org.eclipse.mylyn.commons.ui.GradientToolTip.java Source code

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Here is the source code for org.eclipse.mylyn.commons.ui.GradientToolTip.java

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/*******************************************************************************
 * Copyright (c) 2004, 2009 Tasktop Technologies and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Tasktop Technologies - initial API and implementation
 *******************************************************************************/

package org.eclipse.mylyn.commons.ui;

import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.resource.LocalResourceManager;
import org.eclipse.jface.window.ToolTip;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Event;

/**
 * A Custom JFace ToolTip that applies a gradient to the contents
 * 
 * @author Shawn Minto
 * @since 3.7
 */
public abstract class GradientToolTip extends ToolTip {

    private GradientColors colors;

    private LocalResourceManager resourceManager;

    public GradientToolTip(Control control, int style, boolean manualActivation) {
        super(control, style, manualActivation);
        initResources(control);
    }

    public GradientToolTip(Control control) {
        super(control);
        initResources(control);
    }

    private void initResources(Control control) {
        resourceManager = new LocalResourceManager(JFaceResources.getResources());
        colors = new GradientColors(control.getDisplay(), resourceManager);
    }

    @Override
    protected final Composite createToolTipContentArea(Event event, final Composite parent) {
        GradientCanvas gradient = new GradientCanvas(parent, SWT.NONE);
        gradient.setSeparatorVisible(false);
        GridLayout headLayout = new GridLayout();
        headLayout.marginHeight = 0;
        headLayout.marginWidth = 0;
        headLayout.horizontalSpacing = 0;
        headLayout.verticalSpacing = 0;
        headLayout.numColumns = 1;
        gradient.setLayout(headLayout);

        gradient.setBackgroundGradient(new Color[] { colors.getGradientBegin(), colors.getGradientEnd() },
                new int[] { 100 }, true);

        createToolTipArea(event, gradient);

        // force a null background so that the gradient shines through
        for (Control c : gradient.getChildren()) {
            setNullBackground(c);
        }

        return gradient;
    }

    private void setNullBackground(final Control outerCircle) {
        outerCircle.setBackground(null);
        if (outerCircle instanceof Composite) {
            ((Composite) outerCircle).setBackgroundMode(SWT.INHERIT_FORCE);
            for (Control c : ((Composite) outerCircle).getChildren()) {
                setNullBackground(c);
            }
        }
    }

    protected abstract Composite createToolTipArea(Event event, Composite parent);
}