英文:
Java not creating JFrame with correct size
问题
我正在使用尺寸为 800 x 600 创建一个 JFrame，在我的 MacBook Pro 2018 上，根据“关于本机”选项卡的显示，其分辨率为 2560 x 1600。然而，当我显示窗口时，它的大小比预期要大得多，宽度维度超过屏幕尺寸的 50%（下面是测试代码）。
##由 AT 编辑。
原始代码已经无法达到我的预期，但我需要排除一些可能性并获取更多信息，因此将其编辑为以下代码。
import java.awt.*;
import java.awt.image.*;
import javax.swing.*;
public class TestFrameSize {
// 添加属性以在其他方法中引用frame
JFrame frame;
public TestFrameSize() {
Dimension size = new Dimension(800,600);
frame = new JFrame();
frame.setPreferredSize(size);
frame.pack();
frame.setVisible(true);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
System.out.println("Frame size: " + frame.getSize());
printProperty("java.version");
printProperty("os.name");
getImage();
}
private void printProperty(String name) {
System.out.println(name + ": " + System.getProperty(name));
}
private BufferedImage getImage() {
Dimension d = frame.getSize();
BufferedImage bi = new BufferedImage(d.width, d.height, BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();
Window w = frame;
w.paint(g);
g.dispose();
JOptionPane.showMessageDialog(frame, new ImageIcon(bi));
return bi;
}
public static void main(String[] args) {
Runnable r = new Runnable() {
@Override
public void run() {
TestFrameSize test = new TestFrameSize();
}
};
SwingUtilities.invokeLater(r);
}
}
结果如下图所示：
对于 2560x1600 的显示器，此窗口显然比 800x600 要大！这似乎很奇怪，我尝试查看 Java 认为我的屏幕尺寸是多少：
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
结果显示是 1440 x 900，这与屏幕应有的尺寸不符。难道是 Java 误解了我的显示器尺寸吗？
我有点困惑，经过搜索，我没有找到明显的答案，我不确定这是 Mac 的问题、Java 的问题，还是“我不理解屏幕如何工作”的问题。
英文:
I'm creating a JFrame with size 800 x 600 on a MacBook Pro 2018 that should according to the "About my Mac" tab has a resolution of 2560 x 1600, however when I display the window it appears much larger than it should be with the width dimension being over 50% of the screen size (test code below).
##Edit by AT.
The original code was already not behaving to my expectation, but I needed to dispel some possibilities & get more info so edited it to this code.
import java.awt.*;
import java.awt.image.*;
import javax.swing.*;
public class TestFrameSize {
// made attibute to refer to frame in other methods
JFrame frame;
public TestFrameSize() {
Dimension size = new Dimension(800,600);
frame = new JFrame();
frame.setPreferredSize(size);
frame.pack();
frame.setVisible(true);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
System.out.println("Frame size: " + frame.getSize());
printProperty("java.version");
printProperty("os.name");
getImage();
}
private void printProperty(String name) {
System.out.println(name + ": " + System.getProperty(name));
}
private BufferedImage getImage() {
Dimension d = frame.getSize();
BufferedImage bi = new BufferedImage(d.width, d.height, BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();
Window w = frame;
w.paint(g);
g.dispose();
JOptionPane.showMessageDialog(frame, new ImageIcon(bi));
return bi;
}
public static void main(String[] args) {
Runnable r = new Runnable() {
@Override
public void run() {
TestFrameSize test = new TestFrameSize();
}
};
SwingUtilities.invokeLater(r);
}
}
And the result:
For a display of 2560x1600 this window is certainly larger than 800x600 should be! This seemed strange and I tried to look up what Java thinks my screen size is with
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
and this gave the answer 1440 x 900 which is not what the screen should be. Is it that Java is misinterpreting the size of my display?
I'm at a bit of a loss here, googling around I couldn't see any obvious answers and I'm not sure whether this is a Mac thing, a Java thing, or a "I'm not understanding how the screen works" thing.
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