Getting the length of a line formed by dragging - Javascript Canvas

Javascript examples for Canvas:Mouse

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Description

Getting the length of a line formed by dragging

Demo Code

ResultView the demo in separate window 

<html>
   <head> 
      <meta name="viewport" content="width=device-width, initial-scale=1"> 
      <script type="text/javascript" src="https://code.jquery.com/jquery-1.8.3.js"></script> 
      <style id="compiled-css" type="text/css">

#myCanvas{/*  w  w  w  .j  a v a 2 s.  co m*/
   width: 100%;
   height: 100%;
}


      </style> 
      <script type="text/javascript">
    $(window).load(function(){
var telemetry = {
    $canvas: $('#myCanvas'),
    startPosition: {x:0,y:0},
    distance: 0,
    getMousePosition: function(event){
        var position = {
            x: event.pageX - this.$canvas.offset().left,
            y: event.pageY - this.$canvas.offset().top
        }
        return position;
    },
    getDistance: function(startPosition, endPosition){

        var dx = endPosition.x - startPosition.x;
        var dy = endPosition.y - startPosition.y;

        return Math.sqrt((dx*dx) + (dy*dy));
    },
    onMouseDown: function(event){
        this.startPosition = this.getMousePosition(event);
    },
    onMouseUp: function(event){
        this.distance = this.getDistance(this.startPosition, this.getMousePosition(event));
    }
}
telemetry.$canvas.mousedown(function(event){
    telemetry.onMouseDown(event);
}).mouseup(function(event){
    telemetry.onMouseUp(event);
    console.log('you dragged ' + telemetry.distance + 'px');
});
    });

      </script> 
   </head> 
   <body> 
      <canvas id="myCanvas"></canvas>  
   </body>
</html>

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