在Java中旋转多边形 [英] Rotating a polygon in Java
本文介绍了在Java中旋转多边形的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在编写的程序在屏幕上绘制多个星星，并为它们提供随机指示和速度。星星会从面板的边缘反弹并留在里面。我需要让星星在移动时旋转。我尝试了很多东西，我无法弄明白。下面是我用来绘制星星并移动它们的代码。
其他信息：
- 星星在一个名为星星的集合中
- 我写了两个类，Star和MyJPanel
设置点数:(星级）
for（double current = 0; current< nPoints; current + = 1）
{
i =（int）current;
int [] X = new int [nPoints * 2];
int [] Y = new int [nPoints * 2];
cosX = - （Math.cos（当前*（（2 * Math.PI）/（nPoints）））* radius [i％2]）;
sinY = - （Math.sin（当前*（（2 * Math.PI）/（nPoints）））* radius [i％2]）;
X [i] =（int）cosX + x;
Y [i] =（int）sinY + y;
addPoint（X [i]，Y [i]）;
}
移动方法:(星级）
public void move（int width，int height）
{
if（location.x< = radius [0] || location .x> = width - radius [0]）
{
xIncr = -xIncr;
}
if（location.y< = radius [0] || location.y> = height - radius [0]）
{
yIncr = -yIncr;
}
translate（xIncr，yIncr）;
location.setLocation（location.x + xIncr，location.y + yIncr）;
xInc = xIncr;
}
绘制星星:(在MyJPanel类中）
public void paintComponent（Graphics g）
{
super.paintComponent（g）;
for（int i = 0; i< stars.size（）; i ++）
{
g2d =（Graphics2D）g;
g2d.setComposite（AlphaComposite.getInstance（AlphaComposite.SRC_OVER，stars.get（i）.getAlpha（）））;
g2d.setColor（stars.get（i）.getColor（））;
g2d.fillPolygon（stars.get（i））;
if（stars.get（i）.alpha == 0）
{
stars.remove（stars.indexOf（stars.get（i）））;
}
}
}
如果有更多的代码或信息需要请告诉我，谢谢！
解决方案
我想看看
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.AffineTransform;
import java.awt.geom.Path2D;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class RotateShape {
public static void main（String [] args）{
new RotateShape（）;
}
public RotateShape（）{
EventQueue.invokeLater（new Runnable（）{
@Override
public void run（）{
try {
UIManager.setLookAndFeel（UIManager.getSystemLookAndFeelClassName（））;
} catch（ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex）{
ex.printStackTrace（）;
}
JFrame frame = new JFrame（Testing）;
frame.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）;
frame.add（new TestPane（））;
frame.pack（）;
frame.setLocationRelativeTo（null）;
frame.setVisible（true）;
}
}）;
}
公共类TestPane扩展JPanel {
私有星级星;
private double rotationDelta = 5d;
private int xDelta = 0;
private int yDelta = 0;
public TestPane（）{
star = new Star（50,50）;
star.moveLocatioBy（75,75）;
随机rnd = new Random（）;
xDelta = rnd.nextInt（4）+ 1;
yDelta = rnd.nextInt（4）+ 1;
计时器计时器=新计时器（40，新ActionListener（）{
@Override
public void actionPerformed（ActionEvent e）{
star.moveLocatioBy（xDelta，yDelta） ）;
Rectangle bounds = star.getBounds（）;
int x = star.getX（）;
int y = star.getY（）;
boolean bounced = false;
if（x< 0）{
x = 0;
xDelta * = -1;
bounced = true;
} else if（x + bounds.width> getWidth（））{
x = getWidth（） - bounds.width;
xDelta * = -1;
bounced = true;
}
if（y <0）{
y = 0;
yDelta * = -1;
bounced = true;
}否则if（y + bounds.height> getHeight（））{
y = getHeight（） - bounds.height;
yDelta * = -1;
bounced = true;
}
if（bounced）{
rotationDelta * = -1;
}
star.rotateByDegrees（rotationDelta）;
star.setLocation（x，y）;
repaint（）;
}
}）;
timer.start（）;
}
@Override
public Dimension getPreferredSize（）{
return new Dimension（200,200）;
}
@Override
protected void paintComponent（Graphics g）{
super.paintComponent（g）;
Graphics2D g2d =（Graphics2D）g.create（）;
g2d.setRenderingHint（RenderingHints.KEY_ALPHA_INTERPOLATION，RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY）;
g2d.setRenderingHint（RenderingHints.KEY_ANTIALIASING，RenderingHints.VALUE_ANTIALIAS_ON）;
g2d.setRenderingHint（RenderingHints.KEY_COLOR_RENDERING，RenderingHints.VALUE_COLOR_RENDER_QUALITY）;
g2d.setRenderingHint（RenderingHints.KEY_DITHERING，RenderingHints.VALUE_DITHER_ENABLE）;
g2d.setRenderingHint（RenderingHints.KEY_FRACTIONALMETRICS，RenderingHints.VALUE_FRACTIONALMETRICS_ON）;
g2d.setRenderingHint（RenderingHints.KEY_INTERPOLATION，RenderingHints.VALUE_INTERPOLATION_BILINEAR）;
g2d.setRenderingHint（RenderingHints.KEY_RENDERING，RenderingHints.VALUE_RENDER_QUALITY）;
g2d.setRenderingHint（RenderingHints.KEY_STROKE_CONTROL，RenderingHints.VALUE_STROKE_PURE）;
Shape shape = star.getTransformedInstance（）;
g2d.setColor（Color.BLUE）;
g2d.fill（形状）;
g2d.setColor（Color.RED）;
g2d.draw（形状）;
g2d.dispose（）;
}
}
公共类Star扩展Path2D.Double {
private double angle = 0;
private int x = 0，y = 0;
public Star（int width，int height）{
double heightPart = height / 3d;
double widthPart = width / 3d;
moveTo（width / 2,0）;
lineTo（widthPart * 2，heightPart）;
lineTo（width，heightPart）;
lineTo（widthPart * 2，height / 2）;
lineTo（宽度，高度）;
lineTo（width / 2，heightPart * 2）;
lineTo（0，height）;
lineTo（widthPart，height / 2）;
lineTo（0，heightPart）;
lineTo（widthPart，heightPart）;
closePath（）;
}
public double getAngle（）{
return angle;
}
public int getX（）{
return x;
}
public int getY（）{
return y;
}
public void moveLocatioBy（int xDelta，int yDelta）{
this.x + = xDelta;
this.y + = yDelta;
}
public void rotateByDegrees（double delta）{
angle + = delta;
}
public void setLocation（int x，int y）{
this.x = x;
this.y = y;
}
public Shape getTransformedInstance（）{
AffineTransform at = new AffineTransform（）;
Rectangle bounds = getBounds（）;
at.rotate（Math.toRadians（angle），x +（bounds.width / 2），y +（bounds.height / 2））;
at.translate（x，y）;
返回createTransformedShape（at）;
}
}
}
<扩展这个想法并不需要太多，以便每个开始都有自己的delta值和简单的 update 方法（它传递的宽度/高度容器），所以你可以赚很多明星
The program I am writing draws multiple stars on the screen and gives them random directions and speeds. The stars will bounce off the edges of the panel and stay inside. I need to have the stars rotating as they are moving. I have tried so many things and I cannot figure it out. Below is the code I use to draw the stars and move them.
Additional Information:
-the stars are in a collection called "stars"
-there are two classes that I wrote, "Star" and "MyJPanel"
Set the points: (in Star class)
for (double current = 0; current < nPoints; current += 1)
{
i = (int)current;
int[] X = new int[nPoints * 2];
int[] Y = new int[nPoints * 2];
cosX = -(Math.cos(current*((2*Math.PI)/(nPoints)))*radius[i % 2]);
sinY = -(Math.sin(current*((2*Math.PI)/(nPoints)))*radius[i % 2]);
X[i] = (int) cosX+x;
Y[i] = (int) sinY+y;
addPoint(X[i], Y[i]);
}
Move method: (in Star class)
public void move(int width, int height)
{
if (location.x <= radius[0] || location.x >= width - radius[0])
{
xIncr = -xIncr;
}
if (location.y <= radius[0] || location.y >= height - radius[0])
{
yIncr = -yIncr;
}
translate(xIncr, yIncr);
location.setLocation(location.x + xIncr, location.y + yIncr);
xInc = xIncr;
}
Paint the stars: (in MyJPanel class)
public void paintComponent(Graphics g)
{
super.paintComponent(g);
for(int i = 0; i < stars.size(); i++)
{
g2d = (Graphics2D) g;
g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, stars.get(i).getAlpha()));
g2d.setColor(stars.get(i).getColor());
g2d.fillPolygon(stars.get(i));
if(stars.get(i).alpha == 0)
{
stars.remove(stars.indexOf(stars.get(i)));
}
}
}
If any more code or information is needed please let me know, thank you!
解决方案
I would have a look at Working with Geometry and Transforming Shapes, Text, and Images
Basically, I've created a custom Path2D shape which represents my start. This class carries some additional information with, included it's x/y offset and rotation. It then provides a helper method to create a transformed instance of this shape based on these properties, for example...
public Shape getTransformedInstance() {
AffineTransform at = new AffineTransform();
Rectangle bounds = getBounds();
at.rotate(Math.toRadians(angle), x + (bounds.width / 2), y + (bounds.height / 2));
at.translate(x, y);
return createTransformedShape(at);
}
Basically, this is where the magic happens.
There is a simple Swing Timer which applies a delta to the position and rotation.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.AffineTransform;
import java.awt.geom.Path2D;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class RotateShape {
public static void main(String[] args) {
new RotateShape();
}
public RotateShape() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private Star star;
private double rotationDelta = 5d;
private int xDelta = 0;
private int yDelta = 0;
public TestPane() {
star = new Star(50, 50);
star.moveLocatioBy(75, 75);
Random rnd = new Random();
xDelta = rnd.nextInt(4) + 1;
yDelta = rnd.nextInt(4) + 1;
Timer timer = new Timer(40, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
star.moveLocatioBy(xDelta, yDelta);
Rectangle bounds = star.getBounds();
int x = star.getX();
int y = star.getY();
boolean bounced = false;
if (x < 0) {
x = 0;
xDelta *= -1;
bounced = true;
} else if (x + bounds.width > getWidth()) {
x = getWidth() - bounds.width;
xDelta *= -1;
bounced = true;
}
if (y < 0) {
y = 0;
yDelta *= -1;
bounced = true;
} else if (y + bounds.height > getHeight()) {
y = getHeight() - bounds.height;
yDelta *= -1;
bounced = true;
}
if (bounced) {
rotationDelta *= -1;
}
star.rotateByDegrees(rotationDelta);
star.setLocation(x, y);
repaint();
}
});
timer.start();
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
g2d.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);
Shape shape = star.getTransformedInstance();
g2d.setColor(Color.BLUE);
g2d.fill(shape);
g2d.setColor(Color.RED);
g2d.draw(shape);
g2d.dispose();
}
}
public class Star extends Path2D.Double {
private double angle = 0;
private int x = 0, y = 0;
public Star(int width, int height) {
double heightPart = height / 3d;
double widthPart = width / 3d;
moveTo(width / 2, 0);
lineTo(widthPart * 2, heightPart);
lineTo(width, heightPart);
lineTo(widthPart * 2, height / 2);
lineTo(width, height);
lineTo(width / 2, heightPart * 2);
lineTo(0, height);
lineTo(widthPart, height / 2);
lineTo(0, heightPart);
lineTo(widthPart, heightPart);
closePath();
}
public double getAngle() {
return angle;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public void moveLocatioBy(int xDelta, int yDelta) {
this.x += xDelta;
this.y += yDelta;
}
public void rotateByDegrees(double delta) {
angle += delta;
}
public void setLocation(int x, int y) {
this.x = x;
this.y = y;
}
public Shape getTransformedInstance() {
AffineTransform at = new AffineTransform();
Rectangle bounds = getBounds();
at.rotate(Math.toRadians(angle), x + (bounds.width / 2), y + (bounds.height / 2));
at.translate(x, y);
return createTransformedShape(at);
}
}
}
It wouldn't take a lot to expand this idea so that each start had it's own delta values and simple update method (which passed in the width/height of the Container), so you could make lots-o-stars
这篇关于在Java中旋转多边形的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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