Actionscript:
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/**
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Original function by Pieter Iserbyt:
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http://local.wasp.uwa.edu.au/~pbourke/geometry/pointline/DistancePoint.java
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from Paul Bourke's website:
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http://local.wasp.uwa.edu.au/~pbourke/geometry/pointline/
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*/
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function pointToLineDist(x1:Number, y1:Number, x2:Number, y2:Number,x3:Number, y3:Number):Number {
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var dx:Number=x2-x1;
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var dy:Number=y2-y1;
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if (dx==0&&dy==0) {
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x2+=1;
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y2+=1;
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dx=dy=1;
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}
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var u:Number = ((x3 - x1) * dx + (y3 - y1) * dy) / (dx * dx + dy * dy);
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var closestX:Number;
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var closestY:Number;
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if (u<0) {
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closestX=x1;
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closestY=y1;
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} else if (u> 1) {
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closestX=x2;
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closestY=y2;
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} else {
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closestX=x1+u*dx;
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closestY=y1+u*dy;
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}
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dx=closestX-x3;
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dy=closestY-y3;
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return Math.sqrt(dx * dx + dy * dy);
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}
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/**
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Test out the function
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*/
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var dotA:Sprite = dot(100, 100);
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var dotB:Sprite = dot(200, 200);
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var dotC:Sprite = dot(150, 100, 0x0000FF);
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var txt:TextField = TextField(dotC.addChild(new TextField()));
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with(txt) x = 5, y = 5, autoSize = "left", selectable = false, mouseEnabled = false;
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addEventListener(Event.ENTER_FRAME, onLoop);
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function onLoop(evt:Event):void {
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graphics.clear();
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graphics.lineStyle(0,0x000000);
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graphics.moveTo(dotA.x, dotA.y);
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graphics.lineTo(dotB.x, dotB.y);
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txt.text = pointToLineDist(dotA.x, dotA.y, dotB.x, dotB.y, dotC.x, dotC.y).toFixed(2);
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}
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// draggable dot
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function dot(xp:Number, yp:Number, col:uint = 0xFF0000, rad:Number=4):Sprite {
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var s:Sprite = Sprite(addChild(new Sprite));
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s.x = xp;
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s.y = yp;
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with(s.graphics) beginFill(col), drawCircle(0,0,rad);
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s.buttonMode = true;
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s.addEventListener(MouseEvent.MOUSE_DOWN, onDrag);
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return s;
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}
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function onDrag(evt:MouseEvent):void { evt.currentTarget.startDrag() }
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stage.addEventListener(MouseEvent.MOUSE_UP, onUp);
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function onUp(evt:MouseEvent):void{stopDrag() }
This is the same as yesterdays post about the distance between a point and a line segment. I just took a few minutes to optimize the function - it runs close to 3X faster now. For more info see yesterdays post.
One Comment
Thank u very much , The code is working fine for me.