一定要用java画图的话，我可以提供最简单的思路。JAVA中有一个画图函数paint(Graphics g)。
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例如先绘制出一个坐标轴可用如下代码
public void paint(Graphics g){
int startx = 50;
int starty = 500;
int endx = 500;
int endy = 500;
g.setColor(Color.black);
g.drawLine(startx, starty, startx, endy);
g.drawLine(startx, starty, endx, starty);
}
其中g.drawLine函数很好理解，4个参数分别为起始点和终点的横纵坐标。(注意电脑中的原点坐标其实是定义在左上角，与我们常规认识不同。)
g.setColor即为设定画笔颜色。
若你要画曲线，这里最简单的做法就是不停的画点或者小短线，所有点或短线连起来即为曲线。(人的肉眼难以分辨的。)
其中还有g.drawRect,g.drawImage等函数，看下文档即可。
若其中还没有你要的图形，也可以手工绘制。
希望能帮助到你，望采纳。
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import com.bruceeckel.swing.*;// 这个包你要自己去下，此处无法上传，整个程序你还要修改一下，以满足f(x)=x^2+sin(x)在区间[-3,3]的函数图像
class SineDraw extends JPanel {
static final int SCALEFACTOR = 200;
int cycles;
int points;
double[] sines;
int[] pts;
SineDraw() { setCycles(5); }
public void setCycles(int newCycles) {
cycles = newCycles;
points = SCALEFACTOR * cycles * 2;
sines = new double[points];
pts = new int[points];
for(int i = 0; i points; i++) {
double radians = (Math.PI/SCALEFACTOR) * i;
sines[i] = Math.sin(radians);
}
repaint();
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
int maxWidth = getWidth();
double hstep = (double)maxWidth/(double)points;
int maxHeight = getHeight();
for(int i = 0; i points; i++)
pts[i] = (int)(sines[i] * maxHeight/2 * .95
+ maxHeight/2);
g.setColor(Color.red);
for(int i = 1; i points; i++) {
int x1 = (int)((i - 1) * hstep);
int x2 = (int)(i * hstep);
int y1 = pts[i-1];
int y2 = pts[i];
g.drawLine(x1, y1, x2, y2);
}
}
}
public class SineWave extends JApplet {
SineDraw sines = new SineDraw();
JSlider cycles = new JSlider(1, 30, 5);
public void init() {
Container cp = getContentPane();
cp.add(sines);
cycles.addChangeListener(new ChangeListener(){
public void stateChanged(ChangeEvent e) {
System.out.println( ((JSlider)e.getSource()).getValue());
sines.setCycles( ((JSlider)e.getSource()).getValue());
}
});
cp.add(BorderLayout.SOUTH, cycles);
}
public static void main(String[] args) {
Console.run(new SineWave(), 700, 400);
}
} ///:~
我以前给j2me写的一个类，你看下：
用的时候这么用 private BDS bds=BDS.trans("-x+1");
System.out.println(bds.eval(10));
这样的
另外这里面的Hstx.pow和Hstx.ln可以用数学库里的函数替代，因为j2me里没有的
public class BDS{
public int errn=0;
public int len=0;
public int type[]=new int[100];
public double dd[]=new double[100];
public char dc[]=new char[100];
public static BDS trans(String ts){
BDS tr=new BDS();
char s[]=ts.toCharArray(),stk[]=new char[100];
int l=ts.length(),p=0,sl=0;
if(s[0]=='-')s[0]='~';
for(int i=1;il;i++)
if(s[i]=='-'(s[i-1]'0'||s[i-1]'9')s[i-1]!='x')s[i]='~';
for(int i=0;il;i++){
if(s[i]='0's[i]='9'){
double td=s[i]-'0',mt=1.0;
int hp=0;
i++;
while(il((s[i]='0's[i]='9')||s[i]=='.')){
if(s[i]=='.'){
if(hp==1){
tr.errn=1;
return tr;
}
hp=1;
}else{
if(hp==1){
mt/=10.0;
td+=(s[i]-'0')*mt;
}else td=td*10.0+(s[i]-'0');
}
i++;
}
i--;
if(hp==1mt==1.0){
tr.errn=1;
return tr;
}
tr.type[p]=1;
tr.dd[p]=td;
p++;
continue;
}
if(s[i]=='x'){
tr.type[p]=3;
p++;
continue;
}
if(s[i]=='a'){
if(i+3=l||s[i+1]!='b'||s[i+2]!='s'||s[i+3]!='('){
tr.errn=1;
return tr;
}
stk[sl++]='a';
i+=2;
continue;
}
if(s[i]=='i'){
if(i+3=l||s[i+1]!='n'||s[i+2]!='t'||s[i+3]!='('){
tr.errn=1;
return tr;
}
stk[sl++]='i';
i+=2;
continue;
}
if(s[i]=='l'){
if(i+2=l||s[i+1]!='n'||s[i+2]!='('){
tr.errn=1;
return tr;
}
stk[sl++]='l';
i++;
continue;
}
if(s[i]=='s'){
if(i+3=l||s[i+1]!='i'||s[i+2]!='n'||s[i+3]!='('){
if(i+4=l||s[i+1]!='q'||s[i+2]!='r'||s[i+3]!='t'||s[i+4]!='('){
tr.errn=1;
return tr;
}
stk[sl++]='q';
i+=3;
continue;
}
stk[sl++]='s';
i+=2;
continue;
}
if(s[i]=='c'){
if(i+3=l||s[i+1]!='o'||s[i+2]!='s'||s[i+3]!='('){
tr.errn=1;
return tr;
}
stk[sl++]='c';
i+=2;
continue;
}
if(s[i]=='t'){
if(i+3=l||s[i+1]!='a'||s[i+2]!='n'||s[i+3]!='('){
tr.errn=1;
return tr;
}
stk[sl++]='t';
i+=2;
continue;
}
if(s[i]=='~'||s[i]=='('){
stk[sl++]=s[i];
continue;
}
if(s[i]=='+'||s[i]=='-'){
while(sl0stk[sl-1]!='('){
tr.type[p]=2;
tr.dc[p]=stk[--sl];
p++;
}
stk[sl++]=s[i];
continue;
}
if(s[i]=='*'||s[i]=='/'||s[i]=='^'){
while(sl0(stk[sl-1]!='('stk[sl-1]!='+'stk[sl-1]!='-')){
tr.type[p]=2;
tr.dc[p]=stk[--sl];
p++;
}
stk[sl++]=s[i];
continue;
}
if(s[i]==')'){
while(sl0stk[sl-1]!='('){
tr.type[p]=2;
tr.dc[p]=stk[--sl];
p++;
}
sl--;
if(sl0){
tr.errn=1;
return tr;
}
continue;
}
tr.errn=1;
return tr;
}
while(sl0){
if(stk[sl-1]=='('){
tr.errn=1;
return tr;
}
tr.type[p]=2;
tr.dc[p]=stk[--sl];
p++;
}
tr.len=p;
tr.eval(1);
return tr;
}
public double eval(double x){
int sl=0;
double stk[]=new double[100];
for(int i=0;ilen;i++){
if(type[i]==1)stk[sl++]=dd[i];
else if(type[i]==3)stk[sl++]=x;
else{
if(dc[i]=='+'){
if(sl2){
errn=1;
return 0;
}
stk[sl-2]=stk[sl-2]+stk[sl-1];
sl--;
}
if(dc[i]=='-'){
if(sl2){
errn=1;
return 0;
}
stk[sl-2]=stk[sl-2]-stk[sl-1];
sl--;
}
if(dc[i]=='*'){
if(sl2){
errn=1;
return 0;
}
stk[sl-2]=stk[sl-2]*stk[sl-1];
sl--;
}
if(dc[i]=='/'){
if(sl2){
errn=1;
return 0;
}
stk[sl-2]=stk[sl-2]/stk[sl-1];
sl--;
}
if(dc[i]=='^'){
if(sl2){
errn=1;
return 0;
}
stk[sl-2]=HstxC.pow(stk[sl-2],stk[sl-1]);
sl--;
}
if(dc[i]=='~'){
if(sl1){
errn=1;
return 0;
}
stk[sl-1]=-stk[sl-1];
}
if(dc[i]=='a'){
if(sl1){
errn=1;
return 0;
}
stk[sl-1]=Math.abs(stk[sl-1]);
}
if(dc[i]=='q'){
if(sl1){
errn=1;
return 0;
}
stk[sl-1]=Math.sqrt(stk[sl-1]);
}
if(dc[i]=='i'){
if(sl1){
errn=1;
return 0;
}
stk[sl-1]=Math.floor(stk[sl-1]);
}
if(dc[i]=='s'){
if(sl1){
errn=1;
return 0;
}
stk[sl-1]=Math.sin(stk[sl-1]);
}
if(dc[i]=='c'){
if(sl1){
errn=1;
return 0;
}
stk[sl-1]=Math.cos(stk[sl-1]);
}
if(dc[i]=='t'){
if(sl1){
errn=1;
return 0;
}
stk[sl-1]=Math.tan(stk[sl-1]);
}
if(dc[i]=='l'){
if(sl1){
errn=1;
return 0;
}
stk[sl-1]=HstxC.ln(stk[sl-1]);
}
}
}
if(sl!=1){
errn=1;
return 0;
}
return stk[0];
}
}
写这样的程序非常费时间...除非网上有现成的.否者不可能有人写的...而且才10分
找到了，很久以前写的一个简单画图，呵呵～当时要求用AWT写，很难受。
package net.miqiang.gui;
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Color;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Label;
import java.awt.Panel;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.BufferedImage;
/**
* 简单画图板程序
* 好久没用 AWT 了，写起来真别扭，如果用 swing 会很舒服，有空再改写吧。
*
* @author 米强
*
*/
public class TestMain extends Frame {
// 画板
private Palette palette = null;
// 显示当前颜色的面板
private Panel nonceColor = null;
// 画笔粗细
private Label drawWidth = null;
// 画笔端点的装饰
private Label drawCap = null;
// 选取颜色按钮的监听事件类
private ButtonColorAction buttonColorAction = null;
// 鼠标进入按钮后光标样式的监听事件类
private ButtonCursor buttonCursor = null;
// 画笔样式的监听事件
private ButtonStrokeAction buttonStrokeAction = null;
/**
* 构造方法
*
*/
public TestMain() {
// 设置标题栏文字
super("简易画图板");
// 构造一个画图板
palette = new Palette();
Panel pane = new Panel(new GridLayout(2, 1));
// 画笔颜色选择器
Panel paneColor = new Panel(new GridLayout(1, 13));
// 12 个颜色选择按钮
Button [] buttonColor = new Button[12];
Color [] color = {Color.black, Color.blue, Color.cyan, Color.darkGray, Color.gray, Color.green, Color.magenta, Color.orange, Color.pink, Color.red, Color.white, Color.yellow};
// 显示当前颜色的面板
nonceColor = new Panel();
nonceColor.setBackground(Color.black);
paneColor.add(nonceColor);
buttonColorAction = new ButtonColorAction();
buttonCursor = new ButtonCursor();
for(int i = 0; i buttonColor.length; i++){
buttonColor[i] = new Button();
buttonColor[i].setBackground(color[i]);
buttonColor[i].addActionListener(buttonColorAction);
buttonColor[i].addMouseListener(buttonCursor);
paneColor.add(buttonColor[i]);
}
pane.add(paneColor);
// 画笔颜色选择器
Panel paneStroke = new Panel(new GridLayout(1, 13));
// 控制画笔样式
buttonStrokeAction = new ButtonStrokeAction();
Button [] buttonStroke = new Button[11];
buttonStroke[0] = new Button("1");
buttonStroke[1] = new Button("3");
buttonStroke[2] = new Button("5");
buttonStroke[3] = new Button("7");
buttonStroke[4] = new Button("9");
buttonStroke[5] = new Button("11");
buttonStroke[6] = new Button("13");
buttonStroke[7] = new Button("15");
buttonStroke[8] = new Button("17");
buttonStroke[9] = new Button("■");
buttonStroke[10] = new Button("●");
drawWidth = new Label("3", Label.CENTER);
drawCap = new Label("●", Label.CENTER);
drawWidth.setBackground(Color.lightGray);
drawCap.setBackground(Color.lightGray);
paneStroke.add(drawWidth);
for(int i = 0; i buttonStroke.length; i++){
paneStroke.add(buttonStroke[i]);
buttonStroke[i].addMouseListener(buttonCursor);
buttonStroke[i].addActionListener(buttonStrokeAction);
if(i = 8){
buttonStroke[i].setName("width");
}else{
buttonStroke[i].setName("cap");
}
if(i == 8){
paneStroke.add(drawCap);
}
}
pane.add(paneStroke);
// 将画笔颜色选择器添加到窗体中
this.add(pane, BorderLayout.NORTH);
// 将画图板添加到窗体中
this.add(palette);
// 添加窗口监听，点击关闭按钮时退出程序
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
// 设置窗体 ICON 图标
this.setIconImage(Toolkit.getDefaultToolkit().createImage("images/palette.png"));
// 设置窗口的大小
this.setSize(new Dimension(400, 430));
// 设置窗口位置，处于屏幕正中央
this.setLocationRelativeTo(null);
// 显示窗口
this.setVisible(true);
}
/**
* 程序入口
*
* @param args
* 字符串数组参数
*/
public static void main(String[] args) {
new TestMain();
}
/**
* 选取颜色按钮的监听事件类
* @author 米强
*
*/
class ButtonColorAction implements ActionListener {
public void actionPerformed(ActionEvent e) {
Color color_temp = ((Button)e.getSource()).getBackground();
nonceColor.setBackground(color_temp);
palette.setColor(color_temp);
}
}
/**
* 鼠标进入按钮变换光标样式监听事件类
* @author 米强
*
*/
class ButtonCursor extends MouseAdapter {
public void mouseEntered(MouseEvent e) {
((Button)e.getSource()).setCursor(new Cursor(Cursor.HAND_CURSOR));
}
public void mouseExited(MouseEvent e) {
((Button)e.getSource()).setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
}
}
/**
* 设置画笔的监听事件类
* @author 米强
*
*/
class ButtonStrokeAction implements ActionListener {
public void actionPerformed(ActionEvent e) {
Button button_temp = (Button) e.getSource();
String name = button_temp.getName();
if(name.equalsIgnoreCase("width")){
drawWidth.setText(button_temp.getLabel());
palette.setStroke(Float.parseFloat(button_temp.getLabel()));
}else if(name.equalsIgnoreCase("cap")){
drawCap.setText(button_temp.getLabel());
if(button_temp.getLabel().equals("■")){
palette.setStroke(BasicStroke.CAP_SQUARE);
}else if(button_temp.getLabel().equals("●")){
palette.setStroke(BasicStroke.CAP_ROUND);
}
}
}
}
}
/**
* 画板类
*
* @author 米强
*
*/
class Palette extends Panel implements MouseListener, MouseMotionListener {
// 鼠标 X 坐标的位置
private int mouseX = 0;
// 上一次 X 坐标位置
private int oldMouseX = 0;
// 鼠标 Y 坐标的位置
private int mouseY = 0;
// 上一次 Y 坐标位置
private int oldMouseY = 0;
// 画图颜色
private Color color = null;
// 画笔样式
private BasicStroke stroke = null;
// 缓存图形
private BufferedImage image = null;
/**
* 构造一个画板类
*
*/
public Palette() {
this.addMouseListener(this);
this.addMouseMotionListener(this);
// 默认黑色画笔
color = new Color(0, 0, 0);
// 设置默认画笔样式
stroke = new BasicStroke(3.0f, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND);
// 建立 1280 * 1024 的 RGB 缓存图象
image = new BufferedImage(1280, 1024, BufferedImage.TYPE_INT_RGB);
// 设置颜色
image.getGraphics().setColor(Color.white);
// 画背景
image.getGraphics().fillRect(0, 0, 1280, 1024);
}
/**
* 重写 paint 绘图方法
*/
public void paint(Graphics g) {
super.paint(g);
// 转换为 Graphics2D
Graphics2D g2d = (Graphics2D) g;
// 获取缓存图形 Graphics2D
Graphics2D bg = image.createGraphics();
// 图形抗锯齿
bg.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
// 设置绘图颜色
bg.setColor(color);
// 设置画笔样式
bg.setStroke(stroke);
// 画线，从上一个点到新的点
bg.drawLine(oldMouseX, oldMouseY, mouseX, mouseY);
// 将缓存中的图形画到画板上
g2d.drawImage(image, 0, 0, this);
}
/**
* 重写 update 方法
*/
public void update(Graphics g) {
this.paint(g);
}
/**
* @return stroke
*/
public BasicStroke getStroke() {
return stroke;
}
/**
* @param stroke 要设置的 stroke
*/
public void setStroke(BasicStroke stroke) {
this.stroke = stroke;
}
/**
* 设置画笔粗细
* @param width
*/
public void setStroke(float width) {
this.stroke = new BasicStroke(width, stroke.getEndCap(), stroke.getLineJoin());
}
/**
* 设置画笔端点的装饰
* @param cap 参考 java.awt.BasicStroke 类静态字段
*/
public void setStroke(int cap) {
this.stroke = new BasicStroke(stroke.getLineWidth(), cap, stroke.getLineJoin());
}
/**
* @return color
*/
public Color getColor() {
return color;
}
/**
* @param color 要设置的 color
*/
public void setColor(Color color) {
this.color = color;
}
public void mouseClicked(MouseEvent mouseEvent) {
}
/**
* 鼠标按下
*/
public void mousePressed(MouseEvent mouseEvent) {
this.oldMouseX = this.mouseX = mouseEvent.getX();
this.oldMouseY = this.mouseY = mouseEvent.getY();
repaint();
}
public void mouseReleased(MouseEvent mouseEvent) {
}
/**
* 鼠标进入棋盘
*/
public void mouseEntered(MouseEvent mouseEvent) {
this.setCursor(new Cursor(Cursor.CROSSHAIR_CURSOR));
}
/**
* 鼠标退出棋盘
*/
public void mouseExited(MouseEvent mouseEvent) {
this.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
}
/**
* 鼠标拖动
*/
public void mouseDragged(MouseEvent mouseEvent) {
this.oldMouseX = this.mouseX;
this.oldMouseY = this.mouseY;
this.mouseX = mouseEvent.getX();
this.mouseY = mouseEvent.getY();
repaint();
}
public void mouseMoved(MouseEvent mouseEvent) {
}
}
