Scalable Vector Graphics - Overview

Overview

SVG has been in development since 1999 by a group of companies within the W3C after the competing standards Precision Graphics Markup Language (PGML) – developed from Adobe's PostScript – and Vector Markup Language (VML) – developed from Microsoft's RTF – were submitted to W3C in 1998. SVG drew on experience from the designs of both those formats.

SVG allows three types of graphic objects: vector graphics, raster graphics, and text. Graphical objects, including PNG and JPEG raster images, can be grouped, styled, transformed, and composited into previously rendered objects. SVG does not directly support z-indices that separate drawing order from document order for overlapping objects, unlike some other vector markup languages like VML. Text can be in any XML namespace suitable to the application, which enhances search ability and accessibility of the SVG graphics. The feature set includes nested transformations, clipping paths, alpha masks, filter effects, template objects, and extensibility.

Since 2001, the SVG specification has been updated to version 1.1 (current Recommendation) and 1.2 (still a Working Draft). The SVG Mobile Recommendation introduced two simplified profiles of SVG 1.1, SVG Basic and SVG Tiny, meant for devices with reduced computational and display capabilities. SVG Tiny later became an autonomous Recommendation (current version 1.2) and the basis for SVG 1.2. In addition to these variants and profiles, the SVG Print specification (still a Working Draft) contains guidelines for printable SVG 1.2 and SVG Tiny 1.2 documents.

Although not directly comparable to SVG since it is a bitmap-based format, the Canvas element in HTML5 provides an approach to rendering dynamic graphics in HTML that is procedural rather than declarative: instead of specifying the shapes to draw in XML, the author executes drawing commands from a script. Canvas does not allow for static rendering, and drawn elements are not identifiable in a DOM-like way.