Java2D高级绘图-创新互联

知识要点:

第一节 Java 2D的增强功能

概述、AWT图形能力的不足、Java 2D API

第二节 图形绘制的基本方法

转换Graphics2D对象、Graphics 类特性、绘图的属性和基本编程方法

第三节 曲线问题的高级应用开发

直线问题深入研究、贝塞尔(Bezier)曲线、自定义样条曲线编程、

用户数据的曲线显示、曲线用Applet显示的数据来源问题

第四节 字符串的高级处理

TextLayout类、LineMetrics类

第五节 构造几何形状

2D几何形状的设计、构造型区域几何形状、变换、缓冲的图像

第六节 三维图形处理的设计技术

透视投影、透视图形的显示、隐蔽面消除问题

第七节 同环境交互

GraphicsEnvironment类、GraphicsDevice类、GraphicsConfiguration类

第一节 Java 2D的增强功能

一、概述:

由Sun公司与Adobe系统公司合作推出的Java 2D API,提供了一个功能强大而且非常灵活的二维图形框架。Java 2D API扩展了java.awt包中定义的Graphics类和Image类,提供了高性能的二维图形、图像和文字,同时又维持了对现有AWT应用的兼容。

二、AWT图形能力的不足:

在 AWT 的初始实现中,图形能力并不十分完善。因为开发 JDK 是打算将其作为平台中立的实现平台,所以其原始的功能被限制于“最少公共功能”上,所有被支持的操作系统上保证提供这些公共功能;

在 Java 2D 出现之前,对绘制能力、字体操作和图像控制的支持非常少。而对诸如用图案进行着色、形状操作以及图形变换之类的重要操作的支持则完全没有。

Java 2D 满足了跨平台实现中对这些功能以及其它功能的需求。

三、Java 2D API:

它是JFC (Java Fundation Classes)的一员,加强了传统AWT( Abstract Windowing Toolkit )的描绘功能。在 JDK1.2中已经支援 Java 2D 的使用。透过Java 2D API ,程序员可以轻松地描绘出任意的几何图形、运用不同的填色效果、对图形做旋转( rotate)、缩放( scale)、扭曲( shear)等。如图所示,程序员透过2D API所提供的功能,简单地利用不同类型的线或是填色效果绘出统计图,以区分出不同的资料。

它们是基于Graphics2D类的绘图功能,是对AWT中的Graphics类的进一步的扩展和增强。主要体现在:

1。对渲染质量的控制:消除锯齿以平滑绘制对象的边缘

2.裁剪、合成和透明度:它们允许使用任意形状来限定绘制操作的边界。它们还提供对图形进行分层以及控制透明度和不透明度的能力。

3.控制和填充简单及复杂的形状:这种功能提供了一个 Stroke 代理和一个 Paint 代理,前者定义用来绘制形状轮廓的笔(定义绘制的笔的宽度和样式),后者允许用纯色、渐变色和图案来填充形状。

4。图像处理和变换:Java 2D 同 Java 高级图像 API(Java Advanced Imaging API (JAI))协作,支持用大量图形格式处理复杂的图像。Java 2D 还为您提供了修改图像、形状和字体字符的变换能力。

5。特殊的填充方式,如梯度或者图案

6.高级字体处理和字符串格式化:允许象操作任何其它图形形状一样操作字体字符。除此以外,可以象文字处理程序一样,通过为 String 中的字符应用属性和样式信息来创建格式化文本。

java.awt.geom 包中的Areas类支援联集( union)、交集( intersection)、差集(subtraction )、Exclusive OR (XOR)等布尔运算。最後, AffineTransform 类别则提供图形物件做Scale(比例)、Shear(剪裁) 、Rotate(旋转)等座标上的转换。

第二节 图形绘制的基本方法

一、转换Graphics2D对象

绘制图形时,可以在Graphics对象或者Graphics2D对象上进行,它们都代表了需要绘图的区域,选择那个取决于是否要使用所增加的Java2D的图形功能。但要注意的是,所有的Java2D图形操作都必须在Graphics2D对象上调用。Graphics2D是Graphics的子类,同样包含在java.awt包中。

public void paintComponent(Graphics comp)

{ Graphics2D comp2D=(Graphics2D)comp;

}

或者

public void paint (Graphics comp)

{ Graphics2D comp2D=(Graphics2D)comp;

}

二、Graphics 类特性

Graphics 类支持几种确定图形环境状态的特性。以下列出了部分特性:

1)Color:当前绘制颜色,它属于 java.awt.Color 类型。所有的绘制、着色和纯文本输出都将以指定的颜色显示。

2)Font:当前字体,它属于 java.awt.Font 类型。它是将用于所有纯文本输出的字体。

3)Clip:java.awt.Shape 类型的对象,它充当用来定义几何形状的接口。该特性包含的形状定义了图形环境的区域,绘制将作用于该区域。通常情况下,这一形状与整个图形环境相同,但也并不一定如此。

4)ClipBounds:java.awt.Rectangle 对象,它表示将包围由 Clip 特性定义的 Shape 的最小矩形。它是只读特性。

5)FontMetrics:java.awt.FontMetrics 类型的只读特性。该对象含有关于图形环境中当前起作用的 Font 的信息。如同我们将看到的那样,获取此信息的这种机制已被 LineMetrics 类所取代

6)Paint Mode:该特性控制环境使用当前颜色的方式。如果调用了 setPaintMode() 方法,那么所有绘制操作都将使用当前颜色。如果调用了 setXORMode() 方法(该方法获取一个 Color 类型的参数),那么就用指定的颜色对像素做“XOR”操作。XOR 具有在重新绘制时恢复初始位模式的特性,因此它被用作橡皮擦除和动画操作。

三、绘图的属性和基本编程方法

1)颜色Color类:没有变化。

2)填充方式:

Paint(油漆桶) 接口有几个具体的实现,它们允许用纯色、渐变色或图案来填充形状。

1,纯色填充(Color类):对 java.awt.Color 类做了一些调整以实现 Paint,并且可以用于纯色填充。

2,渐变色来填充(梯度填充GradientPaint类):java.awt.GradientPaint 类允许用线性颜色渐变色来填充形状,线性颜色渐变色允许在两个指定的 Color 对象之间创建过渡。可以将渐变色设置成“周期性的”,这将导致渐变色图案重复出现。

3,图案填充(纹理TexturePaint类):提供了 java.awt.TexturePaint 类,它可以用由 BufferedImage 描述的图案填充形状

编程方法:

使用Graphics2D类中的setPaint()方法并使用Paint对象作为其参数,但由于任何可以作为填充的类如GradientPaint、TexturePaint和Color都实现了Paint接口(该接口注意定义了在Graphics2D下的颜色填充方式),因此可以将它们作为参数。如:

public void paintComponent(Graphics comp)

{ Graphics2D comp2D=(Graphics2D)comp;

GradientPaint pat=new GradientPaint(0f,0f,Color.white,100f,45f,Color.blue);

comp2D.setPaint(pat);

}

3)设置笔的形状:

Stroke 接口由 java.awt.BasicStroke 类实现。该类允许进行大量的选择以修改线的绘制细节。可以编程指定 BasicStroke 宽度,也可以指定对名为柱头和交点的路径上端点和交点的“装饰”。现在也可以绘制点划线了,只须设置 BasicStroke 的破折号属性即可。

在Graphics类中线条是一个点宽,而在Graphics2D中可以通过BasicStoke类中的setStroke()方法来设置。其构造函数是BasicStroke(float width, int cap, int join)

其中width指示线宽(缺省时为1.0)

cap指示线的末端(包头,在BasicStroke类中定义出三个static 类型的常量如CAP_BUTT没有包头( )、CAP_ROUND圆包头( )、CAP_SQUARE方包头( )的样式

join指示线段之间的拐角(在BasicStroke类中定义出三个static 类型的常量如JOIN_BEVEL( )、JOIN_MITER( )、 JOIN_ROUND( )样式。

4)编程方法:

public void paintComponent(Graphics comp)

{ Graphics2D comp2D=(Graphics2D)comp;

BasicStroke pen

=new BasicStroke(2.0f, BasicStroke .CAP_BUTT, BasicStroke .JOIN_ROUND);

comp2D.setStroke (pen);

}

代码示例:

float thick = 0.5f; //设置画刷的粗细为 0.5

BufferedImage bi = new BufferedImage(800, 600, BufferedImage.TYPE_INT_RGB);

Graphics2D g = (Graphics2D)bi.getGraphics();

Stroke stroke = g.getStroke(); //得到当前的画刷

g.setStroke(new BasicStroke(thick, BasicStroke.CAP_SQUARE, BasicStroke.JOIN_ROUND));

g.draw(new Line2D.Float(x1, y1, x2, y2)); 画线

g.setStroke( stroke ); //将画刷复原

5)创建要绘制的形状对象

在Java2D中进行绘图时,不是采用对应的方法来实现,而是为要实现某中形状创建出相应的形状对象。这可以通过使用java.awt.geom包中的类来定义所要创建的形状。如线条Line2D.Float类、距形Rectangle2D.Float或者Rectangle2D.Double类、椭圆Ellipes2D.Float、圆弧Arc2D.Float类等。

6)绘制对象:

1,可以使用Graphics2D类中的方法draw()用于绘制轮廓,而fill()方法用于填充。它们都以前面所创建的图形对象作为参数。

2,Java2D中的字符串的绘制仍然采用drawString()方法,但有drawString(String s, float x, float y)和drawString(String str, int x, int y)。

3,绘制轮廓:draw(Shape s)其中的Shape接口在Graphics2D中被定义

新的 Java 2D Shape 类都有“2D”后缀。这些新的形状使用浮点值(而不是整数)来描述其几何形状。

Polygon类(int[] xpoints, int[] ypoints, int npoints)

RectangularShape(抽象类,其子类有Arc2D, Ellipse2D, Rectangle2D, RoundRectangle2D), Rectangle(距形)

QuadCurve2D(二次贝塞尔样条曲线,贝塞尔曲线由两个端点以及一个或两个控制点指定。贝塞尔曲线创建了适合于大多数表示的曲线。)

CubicCurve2D(三次贝塞尔样条曲线)

Area(区域)

GeneralPath(由直线、二次样条曲线、三次样条曲线所构成)

Line2D

8)基本步骤

绘图的第一个步骤是产生 Graphics2D 对象。 然后设定所要的状态属性。例如你想要对一物件做渐层式的填色,可以设定属性 Paint为 GradientPaint。最後再调用Graphics2D所提供的方法fill或是draw,完成整个绘图的程序。

9)程序实例

例一:

这是一个最简单的例子,也可以认为是绘图的一个最简单的框架。

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import java.awt.geom.*;

public class Map extends JFrame

{ public Map()

{ super("Map");

setSize(350,350);

MapPane map=new MapPane();

getContentPane().add(map);

}

public static void main(String [] arg)

{ Map frame=new Map();

frame.show();

}

}

class MapPane extends JPanel

{ public void paintComponent(Graphics comp)

{ Graphics2D comp2D=(Graphics2D)comp;

comp2D.drawString("sbcd",200,200);

Line2D.Float line=new Line2D.Float(1.0f,2.0f,200.0f,200.0f);

comp2D.draw(line);

}

}

例二:

下面是在Graphics2D模式下的基本绘图框架。我们可以看到,利用:

g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,

RenderingHints.VALUE_ANTIALIAS_ON);

通过该方法的设置,使图形去除锯齿状,可以得到多么细腻的图形。

样例:

import java.awt.*;

import java.awt.event.*;

import java.awt.geom.*;

public class DrawDemo extends JFrame {

public DrawDemo(){

//设置窗口的大小、标题

this.setSize(new Dimension(600, 400));

//创建绘制各种形状的容器

ShapesPanel shapesPanel = new ShapesPanel();

//将该容器加入窗口

getContentPane().add(shapesPanel, BorderLayout.CENTER);

}

public static void main(String[] args) {

DrawDemo frame = new DrawDemo();

frame.setVisible(true);

//当窗口关闭时清空内存

frame.addWindowListener(new WindowAdapter() {

public void windowClosing(WindowEvent e) {

System.exit(0);

}

});

}

}

//创建各种容器的类

class ShapesPanel extends JPanel {

final int maxCharHeight = 15;

final Color bg = Color.white; //声明背景颜色为灰色

final Color fg = Color.blue; //声明前景颜色为蓝色

public ShapesPanel() {

setBackground(bg); //设置背景颜色

setForeground(fg); //设置前景颜色

//创建组合边框

setBorder(BorderFactory.createCompoundBorder(

BorderFactory.createRaisedBevelBorder(),

BorderFactory.createLoweredBevelBorder()));

}

public void paintComponent(Graphics g1) {

super.paintComponent(g1); //清空背景颜色

float thick = 0.5f; //设置画刷的粗细为 0.5

Graphics2D g = (Graphics2D)g1;

Stroke stroke = g.getStroke(); //得到当前的画刷

g.setStroke(new BasicStroke(thick, BasicStroke.CAP_SQUARE, BasicStroke.JOIN_ROUND));

//通过该方法使图形去除锯齿状

g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,

RenderingHints.VALUE_ANTIALIAS_ON);

String txt= "我的文章";

int style=2;//0普通1粗体2斜体3粗斜

g.setFont(new Font("宋体", 2, 15)); //15为字大小

//设置笔刷为黑色

g.setPaint(Color.black);

g.drawString(txt,200,150);

g.setPaint(Color.red);

g.draw(new Line2D.Float(0,0,200,150)); //画线

g.setPaint(Color.blue);

g.draw(new Rectangle2D.Float(200,150,100,100));

g.setStroke(stroke); //将画刷复原

}

}

例三:图形灵活的显示

在上面的例子中,是使用一个继承于JPanel的类,覆盖它的void paintComponent(Graphics g1)事件方法,实现绘图的,这样虽然方便,但显得灵活性不高。

实际上,通过JPanel对象直接赋值给Graphics2D对象,往往可以使程序具有很大的灵活性。程序可以这样来写。

JPanel contentPane= (JPanel) this.getContentPane();

public Graphics2D comp2D=(Graphics2D)contentPane .getGraphics();

样例:

package myDrawDemo;

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import java.awt.geom.*;

public class DrawDemo1 extends JFrame

{

public JPanel contentPane; //绘图窗口

public Graphics2D comp2D; //绘图对象

JPanel jPanel1 = new JPanel();//控件容器

JButton jButton1 = new JButton();

JButton jButton2 = new JButton();

//构造函数

public DrawDemo1() {

enableEvents(AWTEvent.WINDOW_EVENT_MASK);

try {

jbInit();

}

catch(Exception e) {

e.printStackTrace();

}

}

//控件的初始化

private void jbInit() throws Exception {

contentPane = (JPanel) this.getContentPane();

contentPane.setLayout(new BorderLayout());

this.setSize(new Dimension(400, 300));

this.setTitle("Frame Title");

//contentPane.setSize(400,240);

jPanel1.setLayout(null);

jButton1.setBounds(new Rectangle(30, 235, 100, 31));

jButton1.setText("画线保留");

jButton1.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton1_actionPerformed(e);

}

});

jButton2.setBounds(new Rectangle(150, 235, 100, 30));

jButton2.setText("画线删除");

jButton2.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton2_actionPerformed(e);

}

});

contentPane.add(jPanel1, BorderLayout.CENTER);

jPanel1.add(jButton1, null);

jPanel1.add(jButton2, null);

}

public static void main(String[] args) {

DrawDemo1 frame=new DrawDemo1();

frame.show();

frame.comp2D=(Graphics2D)frame.contentPane .getGraphics();

frame.comp2D.setBackground(Color.white);

frame.comp2D.clearRect(0,0,401,221);

}

//Overridden so we can exit when window is closed

protected void processWindowEvent(WindowEvent e) {

super.processWindowEvent(e);

if (e.getID() == WindowEvent.WINDOW_CLOSING) {

System.exit(0);

}

}

void jButton1_actionPerformed(ActionEvent e){

comp2D.setPaint(Color.red);

Line2D.Float line=new Line2D.Float(1.0f,2.0f,200.0f,220.0f);

comp2D.draw(line);

}

void jButton2_actionPerformed(ActionEvent e) {

comp2D.clearRect(0,0,401,221);

comp2D.setPaint(Color.blue);

Line2D.Float line=new Line2D.Float(1.0f,100.0f,300.0f,220.0f);

comp2D.draw(line);

}

}

例四:剪裁

图形处理问题中,剪裁由的时候是非常难处理的,所谓剪裁是指超过绘图取得内容不显示,看起来这是个简单问题,但由于所有的线条必须计算与边界的交点,而且边界有四个方向,这就使问题变得很复杂。java 2D很好的解决了这个问题,请看下面的例子。

package myDrawDemo;

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import java.awt.geom.*;

public class DrawDemo2 extends JFrame

{

public JPanel contentPane; //绘图窗口

public Graphics2D comp2D; //绘图对象

JPanel jPanel1 = new JPanel();//控件容器

JButton jButton1 = new JButton();

JButton jButton2 = new JButton();

//构造函数

public DrawDemo2() {

enableEvents(AWTEvent.WINDOW_EVENT_MASK);

try {

jbInit();

}

catch(Exception e) {

e.printStackTrace();

}

}

//控件初始化

private void jbInit() throws Exception {

contentPane = (JPanel) this.getContentPane();

contentPane.setLayout(new BorderLayout());

this.setSize(new Dimension(400, 300));

this.setTitle("Frame Title");

//contentPane.setSize(400,240);

jPanel1.setLayout(null);

jButton1.setBounds(new Rectangle(30, 235, 100, 31));

jButton1.setText("画线保留");

jButton1.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton1_actionPerformed(e);

}

});

jButton2.setBounds(new Rectangle(150, 235, 100, 30));

jButton2.setText("画线删除");

jButton2.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton2_actionPerformed(e);

}

});

contentPane.add(jPanel1, BorderLayout.CENTER);

jPanel1.add(jButton1, null);

jPanel1.add(jButton2, null);

}

public static void main(String[] args) {

DrawDemo2 frame=new DrawDemo2();

frame.show();

frame.comp2D=(Graphics2D)frame.contentPane .getGraphics();

frame.comp2D.setBackground(Color.white);

frame.comp2D.clearRect(0,0,401,221);

}

//Overridden so we can exit when window is closed

protected void processWindowEvent(WindowEvent e) {

super.processWindowEvent(e);

if (e.getID() == WindowEvent.WINDOW_CLOSING) {

System.exit(0);

}

}

void jButton1_actionPerformed(ActionEvent e){

comp2D.setPaint(Color.red);

Line2D.Float line=new Line2D.Float(1.0f,2.0f,200.0f,220.0f);

comp2D.draw(line);

}

void jButton2_actionPerformed(ActionEvent e) {

comp2D.clearRect(0,0,401,221);

//剪裁

comp2D.setClip(50,50,300,150);

comp2D.setPaint(Color.blue);

Line2D.Float line=new Line2D.Float(1.0f,100.0f,300.0f,220.0f);

comp2D.draw(line);

}

}

第三节 曲线问题的高级应用开发

在jdk尚未支援 2D图形之前,只可以画出直的、相同粗细的线条。现在可以通过2D API绘出不同粗细的线条及圆滑的曲线。在java.awt.geom包中提供了Line2D、 QuadCurve2D(二次贝塞尔曲线)及 CubicCurve2D(三次贝塞尔曲线)等相关的类,让程序员能够轻松地绘出想要的线条。

其实绘图的核心是画线,下面通过一些实例对一些问题进行深入的讨论。

一、直线问题深入研究

样例:

我们通过一个例子,深入的研究一下绘制直线和折线需要掌握哪些内容。

package myDrawDemo;

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import java.awt.geom.*;

public class DrawDemo1 extends JFrame

{

public JPanel contentPane; //绘图窗口

public Graphics2D comp2D; //绘图对象

JPanel jPanel1 = new JPanel();//控件容器

JButton jButton1 = new JButton();

JButton jButton2 = new JButton();

JButton jButton3 = new JButton();

//构造函数

public DrawDemo1() {

enableEvents(AWTEvent.WINDOW_EVENT_MASK);

try {

jbInit();

}

catch(Exception e) {

e.printStackTrace();

}

}

//控件初始化

private void jbInit() throws Exception {

contentPane = (JPanel) this.getContentPane();

contentPane.setLayout(new BorderLayout());

this.setSize(new Dimension(400, 300));

this.setTitle("Frame Title");

//contentPane.setSize(400,240);

jPanel1.setLayout(null);

jButton1.setBounds(new Rectangle(30, 235, 100, 31));

jButton1.setText("园头");

jButton1.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton1_actionPerformed(e);

}

});

jButton2.setBounds(new Rectangle(150, 235, 100, 30));

jButton2.setText("方头");

jButton2.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton2_actionPerformed(e);

}

});

jButton3.setBounds(new Rectangle(270, 235, 100, 30));

jButton3.setText("封闭");

jButton3.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton3_actionPerformed(e);

}

});

contentPane.add(jPanel1, BorderLayout.CENTER);

jPanel1.add(jButton1, null);

jPanel1.add(jButton2, null);

jPanel1.add(jButton3, null);

}

public static void main(String[] args) {

DrawDemo1 frame=new DrawDemo1();

frame.show();

frame.comp2D=(Graphics2D)frame.contentPane .getGraphics();

frame.comp2D.setBackground(Color.white);

frame.comp2D.clearRect(0,0,401,221);

}

//Overridden so we can exit when window is closed

protected void processWindowEvent(WindowEvent e) {

super.processWindowEvent(e);

if (e.getID() == WindowEvent.WINDOW_CLOSING) {

System.exit(0);

}

}

int Xs1[]={10,60,120,200,260,340};

int Ys1[]={10,200,120,180,60,130};

void jButton1_actionPerformed(ActionEvent e){

comp2D.clearRect(0,0,401,221);

//笔宽度

float thick = 10f;

//设置笔刷

//园头园连接

comp2D.setStroke(new BasicStroke(thick,

BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));

comp2D.setPaint(Color.red);

//通过该方法使图形去除锯齿状

comp2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING,

RenderingHints.VALUE_ANTIALIAS_ON);

comp2D.drawPolyline(Xs1,Ys1,Xs1.length);

}

void jButton2_actionPerformed(ActionEvent e) {

comp2D.clearRect(0,0,401,221);

//笔宽度

float thick = 10f;

//设置笔刷

//方头方连接

comp2D.setStroke(new BasicStroke(thick,

BasicStroke.CAP_SQUARE, BasicStroke.CAP_SQUARE));

comp2D.setPaint(Color.blue);

//通过该方法使图形去除锯齿状

//comp2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING,

// RenderingHints.VALUE_ANTIALIAS_ON);

comp2D.drawPolyline(Xs1,Ys1,Xs1.length);

}

void jButton3_actionPerformed(ActionEvent e) {

comp2D.clearRect(0,0,401,221);

//笔宽度

float thick = 1f;

//设置笔刷

//方头方连接

comp2D.setStroke(new BasicStroke(thick,

BasicStroke.CAP_SQUARE, BasicStroke.CAP_SQUARE));

comp2D.setPaint(Color.blue);

//通过该方法使图形去除锯齿状

//comp2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING,

// RenderingHints.VALUE_ANTIALIAS_ON);

//画封闭线

comp2D.drawPolygon(Xs1,Ys1,Xs1.length);

}

}

二、贝塞尔(Bezier)曲线

java 2D提供的QuadCurve2D(二次贝塞尔曲线)及 CubicCurve2D(三次贝塞尔曲线)等相关的类,可以很容易的画出贝赛尔曲线。

QuadCurve2D为三个数据,中间一个为控制点。

CubicCurve2D为四个数据,中间两个为控制点。

样例:

package myDrawDemo;

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import java.awt.geom.*;

public class DrawDemo1 extends JFrame

{

public JPanel contentPane; //绘图窗口

public Graphics2D comp2D; //绘图对象

JPanel jPanel1 = new JPanel();//控件容器

JButton jButton1 = new JButton();

JButton jButton2 = new JButton();

//构造函数

public DrawDemo1() {

enableEvents(AWTEvent.WINDOW_EVENT_MASK);

try {

jbInit();

}

catch(Exception e) {

e.printStackTrace();

}

}

//控件初始化

private void jbInit() throws Exception {

contentPane = (JPanel) this.getContentPane();

contentPane.setLayout(new BorderLayout());

this.setSize(new Dimension(400, 300));

this.setTitle("Frame Title");

//contentPane.setSize(400,240);

jPanel1.setLayout(null);

jButton1.setBounds(new Rectangle(30, 235, 150, 31));

jButton1.setText("二阶贝塞尔");

jButton1.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton1_actionPerformed(e);

}

});

jButton2.setBounds(new Rectangle(200, 235, 150, 30));

jButton2.setText("三阶贝塞尔");

jButton2.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton2_actionPerformed(e);

}

});

contentPane.add(jPanel1, BorderLayout.CENTER);

jPanel1.add(jButton1, null);

jPanel1.add(jButton2, null);

}

public static void main(String[] args) {

DrawDemo1 frame=new DrawDemo1();

frame.show();

frame.comp2D=(Graphics2D)frame.contentPane .getGraphics();

frame.comp2D.setBackground(Color.white);

frame.comp2D.clearRect(0,0,401,221);

}

//Overridden so we can exit when window is closed

protected void processWindowEvent(WindowEvent e) {

super.processWindowEvent(e);

if (e.getID() == WindowEvent.WINDOW_CLOSING) {

System.exit(0);

}

}

void jButton1_actionPerformed(ActionEvent e){

double[] x1={50,180,300};

double[] y1={100,190,100};

comp2D.clearRect(0,0,401,221);

//笔宽度

float thick = 1f;

comp2D.setPaint(Color.red);

QuadCurve2D.Double qc=new QuadCurve2D.Double();

qc.setCurve(x1[0],y1[0],x1[1],y1[1],x1[2],y1[2]);

comp2D.draw(qc);

comp2D.drawLine((int)x1[1]-5,(int)y1[1],(int)x1[1]+5,(int)y1[1]);

comp2D.drawLine((int)x1[1],(int)y1[1]-5,(int)x1[1],(int)y1[1]+5);

comp2D.setPaint(Color.blue);

x1[1]=180;

y1[1]=30;

qc.setCurve(x1[0],y1[0],x1[1],y1[1],x1[2],y1[2]);

comp2D.draw(qc);

comp2D.drawLine((int)x1[1]-5,(int)y1[1],(int)x1[1]+5,(int)y1[1]);

comp2D.drawLine((int)x1[1],(int)y1[1]-5,(int)x1[1],(int)y1[1]+5);

}

void jButton2_actionPerformed(ActionEvent e) {

double[] x1={50,80,200,300};

double[] y1={100,70,190,100};

comp2D.clearRect(0,0,401,221);

//笔宽度

float thick = 1f;

comp2D.setPaint(Color.red);

CubicCurve2D.Double qc=new CubicCurve2D.Double();

qc.setCurve(x1[0],y1[0],x1[1],y1[1],x1[2],y1[2],x1[3],y1[3]);

comp2D.draw(qc);

comp2D.drawLine((int)x1[1]-5,(int)y1[1],(int)x1[1]+5,(int)y1[1]);

comp2D.drawLine((int)x1[1],(int)y1[1]-5,(int)x1[1],(int)y1[1]+5);

comp2D.drawLine((int)x1[2]-5,(int)y1[2],(int)x1[2]+5,(int)y1[2]);

comp2D.drawLine((int)x1[2],(int)y1[2]-5,(int)x1[2],(int)y1[2]+5);

float dash1[] = {10.0f};

//画虚线

BasicStroke dashed = new BasicStroke(1.0f,

BasicStroke.CAP_BUTT,

BasicStroke.JOIN_MITER,

10.0f, dash1, 0.0f);

comp2D.setStroke(dashed);

comp2D.setPaint(Color.darkGray);

comp2D.drawLine((int)x1[1],(int)y1[1],(int)x1[2],(int)y1[2]);

//画实线

BasicStroke stroke = new BasicStroke(1.0f);

comp2D.setStroke(stroke);

comp2D.setPaint(Color.blue);

x1[1]=180;

y1[1]=70;

x1[2]=80;

y1[2]=190;

qc.setCurve(x1[0],y1[0],x1[1],y1[1],x1[2],y1[2],x1[3],y1[3]);

comp2D.draw(qc);

comp2D.drawLine((int)x1[1]-5,(int)y1[1],(int)x1[1]+5,(int)y1[1]);

comp2D.drawLine((int)x1[1],(int)y1[1]-5,(int)x1[1],(int)y1[1]+5);

comp2D.drawLine((int)x1[2]-5,(int)y1[2],(int)x1[2]+5,(int)y1[2]);

comp2D.drawLine((int)x1[2],(int)y1[2]-5,(int)x1[2],(int)y1[2]+5);

comp2D.setStroke(dashed);

comp2D.setPaint(Color.darkGray);

comp2D.drawLine((int)x1[1],(int)y1[1],(int)x1[2],(int)y1[2]);

comp2D.setStroke(stroke);

}

}

三、自定义样条曲线编程

当我们需要平滑多个数据样本点的时候,贝塞尔曲线就不能满足要求了,为此,可以采用最早由美国“波音”飞机制造公司提出来的样条曲线来完成,这种曲线所以称之为样条,是因为它模拟了造船业中的放样原理。

样条曲线的数学原理请参考计算机图形学,这里给出的是由java编写的三次样条曲线的例子。曲线平滑的原则是,必须通过所有的样本点,另外,不论有多少样本点,曲线的阶次大为三次,所以是稳定的。

这里我们可以看出来,程序设计的生命是什么呢?数学!这是程序设计着的生命所在。语言只是一种规范或者是一个工具,要真正写出好的程序,没有深厚的数学功底,是万万不可能的。

样例:

package myDrawDemo;

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import java.awt.geom.*;

public class DrawCurve extends JFrame

{

public JPanel contentPane; //绘图窗口

JPanel jPanel1 = new JPanel();//控件容器

JButton jButton1 = new JButton();

JButton jButton2 = new JButton();

JButton jButton3 = new JButton();

GraphicsCurve gracu;

//构造函数

public DrawCurve() {

enableEvents(AWTEvent.WINDOW_EVENT_MASK);

try {

jbInit();

}

catch(Exception e) {

e.printStackTrace();

}

}

//控件初始化

private void jbInit() throws Exception {

contentPane = (JPanel) this.getContentPane();

contentPane.setLayout(new BorderLayout());

this.setSize(new Dimension(500,400));

this.setTitle("Frame Title");

//contentPane.setSize(400,240);

jPanel1.setLayout(null);

jButton1.setBounds(new Rectangle(30, 310, 100, 31));

jButton1.setText("直线");

jButton1.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton1_actionPerformed(e);

}

});

jButton2.setBounds(new Rectangle(150, 310, 100, 30));

jButton2.setText("样条曲线");

jButton2.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton2_actionPerformed(e);

}

});

jButton3.setBounds(new Rectangle(270, 310, 100, 30));

jButton3.setText("粗线条");

jButton3.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton3_actionPerformed(e);

}

});

contentPane.add(jPanel1, BorderLayout.CENTER);

jPanel1.add(jButton1, null);

jPanel1.add(jButton2, null);

jPanel1.add(jButton3, null);

gracu=new GraphicsCurve();

}

public static void main(String[] args) {

DrawCurve frame=new DrawCurve();

frame.show();

frame.gracu.myGraphics=(Graphics2D)frame.contentPane .getGraphics();

frame.gracu.myGraphics.setBackground(Color.white);

frame.gracu.myGraphics.clearRect(0,0,500,300);

}

//Overridden so we can exit when window is closed

protected void processWindowEvent(WindowEvent e) {

super.processWindowEvent(e);

if (e.getID() == WindowEvent.WINDOW_CLOSING) {

System.exit(0);

}

}

int Xs1[]={10,60,120,200,260,340};

int Ys1[]={10,200,120,180,60,130};

//画折线

void jButton1_actionPerformed(ActionEvent e){

gracu.myGraphics.setPaint(Color.blue);

gracu.myGraphics.drawPolyline(Xs1,Ys1,Xs1.length);

}

//画样条

void jButton2_actionPerformed(ActionEvent e) {

gracu.myGraphics.setPaint(Color.red);

gracu.DrawCurves(Xs1,Ys1);

}

//画粗线

void jButton3_actionPerformed(ActionEvent e) {

//笔宽度

float thick = 10f;

//设置笔刷

//方头园连接

//gracu.myGraphics.setStroke(new BasicStroke(thick, BasicStroke.CAP_SQUARE, BasicStroke.JOIN_ROUND));

//园头园连接

gracu.myGraphics.setStroke(new BasicStroke(thick, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));

gracu.myGraphics.setPaint(Color.blue);

//通过该方法使图形去除锯齿状

gracu.myGraphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING,

RenderingHints.VALUE_ANTIALIAS_ON);

gracu.myGraphics.drawPolyline(Xs1,Ys1,Xs1.length);

}

}

class GraphicsCurve

{

//绘图对象

public Graphics2D myGraphics;

public GraphicsCurve()

{

}

public GraphicsCurve(Graphics2D graphics)

{

this.myGraphics=graphics;

}

//参数表

//x数组,y数组,笔刷

public void DrawCurves(int[] xa,int[] ya)

{

int[] x, y;

double[] a, b, c;

double[] px, py, qx, qy, tt;

double[] dx, dy;

int px1,py1,px2,py2;

x=xa;

y=ya;

px1=x[0];

py1=y[0];

int n=x.length;

a=new double[n];

b=new double[n];

c=new double[n];

px=new double[n];

py=new double[n];

qx=new double[n];

qy=new double[n];

tt=new double[n];

dx=new double[n];

dy=new double[n];

int i, t, es;

double bx3, bx4, by3, by4, cx, cy;

bx4 = 0;

by3 = 0;

es = 3;

px[0] = 1;

py[0] = 1;

px[n-1] = 1;

py[n-1] = 1;

if (n>1)

{

for (i = 1;i
tt[i] = Math.sqrt((x[i] - x[i - 1]) * (x[i] - x[i - 1]) + (y[i] - y[i - 1]) * (y[i] - y[i - 1]));

switch(n)

{

case 2:

break;

case 3:

for (i = 1;i
{

a[i] = 2 * (tt[i] + tt[i + 1]);

b[i] = tt[i + 1];

c[i] = tt[i];

dx[i] = 3 * (tt[i] * (x[i + 1] - x[i]) / tt[i + 1] + tt[i + 1] * (x[i] - x[i - 1]) / tt[i]);

dy[i] = 3 * (tt[i] * (y[i + 1] - y[i]) / tt[i + 1] + tt[i + 1] * (y[i] - y[i - 1]) / tt[i]);

}

dx[1] = dx[1] - tt[2] * px[0];

dx[n - 2] = dx[n - 2] - tt[n - 2] * px[n-1];

dy[1] = dy[1] - tt[2] * py[0];

dy[n - 2] = dy[n - 2] - tt[n - 2] * py[n-1];

//注意,这是n=3的情况专有计算

px[1] = dx[1] / a[1];

py[1] = dy[1] / a[1];

break;

default:

for (i = 1;i
{

a[i] = 2 * (tt[i] + tt[i + 1]);

b[i] = tt[i + 1];

c[i] = tt[i];

dx[i] = 3 * (tt[i] * (x[i + 1] - x[i]) / tt[i + 1] + tt[i + 1] * (x[i] - x[i - 1]) / tt[i]);

dy[i] = 3 * (tt[i] * (y[i + 1] - y[i]) / tt[i + 1] + tt[i + 1] * (y[i] - y[i - 1]) / tt[i]);

}

dx[1] = dx[1] - tt[2] * px[0];

dx[n - 2] = dx[n - 2] - tt[n - 2] * px[n-1];

dy[1] = dy[1] - tt[2] * py[0];

dy[n - 2] = dy[n - 2] - tt[n - 2] * py[n-1];

c[1] = c[1]/ a[1];

for (i = 2 ;i< n - 1;i++)

{

a[i] = a[i] - b[i] * c[i - 1];

c[i] = c[i] / a[i];

}

qx[1] = dx[1] / a[1];

qy[1] = dy[1] / a[1];

for (i = 2 ;i< n - 1;i++)

{

qx[i] = (dx[i] - b[i] * qx[i - 1]) / a[i];

qy[i] = (dy[i] - b[i] * qy[i - 1]) / a[i];

}

px[n - 2] = qx[n - 2];

py[n - 2] = qy[n - 2];

for (i = n - 3;i>=1;i--)

{

px[i] = qx[i] - c[i] * px[i + 1];

py[i] = qy[i] - c[i] * py[i + 1];

}

break;

}

for (i = 0 ;i< n - 1;i++)

{

bx3 = (3 * (x[i + 1] - x[i]) / tt[i + 1] - 2 * px[i] - px[i + 1]) / tt[i + 1];

bx4 = ((2 * (x[i] - x[i + 1]) / tt[i + 1] + px[i] + px[i + 1]) / tt[i + 1]) / tt[i + 1];

by3 = (3 * (y[i + 1] - y[i]) / tt[i + 1] - 2 * py[i] - py[i + 1]) / tt[i + 1];

by4 = ((2 * (y[i] - y[i + 1]) / tt[i + 1] + py[i] + py[i + 1]) / tt[i + 1]) / tt[i + 1];

t = 0;

while (t < tt[i + 1])

{

t = t + es;

cx = x[i] + (px[i] + (bx3 + bx4 * t) * t) * t;

cy = y[i] + (py[i] + (by3 + by4 * t) * t) * t;

px2 = (int)cx;

py2 = (int)cy;

myGraphics.drawLine(px1,py1,px2,py2);

px1 = px2;

py1 = py2;

}

}

}

}

}

四、用户数据的曲线显示

当需要用曲线表达数据的时候,我们虽然可以使用由厂家提供的“图表”组件,但更多的还是需要自己编写的,请仔细研究下面的程序,当对图表设计有更深入的理解。

下面的例子,我们构造一个专门处理用户数据的类,在这个类里,实现了用户坐标和屏幕坐标的转换,同时给出了一个自动绘制坐标的方法。我们也直接使用了上面我们讨论过的样条曲线的类实现数据平滑。例子中的数据可以来自于数据库或其它任何地方,仔细的研究这个例子,可以看出只要我们开动脑筋,把java强大的功能和我们对问题的理解结合在一起,就可以写出多么灵活多变的程序来呀!

样例:

package myDrawDemo;

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import javax.swing.event.*;

import java.awt.geom.*;

public class DataDrawDemo extends JFrame

{

public JPanel contentPane; //控件容器

JPanel jPanel1 = new JPanel();//绘图控件

JButton jButton1 = new JButton();

JButton jButton2 = new JButton();

JButton jButton3 = new JButton();

JButton jButton4 = new JButton();

JButton jButton5 = new JButton();

JButton jButton6 = new JButton();

JButton jButton7 = new JButton();

JButton jButton8 = new JButton();

JButton jButton9 = new JButton();

JButton jButton10 = new JButton();

JTextField jText1=new JTextField();

JTextField jText2=new JTextField();

boolean kcu=true;

//用户坐标转换对象

myGraphicsData mp=new myGraphicsData();

//曲线转换对象

GraphicsCurve gracu=new GraphicsCurve();

//窗口范围

double wx1,wx2,wy1,wy2;

//构造函数

public DataDrawDemo() {

enableEvents(AWTEvent.WINDOW_EVENT_MASK);

try {

jbInit();

}

catch(Exception e) {

e.printStackTrace();

}

}

//初始化代码

private void jbInit() throws Exception {

contentPane = (JPanel) this.getContentPane();

contentPane.setLayout(null);

this.setSize(new Dimension(650, 500));

this.setTitle("Frame Title");

//contentPane.setSize(400,240);

//jPanel1.setLayout(null);

jPanel1.setBounds(0,90,650,420);

jButton1.setBounds(new Rectangle(30, 20, 80, 25));

jButton1.setText("开始");

jButton1.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton1_actionPerformed(e);

}

});

jButton2.setBounds(new Rectangle(120, 20, 80, 25));

jButton2.setText("左移");

jButton2.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton2_actionPerformed(e);

}

});

jButton3.setBounds(new Rectangle(210, 20, 80, 25));

jButton3.setText("右移");

jButton3.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton3_actionPerformed(e);

}

});

jButton4.setBounds(new Rectangle(300, 20, 80, 25));

jButton4.setText("上移");

jButton4.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton4_actionPerformed(e);

}

});

jButton5.setBounds(new Rectangle(390, 20, 80, 25));

jButton5.setText("下移");

jButton5.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton5_actionPerformed(e);

}

});

jButton6.setBounds(new Rectangle(120, 50, 80, 25));

jButton6.setText("X扩");

jButton6.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton6_actionPerformed(e);

}

});

jButton7.setBounds(new Rectangle(210, 50, 80, 25));

jButton7.setText("X缩");

jButton7.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton7_actionPerformed(e);

}

});

jButton8.setBounds(new Rectangle(300, 50, 80, 25));

jButton8.setText("Y扩");

jButton8.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton8_actionPerformed(e);

}

});

jButton9.setBounds(new Rectangle(390, 50, 80, 25));

jButton9.setText("Y缩");

jButton9.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton9_actionPerformed(e);

}

});

//样条控制

jButton10.setBounds(new Rectangle(30, 50, 80, 25));

jButton10.setText("样条");

jButton10.addActionListener(new java.awt.event.ActionListener() {

public void actionPerformed(ActionEvent e) {

jButton10_actionPerformed(e);

}

});

jText1.setBounds(new Rectangle(490, 20, 120, 20));

jText1.setText("");

jText2.setBounds(new Rectangle(490, 50, 120, 20));

jText2.setText("");

//鼠标按下侦听器

jPanel1.addMouseListener(new java.awt.event.MouseAdapter(){

public void mousePressed(MouseEvent e) {

JPanel_mousePressed(e);

}

});

//鼠标拖动侦听器

jPanel1.addMouseMotionListener(new java.awt.event.MouseMotionAdapter(){

public void mouseDragged(MouseEvent e){

JPanel_mouseDragged(e);

}

});

//鼠标释放侦听器

jPanel1.addMouseListener(new java.awt.event.MouseAdapter(){

public void mouseReleased(MouseEvent e) {

JPanel_mouseReleased(e);

}

});

contentPane.add(jPanel1, BorderLayout.CENTER);

contentPane.add(jButton1, null);

contentPane.add(jButton2, null);

contentPane.add(jButton3, null);

contentPane.add(jButton4, null);

contentPane.add(jButton5, null);

contentPane.add(jButton6, null);

contentPane.add(jButton7, null);

contentPane.add(jButton8, null);

contentPane.add(jButton9, null);

contentPane.add(jButton10, null);

contentPane.add(jText1, null);

contentPane.add(jText2, null);

}

public static void main(String[] args) {

DataDrawDemo frame=new DataDrawDemo();

frame.show();

frame.gracu.myGraphics=(Graphics2D)frame.jPanel1.getGraphics();

frame.mp.myGraphics=(Graphics2D)frame.jPanel1.getGraphics();

frame.mp.myGraphics.setBackground(Color.white);

frame.mp.myGraphics.clearRect(0,0,650,375);

}

//第一组数据

double[] Xs1=new double[]{-2,2,4,6,8,10,12,14};

double[] Ys1=new double[]{-4,10,3,14,4,10,6,7};

//第二组数据

double[] Xs2=new double[]{-1,2,4,6,8,10,12,14,16};

double[] Ys2=new double[]{1,5,7,1,13,11,4,10,8};

//这是一个画曲线的程序

void DwData()

{

//剪裁,可以试试没有剪裁是什么表现?

mp.myGraphics.clipRect(10,10,621,351);

//由于是用两个对象绘图,所以应该分别剪切

gracu.myGraphics.clipRect(10,10,621,351);

//清除绘图空间

mp.myGraphics.clearRect(0,0,650,375);

//用户坐标和屏幕坐标转换

mp.truemode(10,630,10,360,wx1,wx2,wy1,wy2);

//设置颜色

mp.myGraphics.setPaint(Color.darkGray);

//画边框

mp.myGraphics.drawRect(10,10,620,350);

mp.myGraphics.setFont(new Font("宋体", 0, 10)); //9为字大小

//画坐标

mp.axis(2,2,2,2);

//画红线

int[] x=new int[Xs1.length];

int[] y=new int[Ys1.length];

int[] myxy;

//统一实现坐标转换

for (int i=0;i
{

myxy=mp.moxy(Xs1[i],Ys1[i]);

x[i]=myxy[0];

y[i]=myxy[1];

}

if (kcu)

{

mp.myGraphics.setPaint(Color.red);

mp.myGraphics.drawPolyline(x,y,x.length);

}

else

{

gracu.myGraphics.setPaint(Color.red);

gracu.DrawCurves(x,y);

}

//画蓝线

x=new int[Xs2.length];

y=new int[Ys2.length];

for (int i=0;i
{

myxy=mp.moxy(Xs2[i],Ys2[i]);

x[i]=myxy[0];

y[i]=myxy[1];

}

if (kcu)

{

mp.myGraphics.setPaint(Color.blue);

mp.myGraphics.drawPolyline(x,y,x.length);

}

else

{

gracu.myGraphics.setPaint(Color.blue);

gracu.DrawCurves(x,y);

}

}

//退出窗口事件

protected void processWindowEvent(WindowEvent e) {

super.processWindowEvent(e);

if (e.getID() == WindowEvent.WINDOW_CLOSING) {

System.exit(0);

}

}

//鼠标按下事件

void JPanel_mousePressed(MouseEvent e)

{

double[] zs=mp.ScrtoCon(e.getX(),e.getY());

jText1.setText(String.valueOf((float)zs[0]));

jText2.setText(String.valueOf((float)zs[1]));

}

//鼠标释放事件

void JPanel_mouseReleased(MouseEvent e)

{

double[] zs=mp.ScrtoCon(e.getX(),e.getY());

jText1.setText("");

jText2.setText("");

//画红线

mp.myGraphics.setPaint(Color.darkGray);

mp.myGraphics.drawLine(e.getX()-3,e.getY(),e.getX()+3,e.getY());

mp.myGraphics.drawLine(e.getX(),e.getY()-3,e.getX(),e.getY()+3);

mp.myGraphics.drawString(String.valueOf((float)zs[0]),e.getX()+10,e.getY());

mp.myGraphics.drawString(String.valueOf((float)zs[1]),e.getX()+10,e.getY()+12);

}

//鼠标拖动事件

void JPanel_mouseDragged(MouseEvent e)

{

double[] zs=mp.ScrtoCon(e.getX(),e.getY());

jText1.setText(String.valueOf((float)zs[0]));

jText2.setText(String.valueOf((float)zs[1]));

}

//开始

void jButton1_actionPerformed(ActionEvent e){

wx1=1000000;

wy1=1000000;

wx2=-1000000;

wy2=-1000000;

//试验中数据来自一个数组,实际中可来自任何地方

//设置初始范围

for (int i=0;i
{

if (Xs1[i]< wx1)

wx1=Xs1[i];

if (Xs1[i]> wx2)

wx2=Xs1[i];

if (Ys1[i]< wy1)

wy1=Ys1[i];

if (Ys1[i]> wy2)

wy2=Ys1[i];

}

for (int i=0;i
{

if (Xs2[i]< wx1)

wx1=Xs2[i];

if (Xs2[i]> wx2)

wx2=Xs2[i];

if (Ys2[i]< wy1)

wy1=Ys2[i];

if (Ys2[i]> wy2)

wy2=Ys2[i];

}

DwData();

}

//左移

void jButton2_actionPerformed(ActionEvent e) {

wx1-=1;

wx2-=1;

DwData();

}

//右移

void jButton3_actionPerformed(ActionEvent e) {

wx1+=1;

wx2+=1;

DwData();

}

//上移

void jButton4_actionPerformed(ActionEvent e) {

wy1-=1;

wy2-=1;

DwData();

}

//下移

void jButton5_actionPerformed(ActionEvent e) {

wy1+=1;

wy2+=1;

DwData();

}

//X扩

void jButton6_actionPerformed(ActionEvent e) {

wx1-=1;

wx2+=1;

DwData();

}

//X缩

void jButton7_actionPerformed(ActionEvent e) {

wx1+=1;

wx2-=1;

DwData();

}

//Y扩

void jButton8_actionPerformed(ActionEvent e) {

wy1-=1;

wy2+=1;

DwData();

}

//Y缩

void jButton9_actionPerformed(ActionEvent e) {

wy1+=1;

wy2-=1;

DwData();

}

//样条控制

void jButton10_actionPerformed(ActionEvent e) {

if (kcu)

{

jButton10.setText("直线");

kcu=false;

}

else

{

jButton10.setText("样条");

kcu=true;

}

DwData();

}

}

//图形处理类

class myGraphicsData

{

//屏幕坐标

private int X11, Y11, X12, Y12; //x1,y1,x2,y2

//用户坐标

private double W1, W2, W3, W4; //x1,x2,y1,y2

//绘图对象

public Graphics2D myGraphics;

double Ax8, Ay8;

//用户窗口与屏幕窗口的转换

//x1,x2,,y1,y2为屏幕坐标

//wx1,wx2,wy1,wy2为用户坐标

public void truemode(int x1, int x2, int y1,int y2, double wx1, double wx2, double wy1, double wy2)

{

X11 = x1 ; X12 = x2;

Y11 = y1 ; Y12 = y2;

W1 = wx1 ; W2 = wx2;

W3 = wy1 ; W4 = wy2;

Ax8 = (X12 - X11) / (wx2 - wx1);

Ay8 = (Y12 - Y11) / (wy2 - wy1);

}

//把用户坐标转为屏幕坐标

public int[] moxy(double Xa, double Ya)

{

int[] myout=new int[2];

myout[0] = (int)(Ax8 * (Xa - W1) + X11);

myout[1] = (int)(Y12 - Ay8 * (Ya - W3));

return myout;

}

//把屏幕坐标转为用户坐标

public double[] ScrtoCon(int X6, int Y6)

{

double[] myout=new double[2];

myout[0] = (X6 - X11) / Ax8 + W1;

myout[1] = (Y12 - Y6) / Ay8 + W3;

return myout;

}

//画线

public void Dline(double xa, double ya, double xb, double yb)

{

try

{

int x6, y6, x7, y7;

x6 = (int)(Ax8 * (xa - W1) + X11);

y6 = (int)(Y12 - Ay8 * (ya - W3));

x7 = (int)(Ax8 * (xb - W1) + X11);

y7 = (int)(Y12 - Ay8 * (yb - W3));

myGraphics.drawLine(x6, y6, x7, y7);

}

catch(Exception e){}

}

//画坐标U,V为 X,Y轴单位,ns,nt为 x,y轴写字间隔

public void axis(double u, double v, int ns, int nt)

{

double p9, q9, s;

int n2, swx,swy;

int xk=0;

int yk=0;

double ge;

int[] showxy=new int[2];

swx = 0;

swy=4;

ge = (double)0.008 * (W2 - W1);

p9 = W1;

q9 = (double)(W3 + (W4 - W3) * 0.05);

if ((W1 < 0) && (W2 > 0)) p9 = 0;

if ((W3 < 0) && (W4 > 0)) q9 = 0;

Dline(p9, W3, p9, W4);

n2 = 0;

s = 0;

while (s < W4)

{

Dline(p9, s, p9 + ge, s);

if (n2 >= nt)

{

Dline(p9, s, p9 + ge + ge, s);

n2 = 1;

showxy=moxy(p9 + ge + ge,s);

myGraphics.drawString(String.valueOf(s),showxy[0] - swx+4, showxy[1] - swy+4);

}

else

{

n2++;

}

s += v;

}

//End While

s = 0;

n2 = 0;

while (s > W3)

{

Dline(p9, s, p9 + ge, s);

if (n2 >= nt)

{

Dline(p9, s, p9 + ge + ge, s);

n2 = 1;

showxy=moxy(p9 + ge + ge, s);

myGraphics.drawString(String.valueOf(s),showxy[0] - swx+4, showxy[1] - swy+4);

}

else

{

n2 ++;

}

s -= v; 
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