PieHelper.java

package com.duguang.baseanimation.ui.canvas.chart.util;


/**
 * Created by Dacer on 11/14/13.
 */
public class PieHelper {

    private float start;
    private float end;
    private float targetStart;
    private float targetEnd;
    int velocity = 5;

    public PieHelper(float startDegree, float endDegree, PieHelper targetPie){
        start = startDegree;
        end = endDegree;
        targetStart = targetPie.getStart();
        targetEnd = targetPie.getEnd();
    }

    public PieHelper(int startHour,int startMin,int endHour,int endMin){
        start = 270+startHour*15+startMin*15/60;
        end = 270+endHour*15+endMin*15/60;
        while(end<start){
            end+=360;
        }
    }

    public PieHelper(int startHour,int startMin,int startSec,int endHour,int endMin,int endSec){
        start = 270+startHour*15+startMin*15/60+startSec*15/3600;
        end = 270+endHour*15+endMin*15/60+endSec*15/3600;
        while(end<start){
            end+=360;
        }
    }
    
    public PieHelper(float startDegree,float endDegree){
        start = startDegree;
        end = endDegree;
        while(end<start){
            end+=360;
        }
    }

    PieHelper setTarget(float targetStart,float targetEnd){
        this.targetStart = targetStart;
        this.targetEnd = targetEnd;
        return this;
    }

    PieHelper setTarget(PieHelper targetPie){
        targetStart = targetPie.getStart();
        targetEnd = targetPie.getEnd();
        return this;
    }

    boolean isAtRest(){
        return (start==targetStart)&&(end==targetEnd);
    }

    void update(){
        start = updateSelf(start, targetStart, velocity);
        end = updateSelf(end, targetEnd, velocity);
    }

    public float getSweep(){
        return end-start;
    }

    public float getStart(){
        return start;
    }

    public float getEnd(){
        return end;
    }

    private float updateSelf(float origin, float target, int velocity){
        if (origin < target) {
            origin += velocity;
        } else if (origin > target){
            origin-= velocity;
        }
        if(Math.abs(target-origin)<velocity){
            origin = target;
        }
        return origin;
    }
}