bundles/org.eclipse.jface/src/org/eclipse/jface/preference/ColorSelector.java

package org.eclipse.jface.preference;

/**********************************************************************
Copyright (c) 2000, 2002 IBM Corp. and others.
All rights reserved. This program and the accompanying materials
are made available under the terms of the Common Public License v1.0
which accompanies this distribution, and is available at
http://www.eclipse.org/legal/cpl-v10.html

Contributors:
    IBM Corporation - Initial implementation
**********************************************************************/

import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;

/**
 * The ColorSelector is a wrapper for a button that displays
 * a selected Color and allows the user to change the selection.
 */
public class ColorSelector {

	private Point fExtent;
	private Image fImage;
	private RGB fColorValue;
	private Color fColor;
	private Button fButton;

	/**
	 * Create a new instance of the reciever and the
	 * button that it wrappers in the supplied parent Composite
	 * @param parent. The parent of the button.
	 */
	public ColorSelector(Composite parent) {

		fButton = new Button(parent, SWT.PUSH);
		fExtent = computeImageSize(parent);
		fImage = new Image(parent.getDisplay(), fExtent.x, fExtent.y);

		GC gc = new GC(fImage);
		gc.setBackground(fButton.getBackground());
		gc.fillRectangle(0, 0, fExtent.x, fExtent.y);
		gc.dispose();

		fButton.setImage(fImage);
		fButton.addSelectionListener(new SelectionAdapter() {
			public void widgetSelected(SelectionEvent event) {
				ColorDialog colorDialog = new ColorDialog(fButton.getShell());
				colorDialog.setRGB(fColorValue);
				RGB newColor = colorDialog.open();
				if (newColor != null) {
					fColorValue = newColor;
					updateColorImage();
				}
			}
		});

		fButton.addDisposeListener(new DisposeListener() {
			public void widgetDisposed(DisposeEvent event) {
				if (fImage != null) {
					fImage.dispose();
					fImage = null;
				}
				if (fColor != null) {
					fColor.dispose();
					fColor = null;
				}
			}
		});
	}

	/**
	 * Return the currently displayed color.
	 * @return RGB
	 */
	public RGB getColorValue() {
		return fColorValue;
	}

	/**
	 * Set the current color value and update the control.
	 * @param rgb. The new color.
	 */
	public void setColorValue(RGB rgb) {
		fColorValue = rgb;
		updateColorImage();
	}

	/**
	 * Get the button control being wrappered by the selector.
	 * @return Button
	 */
	public Button getButton() {
		return fButton;
	}

	/**
	 * Update the image being displayed on the button using
	 * the current color setting,
	 */

	protected void updateColorImage() {

		Display display = fButton.getDisplay();

		GC gc = new GC(fImage);
		gc.setForeground(display.getSystemColor(SWT.COLOR_BLACK));
		gc.drawRectangle(0, 2, fExtent.x - 1, fExtent.y - 4);

		if (fColor != null)
			fColor.dispose();

		fColor = new Color(display, fColorValue);
		gc.setBackground(fColor);
		gc.fillRectangle(1, 3, fExtent.x - 2, fExtent.y - 5);
		gc.dispose();

		fButton.setImage(fImage);
	}

	/**
	 * Compute the size of the image to be displayed.
	 * @return Point
	 * @param window - the window used to calculate
	 */

	private Point computeImageSize(Control window) {
		GC gc = new GC(window);
		Font f =
			JFaceResources.getFontRegistry().get(JFaceResources.DEFAULT_FONT);
		gc.setFont(f);
		int height = gc.getFontMetrics().getHeight();
		gc.dispose();
		Point p = new Point(height * 3 - 6, height);
		return p;
	}

	/**
	 * Set whether or not the button is enabled.
	 */

	public void setEnabled(boolean state) {
		getButton().setEnabled(state);
	}
}