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Merge pull request #5904 from SimonBrandner/normalize-wheel

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Add a WheelEvent normalization function
This commit is contained in:
J. Ryan Stinnett 2021-04-23 12:59:37 +01:00 committed by GitHub
commit c09d4f4a78
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2 changed files with 55 additions and 2 deletions
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7
src/components/views/elements/ImageView.tsx
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@ -32,13 +32,14 @@ import dis from '../../../dispatcher/dispatcher';
import {replaceableComponent} from "../../../utils/replaceableComponent";
import {RoomPermalinkCreator} from "../../../utils/permalinks/Permalinks"
import {MatrixEvent} from "matrix-js-sdk/src/models/event";
import {normalizeWheelEvent} from "../../../utils/Mouse";
const MIN_ZOOM = 100;
const MAX_ZOOM = 300;
// This is used for the buttons
const ZOOM_STEP = 10;
// This is used for mouse wheel events
const ZOOM_COEFFICIENT = 7.5;
const ZOOM_COEFFICIENT = 0.5;
// If we have moved only this much we can zoom
const ZOOM_DISTANCE = 10;
@ -115,7 +116,9 @@ export default class ImageView extends React.Component<IProps, IState> {
private onWheel = (ev: WheelEvent) => {
ev.stopPropagation();
ev.preventDefault();
const newZoom = this.state.zoom - (ev.deltaY * ZOOM_COEFFICIENT);
const {deltaY} = normalizeWheelEvent(ev);
const newZoom = this.state.zoom - (deltaY * ZOOM_COEFFICIENT);
if (newZoom <= MIN_ZOOM) {
this.setState({

50
src/utils/Mouse.ts Normal file
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@ -0,0 +1,50 @@
/*
Copyright 2021 Šimon Brandner <simon.bra.ag@gmail.com>
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
/**
* Different browsers use different deltaModes. This causes different behaviour.
* To avoid that we use this function to convert any event to pixels.
* @param {WheelEvent} event to normalize
* @returns {WheelEvent} normalized event event
*/
export function normalizeWheelEvent(event: WheelEvent): WheelEvent {
const LINE_HEIGHT = 18;
let deltaX;
let deltaY;
let deltaZ;
if (event.deltaMode === 1) { // Units are lines
deltaX = (event.deltaX * LINE_HEIGHT);
deltaY = (event.deltaY * LINE_HEIGHT);
deltaZ = (event.deltaZ * LINE_HEIGHT);
} else {
deltaX = event.deltaX;
deltaY = event.deltaY;
deltaZ = event.deltaZ;
}
return new WheelEvent(
"syntheticWheel",
{
deltaMode: 0,
deltaY: deltaY,
deltaX: deltaX,
deltaZ: deltaZ,
...event,
},
);
}