struts开发实践—曲线图实例

类别:Java 点击:0 评论:0 推荐:

--文章源自一位网友


struts开发实践-曲线图实例

本案主要功能是完成曲线图的绘制,并将曲线图生成jpg图形并显示。

1。画图的主要函数说明

Graphics g

g.drawRect(x_top,x_bottom,width,height):画矩形

g.setColor(color):指定颜色;

g.fillRect(x_top,x_bottom,width,height):画填充的矩形//

g.drawRoundRect(x_top,x_bottom,width,height):画圆边矩形

g.fillRoundRect(x_top,x_bottom,width,height):画一个填充的圆边矩形

g.drawArc(beg_x,beg_y,width,height,beg_tangle,end_tangle):画弧线

g.fillArc(beg_x,beg_y,width,height,beg_tangle,end_tangle):填充弧

g.drawLine(beg_x,beg_y,end_x,end_y):画一条直线

g.drawString(theString,stringTopLeft_x,StringTopLeft_y):画字

g.setFont(font):设置画笔的字体

g.setPaint(color):设置画笔的颜色

2。曲线图绘制文件

/*****************program CurveFrame begin************************/

package test;

import java.awt.*;

import java.awt.geom.*;

import java.awt.image.*;

import javax.swing.JFrame;

import java.lang.Math;

/** *曲线图绘制 */

public class CurveFrame

    extends JFrame {

  /**数据*/

  private double[] result;

  /**数据项名称*/

  private String[] title;

  /**参数:结果集,名称集*/

  public CurveFrame(double[] result, String[] title) {

    this.result = result;

    this.title = title;

  }

  public void paint(Graphics g) {

    Graphics2D g2 = (Graphics2D) g;

    Dimension dim = this.getSize();

    g2.setColor(Color.white);

    g2.fillRect(0, 0, dim.width, dim.height);

    //写title;

    Font font = g2.getFont().deriveFont(12.0f);

    g2.setFont(font);

    FontMetrics metrics = g2.getFontMetrics();

    g2.setPaint(Color.black);

    g2.drawString(title[0], (dim.width - title[0].length() * 5) / 2, 10);

    // draw the x and y axis

    g2.setStroke(new BasicStroke(2.0f));

    g2.draw(new Line2D.Double(40, 30, 40, dim.height - 30));

    g2.draw(new Line2D.Double(40, dim.height - 30,

                              dim.width - 20, dim.height - 30));

    long unit=(Math.round((result[0]+750)/1500))*50;

    long yMax = result[0] == 0 ? unit : Math.round((result[0]+unit/2)/unit) * unit;

    int widthPer = (dim.width - 40) / result.length;

    long heightPer = (dim.height - 60) / (yMax / unit);

    //draw the y axis scale;

    g2.setPaint(Color.lightGray);

    g2.setStroke(new BasicStroke(1.0f));

    for (int i = 0; i<=yMax / unit; i++) {

      g2.draw(new Line2D.Double(40, dim.height - 30 - i * heightPer,

                                dim.width - 40, dim.height - 30 - i * heightPer));

      String ylabel = String.valueOf(i * unit);

      g2.drawString(ylabel, 35 - metrics.stringWidth(ylabel),

                    dim.height - 30 - (i * heightPer));

    }

    //draw x title;

    GeneralPath path = new GeneralPath(GeneralPath.WIND_EVEN_ODD,

                                       result.length - 2);

    for (int i = 1; i < result.length; i++) {

      //draw x scale;

      g2.setPaint(Color.lightGray);

      g2.setStroke(new BasicStroke(1.0f));

      g2.draw(new Line2D.Double(40 + (i - 1) * widthPer, dim.height - 30,

                                40 + (i - 1) * widthPer,30));

      font = g2.getFont().deriveFont(10.0f);

      g2.setFont(font);

      g2.setPaint(Color.black);

      g2.drawString(title[i], 40 + widthPer * (i - 1)-metrics.stringWidth(title[i])/2, dim.height - 10);

      g2.setPaint(Color.red);

      g2.setStroke(new BasicStroke(2.0f));

      if (i == 1) {

        path.moveTo(40,

                    Math.round(dim.height - 30 -

                               (result[i] / unit) * heightPer));

      }

      else {

        path.lineTo(Math.round(widthPer * (i - 1)) + 40,

                    Math.round(dim.height - 30 -

                               (result[i] / unit) * heightPer));

      }

    }

    g2.draw(path);

  }

 

}

/*****************program end************************/

3。生成jpg图形并显示

/*****************program begin************************/

package test;

 

import org.apache.struts.action.*;

import javax.servlet.http.*;

import javax.servlet.*;

import java.io.*;

import java.util.*;

 

import java.awt.*;

import java.awt.image.*;

import com.sun.image.codec.jpeg.*;

 

 

/**

 * 变化曲线

 */

public class WageChangeCurveAction

    extends Action {

  private static final String CONTENT_TYPE = "image/gif";

  private static final int WIDTH = 700;

  private static final int HEIGHT = 500;

  public ActionForward perform(ActionMapping mapping, ActionForm form,

                               HttpServletRequest request,

                               HttpServletResponse response) throws IOException,

      ServletException {

    response.setContentType(CONTENT_TYPE);

    ServletOutputStream out = response.getOutputStream();

    double[] result=。。。String[] title = 。。。//获得图形数据

    try {

      CurveFrame dummy = new CurveFrame(result,title);

      dummy.setSize(new Dimension(WIDTH, HEIGHT));

      BufferedImage image = new BufferedImage(WIDTH, HEIGHT,

                                              BufferedImage.TYPE_INT_RGB);

      Graphics2D g2 = image.createGraphics();

      dummy.paint(g2);

      JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);

      encoder.encode(image);

      out.flush();

    }

    catch (Throwable e) {

      e.printStackTrace();

    }

    return mapping.findForward("success");

  }

 

}

/*****************program end************************/

 

 

 

 

本文地址:http://com.8s8s.com/it/it14799.htm