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/*******************************************************************************
* Copyright (c) 2000, 2013 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.examples.paint;
import org.eclipse.swt.graphics.*;
/**
* Container for Figure objects with stacking preview mechanism.
*/
public class ContainerFigure extends Figure {
private static final int INITIAL_ARRAY_SIZE = 16;
Figure[] objectStack = null;
int nextIndex = 0;
/**
* Constructs an empty Container
*/
public ContainerFigure() {
}
/**
* Adds an object to the container for later drawing.
*
* @param object the object to add to the drawing list
*/
public void add(Figure object) {
if (objectStack == null) {
objectStack = new Figure[INITIAL_ARRAY_SIZE];
} else if (objectStack.length <= nextIndex) {
Figure[] newObjectStack = new Figure[objectStack.length * 2];
System.arraycopy(objectStack, 0, newObjectStack, 0, objectStack.length);
objectStack = newObjectStack;
}
objectStack[nextIndex] = object;
++nextIndex;
}
/**
* Determines if the container is empty.
* @return true if the container is empty
*/
public boolean isEmpty() {
return nextIndex == 0;
}
/**
* Adds an object to the container and draws its preview then updates the supplied preview state.
*
* @param object the object to add to the drawing list
* @param gc the GC to draw on
* @param offset the offset to add to virtual coordinates to get display coordinates
* @param rememberedState the state returned by a previous drawPreview() or addAndPreview()
* using this Container, may be null if there was no such previous call
* @return object state that must be passed to erasePreview() later to erase this object
*/
// public Object addAndPreview(Figure object, GC gc, Point offset, Object rememberedState) {
// Object[] stateStack = (Object[]) rememberedState;
// if (stateStack == null) {
// stateStack = new Object[INITIAL_ARRAY_SIZE];
// } else if (stateStack.length <= nextIndex) {
// Object[] newStateStack = new Object[stateStack.length * 2];
// System.arraycopy(stateStack, 0, newStateStack, 0, stateStack.length);
// stateStack = newStateStack;
// }
// add(object);
// stateStack[nextIndex - 1] = object.drawPreview(gc, offset);
// return stateStack;
// }
/**
* Clears the container.
* <p>
* Note that erasePreview() cannot be called after this point to erase any previous
* drawPreview()'s.
* </p>
*/
public void clear() {
while (--nextIndex > 0) objectStack[nextIndex] = null;
nextIndex = 0;
}
@Override
public void draw(FigureDrawContext fdc) {
for (int i = 0; i < nextIndex; ++i) objectStack[i].draw(fdc);
}
@Override
public void addDamagedRegion(FigureDrawContext fdc, Region region) {
for (int i = 0; i < nextIndex; ++i) objectStack[i].addDamagedRegion(fdc, region);
}
}
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