drawcylinder.jsp

提供 精通Java Web动态图表编程 一书的源代码, 大家赶快下载呀

<!--
	Fig. 6.04_04_03: drawCylinder.jsp
	功能:绘制圆柱体
-->
<%@ page language="java" contentType="image/png;charset=GB2312"
	import="java.awt.image.*"
	import="java.awt.*"
	import="javax.imageio.*"
%>
<%!
    int rectX = 10, rectY = 120;
	int rectWidth = 100, rectHeight = 250;
	int ovalHeight = 40;
	int ovalX1, ovalY1, ovalX2, ovalY2, ovalWidth;
	Color outlineColor = Color.LIGHT_GRAY;
	Color fillColor = Color.RED;
	
	// 计算椭圆的绘制参数
    public void calculateOvalCoordinate()
    {
        ovalWidth = this.rectWidth;
        ovalX1 = this.rectX;
        ovalY1 = this.rectY - ovalHeight / 2;
        ovalX2 = this.rectX;
        ovalY2 = ovalY1 + rectHeight;
    }

    // 设置矩形左上角的坐标
    public void resetRectCoordinate(int rectX, int rectY)
    {
        this.rectX = rectX;
        this.rectY = rectY;
    }

    // 绘制圆柱体
    public void drawCylinder(Graphics g)
    {
        // 计算椭圆的坐标
        calculateOvalCoordinate();

        // 绘制下方椭圆
        g.setColor(fillColor);
        g.fillOval(ovalX2, ovalY2, ovalWidth, ovalHeight);
        g.setColor(outlineColor);
        g.drawOval(ovalX2, ovalY2, ovalWidth, ovalHeight);

        // 绘制中间的矩形
        g.setColor(fillColor);
        g.fillRect(rectX, rectY, rectWidth, rectHeight);

        // 绘制上方的椭圆
        g.setColor(g.getColor().darker());
        g.fillOval(ovalX1, ovalY1, ovalWidth, ovalHeight);
        g.setColor(outlineColor);
        g.drawOval(ovalX1, ovalY1, ovalWidth, ovalHeight);
    }
%>
<%
		// 清空缓冲区
		response.reset();

		// 注意这里的MIME类型
		response.setContentType("image/png");

		// 创建一个 640X480 的图像
		int width = 640, height = 480;

		BufferedImage image = new BufferedImage(width, height,
		  BufferedImage.TYPE_INT_RGB);
		Graphics g = image.getGraphics();

		// 填充背景
		g.setColor(Color.WHITE);
		g.fillRect(0, 0, width, height);

		g.setColor(Color.BLACK);
		

		
        // 设置字体
        g.setFont(new Font("汉真广标", Font.PLAIN, 35));
        g.drawString("圆柱体画法", 10, 40);

        // 调用drawCylinder方法，绘制圆柱体
        drawCylinder(g);

        rectHeight = 350;
        resetRectCoordinate(250, 50);

        fillColor = Color.BLUE;

        // 调用drawCylinder方法，绘制圆柱体
        drawCylinder(g);

		// 部署图形
		g.dispose();

		// 利用ImageIO类的write方法对图像进行编码
		ServletOutputStream sos = response.getOutputStream();
		ImageIO.write(image, "PNG", sos);
		sos.close();
%>


<%
/**************************************************************************
 * (C) Copyright 2004-2005 by Jingkui Zhong(钟京馗) and Huan Tang(唐桓).  *
 * All Rights Reserved.                                                   *
 *                                                                        *
 * DISCLAIMER: The authors of this code have used their                   *
 * best efforts in preparing the code. These efforts include the          *
 * development, research, and testing of the theories and programs        *
 * to determine their effectiveness. The authors and publisher make       *
 * no warranty of any kind, expressed or implied, with regard to these    *
 * programs or to the documentation contained in these codes. The authors *
 * shall not be liable in any event for incidental or consequential       *
 * damages in connection with, or arising out of, the furnishing,         *
 * performance, or use of these programs.                                 *
 **************************************************************************/

%>