A ColorChooserApplet shows six scroll bars that the user can manipulate to set the red, gree, blue, hue, brightness, and saturation components of a color. A color patch shows the selected color, and there are six labels that show the numerical values of all the components. RGB components are specified as integers in the range 0 to 255.
HSB components are specified as float values in the range 0.0F to 1.0F.
/*******************************************************
* MYCPLUS Sample Code - https://www.mycplus.com *
* *
* This code is made available as a service to our *
* visitors and is provided strictly for the *
* purpose of illustration. *
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* Please direct all inquiries to saqib at mycplus.com *
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import java.awt.*;
import java.awt.event.*;
import java.applet.*;
public class ColorChooserApplet extends Applet implements AdjustmentListener {
private float[] hsb = new float[3]; // For holding HSB color components.
private int r = 0, g = 0, b = 0; // The RGB color components.
private Scrollbar hueScroll, brightnessScroll, saturationScroll, // Scroll bars.
redScroll, greenScroll, blueScroll;
private Label hueLabel, brightnessLabel, saturationLabel, // Display component values.
redLabel, greenLabel, blueLabel;
private Canvas colorCanvas; // Color patch for displaying the color.
public void init() {
Color.RGBtoHSB(0,0,0,hsb); // Get HSB equivalent of RGB = (0,0,0);
/* Create Scrollbars with possible values from 0 to 255. */
hueScroll = new Scrollbar(Scrollbar.HORIZONTAL, (int)(255*hsb[0]), 10, 0, 265);
saturationScroll = new Scrollbar(Scrollbar.HORIZONTAL, (int)(255*hsb[1]), 10, 0, 265);
brightnessScroll = new Scrollbar(Scrollbar.HORIZONTAL, (int)(255*hsb[2]), 10, 0, 265);
redScroll = new Scrollbar(Scrollbar.HORIZONTAL, 0, 10, 0, 265);
greenScroll = new Scrollbar(Scrollbar.HORIZONTAL, 0, 10, 0, 265);
blueScroll = new Scrollbar(Scrollbar.HORIZONTAL, 0, 10, 0, 265);
/* Create Labels showing current RGB and HSB values. */
hueLabel = new Label(" H = " + hsb[0]);
saturationLabel = new Label(" S = " + hsb[1]);
brightnessLabel = new Label(" B = " + hsb[2]);
redLabel = new Label(" R = 0");
greenLabel = new Label(" G = 0");
blueLabel = new Label(" B = 0");
/* Set background colors for Scrollbars and Labels, so they don't
inherit the gray background of the applet. */
hueScroll.setBackground(Color.lightGray);
saturationScroll.setBackground(Color.lightGray);
brightnessScroll.setBackground(Color.lightGray);
redScroll.setBackground(Color.lightGray);
greenScroll.setBackground(Color.lightGray);
blueScroll.setBackground(Color.lightGray);
hueLabel.setBackground(Color.white);
saturationLabel.setBackground(Color.white);
brightnessLabel.setBackground(Color.white);
redLabel.setBackground(Color.white);
greenLabel.setBackground(Color.white);
blueLabel.setBackground(Color.white);
/* Set the applet to listen for changes to the Scrollbars' values */
hueScroll.addAdjustmentListener(this);
saturationScroll.addAdjustmentListener(this);
brightnessScroll.addAdjustmentListener(this);
redScroll.addAdjustmentListener(this);
greenScroll.addAdjustmentListener(this);
blueScroll.addAdjustmentListener(this);
/* Create a canvas whose background color will always be set to the
currently selected color. */
colorCanvas = new Canvas();
colorCanvas.setBackground(Color.black);
/* Create the applet format, which consists of a row of
three equal-sized regions holding the Scrollbars,
the Labels, and the color patch. The background color
of the applet is gray, which will show around the edges
and between components. */
setLayout(new GridLayout(1,3,3,3));
setBackground(Color.gray);
Panel scrolls = new Panel();
Panel labels = new Panel();
add(scrolls);
add(labels);
add(colorCanvas);
/* Add the Scrollbars and the Labels to their respective panels. */
scrolls.setLayout(new GridLayout(6,1,2,2));
scrolls.add(redScroll);
scrolls.add(greenScroll);
scrolls.add(blueScroll);
scrolls.add(hueScroll);
scrolls.add(saturationScroll);
scrolls.add(brightnessScroll);
labels.setLayout(new GridLayout(6,1,2,2));
labels.add(redLabel);
labels.add(greenLabel);
labels.add(blueLabel);
labels.add(hueLabel);
labels.add(saturationLabel);
labels.add(brightnessLabel);
} // end init();
public void adjustmentValueChanged(AdjustmentEvent evt) {
// This is called when the user has changed the values on
// one of the scrollbars. All the scrollbars and labels
// and the color patch are reset to correspond to the new color.
int r1, g1, b1;
r1 = redScroll.getValue();
g1 = greenScroll.getValue();
b1 = blueScroll.getValue();
if (r != r1 || g != g1 || b != b1) { // One of the RGB components has changed.
r = r1;
g = g1;
b = b1;
Color.RGBtoHSB(r,g,b,hsb);
}
else { // One of the HSB components has changed.
hsb[0] = hueScroll.getValue()/255.0F;
hsb[1] = saturationScroll.getValue()/255.0F;
hsb[2] = brightnessScroll.getValue()/255.0F;
int rgb = Color.HSBtoRGB(hsb[0],hsb[1],hsb[2]);
r = (rgb >> 16) & 0xFF;
g = (rgb >> 8) & 0xFF;
b = rgb & 0xFF;
}
redLabel.setText(" R = " + r);
greenLabel.setText(" G = " + g);
blueLabel.setText(" B = " + b);
hueLabel.setText(" H = " + hsb[0]);
saturationLabel.setText(" S = " + hsb[1]);
brightnessLabel.setText(" B = " + hsb[2]);
redScroll.setValue(r);
greenScroll.setValue(g);
blueScroll.setValue(b);
hueScroll.setValue((int)(255*hsb[0]));
saturationScroll.setValue((int)(255*hsb[1]));
brightnessScroll.setValue((int)(255*hsb[2]));
colorCanvas.setBackground(new Color(r,g,b));
colorCanvas.repaint(); // Tell the system to redraw the canvas in its new color.
} // end adjustmentValueChanged
public Insets getInsets() {
// The system calls this method to find out how much space to
// leave between the edges of the applet and the components that
// it contains. I want a 3-pixel border at each edge.
return new Insets(3,3,3,3);
}
} // end class ColorChooserApplet
