如何在JPanel上获取图像的坐标 [英] How to get image's coordinate on JPanel
问题描述
这个问题与我以前的问题有关如何生成笛卡尔坐标（x，y）？
我已经成功获取每张图片的坐标，但是当我检查坐标时（System.out.println ）和图像在屏幕上的位置，这似乎是错误的。例如如果在屏幕上显然第一张图片的x点在坐标为20的单元格2上，但程序显示x = 1。是代码的一部分：
public Grid（）{
setPreferredSize（new Dimension（600,600） ）;
....
setLayout（new GridBagLayout（））;
GridBagConstraints gc = new GridBagConstraints（）;
gc.weightx = 1d;
gc.weighty = 1d;
gc.insets = new Insets（0，0，0，0）; //顶部，左边，底部和右边
gc.fill = GridBagConstraints.BOTH;
JLabel [] [] [] label = new JLabel [ROWS] [COLS];
Random rand = new Random（）;
//用标签
填充面板（int i = 0; i< IMAGES; i ++）{
ImageIcon icon = createImageIcon（myPics.jpg）;
int r，c;
do {
//选取空的单元格
r =（int）Math.floor（Math.random（）* ROWS）;
c =（int）Math.floor（Math.random（）* COLS）;
} while（label [r] [c]！= null）;
//随机缩放图片
int x = rand.nextInt（50）+30;
int y = rand.nextInt（50）+30;
Image image = icon.getImage（）。getScaledInstance（x，y，Image.SCALE_SMOOTH）;
icon.setImage（image）;
JLabel lbl = new JLabel（icon）; //实例化GUI组件
gc.gridx = r;
gc.gridy = c;
add（lbl，gc）; // add（component，constraintObj）;
label [r] [c] = lbl;
}
我通过这段代码检查了坐标：
Component [] components = getComponents（）;
for（Component component：components）{
System.out.println（component.getBounds（））;
您可以使用 SwingUtilities convertPointToScreen（）和 convertPointFromScreen（）在屏幕和组件坐标之间进行转换。
$ b
附录：下面是一个简单的示例，我试图了解组件在布局管理器的影响下如何移动和调整大小。
super（new GridLayout（4，4））;
for（int i = 0; i <16; i ++）{
JPanel panel = new JPanel（new GridLayout（））;
panel.add（new CenterLabel（））;
this.add（panel）;
private static void create（）{
JFrame f = new JFrame（）;
f.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）;
f.add（new MyPanel（））;
f.pack（）;
f.setVisible（true）;
public static void main（String [] args）{
EventQueue.invokeLater（new Runnable（）{
$ b $ @Override
public void run（）{
create（）;
}
}）;
私有静态类CenterLabel扩展JLabel {
public CenterLabel（）{
this.setHorizontalAlignment（JLabel.CENTER）;
this.setVerticalAlignment（JLabel.CENTER）;
this.setOpaque（true）;
this.setBackground（Color.lightGray）;
this.setBorder（BorderFactory.createLineBorder（Color.blue））;
this.setPreferredSize（new Dimension（160，100））;
this.addComponentListener（new ComponentAdapter（）{
@Override
public void componentResized（ComponentEvent e）{
int w = e.getComponent（）。getWidth（ ）;
int h = e.getComponent（）。getHeight（）;
CenterLabel.this.setText（[+ w / 2 +\\\┼+ h / 2 +] ）;
}
}）;
}
}
}
This question is related to my previous question How to generate Cartesian Coordinate (x,y) from GridBaglayout?
I have successfully get the coordinate of each pictures, however when I checked the coordinate through (System.out.println) and the placement of the images on the screen, it seems to be wrong. e.g. if on the screen it was obvious that the x point of the first picture is on cell 2 which is on coordinate of 20, but the program shows x=1.
Here is part of the code:
public Grid (){
setPreferredSize(new Dimension(600,600));
....
setLayout(new GridBagLayout());
GridBagConstraints gc = new GridBagConstraints();
gc.weightx = 1d;
gc.weighty = 1d;
gc.insets = new Insets(0, 0, 0, 0);//top, left, bottom, and right
gc.fill = GridBagConstraints.BOTH;
JLabel[][] label = new JLabel[ROWS][COLS];
Random rand = new Random();
// fill the panel with labels
for (int i=0;i<IMAGES;i++){
ImageIcon icon = createImageIcon("myPics.jpg");
int r, c;
do{
//pick random cell which is empty
r = (int)Math.floor(Math.random() * ROWS);
c = (int)Math.floor(Math.random() * COLS);
} while (label[r][c]!=null);
//randomly scale the images
int x = rand.nextInt(50)+30;
int y = rand.nextInt(50)+30;
Image image = icon.getImage().getScaledInstance(x,y, Image.SCALE_SMOOTH);
icon.setImage(image);
JLabel lbl = new JLabel(icon); // Instantiate GUI components
gc.gridx = r;
gc.gridy = c;
add(lbl, gc); //add(component, constraintObj);
label[r][c] = lbl;
}
I checked the coordinate through this code:
Component[] components = getComponents();
for (Component component : components) {
System.out.println(component.getBounds());
}
You can use SwingUtilities convertPointToScreen() and convertPointFromScreen() to convert between screen and component coordinates.
Addendum: Here's a simple example I used when trying to understand how components move and resize under the influence of a layout manager.
public class MyPanel extends JPanel {
public MyPanel() {
super(new GridLayout(4, 4));
for (int i = 0; i < 16; i++) {
JPanel panel = new JPanel(new GridLayout());
panel.add(new CenterLabel());
this.add(panel);
}
}
private static void create() {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new MyPanel());
f.pack();
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
create();
}
});
}
private static class CenterLabel extends JLabel {
public CenterLabel() {
this.setHorizontalAlignment(JLabel.CENTER);
this.setVerticalAlignment(JLabel.CENTER);
this.setOpaque(true);
this.setBackground(Color.lightGray);
this.setBorder(BorderFactory.createLineBorder(Color.blue));
this.setPreferredSize(new Dimension(160, 100));
this.addComponentListener(new ComponentAdapter() {
@Override
public void componentResized(ComponentEvent e) {
int w = e.getComponent().getWidth();
int h = e.getComponent().getHeight();
CenterLabel.this.setText("[" + w/2 + "\u253C" + h/2 + "]");
}
});
}
}
}
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