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/**
* FocusedDisplayCoil
*
* Creates a dispaly coil that centers focus around a particular
* location within the coil. As you spin the coil, it spins
* "through" this location instead of just spinning in place.
*/
package com.senocular.display {
import com.senocular.utils.Output;
public class FocusedDisplayCoil extends DisplayCoil {
protected var spinOffset:Number = Math.PI/2; // offset spin to start facing the user (instead of angle of 0 facting right)
private var _spin:Number = 0; // new spin variable
// new public spin. Spin for FocusedDisplayCoil is not
// bound between -180 and 180 and now goes from spinOffset
// to the spin allowed based on items within the coil
public override function get spin():Number {
return _spin;
}
public override function set spin(n:Number):void {
var index:int = numItems;
// use items to find minimum spin
var spinMin:Number = (index > 1)
? -items[index - 1].angle + spinOffset
: spinOffset;
if (n > spinOffset) {
n = spinOffset;
}else if (n < spinMin) {
n = spinMin;
}
// set this class's spin as well as the superclass's
// spin so that it can be correct when coil is drawn
_spin = n;
super.spin = _spin;
}
// new property itemSpinIndex to identify the
// item index given the current spin of the coil
// note, this can be in decimal value
public function get itemSpinIndex():Number {
return (spacingAngle && coilCos) ? (spinOffset - _spin)/(spacingAngle*coilCos) : 0;
}
public function set itemSpinIndex(n:Number):void {
spin = spinOffset - n*spacingAngle*coilCos;
}
/**
* Constructor
*/
public function FocusedDisplayCoil() {
super();
spin = 0;
}
/**
* draw
* overridden draw to make sure coil is positioned
* to center on focused location in coil
*/
protected override function draw():void {
originY = -coilHeight*(spin - spinOffset)/(Math.PI*2);
super.draw();
}
}
}
