/*******************************************************************************

 * Copyright (c) 2000, 2009 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

 *     Nokia Corporation - S60 implementation

 *******************************************************************************/

package org.eclipse.swt.custom;

import org.eclipse.swt.*;

import org.eclipse.swt.events.*;

import org.eclipse.swt.graphics.*;

import org.eclipse.swt.widgets.*;

/**

 * A ScrolledComposite provides scrollbars and will scroll its content when the user

 * uses the scrollbars.

 *

 *

 * <p>There are two ways to use the ScrolledComposite:

 *

 * <p>

 * 1) Set the size of the control that is being scrolled and the ScrolledComposite

 * will show scrollbars when the contained control can not be fully seen.

 *

 * 2) The second way imitates the way a browser would work.  Set the minimum size of

 * the control and the ScrolledComposite will show scroll bars if the visible area is

 * less than the minimum size of the control and it will expand the size of the control

 * if the visible area is greater than the minimum size.  This requires invoking

 * both setMinWidth(), setMinHeight() and setExpandHorizontal(), setExpandVertical().

 *

 * <code><pre>

 * public static void main (String [] args) {

 *      Display display = new Display ();

 *      Color red = display.getSystemColor(SWT.COLOR_RED);

 *      Color blue = display.getSystemColor(SWT.COLOR_BLUE);

 *      Shell shell = new Shell (display);

 *      shell.setLayout(new FillLayout());

 *

 *      // set the size of the scrolled content - method 1

 *      final ScrolledComposite sc1 = new ScrolledComposite(shell, SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER);

 *      final Composite c1 = new Composite(sc1, SWT.NONE);

 *      sc1.setContent(c1);

 *      c1.setBackground(red);

 *      GridLayout layout = new GridLayout();

 *      layout.numColumns = 4;

 *      c1.setLayout(layout);

 *      Button b1 = new Button (c1, SWT.PUSH);

 *      b1.setText("first button");

 *      c1.setSize(c1.computeSize(SWT.DEFAULT, SWT.DEFAULT));

 *

 *      // set the minimum width and height of the scrolled content - method 2

 *      final ScrolledComposite sc2 = new ScrolledComposite(shell, SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER);

 *      sc2.setExpandHorizontal(true);

 *      sc2.setExpandVertical(true);

 *      final Composite c2 = new Composite(sc2, SWT.NONE);

 *      sc2.setContent(c2);

 *      c2.setBackground(blue);

 *      layout = new GridLayout();

 *      layout.numColumns = 4;

 *      c2.setLayout(layout);

 *      Button b2 = new Button (c2, SWT.PUSH);

 *      b2.setText("first button");

 *      sc2.setMinSize(c2.computeSize(SWT.DEFAULT, SWT.DEFAULT));

 *

 *      Button add = new Button (shell, SWT.PUSH);

 *      add.setText("add children");

 *      final int[] index = new int[]{0};

 *      add.addListener(SWT.Selection, new Listener() {

 *          public void handleEvent(Event e) {

 *              index[0]++;

 *              Button button = new Button(c1, SWT.PUSH);

 *              button.setText("button "+index[0]);

 *              // reset size of content so children can be seen - method 1

 *              c1.setSize(c1.computeSize(SWT.DEFAULT, SWT.DEFAULT));

 *              c1.layout();

 *

 *              button = new Button(c2, SWT.PUSH);

 *              button.setText("button "+index[0]);

 *              // reset the minimum width and height so children can be seen - method 2

 *              sc2.setMinSize(c2.computeSize(SWT.DEFAULT, SWT.DEFAULT));

 *              c2.layout();

 *          }

 *      });

 *

 *      shell.open ();

 *      while (!shell.isDisposed ()) {

 *          if (!display.readAndDispatch ()) display.sleep ();

 *      }

 *      display.dispose ();

 * }

 * </pre></code>

 *

 * <dl>

 * <dt><b>Styles:</b><dd>H_SCROLL, V_SCROLL

 * </dl>

 *

 * @see <a href="http://www.eclipse.org/swt/snippets/#scrolledcomposite">ScrolledComposite snippets</a>

 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>

 */

public class ScrolledComposite extends Composite

{

    Control content;

    Listener contentListener;

    Listener filter;

    int minHeight = 0;

    int minWidth = 0;

    boolean expandHorizontal = false;

    boolean expandVertical = false;

    boolean alwaysShowScroll = false;

    boolean showFocusedControl = false;

    /**

     * Constructs a new instance of this class given its parent

     * and a style value describing its behavior and appearance.

     * <p>

     * The style value is either one of the style constants defined in

     * class <code>SWT</code> which is applicable to instances of this

     * class, or must be built by <em>bitwise OR</em>'ing together

     * (that is, using the <code>int</code> "|" operator) two or more

     * of those <code>SWT</code> style constants. The class description

     * lists the style constants that are applicable to the class.

     * Style bits are also inherited from superclasses.

     * </p>

     *

     * @param parent a widget which will be the parent of the new instance (cannot be null)

     * @param style the style of widget to construct

     *

     * @exception IllegalArgumentException <ul>

     *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>

     * </ul>

     * @exception SWTException <ul>

     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>

     * </ul>

     *

     * @see SWT#H_SCROLL

     * @see SWT#V_SCROLL

     * @see #getStyle()

     */

    public ScrolledComposite(Composite parent, int style)

    {

        super(parent, checkStyle(style));

        super.setLayout(new ScrolledCompositeLayout());

        ScrollBar hBar = getHorizontalBar();

        if (hBar != null)

        {

            hBar.setVisible(false);

            hBar.addListener(SWT.Selection, new Listener()

            {

                public void handleEvent(Event e)

                {

                    hScroll();

                }

            });

        }

        ScrollBar vBar = getVerticalBar();

        if (vBar != null)

        {

            vBar.setVisible(false);

            vBar.addListener(SWT.Selection, new Listener()

            {

                public void handleEvent(Event e)

                {

                    vScroll();

                }

            });

        }

        contentListener = new Listener()

        {

            public void handleEvent(Event e)

            {

                if (e.type != SWT.Resize) return;

                layout(false);

            }

        };

        filter = new Listener()

        {

            public void handleEvent(Event event)

            {

                if (event.widget instanceof Control)

                {

                    Control control = (Control) event.widget;

                    if (contains(control)) showControl(control);

                }

            }

        };

        addDisposeListener(new DisposeListener()

        {

            public void widgetDisposed(DisposeEvent e)

            {

                getDisplay().removeFilter(SWT.FocusIn, filter);

            }

        });

    }

    static int checkStyle(int style)

    {

        int mask = SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER | SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT;

        return style & mask;

    }

    boolean contains(Control control)

    {

        if (control == null || control.isDisposed()) return false;

        Composite parent = control.getParent();

        while (parent != null && !(parent instanceof Shell))

        {

            if (this == parent) return true;

            parent = parent.getParent();

        }

        return false;

    }

    /**

     * Returns the Always Show Scrollbars flag.  True if the scrollbars are

     * always shown even if they are not required.  False if the scrollbars are only

     * visible when some part of the composite needs to be scrolled to be seen.

     * The H_SCROLL and V_SCROLL style bits are also required to enable scrollbars in the

     * horizontal and vertical directions.

     *

     * @return the Always Show Scrollbars flag value

     */

    public boolean getAlwaysShowScrollBars()

    {

        //checkWidget();

        return alwaysShowScroll;

    }

    /**

     * Returns <code>true</code> if the content control

     * will be expanded to fill available horizontal space.

     *

     * @return the receiver's horizontal expansion state

     *

     * @exception SWTException <ul>

     *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>

     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>

     * </ul>

     *

     * @since 3.2

     */

    public boolean getExpandHorizontal()

    {

        checkWidget();

        return expandHorizontal;

    }

    /**

     * Returns <code>true</code> if the content control

     * will be expanded to fill available vertical space.

     *

     * @return the receiver's vertical expansion state

     *

     * @exception SWTException <ul>

     *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>

     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>

     * </ul>

     *

     * @since 3.2

     */

    public boolean getExpandVertical()

    {

        checkWidget();

        return expandVertical;

    }

    /**

     * Returns the minimum width of the content control.

     *

     * @return the minimum width

     *

     * @exception SWTException <ul>

     *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>

     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>

     * </ul>

     *

     * @since 3.2

     */

    public int getMinWidth()

    {

        checkWidget();

        return minWidth;

    }

    /**

     * Returns the minimum height of the content control.

     *

     * @return the minimum height

     *

     * @exception SWTException <ul>

     *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>

     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>

     * </ul>

     *

     * @since 3.2

     */

    public int getMinHeight()

    {

        checkWidget();

        return minHeight;

    }

    /**

     * Get the content that is being scrolled.

     *

     * @return the control displayed in the content area

     */

    public Control getContent()

    {

        //checkWidget();

        return content;

    }

    /**

     * Returns <code>true</code> if the receiver automatically scrolls to a focused child control

     * to make it visible. Otherwise, returns <code>false</code>.

     *

     * @return a boolean indicating whether focused child controls are automatically scrolled into the viewport

     *

     * @exception SWTException <ul>

     *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>

     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>

     * </ul>

     *

     * @since 3.4

     */

    public boolean getShowFocusedControl()

    {

        checkWidget();

        return showFocusedControl;

    }

    void hScroll()

    {

        if (content == null) return;

        Point location = content.getLocation();

        ScrollBar hBar = getHorizontalBar();

        int hSelection = hBar.getSelection();

        content.setLocation(-hSelection, location.y);

    }

    boolean needHScroll(Rectangle contentRect, boolean vVisible)

    {

        ScrollBar hBar = getHorizontalBar();

        if (hBar == null) return false;

        Rectangle hostRect = getBounds();

        int border = getBorderWidth();

        hostRect.width -= 2*border;

        ScrollBar vBar = getVerticalBar();

        if (vVisible && vBar != null) hostRect.width -= vBar.getSize().x;

        if (!expandHorizontal && contentRect.width > hostRect.width) return true;

        if (expandHorizontal && minWidth > hostRect.width) return true;

        return false;

    }

    boolean needVScroll(Rectangle contentRect, boolean hVisible)

    {

        ScrollBar vBar = getVerticalBar();

        if (vBar == null) return false;

        Rectangle hostRect = getBounds();

        int border = getBorderWidth();

        hostRect.height -= 2*border;

        ScrollBar hBar = getHorizontalBar();

        if (hVisible && hBar != null) hostRect.height -= hBar.getSize().y;

        if (!expandVertical && contentRect.height > hostRect.height) return true;

        if (expandVertical && minHeight > hostRect.height) return true;

        return false;

    }

    /**

     * Return the point in the content that currently appears in the top left

     * corner of the scrolled composite.

     *

     * @return the point in the content that currently appears in the top left

     * corner of the scrolled composite.  If no content has been set, this returns

     * (0, 0).

     *

     * @exception SWTException <ul>

     *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>

     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>

     * </ul>

     *

     * @since 2.0

     */

    public Point getOrigin()

    {

        checkWidget();

        if (content == null) return new Point(0, 0);

        Point location = content.getLocation();

        return new Point(-location.x, -location.y);

    }

    /**

     * Scrolls the content so that the specified point in the content is in the top

     * left corner.  If no content has been set, nothing will occur.

     *

     * Negative values will be ignored.  Values greater than the maximum scroll

     * distance will result in scrolling to the end of the scrollbar.

     *

     * @param origin the point on the content to appear in the top left corner

     *

     * @exception SWTException <ul>

     *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>

     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>

     *    <li>ERROR_INVALID_ARGUMENT - value of origin is outside of content

     * </ul>

     * @since 2.0

     */

    public void setOrigin(Point origin)

    {

        setOrigin(origin.x, origin.y);

    }

    /**

     * Scrolls the content so that the specified point in the content is in the top

     * left corner.  If no content has been set, nothing will occur.

     *

     * Negative values will be ignored.  Values greater than the maximum scroll

     * distance will result in scrolling to the end of the scrollbar.

     *

     * @param x the x coordinate of the content to appear in the top left corner

     *

     * @param y the y coordinate of the content to appear in the top left corner

     *

     * @exception SWTException <ul>

     *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>

     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>

     * </ul>

     *

     * @since 2.0

     */

    public void setOrigin(int x, int y)

    {

        checkWidget();

        if (content == null) return;

        ScrollBar hBar = getHorizontalBar();

        if (hBar != null)

        {

            hBar.setSelection(x);

            x = -hBar.getSelection();

        }

        else

        {

            x = 0;

        }

        ScrollBar vBar = getVerticalBar();

        if (vBar != null)

        {

            vBar.setSelection(y);

            y = -vBar.getSelection();

        }

        else

        {

            y = 0;

        }

        content.setLocation(x, y);

    }

    /**

     * Set the Always Show Scrollbars flag.  True if the scrollbars are

     * always shown even if they are not required.  False if the scrollbars are only

     * visible when some part of the composite needs to be scrolled to be seen.

     * The H_SCROLL and V_SCROLL style bits are also required to enable scrollbars in the

     * horizontal and vertical directions.

     *

     * @param show true to show the scrollbars even when not required, false to show scrollbars only when required

     *

     * @exception SWTException <ul>

     *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>

     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>

     * </ul>

     */

    public void setAlwaysShowScrollBars(boolean show)

    {

        checkWidget();

        if (show == alwaysShowScroll) return;

        alwaysShowScroll = show;

        ScrollBar hBar = getHorizontalBar();

        if (hBar != null && alwaysShowScroll) hBar.setVisible(true);

        ScrollBar vBar = getVerticalBar();

        if (vBar != null && alwaysShowScroll) vBar.setVisible(true);

        layout(false);

    }

    /**

     * Set the content that will be scrolled.

     *

     * @param content the control to be displayed in the content area

     *

     * @exception SWTException <ul>

     *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>

     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>

     * </ul>

     */

    public void setContent(Control content)

    {

        checkWidget();

        if (this.content != null && !this.content.isDisposed())

        {

            this.content.removeListener(SWT.Resize, contentListener);

            this.content.setBounds(new Rectangle(-200, -200, 0, 0));

        }

        this.content = content;

        ScrollBar vBar = getVerticalBar();

        ScrollBar hBar = getHorizontalBar();

        if (this.content != null)

        {

            if (vBar != null)

            {

                vBar.setMaximum(0);

                vBar.setThumb(0);

                vBar.setSelection(0);

            }

            if (hBar != null)

            {

                hBar.setMaximum(0);