/*******************************************************************************
* 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
*******************************************************************************/
package org.eclipse.swt.widgets;
import org.eclipse.swt.internal.wpf.*;
import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
/**
* This class is the abstract superclass of all classes which
* represent controls that have standard scroll bars.
* <dl>
* <dt><b>Styles:</b></dt>
* <dd>H_SCROLL, V_SCROLL</dd>
* <dt><b>Events:</b>
* <dd>(none)</dd>
* </dl>
* <p>
* IMPORTANT: This class is intended to be subclassed <em>only</em>
* within the SWT implementation.
* </p>
*
* @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
* @noextend This class is not intended to be subclassed by clients.
*/
public abstract class Scrollable extends Control {
ScrollBar horizontalBar, verticalBar;
int scrolledHandle;
/**
* Prevents uninitialized instances from being created outside the package.
*/
Scrollable () {
}
/**
* 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 composite control which will be the parent of the new instance (cannot be null)
* @param style the style of control 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>
* <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
* </ul>
*
* @see SWT#H_SCROLL
* @see SWT#V_SCROLL
* @see Widget#checkSubclass
* @see Widget#getStyle
*/
public Scrollable (Composite parent, int style) {
super (parent, style);
}
int clientHandle () {
return handle;
}
/**
* Given a desired <em>client area</em> for the receiver
* (as described by the arguments), returns the bounding
* rectangle which would be required to produce that client
* area.
* <p>
* In other words, it returns a rectangle such that, if the
* receiver's bounds were set to that rectangle, the area
* of the receiver which is capable of displaying data
* (that is, not covered by the "trimmings") would be the
* rectangle described by the arguments (relative to the
* receiver's parent).
* </p>
*
* @param x the desired x coordinate of the client area
* @param y the desired y coordinate of the client area
* @param width the desired width of the client area
* @param height the desired height of the client area
* @return the required bounds to produce the given client 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>
*
* @see #getClientArea
*/
public Rectangle computeTrim (int x, int y, int width, int height) {
checkWidget ();
if (verticalBar != null) width += OS.SystemParameters_VerticalScrollBarWidth ();
if (horizontalBar != null) height += OS.SystemParameters_HorizontalScrollBarHeight ();
return new Rectangle (x, y, width, height);
}
ScrollBar createScrollBar (int type) {
return new ScrollBar (this, type);
}
void createWidget () {
super.createWidget ();
if ((style & SWT.H_SCROLL) != 0) horizontalBar = createScrollBar (SWT.H_SCROLL);
if ((style & SWT.V_SCROLL) != 0) verticalBar = createScrollBar (SWT.V_SCROLL);
fixScrollbarVisibility ();
}
void deregister () {
super.deregister ();
if (scrolledHandle != 0) display.removeWidget (scrolledHandle);
}
int findScrollViewer (int current, int scrollViewerType) {
int type = OS.Object_GetType (current);
boolean found = OS.Object_Equals (scrollViewerType, type);
OS.GCHandle_Free (type);
if (found) return current;
int childCount = OS.VisualTreeHelper_GetChildrenCount (current);
for (int i = 0; i < childCount; i++) {
int child = OS.VisualTreeHelper_GetChild (current, i);
int result = findScrollViewer (child, scrollViewerType);
if (child != result) OS.GCHandle_Free (child);
if (result != 0) return result;
}
return 0;
}
void fixScrollbarVisibility () {
if ((style & SWT.H_SCROLL) == 0) {
OS.ScrollViewer_SetHorizontalScrollBarVisibility (handle, OS.ScrollBarVisibility_Hidden);
}
if ((style & SWT.V_SCROLL) == 0) {
OS.ScrollViewer_SetVerticalScrollBarVisibility (handle, OS.ScrollBarVisibility_Hidden);
}
}
/**
* Returns a rectangle which describes the area of the
* receiver which is capable of displaying data (that is,
* not covered by the "trimmings").
*
* @return the client 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>
*
* @see #computeTrim
*/
public Rectangle getClientArea () {
checkWidget ();
int clientHandle = clientHandle ();
int topHandle = topHandle ();
updateLayout (topHandle);
int width = (int) OS.FrameworkElement_ActualWidth (clientHandle);
int height = (int) OS.FrameworkElement_ActualHeight (clientHandle);
return new Rectangle (0, 0, width, height);
}
/**
* Returns the receiver's horizontal scroll bar if it has
* one, and null if it does not.
*
* @return the horizontal scroll bar (or null)
*
* @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 ScrollBar getHorizontalBar () {
checkWidget ();
return horizontalBar;
}
int getScrollBarHandle (int style) {
int scrollbar = 0;
if (scrolledHandle != 0) {
int children = OS.Panel_Children (scrolledHandle);
int enumerator = OS.UIElementCollection_GetEnumerator (children);
int scrollType = OS.ScrollBar_typeid ();
while (OS.IEnumerator_MoveNext (enumerator)) {
int current = OS.IEnumerator_Current (enumerator);
if (OS.Type_IsInstanceOfType (scrollType, current)) {
int orientation = OS.ScrollBar_Orientation (current);
if ((style & SWT.H_SCROLL) != 0 && orientation == OS.Orientation_Horizontal) {
scrollbar = current;
break;
}
if ((style & SWT.V_SCROLL) != 0 && orientation == OS.Orientation_Vertical) {
scrollbar = current;
break;
}
}
OS.GCHandle_Free (current);
}
OS.GCHandle_Free (scrollType);
OS.GCHandle_Free (enumerator);
OS.GCHandle_Free (children);
} else {
updateLayout (handle);
int scrollViewerType = OS.ScrollViewer_typeid ();
int scrollViewer = findScrollViewer (handle, scrollViewerType);
int template = OS.Control_Template (scrollViewer);
int part;
if ((style & SWT.H_SCROLL) != 0) {
part = createDotNetString ("PART_HorizontalScrollBar", false);
} else {
part = createDotNetString ("PART_VerticalScrollBar", false);
}
scrollbar = OS.FrameworkTemplate_FindName (template, part, scrollViewer);
OS.GCHandle_Free (part);
OS.GCHandle_Free (template);
OS.GCHandle_Free (scrollViewer);
OS.GCHandle_Free (scrollViewerType);
}
return scrollbar;
}
/**
* Returns the receiver's vertical scroll bar if it has
* one, and null if it does not.
*
* @return the vertical scroll bar (or null)
*
* @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 ScrollBar getVerticalBar () {
checkWidget ();
return verticalBar;
}
void HandlePreviewMouseWheel (int sender, int e) {
super.HandlePreviewMouseWheel (sender, e);
if (!checkEvent (e)) return;
if ((state & CANVAS) != 0) {
if (verticalBar != null) {
int vHandle = verticalBar.handle;
int delta = OS.MouseWheelEventArgs_Delta (e);
int lines = OS.SystemParameters_WheelScrollLines ();
double value = OS.RangeBase_Value (vHandle);
double newValue = value;
Event event = new Event ();
if (lines != -1) {
double smallIncrement = OS.RangeBase_SmallChange (vHandle);
newValue += smallIncrement * (-delta/120) * lines;
event.detail = delta < 0 ? SWT.ARROW_DOWN : SWT.ARROW_UP;
} else {
double largeIncrement = OS.RangeBase_LargeChange (vHandle);
newValue += largeIncrement * (-delta/120);
event.detail = delta < 0 ? SWT.PAGE_DOWN : SWT.PAGE_UP;
}
OS.RangeBase_Value (vHandle, newValue);
newValue = OS.RangeBase_Value (vHandle);
if (value != newValue) {
verticalBar.postEvent (SWT.Selection, event);
}
}
}
}
void register () {
super.register ();
if (scrolledHandle != 0) display.addWidget (scrolledHandle, this);
}
void releaseChildren (boolean destroy) {
if (horizontalBar != null) {
horizontalBar.release (false);
horizontalBar = null;
}
if (verticalBar != null) {
verticalBar.release (false);
verticalBar = null;
}
super.releaseChildren (destroy);
}
void releaseHandle () {
super.releaseHandle ();
if (scrolledHandle != 0) OS.GCHandle_Free (scrolledHandle);
scrolledHandle = 0;
}
void reskinChildren (int flags) {
if (horizontalBar != null) horizontalBar.reskin (flags);
if (verticalBar != null) verticalBar.reskin (flags);
super.reskinChildren (flags);
}
int topHandle () {
return scrolledHandle != 0 ? scrolledHandle : super.topHandle ();
}
}