JavaScript图形库的详细介绍

JavaScript图形库的详细介绍

JavaScript图形库

VisualSW

WEB开发中,当我们需要在WEB页面上绘制一些图形的时候,就比较困难了,最近的开发中碰到了些需要在客户端绘制图形,比如三角形、椭圆等。好在现在有互联网,到Google一搜,呵呵,还真不少,就这样,找到了一个很好的JavaScriptDhtml的图形库,真的很好,不由得感慨老外开发的专业,^_^,好了,我们就去看看吧。

这位老外Walter Zorn的网址是http://www.walterzorn.com,很好的JavaScript的网站,很强的说。

这次用到的是WEB直接绘图功能,到这个地址下载

http://www.walterzorn.com/scripts/wz_jsgraphics.zip

我们来看看效果:

JavaScript图形库的详细介绍

强吧,呵呵!

页面上的帮助文档很强,不用我来解释了吧。

我在这个上面做了一点点开发,呵呵,大家也可以根据自己的需要开发新的函数哈;

增加了一个方法:带箭头的直线

首先添加一些参数:

/*

=====================================================================================

功能:带箭头直线参数

作者:申旺

日期:2004/04/15

======================================================================

*/

var LineColor="#000000";

var LineWidth=3;

var ArrowHeadWidth=5;

var ArrowHeadAngle=15/180*Math.PI;//弧度

var ArrowBegin=true;

var ArrowEnd=true;

/*

======================================================================

*/

然后添加绘制带箭头直线的函数,可以设置箭头的有无,文字,箭头的角度等

/*

======================================================================

功能:绘制带箭头直线

作者:申旺

日期:2004/04/15

======================================================================

*/

this.setArrowWidth = function(x)

{

ArrowHeadWidth = x;

}

 

this.setArrowAngle = function(x)

{

x=x>90?45:x;

x=x<0?45:x;

ArrowHeadAngle = x*Math.PI/180;

}

 

this.setLineWidth = function(x)

{

LineWidth=x;

}

 

this.setLineColor = function(x)

{

LineColor=x;

}

 

this.setArrowBegin = function(x)

{

ArrowBegin=x;

}

 

this.setArrowEnd = function(x)

{

ArrowEnd=x;

}

 

this.drawArrowHeadLine = function(beginX,beginY,endX,endY)

{

this.setColor(LineColor);

this.setStroke(LineWidth);

 

var dx,dy;

dx=Math.abs(beginX-endX);

dy=Math.abs(beginY-endY);

 

var LineSlope;//直线斜率(弧度)

 

LineSlope=Math.atan(dx/dy);

 

//求出中距每点的坐标

var tmpLine;

 

tmpLine=(LineWidth+ArrowHeadWidth)/(2*Math.sin(ArrowHeadAngle));

 

//起点中点

var BeginCenterX;

var BeginCenterY;

 

//终点中点

var EndCenterX;

var EndCenterY;

 

if(ArrowBegin)

{

//绘制起点三角形

//Begin

 

BeginCenterX=beginX+tmpLine*Math.sin(LineSlope);

BeginCenterY=beginY+tmpLine*Math.cos(LineSlope);

 

//定义起点三角形的三个顶点

var BeginX1,BeginY1;

var BeginX2,BeginY2;

var BeginX3,BeginY3;

 

BeginX1=beginX;

BeginY1=beginY;

 

BeginX2=beginX-tmpLine*Math.sin(ArrowHeadAngle-LineSlope);

BeginY2=beginY+tmpLine*Math.cos(ArrowHeadAngle-LineSlope);

 

BeginX3=beginX+tmpLine*Math.sin(ArrowHeadAngle+LineSlope);

BeginY3=beginY+tmpLine*Math.cos(ArrowHeadAngle+LineSlope);

 

var XBeginpoints = new Array(BeginX1,BeginX2,BeginX3);

var YBeginpoints = new Array(BeginY1,BeginY2,BeginY3);

this.fillPolygon(XBeginpoints, YBeginpoints);

 

//End

}

else

{

BeginCenterX=beginX;

BeginCenterY=beginY;

}

 

 

if(ArrowEnd)

{

//绘制终点三角形

//Begin

 

EndCenterX=endX-tmpLine*Math.sin(LineSlope);

EndCenterY=endY-tmpLine*Math.cos(LineSlope);

 

//定义终点三角形的三个顶点

var EndX1,EndY1;

var EndX2,EndY2;

var EndX3,EndY3;

 

EndX1=endX;

EndY1=endY;

 

EndX2=endX-tmpLine*Math.sin(ArrowHeadAngle+LineSlope);

EndY2=endY-tmpLine*Math.cos(ArrowHeadAngle+LineSlope);

 

EndX3=endX+tmpLine*Math.sin(ArrowHeadAngle-LineSlope);

EndY3=endY-tmpLine*Math.cos(ArrowHeadAngle-LineSlope);

 

var XEndpoints = new Array(EndX1,EndX2,EndX3);

var YEndpoints = new Array(EndY1,EndY2,EndY3);

this.fillPolygon(XEndpoints, YEndpoints);

 

//End

}

else

{

EndCenterX=endX;

EndCenterY=endY;

}

 

//绘制中心线

this.drawLine(BeginCenterX,BeginCenterY,EndCenterX,EndCenterY);

}

 

this.drawFlowLine = function(beginX,beginY,endX,endY,beginText,endText)

{

var TextX;

var TextY;

 

this.drawArrowHeadLine(beginX,beginY,endX,endY);

 

TextX=beginX+20;

TextY=beginY;

this.drawString(beginText,TextX,TextY);

}

下面我们来看看效果:

测试代码:

<HTML>

<HEAD>

<title>DHTML JavaScript Tooltips</title>

<script language="javascript" src="./Graphics.js"></script>

<script language="javascript">

var jg = new jsGraphics();

jg.setArrowWidth(4);

jg.setArrowAngle(20);

jg.setLineWidth(2);

jg.setLineColor("Blue");

jg.drawFlowLine(10,10,200,200,"Line1");

jg.setLineColor("Red");

jg.setArrowBegin(false);

jg.drawFlowLine(110,10,300,200,"Line2","End");

jg.setLineColor("Green");

jg.setArrowBegin(true);

jg.setArrowEnd(false);

jg.drawFlowLine(210,10,400,200,"","Line3");

jg.setArrowEnd(true);

jg.setArrowAngle(15);

jg.drawFlowLine(310,10,500,200,"","Line4");

jg.setArrowAngle(30);

jg.drawFlowLine(410,10,600,200,"","Line5");

 

 

jg.setLineWidth(10)

jg.drawFlowLine(410,10,600,200,"","Line5");

jg.setStroke(10)

jg.drawLine(10,300,400,500);

jg.paint();

</script>

<meta http-equiv="expires" content="0">

</HEAD>

<body>

</body>

</HTML>

JavaScript图形库的详细介绍

可以看到效果还是很好的,只是有一个问题,因为绘制线的时候,线的宽度内部实现上是用正方形实现的,所有当线宽了之后,会在头尾发现不理想的地方,如图。

这位老兄真的满强的,还有其他的类库,

比如:层的东东,可以随便托放,图片可是缩放,隐藏等,new就是被我拖大的哈。

JavaScript图形库的详细介绍

提示栏,呵呵,比我那篇文章里面的功能强多了哈:

JavaScript图形库的详细介绍

还有更强的,在线函数绘制图形,哈哈!

感觉WEB都像CS程序了。

JavaScript图形库的详细介绍

最好的是,这么好的冬冬是free的,GNU

This program is free software;

you can redistribute it and/or modify it under the terms of the

GNU General Public License as published by the Free Software Foundation;

either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY;

without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.