/*******************************************************************************
 * Copyright (c) 2000, 2008 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
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module dwt.widgets.ScrollBar;

import dwt.widgets.Control;
import dwt.widgets.Scrollable;
import dwt.DWT;
import dwt.graphics.Point;
import dwt.internal.gtk.OS;
import dwt.events.SelectionListener;
import dwt.events.SelectionEvent;
import dwt.widgets.Scrollable;
import dwt.widgets.Widget;
import dwt.widgets.Event;
import dwt.widgets.TypedListener;

import Math = tango.math.Math;

/**
 * Instances of this class are selectable user interface
 * objects that represent a range of positive, numeric values.
 * <p>
 * At any given moment, a given scroll bar will have a
 * single 'selection' that is considered to be its
 * value, which is constrained to be within the range of
 * values the scroll bar represents (that is, between its
 * <em>minimum</em> and <em>maximum</em> values).
 * </p><p>
 * Typically, scroll bars will be made up of five areas:
 * <ol>
 * <li>an arrow button for decrementing the value</li>
 * <li>a page decrement area for decrementing the value by a larger amount</li>
 * <li>a <em>thumb</em> for modifying the value by mouse dragging</li>
 * <li>a page increment area for incrementing the value by a larger amount</li>
 * <li>an arrow button for incrementing the value</li>
 * </ol>
 * Based on their style, scroll bars are either <code>HORIZONTAL</code>
 * (which have a left facing button for decrementing the value and a
 * right facing button for incrementing it) or <code>VERTICAL</code>
 * (which have an upward facing button for decrementing the value
 * and a downward facing buttons for incrementing it).
 * </p><p>
 * On some platforms, the size of the scroll bar's thumb can be
 * varied relative to the magnitude of the range of values it
 * represents (that is, relative to the difference between its
 * maximum and minimum values). Typically, this is used to
 * indicate some proportional value such as the ratio of the
 * visible area of a document to the total amount of space that
 * it would take to display it. DWT supports setting the thumb
 * size even if the underlying platform does not, but in this
 * case the appearance of the scroll bar will not change.
 * </p><p>
 * Scroll bars are created by specifying either <code>H_SCROLL</code>,
 * <code>V_SCROLL</code> or both when creating a <code>Scrollable</code>.
 * They are accessed from the <code>Scrollable</code> using
 * <code>getHorizontalBar</code> and <code>getVerticalBar</code>.
 * </p><p>
 * Note: Scroll bars are not Controls.  On some platforms, scroll bars
 * that appear as part of some standard controls such as a text or list
 * have no operating system resources and are not children of the control.
 * For this reason, scroll bars are treated specially.  To create a control
 * that looks like a scroll bar but has operating system resources, use
 * <code>Slider</code>.
 * </p>
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>HORIZONTAL, VERTICAL</dd>
 * <dt><b>Events:</b></dt>
 * <dd>Selection</dd>
 * </dl>
 * <p>
 * Note: Only one of the styles HORIZONTAL and VERTICAL may be specified.
 * </p><p>
 * IMPORTANT: This class is <em>not</em> intended to be subclassed.
 * </p>
 *
 * @see Slider
 * @see Scrollable
 * @see Scrollable#getHorizontalBar
 * @see Scrollable#getVerticalBar
 * @see <a href="http://www.eclipse.org/swt/examples.php">DWT Example: ControlExample</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 */
public class ScrollBar : Widget {
    Scrollable parent;
    GtkAdjustment* adjustmentHandle;
    int detail;
    bool dragSent;

this () {
}

/**
* Creates a new instance of the widget.
*/
this (Scrollable parent, int style) {
    super (parent, checkStyle (style));
    this.parent = parent;
    createWidget (0);
}

/**
 * Adds the listener to the collection of listeners who will
 * be notified when the user changes the receiver's value, by sending
 * it one of the messages defined in the <code>SelectionListener</code>
 * interface.
 * <p>
 * When <code>widgetSelected</code> is called, the event object detail field contains one of the following values:
 * <code>DWT.NONE</code> - for the end of a drag.
 * <code>DWT.DRAG</code>.
 * <code>DWT.HOME</code>.
 * <code>DWT.END</code>.
 * <code>DWT.ARROW_DOWN</code>.
 * <code>DWT.ARROW_UP</code>.
 * <code>DWT.PAGE_DOWN</code>.
 * <code>DWT.PAGE_UP</code>.
 * <code>widgetDefaultSelected</code> is not called.
 * </p>
 *
 * @param listener the listener which should be notified when the user changes the receiver's value
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 * </ul>
 * @exception DWTException <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>
 *
 * @see SelectionListener
 * @see #removeSelectionListener
 * @see SelectionEvent
 */
public void addSelectionListener (SelectionListener listener) {
    checkWidget ();
    if (listener is null) error (DWT.ERROR_NULL_ARGUMENT);
    TypedListener typedListener = new TypedListener (listener);
    addListener (DWT.Selection,typedListener);
    addListener (DWT.DefaultSelection,typedListener);
}

static int checkStyle (int style) {
    return checkBits (style, DWT.HORIZONTAL, DWT.VERTICAL, 0, 0, 0, 0);
}

override void deregister () {
    super.deregister ();
    if (adjustmentHandle !is null) display.removeWidget (cast(GtkWidget*)adjustmentHandle);
}

void destroyHandle () {
    super.destroyWidget ();
}

void destroyWidget () {
    parent.destroyScrollBar (this);
    releaseHandle ();
    //parent.sendEvent (DWT.Resize);
}

/**
 * Returns <code>true</code> if the receiver is enabled, and
 * <code>false</code> otherwise. A disabled control is typically
 * not selectable from the user interface and draws with an
 * inactive or "grayed" look.
 *
 * @return the receiver's enabled state
 *
 * @exception DWTException <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>
 *
 * @see #isEnabled
 */
public bool getEnabled () {
    checkWidget ();
    if (handle !is null) return OS.GTK_WIDGET_SENSITIVE (handle);
    return true;
}

/**
 * Returns the amount that the receiver's value will be
 * modified by when the up/down (or right/left) arrows
 * are pressed.
 *
 * @return the increment
 *
 * @exception DWTException <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 int getIncrement () {
    checkWidget ();
    return cast(int)adjustmentHandle.step_increment;
}

/**
 * Returns the maximum value which the receiver will allow.
 *
 * @return the maximum
 *
 * @exception DWTException <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 int getMaximum () {
    checkWidget ();
    return cast(int)adjustmentHandle.upper;
}

/**
 * Returns the minimum value which the receiver will allow.
 *
 * @return the minimum
 *
 * @exception DWTException <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 int getMinimum () {
    checkWidget ();
    return cast(int)adjustmentHandle.lower;
}

/**
 * Returns the amount that the receiver's value will be
 * modified by when the page increment/decrement areas
 * are selected.
 *
 * @return the page increment
 *
 * @exception DWTException <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 int getPageIncrement () {
    checkWidget ();
    return cast(int)adjustmentHandle.page_increment;
}

/**
 * Returns the receiver's parent, which must be a Scrollable.
 *
 * @return the receiver's parent
 *
 * @exception DWTException <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 Scrollable getParent () {
    checkWidget ();
    return parent;
}

/**
 * Returns the single 'selection' that is the receiver's value.
 *
 * @return the selection
 *
 * @exception DWTException <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 int getSelection () {
    checkWidget ();
    return cast(int)adjustmentHandle.value;
}

/**
 * Returns a point describing the receiver's size. The
 * x coordinate of the result is the width of the receiver.
 * The y coordinate of the result is the height of the
 * receiver.
 *
 * @return the receiver's size
 *
 * @exception DWTException <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 Point getSize () {
    checkWidget ();
    if (handle is null) return new Point (0,0);
    GtkRequisition requisition;
    OS.gtk_widget_size_request (handle, &requisition);
    return new Point (requisition.width, requisition.height);
}

/**
 * Returns the size of the receiver's thumb relative to the
 * difference between its maximum and minimum values.
 *
 * @return the thumb value
 *
 * @exception DWTException <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>
 *
 * @see ScrollBar
 */
public int getThumb () {
    checkWidget ();
    return cast(int)adjustmentHandle.page_size;
}

/**
 * Returns <code>true</code> if the receiver is visible, and
 * <code>false</code> otherwise.
 * <p>
 * If one of the receiver's ancestors is not visible or some
 * other condition makes the receiver not visible, this method
 * may still indicate that it is considered visible even though
 * it may not actually be showing.
 * </p>
 *
 * @return the receiver's visibility state
 *
 * @exception DWTException <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 bool getVisible () {
    checkWidget ();
    auto scrolledHandle = parent.scrolledHandle;
    int hsp, vsp;
    OS.gtk_scrolled_window_get_policy (scrolledHandle, &hsp, &vsp);
    if ((style & DWT.HORIZONTAL) !is 0) {
        return hsp !is OS.GTK_POLICY_NEVER;
    } else {
        return vsp !is OS.GTK_POLICY_NEVER;
    }
}

override int /*long*/ gtk_button_press_event (GtkWidget* widget, GdkEventButton* eventPtr) {
    auto result = super.gtk_button_press_event (widget, eventPtr);
    if (result !is 0) return result;
    detail = OS.GTK_SCROLL_NONE;
    dragSent = false;
    return result;
}

override int /*long*/ gtk_change_value (GtkWidget* widget, int /*long*/ scroll, int /*long*/ value1, int /*long*/ value2) {
    detail = scroll;
    return 0;
}

override int /*long*/ gtk_value_changed (int /*long*/ adjustment) {
    Event event = new Event ();
    dragSent = detail is OS.GTK_SCROLL_JUMP;
    switch (detail) {
        case OS.GTK_SCROLL_NONE:            event.detail = DWT.NONE; break;
        case OS.GTK_SCROLL_JUMP:            event.detail = DWT.DRAG; break;
        case OS.GTK_SCROLL_START:           event.detail = DWT.HOME; break;
        case OS.GTK_SCROLL_END:             event.detail = DWT.END; break;
        case OS.GTK_SCROLL_PAGE_DOWN:
        case OS.GTK_SCROLL_PAGE_RIGHT:
        case OS.GTK_SCROLL_PAGE_FORWARD:    event.detail = DWT.PAGE_DOWN; break;
        case OS.GTK_SCROLL_PAGE_UP:
        case OS.GTK_SCROLL_PAGE_LEFT:
        case OS.GTK_SCROLL_PAGE_BACKWARD:   event.detail = DWT.PAGE_UP; break;
        case OS.GTK_SCROLL_STEP_DOWN:
        case OS.GTK_SCROLL_STEP_RIGHT:
        case OS.GTK_SCROLL_STEP_FORWARD:    event.detail = DWT.ARROW_DOWN; break;
        case OS.GTK_SCROLL_STEP_UP:
        case OS.GTK_SCROLL_STEP_LEFT:
        case OS.GTK_SCROLL_STEP_BACKWARD:   event.detail = DWT.ARROW_UP; break;
        default:
    }
    detail = OS.GTK_SCROLL_NONE;
    if (!dragSent) detail = OS.GTK_SCROLL_NONE;
    postEvent (DWT.Selection, event);
    parent.updateScrollBarValue (this);
    return 0;
}

override int /*long*/ gtk_event_after (GtkWidget* widget, GdkEvent* gdkEvent) {
    switch (gdkEvent.type) {
        case OS.GDK_BUTTON_RELEASE: {
            GdkEventButton* gdkEventButton = cast(GdkEventButton*)gdkEvent;
            if (gdkEventButton.button is 1 && detail is DWT.DRAG) {
                if (!dragSent) {
                    Event event = new Event ();
                    event.detail = DWT.DRAG;
                    postEvent (DWT.Selection, event);
                }
                postEvent (DWT.Selection);
            }
            detail = OS.GTK_SCROLL_NONE;
            dragSent = false;
            break;
        }
        default:
    }
    return super.gtk_event_after (widget, gdkEvent);
}

override void hookEvents () {
    super.hookEvents ();
    if (OS.GTK_VERSION >= OS.buildVERSION (2, 6, 0)) {
        OS.g_signal_connect_closure (handle, OS.change_value.ptr, display.closures [CHANGE_VALUE], false);
    }
    OS.g_signal_connect_closure (adjustmentHandle, OS.value_changed.ptr, display.closures [VALUE_CHANGED], false);
    OS.g_signal_connect_closure_by_id (handle, display.signalIds [EVENT_AFTER], 0, display.closures [EVENT_AFTER], false);
    OS.g_signal_connect_closure_by_id (handle, display.signalIds [BUTTON_PRESS_EVENT], 0, display.closures [BUTTON_PRESS_EVENT], false);
}

/**
 * Returns <code>true</code> if the receiver is enabled and all
 * of the receiver's ancestors are enabled, and <code>false</code>
 * otherwise. A disabled control is typically not selectable from the
 * user interface and draws with an inactive or "grayed" look.
 *
 * @return the receiver's enabled state
 *
 * @exception DWTException <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>
 *
 * @see #getEnabled
 */
public bool isEnabled () {
    checkWidget ();
    return getEnabled () && getParent ().getEnabled ();
}

/**
 * Returns <code>true</code> if the receiver is visible and all
 * of the receiver's ancestors are visible and <code>false</code>
 * otherwise.
 *
 * @return the receiver's visibility state
 *
 * @exception DWTException <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>
 *
 * @see #getVisible
 */
public bool isVisible () {
    checkWidget ();
    return getVisible () && getParent ().isVisible ();
}

override void register () {
    super.register ();
    if (adjustmentHandle !is null) display.addWidget (cast(GtkWidget*)adjustmentHandle, this);
}

void releaseHandle () {
    super.releaseHandle ();
    parent = null;
}

override void releaseParent () {
    super.releaseParent ();
    if (parent.horizontalBar is this) parent.horizontalBar = null;
    if (parent.verticalBar is this) parent.verticalBar = null;
}

override void releaseWidget () {
    super.releaseWidget ();
    //parent = null;
}

/**
 * Removes the listener from the collection of listeners who will
 * be notified when the user changes the receiver's value.
 *
 * @param listener the listener which should no longer be notified
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 * </ul>
 * @exception DWTException <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>
 *
 * @see SelectionListener
 * @see #addSelectionListener
 */
public void removeSelectionListener (SelectionListener listener) {
    checkWidget ();
    if (listener is null) error (DWT.ERROR_NULL_ARGUMENT);
    if (eventTable is null) return;
    eventTable.unhook (DWT.Selection, listener);
    eventTable.unhook (DWT.DefaultSelection,listener);
}

/**
 * Enables the receiver if the argument is <code>true</code>,
 * and disables it otherwise. A disabled control is typically
 * not selectable from the user interface and draws with an
 * inactive or "grayed" look.
 *
 * @param enabled the new enabled state
 *
 * @exception DWTException <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 setEnabled (bool enabled) {
    checkWidget ();
    if (handle !is null) OS.gtk_widget_set_sensitive (handle, enabled);
}

/**
 * Sets the amount that the receiver's value will be
 * modified by when the up/down (or right/left) arrows
 * are pressed to the argument, which must be at least
 * one.
 *
 * @param value the new increment (must be greater than zero)
 *
 * @exception DWTException <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 setIncrement (int value) {
    checkWidget ();
    if (value < 1) return;
    adjustmentHandle.step_increment = cast(float) value;
    OS.g_signal_handlers_block_matched (adjustmentHandle, OS.G_SIGNAL_MATCH_DATA, 0, 0, null, null, udVALUE_CHANGED);
    OS.gtk_adjustment_changed (adjustmentHandle);
    OS.g_signal_handlers_unblock_matched (adjustmentHandle, OS.G_SIGNAL_MATCH_DATA, 0, 0, null, null, udVALUE_CHANGED);
}

/**
 * Sets the maximum. If this value is negative or less than or
 * equal to the minimum, the value is ignored. If necessary, first
 * the thumb and then the selection are adjusted to fit within the
 * new range.
 *
 * @param value the new maximum
 *
 * @exception DWTException <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 setMaximum (int value) {
    checkWidget ();
    int minimum = cast(int)adjustmentHandle.lower;
    if (value <= minimum) return;
    adjustmentHandle.upper = value;
    adjustmentHandle.page_size = Math.min (adjustmentHandle.page_size, value - minimum);
    adjustmentHandle.value = Math.min (adjustmentHandle.value, (value - adjustmentHandle.page_size));
    OS.g_signal_handlers_block_matched (adjustmentHandle, OS.G_SIGNAL_MATCH_DATA, 0, 0, null, null, udVALUE_CHANGED);
    OS.gtk_adjustment_changed (adjustmentHandle);
    OS.g_signal_handlers_unblock_matched (adjustmentHandle, OS.G_SIGNAL_MATCH_DATA, 0, 0, null, null, udVALUE_CHANGED);
}

/**
 * Sets the minimum value. If this value is negative or greater
 * than or equal to the maximum, the value is ignored. If necessary,
 * first the thumb and then the selection are adjusted to fit within
 * the new range.
 *
 * @param value the new minimum
 *
 * @exception DWTException <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 setMinimum (int value) {
    checkWidget ();
    if (value < 0) return;
    int maximum = cast(int)adjustmentHandle.upper;
    if (value >= maximum) return;
    adjustmentHandle.lower = value;
    adjustmentHandle.page_size = Math.min (adjustmentHandle.page_size, maximum - value);
    adjustmentHandle.value = Math.max (adjustmentHandle.value, value);
    OS.g_signal_handlers_block_matched (adjustmentHandle, OS.G_SIGNAL_MATCH_DATA, 0, 0, null, null, udVALUE_CHANGED);
    OS.gtk_adjustment_changed (adjustmentHandle);
    OS.g_signal_handlers_unblock_matched (adjustmentHandle, OS.G_SIGNAL_MATCH_DATA, 0, 0, null, null, udVALUE_CHANGED);
}

void setOrientation () {
    super.setOrientation ();
    if ((parent.style & DWT.MIRRORED) !is 0) {
        if ((parent.state & CANVAS) !is 0) {
            if ((style & DWT.HORIZONTAL) !is 0) {
                OS.gtk_range_set_inverted (handle, true);
            }
        }
    }
}

/**
 * Sets the amount that the receiver's value will be
 * modified by when the page increment/decrement areas
 * are selected to the argument, which must be at least
 * one.
 *
 * @param value the page increment (must be greater than zero)
 *
 * @exception DWTException <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 setPageIncrement (int value) {
    checkWidget ();
    if (value < 1) return;
    adjustmentHandle.page_increment = cast(float) value;
    OS.g_signal_handlers_block_matched (adjustmentHandle, OS.G_SIGNAL_MATCH_DATA, 0, 0, null, null, udVALUE_CHANGED);
    OS.gtk_adjustment_changed (adjustmentHandle);
    OS.g_signal_handlers_unblock_matched (adjustmentHandle, OS.G_SIGNAL_MATCH_DATA, 0, 0, null, null, udVALUE_CHANGED);
}

/**
 * Sets the single <em>selection</em> that is the receiver's
 * value to the argument which must be greater than or equal
 * to zero.
 *
 * @param selection the new selection (must be zero or greater)
 *
 * @exception DWTException <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 setSelection (int value) {
    checkWidget ();
    value = Math.min (value, getMaximum() - getThumb());
    OS.g_signal_handlers_block_matched (adjustmentHandle, OS.G_SIGNAL_MATCH_DATA, 0, 0, null, null, udVALUE_CHANGED);
    OS.gtk_adjustment_set_value (adjustmentHandle, value);
    OS.g_signal_handlers_unblock_matched (adjustmentHandle, OS.G_SIGNAL_MATCH_DATA, 0, 0, null, null, udVALUE_CHANGED);
}

/**
 * Sets the size of the receiver's thumb relative to the
 * difference between its maximum and minimum values.  This new
 * value will be ignored if it is less than one, and will be
 * clamped if it exceeds the receiver's current range.
 *
 * @param value the new thumb value, which must be at least one and not
 * larger than the size of the current range
 *
 * @exception DWTException <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 setThumb (int value) {
    checkWidget ();
    if (value < 1) return;
    value = Math.min (value, cast(int)(adjustmentHandle.upper - adjustmentHandle.lower));
    adjustmentHandle.page_size = cast(double) value;
    adjustmentHandle.value = Math.min (adjustmentHandle.value, (adjustmentHandle.upper - value));
    OS.g_signal_handlers_block_matched (adjustmentHandle, OS.G_SIGNAL_MATCH_DATA, 0, 0, null, null, udVALUE_CHANGED);
    OS.gtk_adjustment_changed (adjustmentHandle);
    OS.g_signal_handlers_unblock_matched (adjustmentHandle, OS.G_SIGNAL_MATCH_DATA, 0, 0, null, null, udVALUE_CHANGED);
}

/**
 * Sets the receiver's selection, minimum value, maximum
 * value, thumb, increment and page increment all at once.
 * <p>
 * Note: This is similar to setting the values individually
 * using the appropriate methods, but may be implemented in a
 * more efficient fashion on some platforms.
 * </p>
 *
 * @param selection the new selection value
 * @param minimum the new minimum value
 * @param maximum the new maximum value
 * @param thumb the new thumb value
 * @param increment the new increment value
 * @param pageIncrement the new pageIncrement value
 *
 * @exception DWTException <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 setValues (int selection, int minimum, int maximum, int thumb, int increment, int pageIncrement) {
    checkWidget ();
    if (minimum < 0) return;
    if (maximum < 0) return;
    if (thumb < 1) return;
    if (increment < 1) return;
    if (pageIncrement < 1) return;
    thumb = Math.min (thumb, maximum - minimum);
    adjustmentHandle.lower = minimum;
    adjustmentHandle.upper = maximum;
    adjustmentHandle.step_increment = increment;
    adjustmentHandle.page_increment = pageIncrement;
    adjustmentHandle.page_size = thumb;
    adjustmentHandle.value = Math.min (Math.max (selection, minimum), maximum - thumb);
    OS.g_signal_handlers_block_matched (adjustmentHandle, OS.G_SIGNAL_MATCH_DATA, 0, 0, null, null, udVALUE_CHANGED);
    OS.gtk_adjustment_changed (adjustmentHandle);
    OS.gtk_adjustment_value_changed (adjustmentHandle);
    OS.g_signal_handlers_unblock_matched (adjustmentHandle, OS.G_SIGNAL_MATCH_DATA, 0, 0, null, null, udVALUE_CHANGED);
}

/**
 * Marks the receiver as visible if the argument is <code>true</code>,
 * and marks it invisible otherwise.
 * <p>
 * If one of the receiver's ancestors is not visible or some
 * other condition makes the receiver not visible, marking
 * it visible may not actually cause it to be displayed.
 * </p>
 *
 * @param visible the new visibility state
 *
 * @exception DWTException <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 setVisible (bool visible) {
    checkWidget ();
    if (parent.setScrollBarVisible (this, visible)) {
        sendEvent (visible ? DWT.Show : DWT.Hide);
        parent.sendEvent (DWT.Resize);
    }
}

}