Writing GUI in Java, an interesting problem has appeared. I apologize for a slightly longer code.
用Java编写GUI,出现了一个有趣的问题。我为稍微长一点的代码道歉。
There is class Graphic derived from JPanel which displays uploaded raster. It implements several features with the raster data including the zoom operations. It also supports a mouse click event which stores coordinates of a point and displays it over the raster. The raster is fitted with the affine transformation.
从JPanel派生的类图形显示上传的栅格。它使用包含缩放操作的栅格数据实现了多个功能。它还支持鼠标单击事件,该事件存储点的坐标并将其显示在栅格上。光栅配有仿射变换。
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.util.Locale;
import javax.imageio.ImageIO;
import javax.swing.*;
public class Graphic extends JPanel{
private BufferedImage image;
private AffineTransform trans;
Point2D.Double point;
public Graphic () {
try {image = ImageIO.read(new File("e:/Work/test.jpg"));}
catch (Exception e) {}
trans = new AffineTransform();
trans.translate(0, 0);
trans.scale(1, 1);
point = new Point2D.Double(0,0);
this.setToolTipText("");
addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
point.x = (e.getPoint().getX() - trans.getTranslateX()) / trans.getScaleX();
point.y = (e.getPoint().getY() - trans.getTranslateY()) / trans.getScaleY();
System.out.println(trans); //Print affine transformation parameters
System.out.println(e.getPoint().getX() + " " + e.getPoint().getY()); //Cursor coordinates
repaint();
}
});
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
if (image != null ){
trans = g2d.getTransform();
Dimension size = this.getVisibleRect().getSize();
double sx = (size.getWidth() - image.getWidth()) / 2;
double sy = (size.getHeight() - image.getHeight()) / 2;
trans.translate(sx, sy);
g2d.setTransform(trans);
g2d.drawImage(image, 0, 0, this);
g2d.fillOval((int)point.x - 10, (int)point.y - 10, 20, 20);
g2d.dispose();
}
}
@Override
public String getToolTipText(MouseEvent e) {
double x = (e.getX() - trans.getTranslateX()) / trans.getScaleX();
double y = (e.getY() - trans.getTranslateY()) / trans.getScaleY();
return String.format(Locale.ROOT, "%2.2f", x) + " " + String.format(Locale.ROOT, "%3.2f", y);
}
public static void main(String[] args){
JFrame f = new JFrame();
f.setSize(800, 600);
f.add(new Graphic());
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
The class redefines the tool tip method and displays coordinates of the cursor.
该类重新定义了工具提示方法并显示了光标的坐标。
Before a tool tip appears the mouse click into the picture works as expected
在出现工具提示之前,鼠标单击图片可以正常工作
Figure1: mouse click, without tool tip
图1:鼠标点击,没有工具提示
a circle appears at the right location.
一个圆圈出现在正确的位置。
Figure 2: drawn point mark, without tool tip
图2:绘制的点标记,没有工具尖端
Subsequently, let us repeat theses steps after a tool tip appears. The mouse click at the picture
随后,让我们在工具提示出现后重复这些步骤。鼠标点击图片
Figure 3: mouse click, tool tip appears
图3:鼠标单击,出现工具提示
behaves unexpectedly, and the point is drawn far away.
表现出乎意料,而且这一点很遥远。
Figure4: drawn point mark, tool tip appeared
图4:绘制的点标记,工具提示出现
Debugging the code, the following problem has has been found... When a tool tip appears, the shift ratios sx=mo2, sy=m12 in the affine transformation change from
调试代码,已发现以下问题...当出现工具提示时,仿射变换中的移位比sx = mo2,sy = m12从
AffineTransform[[1.0, 0.0, -1927.5], [0.0, 1.0, -1435.1]]
379.0 339.0 //Cursor coordinates xc, yc
to
AffineTransform[[1.0, 0.0, -2303.5], [0.0, 1.0, -1794.5]]
376.0 339.0 //Cursor coordinates xc, yc
To avoid a shift of the entire situation, instead m02 and m12 shifts, the transformed coordinates point.x, point.y should be corrected adding cursor coordinates + something. Is it a bug in the Swing library or a feature :-) ?
为了避免整个情况的移位,而是m02和m12移位,应该校正变换后的坐标point.x,point.y,添加光标坐标+东西。它是Swing库中的一个错误还是一个功能:-)?
Thanks for very much for your comments, help or explanation...
非常感谢您的评论,帮助或解释......
The raster file: test.jpg.
光栅文件:test.jpg。
1 个解决方案
#1
1
The solution is surprisingly simple...
解决方案非常简单......
It is necessary to call another repaint() before coordinates of a point are stored. Therefore, the mouse press event foregoing the mouse click event is utilized:
在存储点的坐标之前,必须调用另一个repaint()。因此,利用鼠标点击事件之前的鼠标按压事件:
@Override
public void mousePressed(MouseEvent e) {
repaint();
}
#1
1
The solution is surprisingly simple...
解决方案非常简单......
It is necessary to call another repaint() before coordinates of a point are stored. Therefore, the mouse press event foregoing the mouse click event is utilized:
在存储点的坐标之前,必须调用另一个repaint()。因此,利用鼠标点击事件之前的鼠标按压事件:
@Override
public void mousePressed(MouseEvent e) {
repaint();
}