| /* |
| |
| Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to You under the Apache License, Version 2.0 |
| (the "License"); you may not use this file except in compliance with |
| the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| |
| */ |
| package org.apache.batik.apps.svgbrowser; |
| |
| import java.awt.geom.AffineTransform; |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| /** |
| * This class implements a transform history mechanism. |
| * |
| * @author <a href="mailto:stephane@hillion.org">Stephane Hillion</a> |
| * @version $Id$ |
| */ |
| public class TransformHistory { |
| |
| /** |
| * The transform stack. |
| */ |
| protected List transforms = new ArrayList(); |
| |
| /** |
| * The current position in the stack. |
| */ |
| protected int position = -1; |
| |
| /** |
| * Goes back of one position in the history. |
| * Assumes that <tt>canGoBack()</tt> is true. |
| */ |
| public void back() { |
| position -= 2; |
| } |
| |
| /** |
| * Whether it is possible to go back. |
| */ |
| public boolean canGoBack() { |
| return position > 0; |
| } |
| |
| /** |
| * Goes forward of one position in the history. |
| * Assumes that <tt>canGoForward()</tt> is true. |
| */ |
| public void forward() { |
| } |
| |
| /** |
| * Whether it is possible to go forward. |
| */ |
| public boolean canGoForward() { |
| return position < transforms.size() - 1; |
| } |
| |
| /** |
| * Returns the current transform. |
| */ |
| public AffineTransform currentTransform() { |
| return (AffineTransform)transforms.get(position + 1); |
| } |
| |
| /** |
| * Adds a transform to the history. |
| */ |
| public void update(AffineTransform at) { |
| if (position < -1) { |
| position = -1; |
| } |
| if (++position < transforms.size()) { |
| if (!transforms.get(position).equals(at)) { |
| transforms = transforms.subList(0, position + 1); |
| } |
| transforms.set(position, at); |
| } else { |
| transforms.add(at); |
| } |
| } |
| } |