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