Java 在圆内随机画点
我想在给定的圆内随机画50个点。问题是圆点不包含在圆中。以下是一个可运行的示例:Java 在圆内随机画点,java,swing,awt,graphics2d,Java,Swing,Awt,Graphics2d,我想在给定的圆内随机画50个点。问题是圆点不包含在圆中。以下是一个可运行的示例: package mygraphicsshapehomework; import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import javax.swing.JFrame; public class MyGraphicsShapeHomeWork extends JFrame { public st
package mygraphicsshapehomework;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
public class MyGraphicsShapeHomeWork extends JFrame {
public static void main(String[] args) {
new MyGraphicsShapeHomeWork();
}
public MyGraphicsShapeHomeWork() {
super("Title");
setBounds(600, 400, 700, 400);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
}
@Override
public void paint(Graphics g) {
super.paint(g);
Graphics2D g2 = (Graphics2D) g;
g2.drawOval(40, 40, 90, 90);
Color newColor = new Color(255, 0, 0);
g2.setColor(newColor);
for (int i = 0; i < 50; i++) {
int x = (int) Math.ceil(Math.random() * 10);
int y = (int) Math.ceil(Math.random() * 10);
g2.fillOval(i+x, i+y, 3, 3); // ???
}
}
}
包装mygraphicsshapehomework;
导入java.awt.Color;
导入java.awt.Graphics;
导入java.awt.Graphics2D;
导入javax.swing.JFrame;
公共类MyGraphicsShapeHomeWork扩展了JFrame{
公共静态void main(字符串[]args){
新MyGraphicsShapeHomeWork();
}
公共MyGraphicsShapeHomeWork(){
超级(“标题”);
立根(600400700400);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(真);
}
@凌驾
公共空间涂料(图g){
超级油漆(g);
图形2d g2=(图形2d)g;
g2.drawOval(40,40,90,90);
颜色newColor=新颜色(255,0,0);
g2.设置颜色(新颜色);
对于(int i=0;i<50;i++){
intx=(int)Math.ceil(Math.random()*10);
int y=(int)Math.ceil(Math.random()*10);
g2.椭圆形(i+x,i+y,3,3);/???
}
}
}
以下是它产生的结果:
如何仅在圆内绘制点?对于点的位置,在外圆边界内生成随机坐标。为了生成这些坐标,点从圆心的半径必须小于外圈的半径。使用
float a = Math.random() * Math.PI * 2;
然后,从外半径中减去一个随机值:
outerR - (Math.sqrt(Math.random()) * outerR)
并将职位分配给:
double x = Math.cos(a)*newR;
double y = Math.sin(a)*newR;
我相信有一种更为数学化的方法,但在我看来这是最简单的。对于点的位置,在外圆的边界内生成随机坐标。为了生成这些坐标,点从圆心的半径必须小于外圈的半径。使用
float a = Math.random() * Math.PI * 2;
然后,从外半径中减去一个随机值:
outerR - (Math.sqrt(Math.random()) * outerR)
并将职位分配给:
double x = Math.cos(a)*newR;
double y = Math.sin(a)*newR;
我确信有一种更为数学化的方法,但在我看来这是最简单的。要在半径为R的圆中获得一个随机点,请找到一个随机角度和一个随机半径:
double a = random() * 2 * PI;
double r = R * sqrt(random());
那么点的坐标是:
double x = r * cos(a)
double y = r * sin(a)
以下是有关绘图零件的一些注释。您不应该直接在顶级容器(如JFrame
)上绘制。相反,请使用JComponent
或JPanel
。覆盖用于绘制的paintComponent()
,而不是paint()
,并且不要忘记调用super.paintComponent(g)
有关更多信息,请参阅教程
不要使用setBounds()
,覆盖面板的getPreferredSize()
和pack()
框架。此外,很少需要扩展JFrame
下面是一个演示亚像素精度绘图的基本示例:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.Ellipse2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class TestDots extends JPanel{
public static final int POINTS_NUM = 1000;
public static final Color POINT_COLOR = Color.RED;
@Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);
double padding = 10;
double radius = Math.min(this.getWidth(), this.getHeight()) / 2 - padding * 2;
g2.draw(new Ellipse2D.Double(padding, padding, radius * 2, radius * 2));
g2.setColor(POINT_COLOR);
for (int i = 0; i < POINTS_NUM; i++) {
double a = Math.random() * 2 * Math.PI;
double r = radius * Math.sqrt(Math.random());
double x = r * Math.cos(a) + radius + padding;
double y = r * Math.sin(a) + radius + padding;
g2.draw(new Ellipse2D.Double(x, y, 1, 1));
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame("TestDots");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationByPlatform(true);
frame.add(new TestDots());
frame.pack();
frame.setVisible(true);
}
});
}
}
导入java.awt.Color;
导入java.awt.Dimension;
导入java.awt.Graphics;
导入java.awt.Graphics2D;
导入java.awt.RenderingHints;
导入java.awt.geom.Ellipse2D;
导入javax.swing.JFrame;
导入javax.swing.JPanel;
导入javax.swing.SwingUtilities;
公共类TestDots扩展了JPanel{
公共静态最终整数点_NUM=1000;
公共静态最终色点_Color=Color.RED;
@凌驾
公共维度getPreferredSize(){
返回新维度(400400);
}
@凌驾
受保护组件(图形g){
超级组件(g);
图形2d g2=(图形2d)g;
g2.setRenderingHint(renderingHits.KEY\u ANTIALIASING,renderingHits.VALUE\u ANTIALIAS\u ON);
g2.setRenderingHint(renderingHits.KEY\u STROKE\u控件,renderingHits.VALUE\u STROKE\u PURE);
双填充=10;
double radius=Math.min(this.getWidth(),this.getHeight())/2-padding*2;
g2.绘制(新的椭圆E2D.Double(填充,填充,半径*2,半径*2));
g2.设置颜色(点颜色);
对于(int i=0;i
结果如下:
要获得半径为R的圆中的随机点,请找到随机角度和随机半径:
double a = random() * 2 * PI;
double r = R * sqrt(random());
那么点的坐标是:
double x = r * cos(a)
double y = r * sin(a)
以下是有关绘图零件的一些注释。您不应该直接在顶级容器(如JFrame
)上绘制。相反,请使用JComponent
或JPanel
。覆盖用于绘制的paintComponent()
,而不是paint()
,并且不要忘记调用super.paintComponent(g)
有关更多信息,请参阅教程
不要使用setBounds()
,覆盖面板的getPreferredSize()
和pack()
框架。此外,很少需要扩展JFrame
下面是一个演示亚像素精度绘图的基本示例:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.Ellipse2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class TestDots extends JPanel{
public static final int POINTS_NUM = 1000;
public static final Color POINT_COLOR = Color.RED;
@Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);
double padding = 10;
double radius = Math.min(this.getWidth(), this.getHeight()) / 2 - padding * 2;
g2.draw(new Ellipse2D.Double(padding, padding, radius * 2, radius * 2));
g2.setColor(POINT_COLOR);
for (int i = 0; i < POINTS_NUM; i++) {
double a = Math.random() * 2 * Math.PI;
double r = radius * Math.sqrt(Math.random());
double x = r * Math.cos(a) + radius + padding;
double y = r * Math.sin(a) + radius + padding;
g2.draw(new Ellipse2D.Double(x, y, 1, 1));
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame("TestDots");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationByPlatform(true);
frame.add(new TestDots());
frame.pack();
frame.setVisible(true);
}
});
}
}
导入java.awt.Color;
导入java.awt.Dimension;
导入java.awt.Graphics;
导入java.awt.Graphics2D;
导入java.awt.RenderingHints;
导入java.awt.geom.Ellipse2D;
导入javax.swing.JFrame;
导入javax.swing.JPanel;
导入javax.swing.SwingUtilities;
公共类TestDots扩展了JPanel{