import Volume from "./Volume" ; callback PerChannelCallback param { string } imageurl param { number } channelindex type PerChannelCallback = ( imageurl : string , channelIndex : number ) => void ; interface PackedChannelsImage { name : string ; channels : number [ ] ; } type PackedChannelsImageRequests = Record < string , HTMLImageElement > ; class export default class VolumeLoader { param { Volume } volume param { Array . < { name : string , channels : Array . < number > } > } imageArray param { PerChannelCallback } callback returns { Object . < string , Image > } example static loadVolumeAtlasData ( volume , imageArray , callback ) { const numImages = imageArray . length ; const requests = { } ; for ( let i = 0 ; i < numImages ; ++ i ) { const url = imageArray [ i ] . name ; const batch = imageArray [ i ] . channels ; const img = new Image ( ) ; img . onerror = function ( ) { console . log ( "ERROR LOADING " + url ) ; } ; img . onload = ( function ( thisbatch ) { return function ( event ) { const canvas = document . createElement ( "canvas" ) ; const w = Math . floor ( event . target . naturalWidth ) ; const h = Math . floor ( event . target . naturalHeight ) ; canvas . setAttribute ( "width" , "" + w ) ; canvas . setAttribute ( "height" , "" + h ) ; const ctx = canvas . getContext ( "2d" ) ; if ( ! ctx ) { console . log ( "Error creating canvas 2d context for " + url ) ; return ; } ctx . globalCompositeOperation = "copy" ; ctx . globalAlpha = 1.0 ; ctx . drawImage ( event . target , 0 , 0 , w , h ) ; const iData = ctx . getImageData ( 0 , 0 , w , h ) ; const channelsBits = [ ] ; for ( let ch = 0 ; ch < Math . min ( thisbatch . length , 4 ) ; ++ ch ) { channelsBits . push ( new Uint8Array ( w * h ) ) ; } for ( let j = 0 ; j < Math . min ( thisbatch . length , 4 ) ; ++ j ) { for ( let px = 0 ; px < w * h ; px ++ ) { channelsBits [ j ] [ px ] = iData . data [ px * 4 + j ] ; } } for ( let ch = 0 ; ch < Math . min ( thisbatch . length , 4 ) ; ++ ch ) { volume . setChannelDataFromAtlas ( thisbatch [ ch ] , channelsBits [ ch ] , w , h ) ; callback ( url , thisbatch [ ch ] ) ; } } ; } ) ( batch ) ; img . crossOrigin = "Anonymous" ; img . src = url ; requests [ url ] = img ; } return requests ; } }