Java程序实现图像正逆90度的旋转
代码来源：
http://www.itivy.com/java/archive/2012/3/9/634668887297849382.html
1.[代码][Java]代码
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class RotateImage {
public static void main(String[] args){
JFrame frame=new RotateImgFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
class RotateImgFrame extends JFrame{
public RotateImgFrame(){
setTitle("RotateImgTest");
setSize(WIDTH,HEIGHT);
setAlwaysOnTop(true);
final ImgPanel imgPanel=new ImgPanel();
imgPanel.setBounds(0, 0, 400, 400);
Container con=getContentPane();
con.add(imgPanel);
antiRotateBtn=new JButton("逆转");
rotateBtn=new JButton("正转");
btnPanel=new JPanel();
btnPanel.add(rotateBtn);
btnPanel.add(antiRotateBtn);
con.add(btnPanel,BorderLayout.SOUTH);
antiRotateBtn.addActionListener(new ActionListener(){
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
imgPanel.setRotate(imgPanel.getRotate()-Math.PI/2);
imgPanel.repaint();
}
});
rotateBtn.addActionListener(new ActionListener(){
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
imgPanel.setRotate(imgPanel.getRotate()+Math.PI/2);
imgPanel.repaint();
}
});
}
public static final int WIDTH=400;
public static final int HEIGHT=450;
private JPanel btnPanel;
private JButton antiRotateBtn;
private JButton rotateBtn;
}
class ImgPanel extends JPanel{
public void paintComponent(Graphics g){
Graphics2D g2=(Graphics2D) g;
g.fillRect(0, 0, 400, 400);
g2.rotate(rotate, 200, 200);
image=new ImageIcon("src/test.jpg").getImage();
int imgW=image.getWidth(this);
int imgH=image.getHeight(this);
g2.drawImage(image, (400-imgW)/2, (400-imgH)/2,this);
g2.dispose();
}
public Image getImage(){
return image;
}
public double getRotate(){
return rotate;
}
public void setRotate(double rotate){
this.rotate=rotate;
}
private Image image;
private double rotate=0;
}

[java]代码库import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class RotateImage {
public static void main(String[] args){
JFrame frame=new RotateImgFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
class RotateImgFrame extends JFrame{
public RotateImgFrame(){
setTitle("RotateImgTest");
setSize(WIDTH,HEIGHT);
setAlwaysOnTop(true);
final ImgPanel imgPanel=new ImgPanel();
imgPanel.setBounds(0, 0, 400, 400);
Container con=getContentPane();
con.add(imgPanel);
antiRotateBtn=new JButton("逆转");
rotateBtn=new JButton("正转");
btnPanel=new JPanel();
btnPanel.add(rotateBtn);
btnPanel.add(antiRotateBtn);
con.add(btnPanel,BorderLayout.SOUTH);
antiRotateBtn.addActionListener(new ActionListener(){
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
imgPanel.setRotate(imgPanel.getRotate()-Math.PI/2);
imgPanel.repaint();
}
});
rotateBtn.addActionListener(new ActionListener(){
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
imgPanel.setRotate(imgPanel.getRotate()+Math.PI/2);
imgPanel.repaint();
}
});
}
public static final int WIDTH=400;
public static final int HEIGHT=450;
private JPanel btnPanel;
private JButton antiRotateBtn;
private JButton rotateBtn;
}
class ImgPanel extends JPanel{
public void paintComponent(Graphics g){
Graphics2D g2=(Graphics2D) g;
g.fillRect(0, 0, 400, 400);
g2.rotate(rotate, 200, 200);
image=new ImageIcon("src/test.jpg").getImage();
int imgW=image.getWidth(this);
int imgH=image.getHeight(this);
g2.drawImage(image, (400-imgW)/2, (400-imgH)/2,this);
g2.dispose();
}
public Image getImage(){
return image;
}
public double getRotate(){
return rotate;
}
public void setRotate(double rotate){
this.rotate=rotate;
}
private Image image;
private double rotate=0;
}
//源代码片段来自云代码http://yuncode.net

旋转图像是非三角的,即使是90度也需要一定的工作量。
所以,基于几乎所有关于旋转图像的问题,我会从…
public BufferedImage rotate(BufferedImage image, Double degrees) {
// Calculate the new size of the image based on the angle of rotaion
double radians = Math.toRadians(degrees);
double sin = Math.abs(Math.sin(radians));
double cos = Math.abs(Math.cos(radians));
int newWidth = (int) Math.round(image.getWidth() * cos + image.getHeight() * sin);
int newHeight = (int) Math.round(image.getWidth() * sin + image.getHeight() * cos);
// Create a new image
BufferedImage rotate = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = rotate.createGraphics();
// Calculate the "anchor" point around which the image will be rotated
int x = (newWidth - image.getWidth()) / 2;
int y = (newHeight - image.getHeight()) / 2;
// Transform the origin point around the anchor point
AffineTransform at = new AffineTransform();
at.setToRotation(radians, x + (image.getWidth() / 2), y + (image.getHeight() / 2));
at.translate(x, y);
g2d.setTransform(at);
// Paint the originl image
g2d.drawImage(image, 0, 0, null);
g2d.dispose();
return rotate;
}
当您只旋转90度时,这将计算新图像所需的大小,以便能够以任何角度绘制旋转的图像。
然后它只是利用
AffineTransform
要操纵绘画发生的原点-使用这个,你会做很多。
然后,我加载图像,旋转它们并显示它们…
try {
BufferedImage original = ImageIO.read(getClass().getResource("domino.jpg"));
BufferedImage rotated90 = rotate(original, 90.0d);
BufferedImage rotatedMinus90 = rotate(original, -90.0d);
JPanel panel = new JPanel();
panel.add(new JLabel(new ImageIcon(original)));
panel.add(new JLabel(new ImageIcon(rotated90)));
panel.add(new JLabel(new ImageIcon(rotatedMinus90)));
JOptionPane.showMessageDialog(null, panel, null, JOptionPane.PLAIN_MESSAGE, null);
} catch (IOException ex) {
ex.printStackTrace();
}
我更喜欢用
ImageIO
加载图像,因为它抛出
IOException
当事情出错时,宁愿默默地失败
ImageIcon
.
您还应该将资源嵌入到应用程序的上下文中,这使得在运行时加载它们更加容易。取决于IDE和项目的设置方式,您的设置方式将发生变化,但在“大多数”情况下,您应该能够将资源直接添加到源目录(最好是子目录中),并且IDE将使您可以使用它并在导出项目时对其进行打包

下面的代码绘制了一些简单的x-y数据,但它有两个我不知道如何解决的问题.
首先,它绘制了一些数据点的负值,这意味着在x轴下方向南延伸的线.由于数据点是随机选择的,因此您可能需要稍微调整帧的大小,以便以显示此错误的方式查看要绘制的新随机数.所有数据值都是正数,因此我希望所有偏转都向北投射到蓝色底部标记线上方,并且我需要确保没有偏转在蓝色底部标记线下方向南延伸.
其次,y轴标签在屏幕上占用太多空间.它需要旋转-90度.但是,我看到的所有示例都涉及使用graphics2d对象旋转整个面板.我不想旋转整个面板.相反,我只想旋转y轴标签的文本.
任何人都可以告诉我如何更改下面的代码来解决这两个具体的问题？
代码在以下两个文件中：
GUI.java
import java.awt.*;
import javax.swing.*;
class GUI{
GUI() {
// Create a new JFrame container.
JFrame jfrm = new JFrame("X-Y Plot");
// Specify FlowLayout for the layout manager.
jfrm.getContentPane().setLayout(new FlowLayout());
int frameHeight = 400;
int frameWidth = 300;
// Give the frame an initial size.
jfrm.setSize(frameWidth, frameHeight);
// Terminate the program when the user closes the application.
jfrm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Create a text-based label.
JVertLabel myVLabel = new JVertLabel("y-axis label");
int width = myVLabel.WIDTH;
PaintPanel myPP = new PaintPanel(frameWidth-width-50-20,frameHeight-70);
jfrm.add(myPP);
jfrm.add(myVLabel);// Add the label to the frame.
// Display the frame.
jfrm.setVisible(true);
}
public static void main(String args[]) {
// Create the frame on the event dispatching thread.
SwingUtilities.invokeLater(new Runnable() {public void run(){new GUI();}});
}
public class JVertLabel extends JComponent {
private String text;
public JVertLabel(String s) {
text = s;
}//constructor
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.rotate(Math.toRadians(-90));
g2d.drawString(text, 0, 0);
}
}
}
PaintPanel.java
import java.awt.*;
import javax.swing.*;
import java.util.*;
class PaintPanel extends JPanel {
Insets ins; // holds the panel's insets
Random rand; // used to generate random numbers
PaintPanel(int w, int h) {
setOpaque(true);// Ensure that panel is opaque.
setPreferredSize(new Dimension(w, h));// Set preferred dimension as specfied.
rand = new Random();
}
protected void paintComponent(Graphics g) {// Override paintComponent() method.
super.paintComponent(g);// Always call superclass method first.
int height = getHeight();// Get height of component.
int width = getWidth();// Get width of component.
ins = getInsets();// Get the insets.
// Get dimensions of text
Graphics2D g2d = (Graphics2D) g;
Font font = new Font("Serif", Font.PLAIN, 12);
FontMetrics fontMetrics = g2d.getFontMetrics();
String xString = ("x-axis label");
int xStrWidth = fontMetrics.stringWidth(xString);
int xStrHeight = fontMetrics.getHeight();
String yString = "y-axis-label";
int yStrWidth = fontMetrics.stringWidth(yString);
int yStrHeight = fontMetrics.getHeight();
int leftStartPlotWindow = ins.left + 5 + yStrWidth;
int hPad = 3;
// Fill panel by plotting random data in a bar graph.
for (int i = leftStartPlotWindow + hPad; i <= width - leftStartPlotWindow - hPad + yStrWidth + 1; i += 4) {
int h = Math.abs(rand.nextInt(height - ins.bottom));//Get rand# betw/0 and max height of drawing area.
// If generated value w/in or too close to border, change it to just outside border.
if (h <= ins.top) {
h = ins.top + 1;
}
g.drawLine(i, Math.abs(height - ins.bottom - xStrHeight - 5), i, h);// Draw a line that represents data.
}
g.setColor(Color.blue);
g.drawRect(leftStartPlotWindow, ins.bottom + 2, width - leftStartPlotWindow - ins.right - hPad, height - xStrHeight - 6);
g.setColor(Color.red);
g.drawRect(ins.left, ins.bottom, width - ins.left - 1, height - ins.bottom - 1);
g.drawString(xString, (width / 2) - (xStrWidth / 2), height - ins.bottom - 6);
g.drawString(yString, ins.left, height / 2);
}
}