Displaying Colors

Example 3.3 displays the predefined colors on the screen in a series of filled rectangles. When you press a mouse button, they appear brighter. When you press a key, they appear darker. (Event handling is fully explained in Events.) Figure 3.4 shows the results, although it doesn't look very impressive in black and white.

Example 3.3: Color Display

import java.awt.*;
public class ColorDisplay extends Frame {
 int width, height; static Color colors[] = {Color.black, Color.blue, Color.cyan, Color.darkGray, Color.gray, Color.green, Color.lightGray, Color.magenta, Color.orange, Color.pink, Color.red, Color.white, Color.yellow};
 ColorDisplay () {
 super ("ColorDisplay"); setBackground (Color.white);
}
static public void main (String args[]) {
 ColorDisplay f = new ColorDisplay(); f.resize (300,300); f.show();
}
public void paint (Graphics g) {
 g.translate (insets().left, insets().top); if (width == 0) {
 Insets inset = insets(); width = (size().width - inset.right - inset.left) / 3; height = (size().height - inset.top - inset.bottom) / 5;
}
for (int i = 0; i < 3; i++) {
 for (int j = 0; j < 5; j++) {
 if ((i == 2) && (j >= 3)) break; g.setColor (colors[i*5+j]); g.fillRect (i*width, j*height, width, height);
}
}
}
public boolean keyDown (Event e, int c) {
 for (int i=0;i<colors.length;i++) colors[i] = colors[i].darker(); repaint();
return true;
}
public boolean mouseDown (Event e, int x, int y) {
 for (int i=0;i<colors.length;i++) colors[i] = colors[i].brighter(); repaint();
return true;
}
} 

Figure 3.4: A color display