anchor.diff:    CanvasRenderingContext2D context = canvas.getContext("2d");
     CanvasElement sourceCanvas = querySelector("#"+data);
     double finalHeight = sourceCanvas.height * (canvas.width / sourceCanvas.width);
  -  context.drawImageScaled(sourceCanvas, 0, canvas.height - finalHeight, canvas.width, finalHeight);
  +  context.drawImageScaled(sourceCanvas, 0, (canvas.height - finalHeight - powerHeight), canvas.width, finalHeight);
   }
   
   addImage(event) {
  
positive.code: }
  
  drag(MouseEvent event) {
    print(event.target.id);
    event.dataTransfer.setData("text", event.target.id);
  }
  
  
negative.code: 
  import 'dart:html';
  import 'dart:convert';
  
  final int powerHeight = 85;
  
  removeImage(event) {
    event.target.remove();
  