/*******************************************************************************
* Copyright (c) 2002, 2016 Innoopract Informationssysteme GmbH 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:
* Innoopract Informationssysteme GmbH - initial API and implementation
* EclipseSource - ongoing development
******************************************************************************/
package org.eclipse.swt.widgets;
import org.eclipse.rap.rwt.internal.lifecycle.WidgetLCA;
import org.eclipse.swt.SWT;
import org.eclipse.swt.SWTException;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.internal.graphics.GCAdapter;
import org.eclipse.swt.internal.widgets.canvaskit.CanvasLCA;
/**
* Instances of this class provide a surface for drawing
* arbitrary graphics.
* <dl>
* <dt><b>Styles:</b></dt>
* <dd>(none)</dd>
* <dt><b>Events:</b></dt>
* <dd>(none)</dd>
* </dl>
* <p>
* This class may be subclassed by custom control implementors
* who are building controls that are <em>not</em> constructed
* from aggregates of other controls. That is, they are either
* painted using SWT graphics calls or are handled by native
* methods.
* </p>
*
* @see Composite
* @since 1.0
*/
public class Canvas extends Composite {
private transient GCAdapter gcAdapter;
Canvas( Composite parent ) {
// prevent instantiation from outside this package
super( parent );
}
/**
* 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>
* </ul>
*
* @see SWT
* @see Widget#checkSubclass
* @see Widget#getStyle
*/
public Canvas( Composite parent, int style ) {
super( parent, style );
}
@Override
@SuppressWarnings("unchecked")
public <T> T getAdapter( Class<T> adapter ) {
if( adapter == GCAdapter.class ) {
if( gcAdapter == null ) {
gcAdapter = new GCAdapter();
}
return ( T )gcAdapter;
}
if( adapter == WidgetLCA.class ) {
return ( T )CanvasLCA.INSTANCE;
}
return super.getAdapter( adapter );
}
/**
* Adds the listener to the collection of listeners who will
* be notified when the receiver needs to be painted, by sending it
* one of the messages defined in the <code>PaintListener</code>
* interface.
*
* @param listener the listener which should 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 PaintListener
* @see #removePaintListener
* @since 1.3
*/
public void addPaintListener( PaintListener listener ) {
checkWidget();
if( listener == null ) {
error( SWT.ERROR_NULL_ARGUMENT );
}
TypedListener typedListener = new TypedListener( listener );
addListener( SWT.Paint, typedListener );
}
/**
* Removes the listener from the collection of listeners who will
* be notified when the receiver needs to be painted.
*
* @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 PaintListener
* @see #addPaintListener
* @since 1.3
*/
public void removePaintListener( PaintListener listener ) {
checkWidget();
if( listener == null ) {
error( SWT.ERROR_NULL_ARGUMENT );
}
removeListener( SWT.Paint, listener );
}
/////////////
// repainting
@Override
void notifyResize( Point oldSize ) {
super.notifyResize( oldSize );
if( !oldSize.equals( getSize() ) ) {
repaint( getClientArea() );
}
}
@Override
void internalSetRedraw( boolean redraw ) {
super.internalSetRedraw( redraw );
if( redraw ) {
repaint( getClientArea() );
}
}
@Override
void internalSetRedraw( boolean redraw, int x, int y, int width, int height ) {
super.internalSetRedraw( redraw, x, y, width, height );
if( redraw ) {
repaint( new Rectangle( x, y, width, height ) );
}
}
private void repaint( Rectangle paintRect ) {
if( gcAdapter != null ) {
gcAdapter.clearGCOperations();
gcAdapter.setForceRedraw( true );
}
GC gc = new GC( this );
Event paintEvent = new Event();
paintEvent.gc = gc;
paintEvent.setBounds( paintRect );
notifyListeners( SWT.Paint, paintEvent );
gc.dispose();
if( gcAdapter != null ) {
gcAdapter.setPaintRect( paintRect );
}
}
}