mxutils.java

经典的java图像处理程序源码

	{
		BufferedImage result = null;

		if (w > 0 && h > 0)
		{
			// Checks if there is enough memory for allocating the buffer
			Runtime runtime = Runtime.getRuntime();
			long maxMemory = runtime.maxMemory();
			long allocatedMemory = runtime.totalMemory();
			long freeMemory = runtime.freeMemory();
			long totalFreeMemory = (freeMemory + (maxMemory - allocatedMemory)) / 1024;

			int bytes = 4; // 1 if indexed
			long memoryRequired = w * h * bytes / 1024;

			if (memoryRequired <= totalFreeMemory)
			{
				int type = (background != null) ? BufferedImage.TYPE_INT_RGB
						: BufferedImage.TYPE_INT_ARGB;
				result = new BufferedImage(w, h, type);

				// Clears background
				Graphics2D g2 = (Graphics2D) result.createGraphics();
				clearRect(g2, new Rectangle(w, h), background);
				g2.dispose();
			}
		}

		return result;
	}

	/**
	 * Returns a new, empty DOM document.
	 * 
	 * @return Returns a new DOM document.
	 */
	public static Document createDocument()
	{
		try
		{
			DocumentBuilderFactory factory = DocumentBuilderFactory
					.newInstance();
			DocumentBuilder parser = factory.newDocumentBuilder();

			return parser.newDocument();
		}
		catch (Exception e)
		{
			System.out.println(e.getMessage());
		}

		return null;
	}

	/**
	 * 
	 */
	public static Document createSvgDocument(int width, int height)
	{
		Document document = createDocument();
		Element root = document.createElement("svg");

		String w = String.valueOf(width);
		String h = String.valueOf(height);

		root.setAttribute("width", w);
		root.setAttribute("height", h);
		root.setAttribute("viewBox", "0 0 " + w + " " + h);
		root.setAttribute("version", "1.1");
		root.setAttribute("xmlns", "http://www.w3.org/2000/svg");
		root.setAttribute("xmlns:xlink", "http://www.w3.org/1999/xlink");

		document.appendChild(root);

		return document;
	}

	/**
	 * 
	 */
	public static Document createVmlDocument()
	{
		Document document = createDocument();

		Element root = document.createElement("html");
		root.setAttribute("xmlns:v", "urn:schemas-microsoft-com:vml");
		root.setAttribute("xmlns:o", "urn:schemas-microsoft-com:office:office");

		document.appendChild(root);

		Element head = document.createElement("head");

		Element style = document.createElement("style");
		style.setAttribute("type", "text/css");
		style
				.appendChild(document
						.createTextNode("<!-- v\\:* {behavior: url(#default#VML);} -->"));

		head.appendChild(style);
		root.appendChild(head);

		Element body = document.createElement("body");
		root.appendChild(body);

		return document;
	}

	/**
	 * 
	 */
	public static Document createHtmlDocument()
	{
		Document document = createDocument();

		Element root = document.createElement("html");

		document.appendChild(root);

		Element head = document.createElement("head");
		root.appendChild(head);

		Element body = document.createElement("body");
		root.appendChild(body);

		return document;
	}

	/**
	 * Returns a new, empty DOM document.
	 * 
	 * @return Returns a new DOM document.
	 */
	public static HTMLDocument createHtmlDocument(Hashtable style)
	{
		return createHtmlDocument(style, 1);
	}

	/**
	 * Returns a new, empty DOM document.
	 * 
	 * @return Returns a new DOM document.
	 */
	public static HTMLDocument createHtmlDocument(Hashtable style, double scale)
	{
		// Applies the font settings
		HTMLDocument document = new HTMLDocument();

		StringBuffer rule = new StringBuffer("body {");
		rule.append(" font-family: "
				+ getString(style, mxConstants.STYLE_FONTFAMILY,
						mxConstants.DEFAULT_FONTFAMILIES) + " ; ");
		rule.append(" font-size: "
				+ (int) (getInt(style, mxConstants.STYLE_FONTSIZE,
						mxConstants.DEFAULT_FONTSIZE) * scale) + " pt ;");

		String color = mxUtils.getString(style, mxConstants.STYLE_FONTCOLOR);

		if (color != null)
		{
			rule.append("color: " + color + " ; ");
		}

		int fontStyle = mxUtils.getInt(style, mxConstants.STYLE_FONTSTYLE);

		if ((fontStyle & mxConstants.FONT_BOLD) == mxConstants.FONT_BOLD)
		{
			rule.append(" font-weight: bold ; ");
		}

		if ((fontStyle & mxConstants.FONT_ITALIC) == mxConstants.FONT_ITALIC)
		{
			rule.append(" font-style: italic ; ");
		}

		if ((fontStyle & mxConstants.FONT_UNDERLINE) == mxConstants.FONT_UNDERLINE)
		{
			rule.append(" text-decoration: underline ; ");
		}

		String align = getString(style, mxConstants.STYLE_ALIGN,
				mxConstants.ALIGN_LEFT);

		if (align.equals(mxConstants.ALIGN_CENTER))
		{
			rule.append(" text-align: center ; ");
		}
		else if (align.equals(mxConstants.ALIGN_RIGHT))
		{
			rule.append(" text-align: right ; ");
		}

		rule.append(" } ");
		document.getStyleSheet().addRule(rule.toString());

		return document;
	}

	/**
	 * Creates a table for the given text using the given document to create
	 * the DOM nodes. Returns the outermost table node.
	 */
	public static Element createTable(Document document, String text, int x,
			int y, int w, int h, double scale, Hashtable style)
	{
		// Does not use a textbox as this must go inside another VML shape
		Element table = document.createElement("table");

		if (text != null && text.length() > 0)
		{
			Element tr = document.createElement("tr");
			Element td = document.createElement("td");

			table.setAttribute("cellspacing", "0");
			table.setAttribute("border", "0");
			td.setAttribute("align", "center");

			String fontColor = getString(style, mxConstants.STYLE_FONTCOLOR,
					"black");
			String fontFamily = getString(style, mxConstants.STYLE_FONTFAMILY,
					mxConstants.DEFAULT_FONTFAMILIES);
			int fontSize = (int) (getInt(style, mxConstants.STYLE_FONTSIZE,
					mxConstants.DEFAULT_FONTSIZE) * scale);

			String s = "position:absolute;" + "left:" + String.valueOf(x)
					+ "px;" + "top:" + String.valueOf(y) + "px;" + "width:"
					+ String.valueOf(w) + "px;" + "height:" + String.valueOf(h)
					+ "px;" + "font-size:" + String.valueOf(fontSize) + "px;"
					+ "font-family:" + fontFamily + ";" + "color:" + fontColor
					+ ";";

			// Applies the background color
			String background = getString(style,
					mxConstants.STYLE_LABEL_BACKGROUNDCOLOR);

			if (background != null)
			{
				s += "background:" + background + ";";
			}

			// Applies the border color
			String border = getString(style,
					mxConstants.STYLE_LABEL_BORDERCOLOR);

			if (border != null)
			{
				s += "border:" + border + " solid 1pt;";
			}

			// Applies the opacity
			float opacity = getFloat(style, mxConstants.STYLE_TEXT_OPACITY, 100);

			if (opacity < 100)
			{
				// Adds all rules (first for IE)
				s += "filter:alpha(opacity=" + opacity + ");";
				s += "opacity:" + (opacity / 100) + ";";
			}

			td.setAttribute("style", s);
			String[] lines = text.split("\n");

			for (int i = 0; i < lines.length; i++)
			{
				td.appendChild(document.createTextNode(lines[i]));
				td.appendChild(document.createElement("br"));
			}

			tr.appendChild(td);
			table.appendChild(tr);
		}

		return table;
	}

	/**
	 * 
	 */
	public static Image loadImage(String url)
	{
		Image img = null;
		URL realUrl = null;

		try
		{
			realUrl = new URL(url);

		}
		catch (Exception e)
		{
			realUrl = mxUtils.class.getResource(url);
		}

		if (url != null)
		{
			try
			{
				img = ImageIO.read(realUrl);
			}
			catch (IOException e1)
			{
				// ignore
			}
		}

		return img;
	}

	/**
	 * Returns a new DOM document for the given URI.
	 * 
	 * @param uri URI to parse into the document.
	 * @return Returns a new DOM document for the given URI.
	 */
	public static Document loadDocument(String uri)
	{
		try
		{
			DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory
					.newInstance();
			DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
			return docBuilder.parse(uri);
		}
		catch (Exception e)
		{
			e.printStackTrace();
		}

		return null;
	}

	/**
	 * Returns a new document for the given XML string.
	 * 
	 * @param xml String that represents the XML data.
	 * @return Returns a new XML document.
	 */
	public static Document parse(String xml)
	{
		try
		{
			DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory
					.newInstance();
			DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();

			return docBuilder.parse(new InputSource(new StringReader(xml)));
		}
		catch (Exception e)
		{
			e.printStackTrace();
		}

		return null;
	}

	/**
	 * Evaluates a Java expression to a class member using mxCodecRegistry.
	 * The range of supported expressions is limited to static class
	 * members such as mxEdgeStyle.ElbowConnector.
	 * 
	 * @param expression
	 * @return
	 */
	public static Object eval(String expression)
	{
		int dot = expression.lastIndexOf(".");

		if (dot > 0)
		{
			Class clazz = mxCodecRegistry.getClassForName(expression.substring(
					0, dot));

			if (clazz != null)
			{
				try
				{
					return clazz.getField(expression.substring(dot + 1)).get(
							null);
				}
				catch (Exception e)
				{
					// ignore
				}
			}
		}

		return expression;
	}

	/**
	 * Returns a single node that matches the given XPath expression.
	 * 
	 * @param doc Document that contains the nodes.
	 * @param expression XPath expression to be matched.
	 * @return Returns a single node matching the given expression.
	 */
	public static Node selectSingleNode(Document doc, String expression)
	{
		try
		{
			XPath xpath = XPathFactory.newInstance().newXPath();

			return (Node) xpath.evaluate(expression, doc, XPathConstants.NODE);
		}
		catch (XPathExpressionException e)
		{
			// ignore
		}

		return null;
	}

	/**
	 * Converts the ampersand, quote, prime, less-than and greater-than characters
	 * to their corresponding HTML entities in the given string.
	 */
	public static String htmlEntities(String text)
	{
		return text.replaceAll("&", "&amp;").replaceAll("\"", "&quot;")
				.replaceAll("'", "&prime;").replaceAll("<", "&lt;").replaceAll(
						">", "&gt;");
	}

	/**
	 * Returns a string that represents the given node.
	 * 
	 * @param node Node to return the XML for.
	 * @return Returns an XML string.
	 */
	public static String getXml(Node node)
	{
		try
		{
			TransformerFactory tranFactory = TransformerFactory.newInstance();
			Transformer aTransformer = tranFactory.newTransformer();

			Source src = new DOMSource(node);
			ByteArrayOutputStream stream = new ByteArrayOutputStream();
			Result dest = new StreamResult(stream);
			aTransformer.transform(src, dest);

			return stream.toString("UTF-8");
		}
		catch (Exception e)
		{
			// ignore
		}

		return "";
	}

	/**
	 * Returns a pretty-printed XML string for the given node.
	 * 
	 * @param node Node to return the XML for.
	 * @return Returns a formatted XML string.
	 */
	public static String getPrettyXml(Node node)
	{
		return getPrettyXml(node, "  ", "");
	}

	/**
	 * Returns a pretty-printed XML string for the given node.
	 * 
	 * @param node Node to return the XML for.
	 * @param tab String to be used for indentation of inner nodes.
	 * @param indent Current indentation for the node.
	 * @return Returns a formatted XML string.
	 */
	public static String getPrettyXml(Node node, String tab, String indent)
	{
		StringBuffer result = new StringBuffer();

		if (node != null)
		{
			if (node.getNodeType() == Node.TEXT_NODE)
			{
				result.append(node.getNodeValue());
			}
			else
			{
				result.append(indent + "<" + node.getNodeName());
				NamedNodeMap attrs = node.getAttributes();

				if (attrs != null)
				{
					for (int i = 0; i < attrs.getLength(); i++)
					{
						// TODO: htmlEntities
						String value = attrs.item(i).getNodeValue();
						result.append(" " + attrs.item(i).getNodeName() + "=\""
								+ value + "\"");
					}
				}
				Node tmp = node.getFirstChild();

				if (tmp != null)
				{
					result.append(">\n");

					while (tmp != null)
					{
						result.append(getPrettyXml(tmp, tab, indent + tab));
						tmp = tmp.getNextSibling();
					}

					result.append(indent + "</" + node.getNodeName() + ">\n");
				}
				else
				{
					result.append("/>\n");
				}
			}
		}

		return result.toString();
	}

}