Java 如何在JFrame中实现Hilbert曲线
我正在尝试做一个基于希尔伯特曲线的项目。我能够在Applet中使用代码,但我需要它在JFrame中工作,因为我需要一次打开多个框架来展示我的项目。我有下面小程序中的代码,但我不知道如何更改为JFrame 在小程序窗体中,类似于下面的代码:Java 如何在JFrame中实现Hilbert曲线,java,swing,curve,hilbert-curve,space-filling-curve,Java,Swing,Curve,Hilbert Curve,Space Filling Curve,我正在尝试做一个基于希尔伯特曲线的项目。我能够在Applet中使用代码,但我需要它在JFrame中工作,因为我需要一次打开多个框架来展示我的项目。我有下面小程序中的代码,但我不知道如何更改为JFrame 在小程序窗体中,类似于下面的代码: import java.awt.*; import java.applet.*; public class HilbertCurve extends Applet{ private SimpleGraphics sg = null; private i
import java.awt.*;
import java.applet.*;
public class HilbertCurve extends Applet{
private SimpleGraphics sg = null;
private int dist0=256;
private int dist=dist0;
public void init(){
resize(dist0, dist0);
sg = new SimpleGraphics(getGraphics());}
public void paint(Graphics g){
int level = 4;
dist = dist0;
for(int i=level; i>0; i--) dist/=2;
sg.goToXY (dist/2, dist/2);
HilbertU(level);
}
private void HilbertU(int level){
if(level>0){
HilbertD(level-1); sg.lineRel(0,dist);
HilbertU(level-1); sg.lineRel(dist,0);
HilbertU(level-1); sg.lineRel(0,-dist);
HilbertC(level-1);
}
}
private void HilbertD(int level){
if(level>0){
HilbertU(level-1); sg.lineRel(dist,0);
HilbertD(level-1); sg.lineRel(0,dist);
HilbertD(level-1); sg.lineRel(-dist,0);
HilbertA(level-1);
}
}
private void HilbertC(int level){
if(level>0){
HilbertA(level-1); sg.lineRel(-dist,0);
HilbertC(level-1); sg.lineRel(0,-dist);
HilbertC(level-1); sg.lineRel(dist,0);
HilbertU(level-1);
}
}
private void HilbertA(int level){
if(level>0){
HilbertC(level-1); sg.lineRel(0,-dist);
HilbertA(level-1); sg.lineRel(-dist,0);
HilbertA(level-1); sg.lineRel(0,dist);
HilbertD(level-1);
}
}
import java.awt.*;
import javax.swing.*;
class SimpleGraphics{
private Graphics g = null;
private int x =0, y = 0;
public SimpleGraphics(Graphics g) {
this.g = g;}
public void goToXY(int x, int y){
this.x =x;
this.y= y;
}
public void lineRel(int deltaX, int deltaY){
g.drawLine(x, y, x+deltaX, y+deltaY);
x+=deltaX;
y+=deltaY;}
}
我试着自己把它放到JFrame上,但没能。JFrame将打开,但HilbertCurve不会启动。下面是我的代码,我没有更改SimpleGraphics类
import java.awt.*;
import javax.swing.*;
public class HilbertCurve extends JPanel {
JFrame frame;
private SimpleGraphics sg = null;
private int dist0=256;
private int dist=dist0;
public static void main(String[] args){
HilbertCurve exemplo1 = new HilbertCurve();
exemplo1.fireUpScreen();
}
public void fireUpScreen(){
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(512,512);
frame.setVisible(true);
frame.add(this);
}
public void paint(Graphics g){
int level = 4;
dist = dist0;
for(int i=level; i>0; i--) dist/=2;
sg.goToXY (dist/2, dist/2);
HilbertU(level);
}
private void HilbertU(int level){
if(level>0){
HilbertD(level-1); sg.lineRel(0,dist);
HilbertU(level-1); sg.lineRel(dist,0);
HilbertU(level-1); sg.lineRel(0,-dist);
HilbertC(level-1);
}
}
private void HilbertD(int level){
if(level>0){
HilbertU(level-1); sg.lineRel(dist,0);
HilbertD(level-1); sg.lineRel(0,dist);
HilbertD(level-1); sg.lineRel(-dist,0);
HilbertA(level-1);
}
}
private void HilbertC(int level){
if(level>0){
HilbertA(level-1); sg.lineRel(-dist,0);
HilbertC(level-1); sg.lineRel(0,-dist);
HilbertC(level-1); sg.lineRel(dist,0);
HilbertU(level-1);
}
}
private void HilbertA(int level){
if(level>0){
HilbertC(level-1); sg.lineRel(0,-dist);
HilbertA(level-1); sg.lineRel(-dist,0);
HilbertA(level-1); sg.lineRel(0,dist);
HilbertD(level-1);
}
}
}首先,我建议你从通读开始,更好地理解绘画是如何在摇摆中工作的 示例小程序实际上是如何执行绘制的一个很糟糕的示例,因为您永远不应该维护对
图形的引用,它应该在绘制组件时传递给需要它的方法
您还应该得到一个NullPointerException
,因为sg
从未初始化过
一般来说,首先建立用户界面,然后调用setVisible
最后,它将解决一些简单的问题
没有理由HilbertCurve
需要引用JFrame
,框架可以在main
方法中实例化
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class HilbertCurve extends JPanel {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
HilbertCurve exemplo1 = new HilbertCurve();
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(exemplo1);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
private SimpleGraphics sg = null;
private int dist0 = 256;
private int dist = dist0;
public HilbertCurve() {
sg = new SimpleGraphics();
}
@Override
public Dimension getPreferredSize() {
return new Dimension(512, 512);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
int level = 4;
dist = dist0;
for (int i = level; i > 0; i--) {
dist /= 2;
}
sg.goToXY(dist / 2, dist / 2);
Graphics2D g2d = (Graphics2D) g.create();
hilbertU(g2d, level);
g2d.dispose();
}
private void hilbertU(Graphics2D g, int level) {
if (level > 0) {
hilbertD(g, level - 1);
sg.lineRel(g, 0, dist);
hilbertU(g, level - 1);
sg.lineRel(g, dist, 0);
hilbertU(g, level - 1);
sg.lineRel(g, 0, -dist);
hilbertC(g, level - 1);
}
}
private void hilbertD(Graphics2D g, int level) {
if (level > 0) {
hilbertU(g, level - 1);
sg.lineRel(g, dist, 0);
hilbertD(g, level - 1);
sg.lineRel(g, 0, dist);
hilbertD(g, level - 1);
sg.lineRel(g, -dist, 0);
hilbertA(g, level - 1);
}
}
private void hilbertC(Graphics2D g, int level) {
if (level > 0) {
hilbertA(g, level - 1);
sg.lineRel(g, -dist, 0);
hilbertC(g, level - 1);
sg.lineRel(g, 0, -dist);
hilbertC(g, level - 1);
sg.lineRel(g, dist, 0);
hilbertU(g, level - 1);
}
}
private void hilbertA(Graphics2D g, int level) {
if (level > 0) {
hilbertC(g, level - 1);
sg.lineRel(g, 0, -dist);
hilbertA(g, level - 1);
sg.lineRel(g, -dist, 0);
hilbertA(g, level - 1);
sg.lineRel(g, 0, dist);
hilbertD(g, level - 1);
}
}
class SimpleGraphics {
// private Graphics g = null;
private int x = 0, y = 0;
public SimpleGraphics() {
}
public void goToXY(int x, int y) {
this.x = x;
this.y = y;
}
public void lineRel(Graphics2D g, int deltaX, int deltaY) {
g.drawLine(x, y, x + deltaX, y + deltaY);
x += deltaX;
y += deltaY;
}
}
}
首先使frame.setVisible(true)代码>你在fireUpScreen中调用的最后一件事已经是了,不是吗?不,第二件事。接下来,您应该得到一个NullPointerException
,因为sg
是`nullMethod名称不应该以大写字符开头。学习并遵循Java命名约定。自定义绘制是通过重写JPanel的paintComponent(…)
完成的,不要忘记调用super.paintComponent(…)。应该使用传递给paintComponent()方法的图形对象来完成绘制。非常感谢,非常感谢。我打赌这对你来说是小菜一碟,但在这里是一场艰苦的斗争。干杯我怎样才能在一个新的框架中画出不同的东西。我可以创建新的帧,但不是绘制曲线,我需要写每个点的计数(1、2、3..)