This section provides a tutorial example on how to test the graphics resolution of the local screen using the default Toolkit object returned by the Toolkit.getDefaultToolkit() static method.
To answer my question raised in the previous section, I wrote the following
program and did some tests:
/**
* ScreenResolution.java
* Copyright (c) 2002 by Dr. Herong Yang, http://www.herongyang.com/
*/
import java.awt.*;
import javax.swing.*;
public class ScreenResolution {
static int dpi;
static int width, height;
public static void main(String[] a) {
Toolkit t = Toolkit.getDefaultToolkit();
dpi = t.getScreenResolution();
width = t.getScreenSize().width;
height = t.getScreenSize().height;
System.out.println("Width = "+width);
System.out.println("Height = "+height);
System.out.println("DPI = "+dpi);
JFrame f = new JFrame("Screen Size and Resolution");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setContentPane(new MyComponent());
f.setExtendedState(Frame.MAXIMIZED_BOTH);
f.setVisible(true);
}
static class MyComponent extends JComponent {
public void paint(Graphics g) {
g.drawString("100 pixel boxes",0,20);
for (int i=0; i<width/100+1; i++) {
g.drawRect(i*100,20,100,100);
}
g.drawString("One inch ("+dpi+" pixel) boxes",0,140);
for (int i=0; i<width/dpi+1; i++) {
g.drawRect(i*dpi,140,dpi,dpi);
}
}
}
}
For the first test, I changed my Windows screen setting (Control Panel /
Display / Settings / Screen Area) to 1024 x 786, and executed my program.
It shows about 10.* 100-pixel boxes and 10.* one-inch boxes:
The example program also gives me the following numbers in the console window:
Width = 1024
Height = 768
DPI = 96
For the second test, I changed my Windows screen setting (Control Panel /
Display / Settings / Screen Area) to 800 x 600, and executed my program.
It shows about 8 100-pixel boxes and 8.* one-inch boxes, and
gave me the following in the console window:
Width = 800
Height = 600
DPI = 96
So the result tells me that the size of my one-inch boxes is not really
one inch, if you measure them on the screen. The screen resolution I got
from the default toolkit is not following the screen setting.
In other words, I am not getting the real resolution of my screen.
If anyone knows how to get the real resolution, please tell me.
Sample programs listed in this section have been tested with JDK 1.3.1, 1.4.1, 1.5.0 and 1.6.0.
