拟合直线算法
从网上找的一个，直接上代码：
DynamicDrawer.as
package
{
//
/**
* simple2d.draw.DynamicDrawer
*
本类用于动态绘制某些shape
*/
import flash.display.Sprite;
import flash.geom.Rectangle;
public class DynamicDrawer{
public function DynamicDrawer(){
throw Error("Error: org.vily.utils.draw.DynamicDrawer是静态类，不能创建实例");
}
public static function createByVS(arr:Array):Rectangle {
var rect:Rectangle = null;
if (arr != null && arr.length > 0) {
var len:int = arr.length;
rect = new Rectangle();
var minV:Object = { x:arr.x, y:arr.y };
var maxV:Object = { x:arr.x, y:arr.y };
for (var i:int = 1; i < len; i++ ) {
if (arr.x < minV.x) {
minV.x = arr.x;
}else if (arr.x > maxV.x) {
maxV.x = arr.x;
}
//
if (arr.y < minV.y) {
minV.y = arr.y;
}else if (arr.y > maxV.y) {
maxV.y = arr.y;
}
}
rect.x = minV.x;
rect.y = minV.y;
rect.width = maxV.x - minV.x;
rect.height = maxV.y - minV.y;
}
return rect;
}
public static function clear(spr:Sprite):void{
spr.graphics.clear();
}
/**
绘制包含边框和填充的矩形
*/
public static function drawRect(spr:Sprite,rect:Rectangle,thickness:Number = 1.0, l_color:uint = 0x0,l_alphaNum:Number = 0.5, color:uint = 0x0,alphaNum:Number = 0.5):void{
//spr.graphics.clear();
spr.graphics.lineStyle(thickness,l_color,l_alphaNum)
spr.graphics.beginFill(color,alphaNum);
spr.graphics.drawRect(rect.x,rect.y,rect.width,rect.height);
spr.graphics.endFill();
}
//绘制直线
public static function drawLine(spr:Sprite,posA:Object,posB:Object,thickness:Number = 1.0, l_color:uint = 0x0,l_alphaNum:Number = 0.5):void{
spr.graphics.lineStyle(thickness,l_color,l_alphaNum);
spr.graphics.moveTo(posA.x, posA.y);
spr.graphics.lineTo(posB.x, posB.y);
}
}
}
Main.as
package
{
import flash.display.Sprite;
import flash.events.Event;
import flash.geom.Rectangle;
//
/**
* ...
* @author vilylei
*/
public class Main extends Sprite
{
public function Main():void
{
if (stage) init();
else addEventListener(Event.ADDED_TO_STAGE, init);
}
private function init(e:Event = null):void
{
removeEventListener(Event.ADDED_TO_STAGE, init);
// entry point
// 创建数据
var rect:Rectangle = new Rectangle(100, 50, 200, 200);
var vs:Array = [];
var len:int = 6;
for (var i:int = 0; i < len; i++) {
vs.push( { x:rect.x + Math.random() * rect.width, y:rect.y + Math.random() * rect.height } );
var tr:Rectangle = new Rectangle();
tr.x = vs.x - 2;
tr.y = vs.y - 2;
tr.width = 4;
tr.height = 4;
DynamicDrawer.drawRect(this, tr);
}
var pa:Object = { x:0, y:0 };
var pb:Object = { x:0, y:0 };
linearFitting(vs, len, pa, pb);
DynamicDrawer.drawLine(this,pa,pb,2.0,0xff0000);
}
//
/*
* 直线拟合实现
* @param vs 是一个数组,包含若干待计算点(每一个点是{x:0,y:0}型的Object的对象)
* @param len 是vs数组的长度
* @param pa 是一个as3 Object对象->{x:0,y:0},是计算出来线段的第一个端点
* @param pb 是一个as3 Object对象->{x:0,y:0},是计算出来线段的第二个端点
* **/
private function linearFitting(vs:Array,len:int,pa:Object, pb:Object):void {
var A:Number = sumVSY( vs );
var B:Number = sumVSX( vs );
//
var C:Number = sumVSXMultY( vs );
var D:Number = sumVSXMultX( vs );
// 计算出直线的参数k和b(基于:y= k*x + b)
var k:Number = (A * B - len * C) / (B * B- len * D);
var b:Number = (B * C - A * D) / (B * B - len * D);
//
var fr:Rectangle = DynamicDrawer.createByVS(vs);
pa.x = fr.x;
pb.x = fr.right;
pa.y = k * pa.x + b;
pb.y = k * pb.x + b;
}
private function sumVSY(vs:Array):Number {
var len:int = vs.length;
var tem:Number = 0;
for (var i:int = 0; i < len; i++) {
tem += vs.y;
}
return tem;
}
private function sumVSX(vs:Array):Number {
var len:int = vs.length;
var tem:Number = 0;
for (var i:int = 0; i < len; i++) {
tem += vs.x;
}
return tem;
}
private function sumVSXMultY(vs:Array):Number {
var len:int = vs.length;
var tem:Number = 0;
for (var i:int = 0; i < len; i++) {
tem += vs.x * vs.y;
}
return tem;
}
private function sumVSXMultX(vs:Array):Number {
var len:int = vs.length;
var tem:Number = 0;
for (var i:int = 0; i < len; i++) {
tem += vs.x * vs.x;
}
return tem;
}
//
}
}
源码：
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