/**
* Copyright (c) 2007, Gaudenz Alder
*/
package com.mxgraph.reader;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
import java.util.Map;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import com.mxgraph.canvas.mxICanvas;
import com.mxgraph.util.mxPoint;
import com.mxgraph.util.mxRectangle;
import com.mxgraph.util.mxUtils;
import com.mxgraph.view.mxCellState;
/**
* An abstract converter that renders display XML data onto a canvas.
*/
public abstract class mxGraphViewReader extends DefaultHandler
{
/**
* Holds the canvas to be used for rendering the graph.
*/
protected mxICanvas canvas;
/**
* Holds the global scale of the graph. This is set just before
* createCanvas is called.
*/
protected double scale = 1;
/**
* Specifies if labels should be rendered as HTML markup.
*/
protected boolean htmlLabels = false;
/**
* Sets the htmlLabels switch.
*/
public void setHtmlLabels(boolean value)
{
htmlLabels = value;
}
/**
* Returns the htmlLabels switch.
*/
public boolean isHtmlLabels()
{
return htmlLabels;
}
/**
* Returns the canvas to be used for rendering.
*
* @param attrs Specifies the attributes of the new canvas.
* @return Returns a new canvas.
*/
public abstract mxICanvas createCanvas(Map<String, Object> attrs);
/**
* Returns the canvas that is used for rendering the graph.
*
* @return Returns the canvas.
*/
public mxICanvas getCanvas()
{
return canvas;
}
/* (non-Javadoc)
* @see org.xml.sax.helpers.DefaultHandler#startElement(java.lang.String, java.lang.String, java.lang.String, org.xml.sax.Attributes)
*/
public void startElement(String uri, String localName, String qName,
Attributes atts) throws SAXException
{
String tagName = qName.toUpperCase();
Map<String, Object> attrs = new Hashtable<String, Object>();
for (int i = 0; i < atts.getLength(); i++)
{
String name = atts.getQName(i);
// Workaround for possible null name
if (name == null || name.length() == 0)
{
name = atts.getLocalName(i);
}
attrs.put(name, atts.getValue(i));
}
parseElement(tagName, attrs);
}
/**
* Parses the given element and paints it onto the canvas.
*
* @param tagName Name of the node to be parsed.
* @param attrs Attributes of the node to be parsed.
*/
public void parseElement(String tagName, Map<String, Object> attrs)
{
if (canvas == null && tagName.equalsIgnoreCase("graph"))
{
scale = mxUtils.getDouble(attrs, "scale", 1);
canvas = createCanvas(attrs);
if (canvas != null)
{
canvas.setScale(scale);
}
}
else if (canvas != null)
{
boolean edge = tagName.equalsIgnoreCase("edge");
boolean group = tagName.equalsIgnoreCase("group");
boolean vertex = tagName.equalsIgnoreCase("vertex");
if ((edge && attrs.containsKey("points"))
|| ((vertex || group) && attrs.containsKey("x")
&& attrs.containsKey("y")
&& attrs.containsKey("width") && attrs
.containsKey("height")))
{
mxCellState state = new mxCellState(null, null, attrs);
String label = parseState(state, edge);
canvas.drawCell(state);
canvas.drawLabel(label, state, isHtmlLabels());
}
}
}
/**
* Parses the bounds, absolute points and label information from the style
* of the state into its respective fields and returns the label of the
* cell.
*/
public String parseState(mxCellState state, boolean edge)
{
Map<String, Object> style = state.getStyle();
// Parses the bounds
state.setX(mxUtils.getDouble(style, "x"));
state.setY(mxUtils.getDouble(style, "y"));
state.setWidth(mxUtils.getDouble(style, "width"));
state.setHeight(mxUtils.getDouble(style, "height"));
// Parses the absolute points list
List<mxPoint> pts = parsePoints(mxUtils.getString(style, "points"));
if (pts.size() > 0)
{
state.setAbsolutePoints(pts);
}
// Parses the label and label bounds
String label = mxUtils.getString(style, "label");
if (label != null && label.length() > 0)
{
mxPoint offset = new mxPoint(mxUtils.getDouble(style, "dx"),
mxUtils.getDouble(style, "dy"));
mxRectangle vertexBounds = (!edge) ? state : null;
state.setLabelBounds(mxUtils.getLabelPaintBounds(label, state
.getStyle(), mxUtils.isTrue(style, "html", false), offset,
vertexBounds, scale));
}
return label;
}
/**
* Parses the list of points into an object-oriented representation.
*
* @param pts String containing a list of points.
* @return Returns the points as a list of mxPoints.
*/
public static List<mxPoint> parsePoints(String pts)
{
List<mxPoint> result = new ArrayList<mxPoint>();
if (pts != null)
{
int len = pts.length();
String tmp = "";
String x = null;
for (int i = 0; i < len; i++)
{
char c = pts.charAt(i);
if (c == ',' || c == ' ')
{
if (x == null)
{
x = tmp;
}
else
{
result.add(new mxPoint(Double.parseDouble(x), Double
.parseDouble(tmp)));
x = null;
}
tmp = "";
}
else
{
tmp += c;
}
}
result.add(new mxPoint(Double.parseDouble(x), Double
.parseDouble(tmp)));
}
return result;
}
}