org.eclipse.ui.internal.DragHandle.java Source code

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Here is the source code for org.eclipse.ui.internal.DragHandle.java

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/*******************************************************************************
 * Copyright (c) 2005, 2006 IBM Corporation 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.internal;

import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.Cursor;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.ui.plugin.AbstractUIPlugin;

public class DragHandle extends Composite implements PaintListener {

    Cursor dragCursor;
    Image handleImage;
    ImageDescriptor descriptor;
    private boolean isHorizontal;

    private static int margin = 2;

    public DragHandle(Composite parent) {
        super(parent, SWT.NONE);

        dragCursor = new Cursor(parent.getDisplay(), SWT.CURSOR_SIZEALL);

        addPaintListener(this);

        descriptor = AbstractUIPlugin.imageDescriptorFromPlugin(WorkbenchPlugin.PI_WORKBENCH,
                "icons/misc/handle.gif"); //$NON-NLS-1$

        handleImage = new Image(parent.getDisplay(), 4, 4);
        GC context = new GC(handleImage);
        context.setForeground(parent.getDisplay().getSystemColor(SWT.COLOR_WIDGET_BACKGROUND));
        context.drawPoint(0, 0);
        context.drawPoint(2, 0);
        context.drawPoint(3, 0);
        context.drawPoint(3, 1);
        context.drawPoint(0, 2);
        context.drawPoint(3, 2);
        context.drawPoint(0, 3);
        context.drawPoint(1, 3);
        context.drawPoint(2, 3);
        context.drawPoint(3, 3);

        context.setForeground(parent.getDisplay().getSystemColor(SWT.COLOR_WIDGET_NORMAL_SHADOW));
        context.drawPoint(1, 0);
        context.drawPoint(0, 1);

        context.setForeground(parent.getDisplay().getSystemColor(SWT.COLOR_WIDGET_DARK_SHADOW));
        context.drawPoint(1, 1);

        context.setForeground(parent.getDisplay().getSystemColor(SWT.COLOR_WIDGET_HIGHLIGHT_SHADOW));
        context.drawPoint(1, 2);
        context.drawPoint(2, 1);
        context.drawPoint(2, 2);

        context.dispose();

        setCursor(dragCursor);
    }

    public void paintControl(PaintEvent e) {
        Point size = getSize();

        if (handleImage != null) {
            Rectangle ibounds = handleImage.getBounds();

            int x = ((size.x - 2 * margin) % ibounds.width) / 2 + margin;
            int y = ((size.y - 2 * margin) % ibounds.height) / 2 + margin;

            for (;;) {
                e.gc.drawImage(handleImage, x, y);
                if (isHorizontal) {
                    x += ibounds.width;
                    if (x + ibounds.width > size.x - margin) {
                        break;
                    }
                } else {
                    y += ibounds.height;
                    if (y + ibounds.height > size.y - margin) {
                        break;
                    }
                }
            }
        }
    }

    public Point computeSize(int wHint, int hHint, boolean changed) {
        Point result = new Point(wHint, hHint);

        Rectangle ibounds = handleImage.getBounds();

        if (wHint == SWT.DEFAULT) {
            result.x = ibounds.width + 2 * margin;
        }

        if (hHint == SWT.DEFAULT) {
            result.y = ibounds.height + 2 * margin;
        }

        return result;
    }

    public void setHorizontal(boolean isHorizontal) {
        this.isHorizontal = isHorizontal;
    }

    public void dispose() {
        if (isDisposed()) {
            return;
        }
        super.dispose();
        dragCursor.dispose();
        handleImage.dispose();
        JFaceResources.getResources().destroyImage(descriptor);
    }
}