asp.net C#绘制太极图

成品图:


html页面:

注意设置

 ContentType="Image/Jpeg"

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="TaiJiTu.aspx.cs" Inherits="TaiJiTu" ContentType="Image/Jpeg" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
    </div>
    </form>
</body>
</html>

后台代码:

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;

public partial class TaiJiTu : System.Web.UI.Page
{
    private Encoder myEncoder;
    private EncoderParameter myEncoderParameter;
    private EncoderParameters myEncoderParameters;
    protected void Page_Load(object sender, EventArgs e)
    {
        int imgWidth = 400;                 //图象尺寸
        int eyeRadius = imgWidth / 20;      //鱼眼半径
        int headDiameter = imgWidth / 2;    //鱼头直径

        Bitmap image = new Bitmap(imgWidth, imgWidth);
        image.SetResolution(300, 300);

        Graphics graphics = Graphics.FromImage(image);

        //设置图像质量
        graphics.CompositingQuality = CompositingQuality.HighQuality;
        graphics.SmoothingMode = SmoothingMode.AntiAlias;
        graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;

        //底色填充为白色
        Brush white = new SolidBrush(Color.White);
        graphics.FillRectangle(white, new Rectangle(0, 0, imgWidth, imgWidth));

        Brush blue = new SolidBrush(Color.Blue);//定义蓝色笔刷
        Brush red = new SolidBrush(Color.Red);//定义红色笔刷

        //整个圆形填充蓝色
        graphics.FillPie(blue, 0, 0, imgWidth, imgWidth, 0, 360);

        //定义右边的路径(红色部分)
        GraphicsPath redPath = new GraphicsPath();//初始化路径
        redPath.AddArc(0, 0, imgWidth, imgWidth, 0, -180);
        redPath.AddArc(0, headDiameter / 2, headDiameter, headDiameter, 0, -180);
        redPath.AddArc(headDiameter, headDiameter / 2, headDiameter, headDiameter, 0, 180);

        //填充右边部分
        graphics.FillPath(red, redPath);

        //填充红色眼睛
        graphics.FillPie(red, new Rectangle(headDiameter / 2 - eyeRadius, headDiameter - eyeRadius, eyeRadius * 2, eyeRadius * 2), 0, 360);
        //填充蓝色眼睛
        graphics.FillPie(blue, new Rectangle(headDiameter + headDiameter / 2 - eyeRadius, headDiameter - eyeRadius, eyeRadius * 2, eyeRadius * 2), 0, 360);
        
        graphics.Dispose();

        //写入到Response输出流中去,普通质量
        //image.Save(Response.OutputStream, ImageFormat.Jpeg);


        //修改图片保存质量
        ImageCodecInfo myImageCodecInfo = GetEncoder(ImageFormat.Jpeg);
        myEncoder = Encoder.Quality;
        myEncoderParameters = new EncoderParameters(1);
        //图片质量等级
        myEncoderParameter = new EncoderParameter(myEncoder, 100L);
        myEncoderParameters.Param[0] = myEncoderParameter;

        //使用指定参数输出
        image.Save(Response.OutputStream, myImageCodecInfo, myEncoderParameters);
    }
    private static ImageCodecInfo GetEncoder(ImageFormat format)
    {
        ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();

        foreach (ImageCodecInfo codec in codecs)
        {
            if (codec.FormatID == format.Guid)
            {
                return codec;
            }
        }
        return null;
    }
}


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