Result<(),
egui::pos2(event.client_x() as f32, event.client_y() as f32),
) {
let egui_event = egui::Event::PointerMoved(pos);
let should_propagate = (runner.web_options.should_propagate_event)(&egui_event);
let should_stop_propagation = (runner.web_options.should_stop_propagation)(&egui_event);
let should_prevent_default = (runner.web_options.should_prevent_default)(&egui_event);
runner.input.raw.events.push(egui_event);
runner.needs_repaint.repaint_asap();

// Use web options to tell if the web event should be propagated to parent elements based on the egui event.
if !should_propagate {
if should_stop_propagation {
event.stop_propagation();
}
event.prevent_default();

if should_prevent_default {
event.prevent_default();
}
}
})
}
Expand All @@ -622,10 +649,13 @@ fn install_mouseleave(runner_ref: &WebRunner, target: &EventTarget) -> Result<()
runner.needs_repaint.repaint_asap();

// Use web options to tell if the web event should be propagated to parent elements based on the egui event.
if !(runner.web_options.should_propagate_event)(&egui::Event::PointerGone) {
if (runner.web_options.should_stop_propagation)(&egui::Event::PointerGone) {
event.stop_propagation();
}
event.prevent_default();

if (runner.web_options.should_prevent_default)(&egui::Event::PointerGone) {
event.prevent_default();
}
},
)
}
Expand All @@ -635,26 +665,31 @@ fn install_touchstart(runner_ref: &WebRunner, target: &EventTarget) -> Result<()
target,
"touchstart",
|event: web_sys::TouchEvent, runner| {
let mut should_propagate = false;
let mut should_stop_propagation = true;
let mut should_prevent_default = true;
if let Some((pos, _)) = primary_touch_pos(runner, &event) {
let egui_event = egui::Event::PointerButton {
pos,
button: egui::PointerButton::Primary,
pressed: true,
modifiers: runner.input.raw.modifiers,
};
should_propagate = (runner.web_options.should_propagate_event)(&egui_event);
should_stop_propagation = (runner.web_options.should_stop_propagation)(&egui_event);
should_prevent_default = (runner.web_options.should_prevent_default)(&egui_event);
runner.input.raw.events.push(egui_event);
}

push_touches(runner, egui::TouchPhase::Start, &event);
runner.needs_repaint.repaint_asap();

// Use web options to tell if the web event should be propagated to parent elements based on the egui event.
if !should_propagate {
if should_stop_propagation {
event.stop_propagation();
}
event.prevent_default();

if should_prevent_default {
event.prevent_default();
}
},
)
}
Expand All @@ -667,17 +702,23 @@ fn install_touchmove(runner_ref: &WebRunner, target: &EventTarget) -> Result<(),
egui::pos2(touch.client_x() as f32, touch.client_y() as f32),
) {
let egui_event = egui::Event::PointerMoved(pos);
let should_propagate = (runner.web_options.should_propagate_event)(&egui_event);
let should_stop_propagation =
(runner.web_options.should_stop_propagation)(&egui_event);
let should_prevent_default =
(runner.web_options.should_prevent_default)(&egui_event);
runner.input.raw.events.push(egui_event);

push_touches(runner, egui::TouchPhase::Move, &event);
runner.needs_repaint.repaint_asap();

// Use web options to tell if the web event should be propagated to parent elements based on the egui event.
if !should_propagate {
if should_stop_propagation {
event.stop_propagation();
}
event.prevent_default();

if should_prevent_default {
event.prevent_default();
}
}
}
})
Expand All @@ -691,29 +732,37 @@ fn install_touchend(runner_ref: &WebRunner, target: &EventTarget) -> Result<(),
egui::pos2(touch.client_x() as f32, touch.client_y() as f32),
) {
// First release mouse to click:
let mut should_propagate = false;
let mut should_stop_propagation = true;
let mut should_prevent_default = true;
let egui_event = egui::Event::PointerButton {
pos,
button: egui::PointerButton::Primary,
pressed: false,
modifiers: runner.input.raw.modifiers,
};
should_propagate |= (runner.web_options.should_propagate_event)(&egui_event);
should_stop_propagation &=
(runner.web_options.should_stop_propagation)(&egui_event);
should_prevent_default &= (runner.web_options.should_prevent_default)(&egui_event);
runner.input.raw.events.push(egui_event);
// Then remove hover effect:
should_propagate |=
(runner.web_options.should_propagate_event)(&egui::Event::PointerGone);
should_stop_propagation &=
(runner.web_options.should_stop_propagation)(&egui::Event::PointerGone);
should_prevent_default &=
(runner.web_options.should_prevent_default)(&egui::Event::PointerGone);
runner.input.raw.events.push(egui::Event::PointerGone);

push_touches(runner, egui::TouchPhase::End, &event);

runner.needs_repaint.repaint_asap();

// Use web options to tell if the web event should be propagated to parent elements based on the egui event.
if !should_propagate {
if should_stop_propagation {
event.stop_propagation();
}
event.prevent_default();

if should_prevent_default {
event.prevent_default();
}

// Fix virtual keyboard IOS
// Need call focus at the same time of event
Expand Down Expand Up @@ -769,16 +818,20 @@ fn install_wheel(runner_ref: &WebRunner, target: &EventTarget) -> Result<(), JsV
modifiers,
}
};
let should_propagate = (runner.web_options.should_propagate_event)(&egui_event);
let should_stop_propagation = (runner.web_options.should_stop_propagation)(&egui_event);
let should_prevent_default = (runner.web_options.should_prevent_default)(&egui_event);
runner.input.raw.events.push(egui_event);

runner.needs_repaint.repaint_asap();

// Use web options to tell if the web event should be propagated to parent elements based on the egui event.
if !should_propagate {
if should_stop_propagation {
event.stop_propagation();
}
event.prevent_default();

if should_prevent_default {
event.prevent_default();
}
})
}

Expand Down
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