Java、Swing、Awt—在图像上绘制一个矩形并使其可见
我试图打开一个图像,在拖动鼠标时在其上绘制一个矩形(鼠标拖动),并在释放鼠标时绘制最后一个矩形 我实现了在拖动时绘制矩形,但目前无法收集最后一点的坐标来绘制矩形并存储数据。你有什么想法来改进我的代码吗?(在背景中添加一个图像,即使在其上绘制了多个图像,也可以在其上保持矩形大小) 我想Mousevent可以帮助我,但我不确定该如何使用它 编辑:在绘制第一个矩形后,如果绘制第二个矩形,我希望它保持可见Java、Swing、Awt—在图像上绘制一个矩形并使其可见,java,swing,awt,Java,Swing,Awt,我试图打开一个图像,在拖动鼠标时在其上绘制一个矩形(鼠标拖动),并在释放鼠标时绘制最后一个矩形 我实现了在拖动时绘制矩形,但目前无法收集最后一点的坐标来绘制矩形并存储数据。你有什么想法来改进我的代码吗?(在背景中添加一个图像,即使在其上绘制了多个图像,也可以在其上保持矩形大小) 我想Mousevent可以帮助我,但我不确定该如何使用它 编辑:在绘制第一个矩形后,如果绘制第二个矩形,我希望它保持可见 package selectZone; import java.awt.event.*; imp
package selectZone;
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
public class Rec extends JFrame {
public Rec() {
super("rectangle");
setPreferredSize(new java.awt.Dimension(400, 400));
setDefaultCloseOperation(EXIT_ON_CLOSE);
JPanel pane = new Pan();
add(pane);
pack();
setVisible(true);
}
public static void main(String[] args) {
new Rec();
}
}
class Pan extends JPanel {
private Point origin;
private Point end;
private Point endFinal;
public Pan() {
MouseAdapter adapter = new Lis();
addMouseMotionListener(adapter);
addMouseListener(adapter);
}
class Lis extends MouseAdapter {
public void mouseDragged(MouseEvent e) {
end = e.getPoint();
repaint();
}
public void mousePressed(MouseEvent e) {
origin = e.getPoint();
}
public void mouseReleased(MouseEvent e, Graphics g) {
endFinal = e.getPoint();
g.clearRect(0, 0, getWidth(), getHeight());
g.setColor(Color.RED);
int x1 = (int) (origin.getX());
int y1 = (int) (origin.getY());
int x2 = (int) (endFinal.getX());
int y2 = (int) (endFinal.getY());
g.drawRect(x1, y1, x2 - x1, y2 - y1);
}
}
public void paint(Graphics g) {
g.clearRect(0, 0, getWidth(), getHeight());
g.setColor(Color.RED);
if (origin != null) {
int tmp;
int x1 = (int) (origin.getX());
int y1 = (int) (origin.getY());
int x2 = (int) (end.getX());
int y2 = (int) (end.getY());
if (x1 > x2) {
tmp = x1;
x1 = x2;
x2 = tmp;
}
if (y1 > y2) {
tmp = y1;
y1 = y2;
y2 = tmp;
}
g.drawRect(x1, y1, x2 - x1, y2 - y1);
}
}
}
谢谢你们的时间,伙计们
我试图打开一个图像,在上面画一个矩形
在绘制第一个矩形后,如果绘制第二个矩形,我希望它保持可见
package selectZone;
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
public class Rec extends JFrame {
public Rec() {
super("rectangle");
setPreferredSize(new java.awt.Dimension(400, 400));
setDefaultCloseOperation(EXIT_ON_CLOSE);
JPanel pane = new Pan();
add(pane);
pack();
setVisible(true);
}
public static void main(String[] args) {
new Rec();
}
}
class Pan extends JPanel {
private Point origin;
private Point end;
private Point endFinal;
public Pan() {
MouseAdapter adapter = new Lis();
addMouseMotionListener(adapter);
addMouseListener(adapter);
}
class Lis extends MouseAdapter {
public void mouseDragged(MouseEvent e) {
end = e.getPoint();
repaint();
}
public void mousePressed(MouseEvent e) {
origin = e.getPoint();
}
public void mouseReleased(MouseEvent e, Graphics g) {
endFinal = e.getPoint();
g.clearRect(0, 0, getWidth(), getHeight());
g.setColor(Color.RED);
int x1 = (int) (origin.getX());
int y1 = (int) (origin.getY());
int x2 = (int) (endFinal.getX());
int y2 = (int) (endFinal.getY());
g.drawRect(x1, y1, x2 - x1, y2 - y1);
}
}
public void paint(Graphics g) {
g.clearRect(0, 0, getWidth(), getHeight());
g.setColor(Color.RED);
if (origin != null) {
int tmp;
int x1 = (int) (origin.getX());
int y1 = (int) (origin.getY());
int x2 = (int) (end.getX());
int y2 = (int) (end.getY());
if (x1 > x2) {
tmp = x1;
x1 = x2;
x2 = tmp;
}
if (y1 > y2) {
tmp = y1;
y1 = y2;
y2 = tmp;
}
g.drawRect(x1, y1, x2 - x1, y2 - y1);
}
}
}
保留要绘制的矩形阵列列表。然后在显示图像的组件的paintComponent()方法中,迭代列表以绘制矩形
查看中的drawincomponet
example以获取一个工作示例,帮助您入门
该示例仅绘制矩形,因此您还需要绘制图像。或者您可以扩展JLabel,这样标签会绘制图像,然后您只需绘制矩形。不要覆盖
paint
,而是使用paintComponent
,并确保在执行任何自定义绘制之前调用super.paintComponent
,你会发现它产生的问题更少我不明白mouseRelease
事件的目的。origin
和end
已经设置得非常远,如果你调用repaint
,矩形将被绘制。谢谢,我看到了你的观点,但是当我添加图像时,我看不到我正在绘制的矩形。我怎样才能解决这个问题?你不能将图像“添加”到面板中。使用面板的相同paintComponent()方法绘制图像和矩形。所以你先画图像,然后再画矩形,这样他们就可以在图像的顶部作画