本文用AS3分别描绘了曲线、直线、圆、椭圆和矩形5种绘制方法，希望能给大家带来帮助！
（1）：曲线
知识点：
1、添加鼠标监听事件MouseEvent；
2、规定画布大小；
3、moveTo和lineTo；
4、绘制开始与结束判断。
代码：
var huabu:Sprite=new Sprite();
huabu.graphics.beginFill(0xFFFFFF);
huabu.graphics.drawRect(20,20,510,360);
huabu.graphics.endFill();
addChild(huabu);
var _drawing:Boolean;
var quxian:Sprite=new Sprite();
quxian.graphics.lineStyle( 2, 0xFF0000 );
huabu.addChild(quxian);
_drawing = false;
huabu.addEventListener( MouseEvent.MOUSE_DOWN, startDrawing );
huabu.addEventListener( MouseEvent.MOUSE_MOVE,moving);
huabu.addEventListener( MouseEvent.MOUSE_UP, stopDrawing );
stage.addEventListener(MouseEvent.MOUSE_UP,stopDrawing);
function startDrawing( event:MouseEvent ):void {
quxian.graphics.moveTo( mouseX, mouseY );
_drawing = true;
}
function moving( event:MouseEvent ):void {
if ( _drawing ) {
quxian.graphics.lineTo( mouseX, mouseY );
}
}
function stopDrawing( event:MouseEvent ):void {
_drawing = false;
}
（2）：直线
知识点：
1、添加鼠标监听事件MouseEvent；
2、规定画布大小；
3、moveTo和lineTo；
4、绘制开始与结束判断。
难点：
绘制多条直线
代码：
var huabu:Sprite=new Sprite();
huabu.graphics.beginFill(0xFFFFFF);
huabu.graphics.drawRect(20,20,510,360);
huabu.graphics.endFill();
addChild(huabu);
var _drawing:Boolean=false;
var zhixian:Sprite=new Sprite();
huabu.addChild(zhixian);
var _color:Number=0xFF0000;
var zx:int=1;
var ys_x:Number;
var ys_y:Number;
huabu.addEventListener( MouseEvent.MOUSE_DOWN, startDrawing );
huabu.addEventListener( MouseEvent.MOUSE_MOVE,moving);
huabu.addEventListener( MouseEvent.MOUSE_UP, stopDrawing );
stage.addEventListener( MouseEvent.MOUSE_UP, stopDrawing );
function startDrawing( event:MouseEvent ):void {
ys_x=mouseX;
ys_y=mouseY;
_drawing = true;
}
function moving( event:MouseEvent ):void {
if (_drawing) {
huabu.removeChild(zhixian);
zhixian=new Sprite();
zhixian.graphics.lineStyle( zx, _color );
zhixian.graphics.moveTo(ys_x,ys_y);
zhixian.graphics.lineTo(mouseX,mouseY);
huabu.addChild(zhixian);
}
}
function stopDrawing( event:MouseEvent ):void {
zhixian=new Sprite();
huabu.addChild(zhixian);
//没有以上两句，只能画一条直线
_drawing = false;
}
（3）：圆
知识点：
1、添加鼠标监听事件MouseEvent；
2、绘制过程中显示半径（两点间的距离Point.distance(坐标1,坐标2)）；
3、drawCircle、moveTo和lineTo；
4、绘制开始与结束判断。
难点：
绘制多个圆
代码：
var _drawing:Boolean;
var yuan:Sprite=new Sprite();
addChild(yuan);
var banjing:Sprite=new Sprite();
addChild(banjing);
var yuanxin_x:Number;
var yuanxin_y:Number;
var zuobiao1:Point;
var zuobiao2:Point;
var bj:Number;
_drawing = false;
stage.addEventListener( MouseEvent.MOUSE_DOWN, startDrawing );
stage.addEventListener( MouseEvent.MOUSE_MOVE,yd);
stage.addEventListener( MouseEvent.MOUSE_UP, stopDrawing );
function startDrawing( event:MouseEvent ):void {
yuanxin_x=mouseX;//鼠标按下的位置就是圆心的位置
yuanxin_y=mouseY;
_drawing = true;
}
function yd( event:MouseEvent ):void {
if ( _drawing ) {
zuobiao1 = new Point(yuanxin_x,yuanxin_y);
zuobiao2 = new Point(mouseX, mouseY);
bj= Point.distance(zuobiao1, zuobiao2);//显示两点之间的距离即为半径
removeChild(yuan);
yuan=new Sprite();
yuan.graphics.lineStyle( 2, 0xFF0000 );
yuan.graphics.drawCircle(yuanxin_x,yuanxin_y,bj);
addChild(yuan);
removeChild(banjing);
banjing=new Sprite();
banjing.graphics.lineStyle(2,0xFF0000,0.5);
banjing.graphics.moveTo(yuanxin_x,yuanxin_y);
banjing.graphics.lineTo(mouseX,mouseY);
addChild(banjing);
}
}
function stopDrawing( event:MouseEvent ):void {
removeChild(banjing);//绘制结束时半径线消失
banjing=new Sprite();//每次画圆过程中都显示半径
addChild(banjing);
yuan=new Sprite();//可绘制多个圆
addChild(yuan);
_drawing = false;
}
（4）：椭圆
知识点：
1、添加鼠标监听事件MouseEvent和键盘监听事件KeyboardEvent；
2、椭圆的宽与高；
3、drawEllipse；
4、绘制开始与结束判断；
5、按下Shift键绘制正圆。
难点：
按下Shift键绘制正圆
代码：
var _drawing:Boolean=false;
var ellipse:Sprite=new Sprite();
addChild(ellipse);
var kaishi_x:Number;
var kaishi_y:Number;
var w:Number;
var h:Number;
var _max:Number;
stage.addEventListener( MouseEvent.MOUSE_DOWN, startDrawing );
stage.addEventListener( MouseEvent.MOUSE_MOVE,moving);
stage.addEventListener( MouseEvent.MOUSE_UP, stopDrawing );
function startDrawing( event:MouseEvent ):void {
kaishi_x=mouseX;
kaishi_y=mouseY;
_drawing = true;
}
function moving( event:MouseEvent ):void {
if (_drawing) {
w=mouseX-kaishi_x;
h=mouseY-kaishi_y;
removeChild(ellipse);
ellipse=new Sprite();
ellipse.graphics.lineStyle( 2, 0xFF0000 );
ellipse.graphics.drawEllipse(kaishi_x,kaishi_y,w,h);
addChild(ellipse);
}
}
function stopDrawing( event:MouseEvent ):void {
ellipse=new Sprite();
addChild(ellipse);
_drawing = false;
}
stage.focus=this;
stage.addEventListener(KeyboardEvent.KEY_DOWN, shift);
function shift(event:KeyboardEvent):void {
if (event.charCode==0) {
if (_drawing) {
w=mouseX-kaishi_x;
h=mouseY-kaishi_y;
_max=Math.max(Math.abs(w),Math.abs(h));
if (w<0 && h<0) {
w=-_max;
h=-_max;
}
if (w>0 && h>0) {
w=_max;
h=_max;
}
if (w<0 && h>0) {
w=-_max;
h=_max;
}
if (w>0 && h<0) {
w=_max;
h=-_max;
}
removeChild(ellipse);
ellipse=new Sprite();
ellipse.graphics.lineStyle( 2, 0xFF0000 );
ellipse.graphics.drawEllipse(kaishi_x,kaishi_y,w,h);
addChild(ellipse);
}
}
}
（5）：矩形
知识点：
1、添加鼠标监听事件MouseEvent和键盘监听事件KeyboardEvent；
2、椭圆的宽与高；
3、drawRect；
4、绘制开始与结束判断；
5、按下Shift键绘制正方形。
难点：
按下Shift键绘制正方形
代码：
var _drawing:Boolean=false;
var _drawrect:Sprite=new Sprite();
addChild(_drawrect);
var yx_x:Number;
var yx_y:Number;
var w:Number;
var h:Number;
var _max:Number;
stage.addEventListener( MouseEvent.MOUSE_DOWN, startDrawing );
stage.addEventListener( MouseEvent.MOUSE_MOVE,moving);
stage.addEventListener( MouseEvent.MOUSE_UP, stopDrawing );
function startDrawing( event:MouseEvent ):void {
yx_x=mouseX;
yx_y=mouseY;
_drawing = true;
}
function moving( event:MouseEvent ):void {
if (_drawing) {
w=mouseX-yx_x;
h=mouseY-yx_y;
removeChild(_drawrect);
_drawrect=new Sprite();
_drawrect.graphics.lineStyle( 2, 0xFF0000 );
_drawrect.graphics.drawRect(yx_x,yx_y,w,h);
addChild(_drawrect);
}
}
function stopDrawing( event:MouseEvent ):void {
_drawrect=new Sprite();
addChild(_drawrect);
_drawing = false;
}
stage.focus=this;
stage.addEventListener(KeyboardEvent.KEY_DOWN, shift);
function shift(event:KeyboardEvent):void {
if (event.charCode==0) {
if (_drawing) {
_max=Math.max(Math.abs(w),Math.abs(h));
if (w<0 && h<0) {
w=-_max;
h=-_max;
}
if (w>0 && h>0) {
w=_max;
h=_max;
}
if (w<0 && h>0) {
w=-_max;
h=_max;
}
if (w>0 && h<0) {
w=_max;
h=-_max;
}
removeChild(_drawrect);
_drawrect=new Sprite();
_drawrect.graphics.lineStyle( 2, 0xFF0000 );
_drawrect.graphics.drawRect(yx_x,yx_y,w,h);
addChild(_drawrect);
}
}
}