任何帮助都会受到大力赞赏！因为我在java图形方面似乎有一个心理障碍:(。
问题在于标记图像，但是由于各种原因我有一半图像丢失的问题，除非我在框架周围移动然后它又回来了。同样，如果我尝试删除BufferedImage上绘制的'标签'，我必须在Jframe周围移动才能看到结果。
最后，当JOptionPane弹出以询问标签名称时，它会在关闭时执行此操作：
发布图片 https://docs.google.com/document/d/1I5rFH23a75IHB6twTu1dPRwmRt-By1sIUvDvI6FE_OY/edit
package hci;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
/**
* Deals with the label tools
*/
public class LabelToolGUI extends JPanel implements ActionListener {
JButton newButton = new JButton("New");
JButton deleteButton = new JButton("Delete");
JButton editButton = new JButton("Edit");
JButton undoButton = new JButton("Undo");
JComboBox labelsBox = new JComboBox();
String saveIcon = "./images/icons/save.jpg";
String deleteIcon = "./images/icons/delete.jpg";
String openIcon = "./images/icons/open.jpg";
String newIcon = "./images/icons/new.jpg";
String helpIcon = "./images/icons/help.jpg";
String labelsIcon = "./images/icons/help.jpg";
String fname = "";
String fnameURL = "";
public LabelToolGUI() {
super();
newButton.addActionListener(this);
deleteButton.addActionListener(this);
editButton.addActionListener(this);
undoButton.addActionListener(this);
setLayout(new BorderLayout());
setBorder(BorderFactory.createTitledBorder("Label tools"));
add(newButton, BorderLayout.WEST);
add(deleteButton, BorderLayout.EAST);
add(editButton, BorderLayout.CENTER);
add(labelsBox, BorderLayout.NORTH);
add(undoButton, BorderLayout.SOUTH);
}
@Override
public void actionPerformed(ActionEvent e) {
Object src = e.getSource();
if(src == newButton) {
String labelName = JOptionPane.showInputDialog("Please input a value");
ImageLabeller.addNewPolygon(labelName);
labelsBox.addItem(labelName);
} else if(src == deleteButton) {
String toDelete = labelsBox.getSelectedItem().toString();
System.out.println("Deleting " + toDelete);
labelsBox.removeItem(labelsBox.getSelectedItem());
ImageLabeller.removeLabel(toDelete);
} else if(src == undoButton) {
ImageLabeller.undo();
ImageLabeller.imagePanel.repaint();
}
}
}
package hci;
import javax.swing.*;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
/**
* Main class of the program - handles display of the main window
* @author Michal
*
*/
public class ImageLabeller extends JFrame implements ActionListener {
/**
* some java stuff to get rid of warnings
*/
private static final long serialVersionUID = 1L;
/**
* main window panel
*/
JPanel appPanel = null;
/**
* toolbox - put all buttons and stuff here!
*/
JPanel toolboxPanel = null;
/**
* image panel - displays image and editing area
*/
static ImagePanel imagePanel = null;
/**
* handles New Object button action
*/
public static void addNewPolygon(String labelName) {
imagePanel.addNewPolygon(labelName);
}
public static void removeLabel(String labelName) {
LabelHandler.deleteLabel(labelName);
}
/**
* Removes last point added to the label.
*/
public static void undo() {
imagePanel.currentLabel.removeLast();
}
/*@Override
public void paint(Graphics g) {
super.paint(g);
imagePanel.paint(g); //update image panel
} */
/**
* sets up application window
* @param imageFilename image to be loaded for editing
* @throws Exception
*/
public void setupGUI(String imageFilename) throws Exception {
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent event) {
//here we exit the program (maybe we should ask if the user really wants to do it?)
//maybe we also want to store the polygons somewhere? and read them next time
System.out.println("Bye bye!");
System.exit(0);
}
});
//setup main window panel
appPanel = new JPanel();
this.setLayout(new BoxLayout(appPanel, BoxLayout.X_AXIS));
this.setContentPane(appPanel);
//Create and set up the image panel.
imagePanel = new ImagePanel(imageFilename);
imagePanel.setOpaque(true); //content panes must be opaque
appPanel.add(imagePanel);
//add toolbox to window
appPanel.add(new LabelToolGUI());
//display all the stuff
this.pack();
this.setVisible(true);
}
/**
* Runs the program
* @param argv path to an image
*/
public static void main(String argv[]) {
try {
//create a window and display the image
ImageLabeller window = new ImageLabeller();
window.setupGUI(argv[0]);
} catch (Exception e) {
System.err.println("Image: " + argv[0]);
e.printStackTrace();
}
}
@Override
public void actionPerformed(ActionEvent e) {
System.out.println("Action clicked");
imagePanel.paint(imagePanel.getGraphics());
}
}
package hci;
import javax.imageio.ImageIO;
import javax.swing.JPanel;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.util.ArrayList;
import hci.utils.*;
/**
* Handles image editing panel
* @author Michal
*
*/
public class ImagePanel extends JPanel implements MouseListener {
/**
* some java stuff to get rid of warnings
*/
private static final long serialVersionUID = 1L;
/**
* image to be tagged
*/
BufferedImage image = null;
/**
* list of current polygon's vertices
*/
Label currentLabel = null;
/**
* default constructor, sets up the window properties
*/
public ImagePanel() {
currentLabel = new Label();
this.setVisible(true);
Dimension panelSize = new Dimension(800, 600);
this.setSize(panelSize);
this.setMinimumSize(panelSize);
this.setPreferredSize(panelSize);
this.setMaximumSize(panelSize);
addMouseListener(this);
}
/**
* extended constructor - loads image to be labelled
* @param imageName - path to image
* @throws Exception if error loading the image
*/
public ImagePanel(String imageName) throws Exception{
this();
image = ImageIO.read(new File(imageName));
if (image.getWidth() > 800 || image.getHeight() > 600) {
int newWidth = image.getWidth() > 800 ? 800 : (image.getWidth() * 600)/image.getHeight();
int newHeight = image.getHeight() > 600 ? 600 : (image.getHeight() * 800)/image.getWidth();
System.out.println("SCALING TO " + newWidth + "x" + newHeight );
Image scaledImage = image.getScaledInstance(newWidth, newHeight, Image.SCALE_FAST);
image = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_RGB);
image.getGraphics().drawImage(scaledImage, 0, 0, this);
}
}
/**
* Displays the image
*/
public void ShowImage() {
Graphics g = this.getGraphics();
if (image != null) {
g.drawImage(image, 0, 0, null);
}
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
//display iamge
ShowImage();
//display all the completed polygons
for(Label l : LabelHandler.labels) {
drawLabel(l);
finishPolygon(l);
}
//display current polygon
drawLabel(currentLabel);
}
/**
* displays a polygon without last stroke
* @param l label to be displayed
*/
public void drawLabel(Label l) {
Graphics2D g = (Graphics2D)this.getGraphics();
g.setColor(Color.GREEN);
for(int i = 0; i < l.size(); i++) {
Point currentVertex = l.getPoint(i);
if (i != 0) {
Point prevVertex = l.getPoint(i - 1);
g.drawLine(prevVertex.getX(), prevVertex.getY(), currentVertex.getX(), currentVertex.getY());
}
g.fillOval(currentVertex.getX() - 5, currentVertex.getY() - 5, 10, 10);
}
}
/**
* displays last stroke of the polygon (arch between the last and first vertices)
* @param l label to be finished
*/
public void finishPolygon(Label l) {
//if there are less than 3 vertices than nothing to be completed
if (l.size() >= 3) {
Point firstVertex = l.getPoint(0);
Point lastVertex = l.getPoint(l.size() - 1);
Graphics2D g = (Graphics2D)this.getGraphics();
g.setColor(Color.GREEN);
g.drawLine(firstVertex.getX(), firstVertex.getY(), lastVertex.getX(), lastVertex.getY());
}
}
/**
* moves current polygon to the list of polygons and makes pace for a new one
*/
public void addNewPolygon(String labelName) {
//finish the current polygon if any
if (currentLabel != null ) {
finishPolygon(currentLabel);
LabelHandler.addLabel(currentLabel);
}
currentLabel = new Label(labelName);
}
@Override
public void mouseClicked(MouseEvent e) {
int x = e.getX();
int y = e.getY();
//check if the cursos withing image area
if (x > image.getWidth() || y > image.getHeight()) {
//if not do nothing
return;
}
Graphics2D g = (Graphics2D)this.getGraphics();
//if the left button than we will add a vertex to poly
if (e.getButton() == MouseEvent.BUTTON1) {
g.setColor(Color.GREEN);
if (currentLabel.size() != 0) {
Point lastVertex = currentLabel.getPoint(currentLabel.size() - 1);
g.drawLine(lastVertex.getX(), lastVertex.getY(), x, y);
}
g.fillOval(x-5,y-5,10,10);
currentLabel.addPoint(new Point(x,y));
System.out.println(x + " " + y);
}
}
@Override
public void mouseEntered(MouseEvent arg0) {
}
@Override
public void mouseExited(MouseEvent arg0) {
}
@Override
public void mousePressed(MouseEvent arg0) {
}
@Override
public void mouseReleased(MouseEvent arg0) {
}
}
答案 0 :(得分：4)
不要将getGraphics()用于您的绘画，因为它是临时缓冲区，在下次重绘时会被回收。您是否在paintComponent()中绘画并在需要时调用repaint()。
也不要手动调用paint()（即：imagePanel.paint(imagePanel.getGraphics());）
有关详细信息，请参阅Performing Custom Painting。另请参阅Painting in AWT and Swing。
答案 1 :(得分：2)
在ImagePanel.paintComponent中ShowImage();替换if (image != null) g.drawImage( image, 0, 0, this );。
设备上下文g由swing初始化，您不必通过getGraphics()获取另一个。