Pixels or Perish
The art of scientific illustration will have to adapt to the new age of online publishing
The Web Playground
In some respects the Web is an unlikely source for innovations in high-quality graphics. It began as a text-only service, and when graphics were first introduced—through the <img> element of HTML—the only acceptable formats were raster images. Proposals for including vector graphics in Web pages were discussed all through the 1990s, and standards were drafted soon after. Nevertheless, vector formats have become a convenient and practical option for Web graphics only in the past few years.
In spite of this long struggle to bring drawing to the Web, the medium has attracted a community of talented programmers, designers and artists, who find it a friendly place for experimenting with new ideas and showing off the results. By its nature, the Web is a very open system, where anyone who can view a page can also see the code that created it.
We now have two widely supported schemes for drawing on Web pages. (Two is not necessarily better than one.) The <canvas> element of HTML is closely analogous to the <img> tag but accommodates vector graphics. Scalable Vector Graphics, or SVG, introduces an entire sublanguage similar in structure to HTML.
SVG works a little differently. Instead of setting aside a rectangular region that isolates the drawing from other elements of the document, SVG incorporates the drawing commands into the same data structure (called the Document Object Model, or DOM) that holds all the HTML. Indeed, the SVG language is a close cousin of HTML, with a similar syntax based on tags enclosed in angle brackets. And, like HTML, SVG is a noun language; but the nouns are different, defining lines and curves rather than paragraphs, tables and lists.
SVG also borrows heavily from PostScript (including the line caps and joints). And in this case the drawing space truly is device-independent and capable of very high precision. Anything displayed on the screen must ultimately be mapped to a finite number of pixels, but SVG drawings take maximum advantage of the available resolution, just as PostScript figures do.
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