import LuminanceSource from './LuminanceSource' ; /**
 * A wrapper implementation of  LuminanceSource which inverts the luminances it returns -- black becomes
 * white and vice versa, and each value becomes (255-value).
 *
 *  author Sean Owen
  export default class InvertedLuminanceSource extends LuminanceSource { public constructor ( private delegate ) { super ( delegate . getWidth ( ) , delegate . getHeight ( ) ) ; } public getRow ( y , row ? ) { const sourceRow = this . delegate . getRow ( y , row ) ; const width = this . getWidth ( ) ; for ( let i = 0 ; i < width ; i ++ ) { sourceRow [ i ] = ( 255 - ( sourceRow [ i ] & 0xFF ) ) ; } return sourceRow ; } public getMatrix ( ) { const matrix = this . delegate . getMatrix ( ) ; const length = this . getWidth ( ) * this . getHeight ( ) ; const invertedMatrix = new Uint8ClampedArray ( length ) ; for ( let i = 0 ; i < length ; i ++ ) { invertedMatrix [ i ] = ( 255 - ( matrix [ i ] & 0xFF ) ) ; } return invertedMatrix ; } public isCropSupported ( ) { return this . delegate . isCropSupported ( ) ; } public crop ( left , top , width , height ) { return new InvertedLuminanceSource ( this . delegate . crop ( left , top , width , height ) ) ; } public isRotateSupported ( ) { return this . delegate . isRotateSupported ( ) ; } return original delegate  LuminanceSource since invert undoes itself
      public invert ( ) { return this . delegate ; } public rotateCounterClockwise ( ) { return new InvertedLuminanceSource ( this . delegate . rotateCounterClockwise ( ) ) ; } public rotateCounterClockwise45 ( ) { return new InvertedLuminanceSource ( this . delegate . rotateCounterClockwise45 ( ) ) ; } }