Pointers on Background of SVG Borders on Mutiny

With SVG being integrated more and more into HTML5, both included via <object> and <img> elements, and inline in the same document, some natural questions about SVG and CSS are receiving more focus. This includes box model questions like background and border, and pointer events.

I’m interested in comments from the community on what direction SVG should take.

Continue reading “Pointers on Background of SVG Borders on Mutiny”

Getting to the Point

SVG paths have a pretty good set of shape commands, enough to let you draw any 2D shape you might want in an authoring tool: horizontal, vertical, and diagonal straight lines, elliptical arc segments, and cubic and quadratic Bézier curves. Béziers are great, giving you precise control over the position and curve interpolation of each point in a concise format, using control points (“handles”), and are easily chained together to create complex shapes.

But let’s say you have a series of points, and you want to draw a smooth line between them, e.g. for stock data, an audio wave, or a mathematical graphing equation. Béziers are not as handy there, because not all the points needed to define a Bézier spline are on the curve itself. Obviously, you can decompose any set of points into a set of Béziers, but that takes math, and who wants to do that? (Put your hand down, nerd. I’m talking to the normals.)

Sometimes, you just want to lay down a set of points, and let the browser draw a smooth curve (unlike polylines, where each segment is just a straight line between the points). Like this:

Please use a modern browser.
Continue reading “Getting to the Point”

Web Audio Goes to Eleven

I’m really excited about W3C’s new public Audio Incubator Group, just launched today, and open for collaborators, innovators, and instigators. Go take a look for yourself, and see if you can contribute.

To celebrate the occasion, here’s a simple example of an experimental audio inteface, in the world’s first (and worst) audio synthesizer in SVG (you’ll need a special Minefield build to use it). Just click on the keyboard… it’s pretty rough still, but it shows some of the potential:

(standalone SVG file)

For some background, read on after this break…
Continue reading “Web Audio Goes to Eleven”

Stumbling Towards a Graphical Workflow

I’m working with a professional designer, Michael, on some graphics for my upcoming MIX presentation.  I’ve worked with designers before on various projects, some SVG, some traditional Web design, but this is my first time working on an SVG project with someone who never used SVG before, and it’s been an interesting experience, which I thought I’d jot down for anyone interested.

Both of us have been busy with other projects, and since we are in different places (me in Chapel Hill NC, him in Atlanta GA), we have only gotten to touch base a few times.  Michael has delivered some first drafts of the graphics, which look lovely, and I decided to dig into the underlying code, confident that I could trim down the file size and thus help browser performance.

My personal graphical editor of choice is Inkscape, which is a fine tool for all its warts (though it’s a little painful on Mac, where it is hosted as an X-11 application); typically, though, I create SVG either programmatically with a script or manually with a text editor (yes, I know that’s crazy… but it can be done).  Michael, being a professional designer, uses Adobe Illustrator, and I am keen to have him use the tools he is most comfortable with.  Since I want SVG to be used by mainstream designers, I want to understand how their tools work and what their workflow is like.

So, in order to make sure that we can roundtrip the files as seamlessly as possible, while still leveraging the features of SVG, I set about today to establish a workflow with Illustrator, TextMate (my go-to text editor, with a custom SVG code template bundle), Firefox, and its native debugger extension Firebug (with its handy “Inspect Element” context-menu selection).  My goal: to make reusable icons out of some of the graphical assets in the larger image, to be referenced by SVG’s <use> element. Continue reading “Stumbling Towards a Graphical Workflow”

Platform Games

I attended Google I/O a couple weeks ago, and had a great time.  They really put the “hype” in HyperText Markup Language 5, identifying things like the Geolocation API and some of the WebApps Working Group deliverables as part of “HTML5”.  Not quite accurate, but it was a branding exercise, not a technical one.  Notably absent from the things they rolled into HTML5 during the keynote, though, was SVG… in fact, they seemed to go out of their way to avoid it.

But it’s in there. Continue reading “Platform Games”


A while back, Henri Sivonen stumbled upon a diagram on the W3C site of the technology stack, a curvy-block Venn-diagram overview of the different technologies from W3C and where they fit into the Big Picture.  It’s an attractive diagram, but it oversimplifies things, and shows a decidedly W3C bias toward the Web.  It’s clearly been used past its expiration date, and those who consume it might feel a bit queasy.

Henri strongly criticized this depiction.  He rightfully points out that HTML is not included in this vision (showing XHTML only, which looks a bit silly these days), but then complains that HTML5 and XHR are not included in the diagram.  But of course, HTML5 isn’t even in Last Call yet, much less a W3C Recommendation, so it doesn’t really belong in that particular diagram (oddly, Henri credits XMLHTTPRequest to WHATWG, rather than its originator, Microsoft).

To his credit, Henri put his money where his mouth is, and took the trouble to make a diagram of the Web stack the way he sees it, which presumably better reflects the “real Web”.  It omits many of the W3C technologies, and inserts some of the more common ones that aren’t from W3C (most notably Javascript).  It’s a good diagram, but oversimplifies the landscape dramatically.  He follows the W3C diagram in putting “Internet” at the base of the stack, but doesn’t correct it to include such ubiquitous technologies as email or chat (XMPP, IRC, etc.) even though those are often part of browser-based technologies (GMail, et al).  Of course, he deliberately omits intranets-connected devices, even though that’s part of the browser world, because the official doctrine of the WHATWG is that the intranets (including those that are partly open, such as at universities) are “not the Web”.  I will also quibble that he overlaps Accessibility only with HTML, not with SVG.  But most glaringly, he includes Ogg Vorbis and Ogg Theora, though they aren’t (yet!) really used on the Web, and omits the dominant technologies in that space, MP3 and Flash (and more specifically, H.264).  He covers himself here by saying that this is for a “contemporary browser”, with the insinuation that it doesn’t include plugins, though to users and authors that is a pale distinction.  He also neglects PDF (ISO 32000), which is all too prevalent on the Web, and which several browsers do render (if I recall correctly).  So, it’s not really a picture of the real-world Web stack, either.

The Frames remind us, in their song in “God Bless Mom”:

You’ll see how hard it can be
To keep your side of the deal,
And you’ll see how hard it can be
To keep one foot in the real.

So, his diagram is flawed.  So what?  Why am I picking on it?  I’m not, really… it’s a good diagram, and it serves a certain purpose.  I’m picking on that purpose itself.  Henri was quick to criticize the W3C diagram (on a page where nobody can comment, I note), not because it wasn’t accurate, but because it advanced his agenda to do so (just as the W3C was advancing its agenda by making the original diagram).

Data visualization, like statistics or slogans, has a way of territorializing the map, in a kind of graphical gerrymandering. I’m sure that Henri didn’t mean to make such glaring omissions, but I’m equally sure that the creator of the original W3C diagram didn’t have sinister motives either.  People get busy, and reuse what they have to hand that meets their needs, even when it’s sometimes not quite correct.

I really respect Henri, but what he fails to understand here, or at least to admit, is that different data visualizations are best suited for different audiences and different purposes.  He’s shown a clear bias in his diagram toward depicting the “Open Web Stack” (a bias I have to admit I share) and toward desktop browsers (which I find too narrow), with a Web developer audience.  That’s perfectly cromulent.  But his diagram is not at all suited toward showing the different work going on at W3C, and where it fits in the larger Internet, in an executive summary.  Both the offending W3C diagram and Henri’s own diagram are gross oversimplifications… which is the point of data visualizations.  The map is not the territory.  If I were to make a diagram that encompasses the Web tech landscape, it would include both W3C technologies and technologies from other sources, and code the origins with styling; it would clearly indicate which technologies are open (that is, not proprietary), which are under development and which are stable, and link each node to the definitive resource for that tech; it would not stack them up in a neat little box, but would show the interconnections via lines.  And it would serve a different purpose than either of these other diagrams.

Why was only XHTML included in that W3C diagram, and not HTML?  Wishful thinking.  Say it enough times, and it just might come true, and a picture is worth a thousand words.  We’re all dreaming the Web we want into reality, every day.  I’m tired of the false dichotomy that’s too often drawn between W3C and its members and participants.  How about we lay off the divisive rhetoric?

Site Unseen

So, I don’t really pay much attention to my blog, or my site stats, or any of that… probably not nearly as much as I should, given how effective a medium blogs are at promoting ideas in the Web Standards profession.  I tend to write quite a lot, but most of it is emails to various technical mailing lists, especially W3C lists.  I should probably pay more attention to getting ideas out into a broader public sphere, with more diverse comments and feedback, like you can do with a blog.

But not this blog… not right now.  Because this blog is invisible.  If I recall correctly, I had a PageRank of 6, which seems to be moderately respectable.  But since my blog was hacked (maybe because it had a PageRank of 6), no amount of PageRank will help, because Google has cut me off.  So, as I mentioned on my last post, I did all the voodoo, adjusted the bones just so, and asked Google pretty-please won’t they reindex my site.  They replied that they will think about it, in a few weeks (just slightly passive-aggressive in a way only the popular kid can be).  I wonder if my PageRank will emerge intact?

But on the up side, I took the opportunity to clean out my virtual attic.  I took down old content and databases and experimental installations of software, wiped out old user accounts and email addresses, and generally made it easier for me to manage everything.  Installing the latest version of WordPress also gave me the chance to reorganize the sidebar a bit, adding my Twitter feed and removing dead blogroll links (though I need to add some new ones).

I should also try to figure out a way to finally expose an index of all the hundreds of SVG files I have hidden in the back alleys of my site.  Some of them are just experiments, some are examples of best practice, some are fairly cool and elaborate, some are just conformance tests.  I’ve hesitated because some of them are also rather crappy code that was written for the Adobe SVG Viewer, and either doesn’t have a namespace declaration (so it won’t work in modern browsers), or it uses some feature not supported in most browsers.  I’ve now put up an empty placeholder page, just to lay the groundwork.

I’ve also entertained the notion of running an index of my posts to public W3C lists, but out of context, it probably wouldn’t mean anything, and wouldn’t offer more than you could get by just searching the lists manually.  Maybe a weekly summary would be better?  Or maybe no mention of it at all would be most preferable… I think a certain amount of silence from me would do me and the people around me a world of good.

Maybe getting blocked by Google is a good thing after all… 🙂

CSS Link Hack in SVG

While answering a question about styling SVG with CSS in the Freenode #svg IRC channel (yes, people still use IRC), I threw together a simple example to illustrate.  I like to do this, since in keeps me in practice, and gives me a chance to check the state of current implementations in the fast-changing world of SVG browser support.

The question was how to use CSS stylesheets, both internal and external, with SVG in Inkscape.  While I know that Inkscape makes heavy use of CSS inline style declarations on elements (more than is to my personal taste, to be honest), I didn’t (and don’t) know if it has any UI features for adding internal stylesheet blocks, or links to external stylesheets.  So I made a little test…


<?xml-stylesheet type="text/css" href="svgstyle.css" ?>
<svg xmlns="http://www.w3.org/2000/svg"
     width="100%" height="100%" viewBox="40 0 145 70">

  <style type="text/css"><![CDATA[
       fill: lime;
       stroke: green;
       stroke-width: 10px;

  <rect id="inline" x="50" y="10" width="30" height="50"
        rx="5" ry="5"
        style="fill:lime; stroke:green; stroke-width:3px;"/>
  <ellipse id="internal" cx="103" cy="35" rx="15" ry="25"
  <circle id="external" cx="150" cy="35" r="25"


   fill: lime;
   stroke: green;
   stroke-width: 10px;

Which looks like this (at least, in Firefox, Opera, Safari, and presumably Chrome):

Both internal styles worked fine in Inkscape, but the external reference did not, showing just a black circle.  I’m not really surprised.  Note the clunky way that you have to link to external stylesheets in SVG:

<?xml-stylesheet type="text/css" href="svgstyle.css" ?>

That’s really XSLT-licious. I have to confess, I don’t really care for PIs (insert dated Magnum PI joke here), or XML prologs in general… they seem somehow clumsy and un-XMLy, like a throwback to SGML. And as far as I know, they can’t be created or changed dynamically via clientside script. Compare that to the relatively easy and straightforward X/HTML way of linking to external stylesheets:

<link href="svgstyle.css" rel="stylesheet" type="text/css"/>

In the SVG WG, we intend to allow authors to reference external stylesheets in a manner a little more modern and consistent with what authors are already used to using, in some upcoming spec. We could do that a couple of different ways. We could allow them to use an xlink:href attribute on the <style> element, in the same way we currently treat the <script> element (that is, if there’s a resolvable external link, we use that, otherwise we use the child content of the element), or we could add a <link> element like X/HTML, or both. I kinda like the idea of allowing either.

To that end, I made a couple of tests, just playing around, to see if any browsers accidentally supported either of those options, by merit of having some shared codebase with X/HTML in their implementations. Unsurprisingly, neither worked.

But then I had another idea… use the an <xhtml:link> element in the XHTML namespace…

<xhtml:link href="svgstyle.css" rel="stylesheet" type="text/css"/>

With this rather happy result, which works in at least Firefox, Opera, and Safari.

I don’t know if this is by design, or if it just fell out of the model, but I have to say I’m pleased as punch that it works. If nothing else, it’s a great proof of concept for adding more ways of linking to CSS in the SVG spec. This one goes in my toolkit, and I’m going to try to ensure that it gets standardized, if it’s not already there in some corner of some other spec. Probably somebody already knows about this (hell, probably everybody does, and I’m late to the party), but for me it was a w00ty discovery.

Update: heycam speculated that you might also be able to use @import rules, and indeed you can:

<style type="text/css">@import url(svgstyle.css);</style>