src/documentation/content/xdocs/dev/design/svg.xml - xmlgraphics-fop - Git at Google

 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <!--
   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.
 -->
 <!-- $Id$ -->
 <!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.3//EN" "http://forrest.apache.org/dtd/document-v13.dtd">

 <document>
   <header>
     <title>Apache™ FOP Design: SVG</title>
     <version>$Revision$</version>
   </header>
   <body>
 <section id="intro">
   <title>Introduction</title>
     <p>SVG is rendered through Apache™ Batik.</p><p>The XML from the XSL:FO document
       is converted into an SVG DOM with batik. This DOM is then set as the Document
       on the Foreign Object area in the Area Tree.</p><p>This DOM is then available to
       be rendered by the renderer.</p><p>SVG is rendered in the renderers via an
       XMLHandler in the FOUserAgent. This XML handler is used to render the SVG. The
       SVG is rendered by using batik. Batik converts the SVG DOM into an internal
       structure that can be drawn into a Graphics2D. So for PDF we use a
       PDFGraphics2D to draw into.</p><p>This creates the necessary PDF information to
       create the SVG image in the PDF document.</p><p>Most of the work is done in the
       PDFGraphics2D class. There are also a few bridges that are plugged into batik
       to provide different behaviour for some SVG elements.</p>
 </section>
 <section>
   <title>Text Drawing</title>
 <p>Normally batik converts text into a set of curved
        shapes. </p><p>This is handled as any other shapes when rendering to the output. This
        is not always desirable as the shapes have very fine curves. This can cause the
        output to look a bit bad in PDF and PS (it can be drawn properly but is not by
        default). These curves also require much more data than the original
        text.</p><p>To handle this there is a PDFTextElementBridge that is set when
        using the bridge in batik. If the text is simple enough for the text to be
        drawn in the PDF as with all other text then this sets the TextPainter to use
        the PDFTextPainter. This inserts the text directly into the PDF using the       drawString method on the PDFGraphics2D.</p><p>Text is considered simple if the
        font is available, the font size is useable and there are no tspans or other
        complications. This can make the resulting PDF significantly
        smaller.</p>
 </section>
 <section>
   <title>PDF Links</title>
 <p>To support links in PDF another batik
        element bridge is used. The PDFAElementBridge creates a PDFANode which inserts
        a link into the PDF document via the PDFGraphics2D.</p><p>Since links are       positioned on the page without any transforms then we need to transform the
        coordinates of the link area so that they match the current position of the a
        element area. This transform may also need to account for the svg being
        positioned on the page.</p>
 </section>
 <section>
   <title>Images</title>
 <p>Images are normally drawn
        into the PDFGraphics2D. This then creates a bitmap of the image data that can
        be inserted into the PDF document. </p><p>As PDF can support jpeg images then another
        element bridge is used so that the jpeg can be directly inserted into the       PDF.</p>
 </section>
 <section>
   <title>PDF Transcoder</title>
 <p>Batik provides a mechanism to
        convert SVG into various formats. Through FOP we can convert an SVG document
        into a single paged PDF document. The page contains the SVG drawn as best as
        possible on the page. There is a PDFDocumentGraphics2D that creates a
        standalone PDF document with a single page. This is then drawn into by batik in
        the same way as with the PDFGraphics2D.</p>
 </section>
 <section>
    <title>Other Outputs</title>
 <p>When rendering to AWT the SVG is simply drawn onto the
        awt canvas using batik.</p><p>The PS Renderer uses a similar technique as the
        PDF Renderer.</p><p>The SVG Renderer simply embeds the SVG inside an svg
        element.</p>
 </section>

     </body>
 </document>
	<?xml version="1.0" encoding="UTF-8" standalone="no"?>
	<!--
	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.
	-->
	<!-- $Id$ -->
	<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.3//EN" "http://forrest.apache.org/dtd/document-v13.dtd">

	<document>
	<header>
	<title>Apache™ FOP Design: SVG</title>
	<version>$Revision$</version>
	</header>
	<body>
	<section id="intro">
	<title>Introduction</title>
	<p>SVG is rendered through Apache™ Batik.</p><p>The XML from the XSL:FO document
	is converted into an SVG DOM with batik. This DOM is then set as the Document
	on the Foreign Object area in the Area Tree.</p><p>This DOM is then available to
	be rendered by the renderer.</p><p>SVG is rendered in the renderers via an
	XMLHandler in the FOUserAgent. This XML handler is used to render the SVG. The
	SVG is rendered by using batik. Batik converts the SVG DOM into an internal
	structure that can be drawn into a Graphics2D. So for PDF we use a
	PDFGraphics2D to draw into.</p><p>This creates the necessary PDF information to
	create the SVG image in the PDF document.</p><p>Most of the work is done in the
	PDFGraphics2D class. There are also a few bridges that are plugged into batik
	to provide different behaviour for some SVG elements.</p>
	</section>
	<section>
	<title>Text Drawing</title>
	<p>Normally batik converts text into a set of curved
	shapes. </p><p>This is handled as any other shapes when rendering to the output. This
	is not always desirable as the shapes have very fine curves. This can cause the
	output to look a bit bad in PDF and PS (it can be drawn properly but is not by
	default). These curves also require much more data than the original
	text.</p><p>To handle this there is a PDFTextElementBridge that is set when
	using the bridge in batik. If the text is simple enough for the text to be
	drawn in the PDF as with all other text then this sets the TextPainter to use
	the PDFTextPainter. This inserts the text directly into the PDF using the drawString method on the PDFGraphics2D.</p><p>Text is considered simple if the
	font is available, the font size is useable and there are no tspans or other
	complications. This can make the resulting PDF significantly
	smaller.</p>
	</section>
	<section>
	<title>PDF Links</title>
	<p>To support links in PDF another batik
	element bridge is used. The PDFAElementBridge creates a PDFANode which inserts
	a link into the PDF document via the PDFGraphics2D.</p><p>Since links are positioned on the page without any transforms then we need to transform the
	coordinates of the link area so that they match the current position of the a
	element area. This transform may also need to account for the svg being
	positioned on the page.</p>
	</section>
	<section>
	<title>Images</title>
	<p>Images are normally drawn
	into the PDFGraphics2D. This then creates a bitmap of the image data that can
	be inserted into the PDF document. </p><p>As PDF can support jpeg images then another
	element bridge is used so that the jpeg can be directly inserted into the PDF.</p>
	</section>
	<section>
	<title>PDF Transcoder</title>
	<p>Batik provides a mechanism to
	convert SVG into various formats. Through FOP we can convert an SVG document
	into a single paged PDF document. The page contains the SVG drawn as best as
	possible on the page. There is a PDFDocumentGraphics2D that creates a
	standalone PDF document with a single page. This is then drawn into by batik in
	the same way as with the PDFGraphics2D.</p>
	</section>
	<section>
	<title>Other Outputs</title>
	<p>When rendering to AWT the SVG is simply drawn onto the
	awt canvas using batik.</p><p>The PS Renderer uses a similar technique as the
	PDF Renderer.</p><p>The SVG Renderer simply embeds the SVG inside an svg
	element.</p>
	</section>

	</body>
	</document>