SVG
From MobileRead
ePUB OPS Reading Systems must support SVG (Scalable Vector Graphics) as an OPS Core Media Type.
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[edit] Overview
Many images, such as maps, charts, graphs, etc., originate from vector graphics systems, not photographs. Such images can be represented in a vector (as opposed to raster) format that describes the image in terms of lines, curves and absolutely positioned blocks of text (as opposed to an array of pixels). Replacing raster images with vector ones makes documents more accessible and searchable. This additional effort on the part of Reading Systems provides a framework that authors can use to improve accessibility significantly. Vector images also improve the visual quality of documents (since vector images are inherently scalable) and tend to decrease document sizes.
Scalable Vector Graphics (SVG) is a text-based graphics language that describes images with vector shapes, text, and embedded raster graphics. SVG is an XML markup language for describing two-dimensional vector graphics. It is a W3C standard. Basically SVG is to vector graphics what XHTML is to text. It is explicitly designed to work with other W3C standards such as CSS, DOM and SMIL.
[edit] Example
Here is an example of a SVG file format. SVG can also be embedded in an HTML, XHTML or XML document.
<?xml version="1.0" standalone="no"?> <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd"> <svg width="5cm" height="4cm" version="1.1" xmlns="http://www.w3.org/2000/svg"> <desc>Four separate rectangles </desc> <rect x="0.5cm" y="0.5cm" width="2cm" height="1cm"/> <rect x="0.5cm" y="2cm" width="1cm" height="1.5cm"/> <rect x="3cm" y="0.5cm" width="1.5cm" height="2cm"/> <rect x="3.5cm" y="3cm" width="1cm" height="0.5cm"/> <rect x=".01cm" y=".01cm" width="4.98cm" height="3.98cm" fill="none" stroke="blue" stroke-width=".02cm" /> </svg>
[edit] General Notes on SVG Usage in ePUB
OPS supports the full SVG 1.1 Recommendation. The only exception is that, since OPS is not targeting interactive content, SVG animation and scripting features are not supported. These features must not be used by publication authors; a Reading System should not render such content. CSS styling of SVG must be fully supported.
Text in SVG images should be selectable and searchable. SVG images may contain links (a elements) and thus may be used for navigation. If a Reading System supports "tabbing" through links, SVG links must be included.
Inline SVG is only supported within documents using the XHTML Preferred Vocabulary. It must not be used within DTBook documents.
[edit] For more information
The w3.org specification - for SVG 1.1
