在Java中旋轉BufferedImage無需更改大小

Question

我想在不改變大小的情況下在Java中旋轉BufferedImage。 寬度= 232 HEIGHT = 174

寬度= 232 HEIGHT =我使用該代碼，但我的圖像174

不`噸旋轉：

AffineTransform at = new AffineTransform(); 
at.translate(four2.getWidth()/2, four2.getHeight()/2); 
at.rotate(Math.PI/2); 
at.scale(0.5, 0.5); 
at.translate(-four2.getWidth()/2, -four2.getHeight()/2); 
Graphics2D g2d = (Graphics2D) four2.getGraphics(); 
g2d.drawImage(four2, at, null); 
g2d.dispose(); 

Answer 1

旋轉非正方形的圖像在相同的邊界內將會裁剪圖像。

你可以改變Graphics剪裁界限，但這是危險的，因爲你實際上可以提供給Graphics背景下，這會導致一些非常奇怪的，一般不歡迎結果可視範圍之外的結束畫。

一個簡單的解決方案可能是隻從原始一個新的形象和它自己的範圍內旋轉，例如...

import java.awt.Dimension; 
import java.awt.EventQueue; 
import java.awt.Graphics; 
import java.awt.Graphics2D; 
import java.awt.geom.AffineTransform; 
import java.awt.image.BufferedImage; 
import java.io.File; 
import java.io.IOException; 
import javax.imageio.ImageIO; 
import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.UIManager; 
import javax.swing.UnsupportedLookAndFeelException; 

public class Test { 

    public static void main(String[] args) { 
     new Test(); 
    } 

    public Test() { 
     EventQueue.invokeLater(new Runnable() { 
      @Override 
      public void run() { 
       try { 
        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); 
       } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) { 
        ex.printStackTrace(); 
       } 

       try { 
        JFrame frame = new JFrame("Testing"); 
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
        frame.add(new TestPane()); 
        frame.pack(); 
        frame.setLocationRelativeTo(null); 
        frame.setVisible(true); 
       } catch (IOException iOException) { 
        iOException.printStackTrace(); 
       } 
      } 
     }); 
    } 

    public class TestPane extends JPanel { 

     private BufferedImage master; 
     private BufferedImage rotated; 

     public TestPane() throws IOException { 
      master = ImageIO.read(new File("/Volumes/Disk02/Dropbox/MegaTokyo/issue142.jpg")); 
      rotated = new BufferedImage(master.getWidth(), master.getHeight(), BufferedImage.TYPE_INT_ARGB); 
      Graphics2D g2d = rotated.createGraphics(); 
      AffineTransform at = new AffineTransform(); 
      at.rotate(Math.PI/2, master.getWidth()/2, master.getHeight()/2); 
      g2d.setTransform(at); 
      g2d.drawImage(master, 0, 0, this); 
      g2d.dispose(); 
     } 

     @Override 
     public Dimension getPreferredSize() { 
      return new Dimension(master.getWidth() * 2, master.getHeight()); 
     } 

     @Override 
     protected void paintComponent(Graphics g) { 
      super.paintComponent(g); 
      Graphics2D g2d = (Graphics2D) g.create(); 
      int x = (getWidth() - (master.getWidth() * 2))/2; 
      int y = (getHeight() - master.getHeight())/2; 
      g2d.drawImage(master, x, y, this); 
      g2d.drawImage(rotated, x + master.getWidth(), y, this); 
      g2d.dispose(); 
     } 

    } 

}