com.google.devtools.depan.view_doc.layout.hierarchy.HierarchicalTreeLayout.java Source code

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Here is the source code for com.google.devtools.depan.view_doc.layout.hierarchy.HierarchicalTreeLayout.java

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/*
 * Copyright 2008 The Depan Project Authors
 *
 * Licensed 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 com.google.devtools.depan.view_doc.layout.hierarchy;

import com.google.devtools.depan.graph.api.EdgeMatcher;
import com.google.devtools.depan.model.GraphModel;
import com.google.devtools.depan.model.GraphNode;
import com.google.devtools.depan.view_doc.model.Point2dUtils;

import com.google.common.collect.Maps;

import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.util.Map;

/**
 * Assign locations to the graph nodes so they are rendered in a 
 * left-to-right hierarchy.  With suitable options top-to-bottom and other
 * layout variations are readily accommodated.
 * 
 * @author <a href='mailto:leeca@google.com'>Lee Carver </a>
 */
public abstract class HierarchicalTreeLayout {

    /** The source of nodes for layout. */
    protected final GraphModel graphModel;

    /** Edge matcher that defines the tree hierarchy. */
    protected final EdgeMatcher<String> edgeMatcher;

    /** The region to fill with the layout. */
    protected final Rectangle2D region;

    /**
     * The computed positions for the nodes.  Allocated just before the
     * positions are computed.
     */
    protected Map<GraphNode, Point2D> positions;

    /**
     * @param graphModel nodes and edges to layout
     * @param edgeMatcher edge matcher that defines the hierarchy
     * @param size available rendering space (ignored)
     */
    protected HierarchicalTreeLayout(GraphModel graphModel, EdgeMatcher<String> edgeMatcher, Rectangle2D region) {
        this.graphModel = graphModel;
        this.edgeMatcher = edgeMatcher;
        this.region = region;
    }

    protected abstract HierarchicalLayoutTool buildLayoutTool();

    /**
     * Does the complete left-to-right planar layout.
     */
    public void initialize() {
        HierarchicalLayoutTool layoutTool = buildLayoutTool();

        positions = Maps.newHashMapWithExpectedSize(graphModel.getNodes().size());
        layoutTool.layoutTree();
        Point2dUtils.translatePos(region, graphModel.getNodes(), positions);
    }

    public Point2D getPosition(GraphNode node) {
        return positions.get(node);
    }
}