繪出圓弧 – Claire's Blog

最近在試著把12個按鈕排成圓弧狀
下面是我找的一些有關於三角函數的資料
http://edscb.blogspot.com/2008/03/blog-post.html
http://delphi.ktop.com.tw/board.php?cid=31&fid=79&tid=53846
在as裡使用sin和cos函數都是輸入弧度
因此要先將角度用角度與弧度的轉換:
radians = degrees * Math.PI / 180
degrees = radians *180 / Math.PI
去轉換後再傳進去，才可獲得正確的值

以下類別是我寫的排列函數
傳進的參數為
範例:

ArrangeTool.getInstance().drawArc(100,500,100,400,canvasContent);
//弧形開端、弧形結束端、水平y座標、半徑、存放要排列的物件的陣列

1 2	ArrangeTool.getInstance().drawArc(100,500,100,400,canvasContent); //弧形開端、弧形結束端、水平y座標、半徑、存放要排列的物件的陣列

類別內容:

package com.demo
{
    import flash.geom.Point;

    public final class ArrangeTool
    {
        private static var instance:ArrangeTool;
        public static function getInstance():ArrangeTool{
            if (instance == null){
                instance = new ArrangeTool();
            }
            return instance;
        }
        /**
         * 將物件排成弧型
         */
        public function drawArc(startX:int,endX:int,Y:int,radius:int,items:Array):void{
            //先算出圓心座標
            var center:Point = new Point((startX+endX)/2,Y+Math.sqrt(radius*radius-Math.pow(startX-endX,2)/4));
            //將該區域的圓切成相同大小等份，先算整個弧線的角度，以角度切
            var totalAngel:int = Math.asin((endX - center.x)/radius)*360/Math.PI;
            var onePiece:int = totalAngel/(items.length-1);
            //要取出該弧形的點的座標及角度
            var angle:int;
            for(var i:int=0;i< span="">
                angle = 90-(totalAngel/2)+onePiece*i;
                var tmp:Point = getPoint(radius,angle);
                items[i].x = center.x-tmp.x-(items[i].width/2);
                items[i].y = center.y-tmp.y-(items[i].height/2);
                //以程式改變註冊點
                var A:Point=items[i].localToGlobal(new Point(items[i].width/2,items[i].height/2));
                items[i].rotation = (angle-90);
                var B:Point=items[i].localToGlobal(new Point(items[i].width/2,items[i].height/2));
                items[i].x-=B.x-A.x;
                items[i].y-=B.y-A.y;
            }
        }
        private function getPoint(radius:int,angel:int):Point{
            var y:int = Math.sin(angel*Math.PI/180)*radius;
            var x:int = Math.cos(angel*Math.PI/180)*radius;
            return new Point(x,y);

        }
    }
}

package com.demo

{

import flash.geom.Point;

public final class ArrangeTool

{

private static var instance:ArrangeTool;

public static function getInstance():ArrangeTool{

if (instance == null){

instance = new ArrangeTool();

}

return instance;

}

/**

* 將物件排成弧型

public function drawArc(startX:int,endX:int,Y:int,radius:int,items:Array):void{

//先算出圓心座標

var center:Point = new Point((startX+endX)/2,Y+Math.sqrt(radius*radius-Math.pow(startX-endX,2)/4));

//將該區域的圓切成相同大小等份，先算整個弧線的角度，以角度切

var totalAngel:int = Math.asin((endX - center.x)/radius)*360/Math.PI;

var onePiece:int = totalAngel/(items.length-1);

//要取出該弧形的點的座標及角度

var angle:int;

for(var i:int=0;i< span="">

angle = 90-(totalAngel/2)+onePiece*i;

var tmp:Point = getPoint(radius,angle);

items[i].x = center.x-tmp.x-(items[i].width/2);

items[i].y = center.y-tmp.y-(items[i].height/2);

//以程式改變註冊點

var A:Point=items[i].localToGlobal(new Point(items[i].width/2,items[i].height/2));

items[i].rotation = (angle-90);

var B:Point=items[i].localToGlobal(new Point(items[i].width/2,items[i].height/2));

items[i].x-=B.x-A.x;

items[i].y-=B.y-A.y;

}

private function getPoint(radius:int,angel:int):Point{

var y:int = Math.sin(angel*Math.PI/180)*radius;

var x:int = Math.cos(angel*Math.PI/180)*radius;

return new Point(x,y);

}