react-filerobot-video-editor/lib/components/MainCanvas/touchZoomingEvents.js

React component version of filerobot video editor (FVE).

import _defineProperty from"@babel/runtime/helpers/defineProperty";function ownKeys(a,b){var c=Object.keys(a);if(Object.getOwnPropertySymbols){var d=Object.getOwnPropertySymbols(a);b&&(d=d.filter(function(b){return Object.getOwnPropertyDescriptor(a,b).enumerable})),c.push.apply(c,d)}return c}function _objectSpread(a){for(var b,c=1;c<arguments.length;c++)b=null==arguments[c]?{}:arguments[c],c%2?ownKeys(Object(b),!0).forEach(function(c){_defineProperty(a,c,b[c])}):Object.getOwnPropertyDescriptors?Object.defineProperties(a,Object.getOwnPropertyDescriptors(b)):ownKeys(Object(b)).forEach(function(c){Object.defineProperty(a,c,Object.getOwnPropertyDescriptor(b,c))});return a}import{DEFAULT_ZOOM_FACTOR}from"../../utils/constants";function getDistance(a,b){return Math.sqrt(Math.pow(b.x-a.x,2)+Math.pow(b.y-a.y,2))}function getCenter(a,b){return{x:(a.x+b.x)/2,y:(a.y+b.y)/2}}var lastCenter=null,lastDist=0;export var zoomOnTouchesMove=function(a,b){a.evt.preventDefault();var c=a.evt.touches[0],d=a.evt.touches[1];if(c&&d){var e=a.currentTarget;e.isDragging()&&e.stopDrag();var f={x:c.clientX,y:c.clientY},g={x:d.clientX,y:d.clientY};if(!lastCenter)return void(lastCenter=getCenter(f,g));var h=getCenter(f,g),i=getDistance(f,g);lastDist||(lastDist=i);var j=e.attrs.zoomFactor||DEFAULT_ZOOM_FACTOR,k={x:(h.x-e.x())/j,y:(h.y-e.y())/j},l=(j||DEFAULT_ZOOM_FACTOR)*(i/lastDist),m=h.x-lastCenter.x,n=h.y-lastCenter.y,o={x:h.x-k.x*l+m,y:h.y-k.y*l+n};lastDist=i,lastCenter=h,b(_objectSpread(_objectSpread({},o),{},{factor:l,preparedDimensions:!0}))}};export var endTouchesZooming=function(a){lastDist=0,lastCenter=null,"function"==typeof a&&a()};