bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/ScrollBar.java - platform/eclipse.platform.swt - Git at Google

 /*******************************************************************************
  * 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
  *******************************************************************************/
 package org.eclipse.swt.widgets;


 import org.eclipse.swt.internal.cocoa.*;

 import org.eclipse.swt.*;
 import org.eclipse.swt.events.*;
 import org.eclipse.swt.graphics.*;

 /**
  * 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. SWT 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">SWT Example: ControlExample</a>
  * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
  */
 public class ScrollBar extends Widget {
 	NSScroller view;
 	Scrollable parent;
 	int minimum, maximum = 100, thumb = 10;
 	int increment = 1;
 	int pageIncrement = 10;
 	id target;
 	int /*long*/ actionSelector;;

 ScrollBar () {
 	/* Do nothing */
 }

 /**
  * 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>SWT.NONE</code> - for the end of a drag.
  * <code>SWT.DRAG</code>.
  * <code>SWT.HOME</code>.
  * <code>SWT.END</code>.
  * <code>SWT.ARROW_DOWN</code>.
  * <code>SWT.ARROW_UP</code>.
  * <code>SWT.PAGE_DOWN</code>.
  * <code>SWT.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 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>
  *
  * @see SelectionListener
  * @see #removeSelectionListener
  * @see SelectionEvent
  */
 public void addSelectionListener(SelectionListener listener) {
 	checkWidget();
 	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
 	TypedListener typedListener = new TypedListener(listener);
 	addListener(SWT.Selection,typedListener);
 	addListener(SWT.DefaultSelection,typedListener);
 }

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

 void deregister () {
 	super.deregister ();
 	display.removeWidget (view);
 }

 boolean getDrawing () {
 	return parent.getDrawing ();
 }

 /**
  * 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 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>
  *
  * @see #isEnabled
  */
 public boolean getEnabled () {
 	checkWidget();
 	return (state & DISABLED) == 0;
 }

 /**
  * 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 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 int getIncrement () {
 	checkWidget();
     return increment;
 }

 /**
  * Returns the maximum value which the receiver will allow.
  *
  * @return the maximum
  *
  * @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 int getMaximum () {
 	checkWidget();
 	return maximum;
 }

 /**
  * Returns the minimum value which the receiver will allow.
  *
  * @return the minimum
  *
  * @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 int getMinimum () {
 	checkWidget();
 	return minimum;
 }

 /**
  * 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 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 int getPageIncrement () {
 	checkWidget();
     return pageIncrement;
 }

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

 /**
  * Returns the single 'selection' that is the receiver's value.
  *
  * @return the selection
  *
  * @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 int getSelection () {
 	checkWidget();
 	NSScroller widget = (NSScroller)view;
 	double value = widget.doubleValue();
     return (int)(0.5f + ((maximum - thumb - minimum) * value + minimum));
 }

 /**
  * 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 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 Point getSize () {
 	checkWidget();
 	NSRect rect = ((NSScroller)view).frame();
 	return new Point((int)rect.width, (int)rect.height);
 }

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

 /**
  * 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 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 boolean getVisible () {
 	checkWidget();
 	return (state & HIDDEN) == 0;
 }

 /**
  * 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 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>
  *
  * @see #getEnabled
  */
 public boolean isEnabled () {
 	checkWidget();
 	return getEnabled () && parent.isEnabled ();
 }

 boolean isDrawing () {
 	return getDrawing() && parent.isDrawing ();
 }

 /**
  * 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 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>
  *
  * @see #getVisible
  */
 public boolean isVisible () {
 	checkWidget();
 	return getVisible () && parent.isVisible ();
 }

 /**
  * 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 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>
  *
  * @see SelectionListener
  * @see #addSelectionListener
  */
 public void removeSelectionListener(SelectionListener listener) {
 	checkWidget();
 	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
 	if (eventTable == null) return;
 	eventTable.unhook(SWT.Selection, listener);
 	eventTable.unhook(SWT.DefaultSelection,listener);
 }

 void register () {
 	super.register ();
 	display.addWidget (view, this);
 }

 void releaseHandle () {
 	super.releaseHandle ();
 	if (view != null) view.release();
 	view = null;
 }

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

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

 void sendSelection () {
 	int value = 0;
 	if (target != null) {
 		view.sendAction(actionSelector, target);
 	} else {
 		value = getSelection ();
 	}
 	Event event = new Event();
 	int hitPart = (int)/*64*/((NSScroller)view).hitPart();
 	switch (hitPart) {
 	    case OS.NSScrollerDecrementLine:
 	        value -= increment;
 	        event.detail = SWT.ARROW_UP;
 	        break;
 	    case OS.NSScrollerDecrementPage:
 	        value -= pageIncrement;
 	        event.detail = SWT.PAGE_UP;
 	        break;
 	    case OS.NSScrollerIncrementLine:
 	        value += increment;
 	        event.detail = SWT.ARROW_DOWN;
 	        break;
 	    case OS.NSScrollerIncrementPage:
 	        value += pageIncrement;
 	        event.detail = SWT.PAGE_DOWN;
 	        break;
 	    case OS.NSScrollerKnob:
 			event.detail = SWT.DRAG;
 	        break;
 	}
 	if (target == null) {
 		if (event.detail != SWT.DRAG) {
 			setSelection(value);
 		}
 	}
 	sendEvent(SWT.Selection, event);
 }

 /**
  * 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 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 setIncrement (int value) {
 	checkWidget();
 	if (value < 1) return;
 	increment = value;
 }

 void setClipRegion (float /*double*/ x, float /*double*/ y) {
 	NSRect frame = view.frame();
 	parent.setClipRegion(frame.x + x, frame.y + y);
 }

 /**
  * 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 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 setEnabled (boolean enabled) {
 	checkWidget();
 	if (enabled) {
 		if ((state & DISABLED) == 0) return;
 		state &= ~DISABLED;
 	} else {
 		if ((state & DISABLED) != 0) return;
 		state |= DISABLED;
 	}
 	enableWidget (enabled);
 }

 void enableWidget (boolean enabled) {
 	if (!enabled || (state & DISABLED) == 0) {
 		view.setEnabled (enabled);
 	}
 }

 /**
  * 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 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 setMaximum (int value) {
 	checkWidget();
 	if (value < 0) return;
 	if (value <= minimum) return;
 	if (value - minimum < thumb) {
 		thumb = value - minimum;
 	}
 	int selection = Math.max(minimum, Math.min (getSelection (), value - thumb));
 	this.maximum = value;
 	updateBar(selection, minimum, value, thumb);
 }

 /**
  * 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 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 setMinimum (int value) {
 	checkWidget();
 	if (value < 0) return;
 	if (value >= maximum) return;
 	if (maximum - value < thumb) {
 		thumb = maximum - value;
 	}
 	int selection = Math.min(maximum - thumb, Math.max (getSelection (), value));
 	this.minimum = value;
 	updateBar(selection, value, maximum, thumb);
 }

 /**
  * 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 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 setPageIncrement (int value) {
 	checkWidget();
 	if (value < 1) return;
 	pageIncrement = value;
 }

 /**
  * 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 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 setSelection (int value) {
 	checkWidget();
 	updateBar(value, minimum, maximum, thumb);
 }

 /**
  * 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 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 setThumb (int value) {
 	checkWidget();
 	if (value < 1) return;
 	value = Math.min (value, maximum - minimum);
 	updateBar(getSelection(), minimum, maximum, value);
 	this.thumb = value;
 }

 /**
  * 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 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 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;
 	this.thumb = thumb = Math.min (thumb, maximum - minimum);
 	this.maximum = maximum;
 	this.minimum = minimum;
 	this.increment = increment;
 	this.pageIncrement = pageIncrement;
 	updateBar (selection, minimum, maximum, thumb);
 }

 /**
  * 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 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 setVisible (boolean visible) {
 	checkWidget();
 	parent.setScrollBarVisible (this, visible);
 }

 void updateBar (int selection, int minimum, int maximum, int thumb) {
 	NSScroller widget = (NSScroller) view;
 	selection = Math.max (minimum, Math.min (maximum - thumb, selection));
 	int range = maximum - thumb - minimum;
 	float fraction = range <= 0 ? 1 : (float) (selection - minimum) / range;
 	float knob = range <= 0 ? 1 : (float) thumb / (maximum - minimum);
 	widget.setFloatValue (fraction, knob);
 	widget.setEnabled (range > 0);
 }

 }
	/*******************************************************************************
	* 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
	*******************************************************************************/
	package org.eclipse.swt.widgets;


	import org.eclipse.swt.internal.cocoa.*;

	import org.eclipse.swt.*;
	import org.eclipse.swt.events.*;
	import org.eclipse.swt.graphics.*;

	/**
	* 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. SWT 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">SWT Example: ControlExample</a>
	* @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
	*/
	public class ScrollBar extends Widget {
	NSScroller view;
	Scrollable parent;
	int minimum, maximum = 100, thumb = 10;
	int increment = 1;
	int pageIncrement = 10;
	id target;
	int /long/ actionSelector;;

	ScrollBar () {
	/* Do nothing */
	}

	/**
	* 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>SWT.NONE</code> - for the end of a drag.
	* <code>SWT.DRAG</code>.
	* <code>SWT.HOME</code>.
	* <code>SWT.END</code>.
	* <code>SWT.ARROW_DOWN</code>.
	* <code>SWT.ARROW_UP</code>.
	* <code>SWT.PAGE_DOWN</code>.
	* <code>SWT.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 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>
	*
	* @see SelectionListener
	* @see #removeSelectionListener
	* @see SelectionEvent
	*/
	public void addSelectionListener(SelectionListener listener) {
	checkWidget();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	TypedListener typedListener = new TypedListener(listener);
	addListener(SWT.Selection,typedListener);
	addListener(SWT.DefaultSelection,typedListener);
	}

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

	void deregister () {
	super.deregister ();
	display.removeWidget (view);
	}

	boolean getDrawing () {
	return parent.getDrawing ();
	}

	/**
	* 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 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>
	*
	* @see #isEnabled
	*/
	public boolean getEnabled () {
	checkWidget();
	return (state & DISABLED) == 0;
	}

	/**
	* 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 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 int getIncrement () {
	checkWidget();
	return increment;
	}

	/**
	* Returns the maximum value which the receiver will allow.
	*
	* @return the maximum
	*
	* @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 int getMaximum () {
	checkWidget();
	return maximum;
	}

	/**
	* Returns the minimum value which the receiver will allow.
	*
	* @return the minimum
	*
	* @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 int getMinimum () {
	checkWidget();
	return minimum;
	}

	/**
	* 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 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 int getPageIncrement () {
	checkWidget();
	return pageIncrement;
	}

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

	/**
	* Returns the single 'selection' that is the receiver's value.
	*
	* @return the selection
	*
	* @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 int getSelection () {
	checkWidget();
	NSScroller widget = (NSScroller)view;
	double value = widget.doubleValue();
	return (int)(0.5f + ((maximum - thumb - minimum) * value + minimum));
	}

	/**
	* 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 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 Point getSize () {
	checkWidget();
	NSRect rect = ((NSScroller)view).frame();
	return new Point((int)rect.width, (int)rect.height);
	}

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

	/**
	* 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 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 boolean getVisible () {
	checkWidget();
	return (state & HIDDEN) == 0;
	}

	/**
	* 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 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>
	*
	* @see #getEnabled
	*/
	public boolean isEnabled () {
	checkWidget();
	return getEnabled () && parent.isEnabled ();
	}

	boolean isDrawing () {
	return getDrawing() && parent.isDrawing ();
	}

	/**
	* 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 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>
	*
	* @see #getVisible
	*/
	public boolean isVisible () {
	checkWidget();
	return getVisible () && parent.isVisible ();
	}

	/**
	* 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 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>
	*
	* @see SelectionListener
	* @see #addSelectionListener
	*/
	public void removeSelectionListener(SelectionListener listener) {
	checkWidget();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	if (eventTable == null) return;
	eventTable.unhook(SWT.Selection, listener);
	eventTable.unhook(SWT.DefaultSelection,listener);
	}

	void register () {
	super.register ();
	display.addWidget (view, this);
	}

	void releaseHandle () {
	super.releaseHandle ();
	if (view != null) view.release();
	view = null;
	}

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

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

	void sendSelection () {
	int value = 0;
	if (target != null) {
	view.sendAction(actionSelector, target);
	} else {
	value = getSelection ();
	}
	Event event = new Event();
	int hitPart = (int)/64/((NSScroller)view).hitPart();
	switch (hitPart) {
	case OS.NSScrollerDecrementLine:
	value -= increment;
	event.detail = SWT.ARROW_UP;
	break;
	case OS.NSScrollerDecrementPage:
	value -= pageIncrement;
	event.detail = SWT.PAGE_UP;
	break;
	case OS.NSScrollerIncrementLine:
	value += increment;
	event.detail = SWT.ARROW_DOWN;
	break;
	case OS.NSScrollerIncrementPage:
	value += pageIncrement;
	event.detail = SWT.PAGE_DOWN;
	break;
	case OS.NSScrollerKnob:
	event.detail = SWT.DRAG;
	break;
	}
	if (target == null) {
	if (event.detail != SWT.DRAG) {
	setSelection(value);
	}
	}
	sendEvent(SWT.Selection, event);
	}

	/**
	* 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 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 setIncrement (int value) {
	checkWidget();
	if (value < 1) return;
	increment = value;
	}

	void setClipRegion (float /double/ x, float /double/ y) {
	NSRect frame = view.frame();
	parent.setClipRegion(frame.x + x, frame.y + y);
	}

	/**
	* 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 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 setEnabled (boolean enabled) {
	checkWidget();
	if (enabled) {
	if ((state & DISABLED) == 0) return;
	state &= ~DISABLED;
	} else {
	if ((state & DISABLED) != 0) return;
	state \|= DISABLED;
	}
	enableWidget (enabled);
	}

	void enableWidget (boolean enabled) {
	if (!enabled \|\| (state & DISABLED) == 0) {
	view.setEnabled (enabled);
	}
	}

	/**
	* 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 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 setMaximum (int value) {
	checkWidget();
	if (value < 0) return;
	if (value <= minimum) return;
	if (value - minimum < thumb) {
	thumb = value - minimum;
	}
	int selection = Math.max(minimum, Math.min (getSelection (), value - thumb));
	this.maximum = value;
	updateBar(selection, minimum, value, thumb);
	}

	/**
	* 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 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 setMinimum (int value) {
	checkWidget();
	if (value < 0) return;
	if (value >= maximum) return;
	if (maximum - value < thumb) {
	thumb = maximum - value;
	}
	int selection = Math.min(maximum - thumb, Math.max (getSelection (), value));
	this.minimum = value;
	updateBar(selection, value, maximum, thumb);
	}

	/**
	* 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 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 setPageIncrement (int value) {
	checkWidget();
	if (value < 1) return;
	pageIncrement = value;
	}

	/**
	* 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 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 setSelection (int value) {
	checkWidget();
	updateBar(value, minimum, maximum, thumb);
	}

	/**
	* 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 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 setThumb (int value) {
	checkWidget();
	if (value < 1) return;
	value = Math.min (value, maximum - minimum);
	updateBar(getSelection(), minimum, maximum, value);
	this.thumb = value;
	}

	/**
	* 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 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 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;
	this.thumb = thumb = Math.min (thumb, maximum - minimum);
	this.maximum = maximum;
	this.minimum = minimum;
	this.increment = increment;
	this.pageIncrement = pageIncrement;
	updateBar (selection, minimum, maximum, thumb);
	}

	/**
	* 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 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 setVisible (boolean visible) {
	checkWidget();
	parent.setScrollBarVisible (this, visible);
	}

	void updateBar (int selection, int minimum, int maximum, int thumb) {
	NSScroller widget = (NSScroller) view;
	selection = Math.max (minimum, Math.min (maximum - thumb, selection));
	int range = maximum - thumb - minimum;
	float fraction = range <= 0 ? 1 : (float) (selection - minimum) / range;
	float knob = range <= 0 ? 1 : (float) thumb / (maximum - minimum);
	widget.setFloatValue (fraction, knob);
	widget.setEnabled (range > 0);
	}

	}