YAAB - Yet Another Actionscript Blog

public static function dashLine(g:Graphics,x1:Number,y1:Number,x2:Number,y2:Number,onLength:Number = 0,offLength:Number = 0):void {
g.moveTo(x1,y1);
if (offLength==0) {
    g.lineTo(x2,y2);
    return;
}

var dx:Number = x2-x1,
    dy:Number = y2-y1,
    lineLen:Number = Math.sqrt(dx*dx + dy*dy),
    angle:Number = Math.atan2(dy, dx),
    cosAngle:Number = Math.cos(angle),
    sinAngle:Number = Math.sin(angle),
    ondx:Number  = cosAngle*onLength,
    ondy:Number  = sinAngle*onLength,
    offdx:Number = cosAngle*offLength,
    offdy:Number = sinAngle*offLength,

    x:Number = x1,
    y:Number = y1;


var fullDashCountNumber:int = Math.floor(lineLen/(onLength+offLength));

for (var i:int=0; i<fullDashCountNumber; i++){
        g.lineTo(x+=ondx,y+=ondy);
     g.moveTo(x+=offdx,y+=offdy);
    }

    var remainder:Number = lineLen - ((onLength+offLength)*fullDashCountNumber);

    if (remainder>=onLength) {
    g.lineTo(x+=ondx,y+=ondy);
    } else {
        g.lineTo(x2,y2);
    }
}

11 comments:

1. Anonymous says: 30 September 2007 at 07:05  

   Thx a lot for your simple code.
   I didn't need the whole senocular hammer.

2. Empy says: 13 March 2008 at 17:40  

   Thank you very much! Simple and it works.

3. Unknown says: 19 March 2008 at 14:39  

   IOYAB (I owe you a beer).
   
   Thanks for the solution.

4. Rohit Sharma says: 9 April 2008 at 12:28  

   Thanks a lot for your code.It saved me a lot of time.

5. Anonymous says: 17 June 2008 at 23:36  

   Brillant! Thanks for sharing such a straight forward, easy to use routine!

6. Anonymous says: 15 July 2008 at 01:07  

   Could you please add the calling code as to how we can make this to use
   Thanks

7. Anonymous says: 12 February 2009 at 05:52  

   Got erratic painting results until I broke out each variable. For example:
   var dx:Number = x2-x1;
   var dy:Number = y2-y1;
   var lineLen:Number = Math.sqrt(dx*dx + dy*dy);
   var angle:Number = Math.atan2(dy, dx);
   
   ...

8. Anonymous says: 10 December 2009 at 10:04  

   When you call this, what should the first param "g' be?

9. melodave says: 26 April 2010 at 15:14  

   Thanks a lot! Beauty solution.
   
   
   
   ...excellent :)

10. Unknown says: 22 July 2010 at 02:09  

    Thank you for simple and time saving solution
    
    here is an example call to the function, you need to give a line style to your graphic object as seen below
    
    dottedLine.graphics.clear();
    dott dottedLine.graphics.lineStyle(2,0x000000,1);
    LineUtils.dashLine(dottedLine.graphics, 50, 50, 200, 200,3, 10);
    dottedLine.graphics.endFill();

11. Samuel says: 15 April 2013 at 17:48  

    You don't need to calculate the sine and cosine of the dx/dy values... once your normalize them, they are the sine and cosine values
    
    dX
    dY
    length = Math.sqrt(dX*dX + dY*dY);
    iLength = 1.0/length;
    cos = dX*iLength;
    sin = dY*iLength;
    
    doing this also gets rid of your need for the atan2 function.
    
    all in all... once you have the normalized values sin and cos, you're good to go. This is a huge speed increase if you have a LOT of lines to draw
    

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