emscripten-core/emscripten
Auf GitHub ansehenBug: emscripten_set_wheel_callback is passive
Open
#10.091 geöffnet am 20. Dez. 2019
good first bughelp wanted
Repository-Metriken
- Stars
- (27.361 Stars)
- PR-Merge-Metriken
- (Durchschn. Merge 19T 10h) (147 gemergte PRs in 30 T)
Beschreibung
Repro:
#include <emscripten/emscripten.h>
#include <emscripten/html5.h>
int callback(int a, const EmscriptenWheelEvent* b, void* c) {
return EM_TRUE; // Call preventDefault() on the event
}
int main() {
emscripten_set_wheel_callback(0, 0, 0, callback);
return 0;
}
Compile the above with 1.38.43-upstream and embed in a HTML file with <script src="a.out.js"></script>. Open the HTML file and scroll with the mouse wheel.
Unexpected: Chrome prints out this to the console:
[Intervention] Unable to preventDefault inside passive event listener due to target being treated as passive. See https://www.chromestatus.com/features/6662647093133312
The fix is to add {passive: false} to the call to addEventListener like this:
window.addEventListener("wheel", callback, {passive: false});
Ideally this would be configurable in the emscripten_set_wheel_callback API call, but I don't see a way to do that.
See https://developers.google.com/web/updates/2017/01/scrolling-intervention for more information.