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我尝试使用 AffineTransform 以及 Scalr.resize 调整缓冲图像的大小

这是我的代码。

使用 Scalar.resize：

    BufferedImage buff = robot.createScreenCapture(new Rectangle(bufx,bufy,bufwidth,bufheight)); // x-coord, y-coord, width, height

    BufferedImage scrCapt = Scalr.resize(buff, Method.BALANCED, scrwidth, scrheight);

使用仿射变换：

BufferedImage buff = robot.createScreenCapture(new Rectangle(bufx,bufy,bufwidth,bufheight)); // x-coord, y-coord, width, height

BufferedImage scrCapt = new BufferedImage(bufwidth,bufheight,BufferedImage.TYPE_INT_ARGB);
AffineTransform atscr = new AffineTransform();


atscr.scale(aspectRatioWidth,aspectRatioHeight);
AffineTransformOp scaleOp = new AffineTransformOp(atscr, AffineTransformOp.TYPE_BILINEAR);
scrCapt = scaleOp.filter(buff, scrCapt);

变量已在类的开头声明：

static int bufx = 0;
static int bufy = 0;
static int bufwidth = 1;
static int bufheight = 1;
static int scrwidth = 0;
static int scrheight = 0;
static float aspectRatioWidth = 0;
static float aspectRatioHeight = 0;

我在不同的方法中动态获取所有变量的值：

aspectRatioWidth = bufwidth/scrwidth;
aspectRatioHeight = bufheight/scrheight;

但是，当我运行此代码时，我在函数 AffineTransform 和 Scalar.resize 中都出现错误：

标量调整大小：

Exception in thread "Thread-2" java.lang.IllegalArgumentException: Width (0) and height (0) cannot be <= 0
at java.awt.image.DirectColorModel.createCompatibleWritableRaster(DirectColorModel.java:1016)
at java.awt.image.BufferedImage.<init>(BufferedImage.java:331)
at org.imgscalr.Scalr.createOptimalImage(Scalr.java:2006)
at org.imgscalr.Scalr.scaleImage(Scalr.java:2133)
at org.imgscalr.Scalr.resize(Scalr.java:1667)
at org.imgscalr.Scalr.resize(Scalr.java:1415)

仿射变换：

Exception in thread "Thread-2" java.awt.image.ImagingOpException: Unable to invert transform AffineTransform[[0.0, 0.0, 0.0], [0.0, 1.0, 0.0]]
at java.awt.image.AffineTransformOp.validateTransform(AffineTransformOp.java:558)
at java.awt.image.AffineTransformOp.<init>(AffineTransformOp.java:151)

我该怎么做？我知道发生这种情况是因为我正在以不同的方法更改变量并以另一种方法访问它们。但这两种方法不能结合使用。有什么办法可以使这项工作？

编辑：

我改变了调整大小的方法这就是我现在所做的

public static BufferedImage resizeImage(BufferedImage image, double scalewidth, double scaleheight){

    BufferedImage img = new BufferedImage(image.getWidth(), image.getHeight(),BufferedImage.SCALE_FAST);
    Graphics2D g = img.createGraphics();
    g.scale(scalewidth, scaleheight);
    g.drawImage(image, null, 0, 0);
    g.dispose();
    return image;
}

编辑（2）：

为了更清楚地了解到底发生了什么：

这是一个返回 scrwidth 和 scrheight 的方法

public static void showOnScreen( int screen, JFrame framenew )
   {
    GraphicsEnvironment ge = GraphicsEnvironment
      .getLocalGraphicsEnvironment();
    GraphicsDevice[] gs = ge.getScreenDevices();

  for (int i = 0; i < gs.length; i++) {
      screenwidth.add(gs[i].getDisplayMode().getWidth());
      screenheight.add(gs[i].getDisplayMode().getHeight());
}

scrwidth = screenwidth.get(screenwidth.size()-1);
scrheight = screenheight.get(screenheight.size()-1);




  System.out.print(ge);
  System.out.print(gs);
  if( screen > -1 && screen < gs.length )
  {gs[screen].setFullScreenWindow( framenew );}
  else if( gs.length > 0 )
  {gs[0].setFullScreenWindow( framenew );}
  else
  {throw new RuntimeException( "No Screens Found" );}}

这是返回 bufwidth 和 bufheight 的 actionlistener：

  btnNewButton.addActionListener(new ActionListener() {      
  public void actionPerformed(ActionEvent e)
  {
      //Execute when button is pressed
      System.out.println("You clicked the button");

      int ind = c.getSelectedIndex();
        bufx = capx.get(ind);
        bufy = capy.get(ind);
        bufwidth = capwidth.get(ind);
        bufheight = capheight.get(ind);
        frame.setVisible(false);
        framenew.setVisible(true);
        showOnScreen(1,framenew);

        aspectRatioWidth = (double) bufwidth/scrwidth;
        aspectRatioHeight = (double) bufheight/scrheight;   

            System.out.print("aspectRatioWidth:  ");
            System.out.println(aspectRatioWidth);

            System.out.print("aspectRatioHeight:  ");
            System.out.println(aspectRatioHeight);          
  }
  });

并且在运行中使用 aspectRatios：

public void run() {
System.out.print("aspectRatioWidth:  ");
System.out.println(aspectRatioWidth);

System.out.print("aspectRatioHeight:  ");
System.out.println(aspectRatioHeight);

while(true){
    BufferedImage buff = robot.createScreenCapture(new Rectangle(bufx,bufy,bufwidth,bufheight)); // x-coord, y-coord, width, height

    BufferedImage resizedbuff = resizeImage(buff, aspectRatioWidth, aspectRatioHeight);}
4

1 回答 1

5

您正在执行 int 除法，它始终返回一个 int，此处为 0，因为您的屏幕尺寸可能会大于您的图像尺寸：

aspectRatioWidth = bufwidth/scrwidth;
aspectRatioHeight = bufheight/scrheight;

解决方案：将数字转换为双精度，然后进行双除法。

aspectRatioWidth = (double) bufwidth/scrwidth;
aspectRatioHeight = (double) bufheight/scrheight;

编辑

不确定您最终想要做什么——在您的 GUI 中发布计算机屏幕的图像？如果是这样，也许像...

import java.awt.AWTException;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.Toolkit;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.geom.AffineTransform;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;
import java.util.List;

import javax.swing.*;

public class ChangeVars extends JPanel {
   private static final int PREF_W = 400;
   private static final int PREF_H = PREF_W;
   private static final int DELAY = 20;
   public BufferedImage displayImage;
   private MyWorker myWorker;

   public ChangeVars() {
      try {
         myWorker = new MyWorker(DELAY);
         myWorker.execute();
      } catch (AWTException e) {
         e.printStackTrace();
      }
   }

   @Override
   // to initialize the panel to something
   public Dimension getPreferredSize() {
      if (isPreferredSizeSet()) {
         return super.getPreferredSize();
      }
      return new Dimension(PREF_W, PREF_H);
   }

   @Override
   protected void paintComponent(Graphics g) {
      super.paintComponent(g);
      if (displayImage != null) {
         g.drawImage(displayImage, 0, 0, null);
      }
   }

   public void stopWorker() {
      if (myWorker != null && !myWorker.isDone()) {
         myWorker.setRunning(false);
         myWorker.cancel(true);
      }
   }

   private class MyWorker extends SwingWorker<Void, BufferedImage> {

      private volatile boolean running = true;
      private Robot robot;
      private int delay;

      public MyWorker(int delay) throws AWTException {
         this.delay = delay;
         robot = new Robot();
      }

      @Override
      protected Void doInBackground() throws Exception {
         while (running) {
            Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
            Rectangle screenRect = new Rectangle(0, 0, d.width, d.height);
            BufferedImage img = robot.createScreenCapture(screenRect);
            publish(img);
            Thread.sleep(delay);
         }
         return null;
      }

      @Override
      protected void process(List<BufferedImage> chunks) {
         for (BufferedImage image : chunks) {
            Dimension sz = getSize();
            double scaleX = (double) sz.width / image.getWidth();
            double scaleY = (double) sz.height / image.getHeight();
            AffineTransform transform = AffineTransform.getScaleInstance(
                  scaleX, scaleY);
            AffineTransformOp transformOp = new AffineTransformOp(transform,
                  AffineTransformOp.TYPE_BILINEAR);
            displayImage = new BufferedImage(sz.width, sz.height,
                  BufferedImage.TYPE_INT_ARGB);
            displayImage = transformOp.filter(image, displayImage);
            repaint();
         }
      }

      public void setRunning(boolean running) {
         this.running = running;
      }

      public boolean getRunning() {
         return running;
      }

   }

   private static void createAndShowGui() {
      final ChangeVars changeVars = new ChangeVars();

      JFrame frame = new JFrame("ChangeVars");
      frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
      frame.addWindowListener(new WindowAdapter() {

         @Override
         public void windowClosing(WindowEvent e) {
            if (changeVars != null) {
               changeVars.stopWorker();
            }
            System.exit(0);
         }

      });
      frame.getContentPane().add(changeVars);
      frame.pack();
      frame.setLocationByPlatform(true);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}

虽然更简单的是让paintComponent进行缩放：

@Override
protected void paintComponent(Graphics g) {
  super.paintComponent(g);
  if (displayImage != null) {
     int width = getWidth();
     int height = getHeight();
     g.drawImage(displayImage, 0, 0, width, height, null);
  }
}

// ....

  @Override
  protected void process(List<BufferedImage> chunks) {
     for (BufferedImage image : chunks) {
        displayImage = image;
        repaint();
     }
  }
于 2015-05-30T13:48:36.747 回答