[Chapter 3] 3.5 Displaying Colors

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| Chapter 3 Fonts and Colors |

## 3.5 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 Chapter 4, 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

SystemColor |  | Using Desktop Colors