I also disagree with Vladimir, but for different reasons. :-D I strongly dislike <canvas> (but I'm not familiar with this whole stack-based drawing concept either), but SVG isn't better or worse (in my opinion) for any of the listed reasons so far.
The reason SVG is better is because it exists as an XML application and the individual elements each get their own rendering frames. An immediate advantage to this that Flash or Canvas or *any* other plugin technology will never be able to duplicate is that you can interact with SVG at *exactly* the same level as XHTML. There are no hoops to jump through, the DOM is the DOM. Furthermore, each element, XHTML or SVG, get the same kind of rendering frame, so I have been able to write scripts which handle dragging/dropping XHTML elements onto SVG and SVG onto XHTML (in compound documents) just as easily as current scripts handle HTML elements onto HTML elements. Similarly, I can (and will soon) implement the same behavior for MathML. If someone wants to standardize a 3D graphics XML language, I can do the namespace-agnostic, drag/drop code for that too. The fact that they all exist at the same level makes effects trivial for integration with existing markup. Canvas simply doesn't have that. Also, as far as my understanding of canvas goes, it doesn't have user-interaction events (how could it?). So how exactly are you supposed to build your interactive vector graphics web 5.0 ajax web application without user-events? --- In svg-developers@yahoogroups.com, "Doug Schepers" <[EMAIL PROTECTED]> wrote: > > Hear, hear! > > Jeff, contact me offlist and I can give you some of my SVG eye-candy. > > It seems like some Mozilla folks (with very notable exceptions) have a case > of "not invented here" (where "here" is anywhere but the W3C). In the face > of such a blatant bit of FUD, I feel I have to serve as an SVG apologist. > Stop reading here if you're not in the mood for a... > > <rant> > > Some criticisms of SVG that Vladimir cites: > > * "Has scene DOM (SVG DOM, though)": "Has scene DOM"? No, it hasn't. SVG has > a timeline-based animation mechanism; Flash is frame-based (which is more > like scenes). And the SVG DOM *is* the DOM, with compatible extensions that > allow for graphics-specific functions. Is he criticizing it because it uses > graphical features? I suppose that SVG should be more like Canvas, which > uses standard DOM methods like: > beginPath(); > moveTo(10, 90); > lineTo(50, 10); > lineTo(90, 90); > lineTo(10, 90); > stroke(); > > * SVG is "Somewhat hard to mix with HTML (not XHTML)" while Canvas "Behaves > like an image in both": What's hard about using SVG with HTML? I've been > doing exactly that for 6 years, and it's not hard... because it has a DOM. > Is he talking about inline SVG? If so, it's natural that SVG shouldn't work > as well as with XHTML, since HTML is not XML, and thus cannot have mixed > namespaces. But the kicker is comparing that unfactoid with the > apples-to-oranges non-DOM raster nature of canvas. Why are those on the same > line? > > * "Difficult to do data-driven rendering... Need to do DOM manipulation for > each change": First, only true with scripted changes, not declarative > animation. Second, that's the *point* of the DOM.... to reflect the current > state of the document! > > * "Complex to write by hand": Unlike Canvas... which is impossible to write > by hand, since it's only an ephemeral scripted display. > > * "Spec tries to cover too much": Just wait until Canvas matures... when > they try to meet a wider array of actual user needs, canvas will bloat like > a dead fish. > > * "Multiple Profiles": Apparently, the intention of unifying devices of all > types around a single Web is a bad idea... > > * "Tooltips? Audio/Video? Network IO??": HTML (a document description > language) has tooltips, the object tag for multiple media types, and > declarative server access (through forms). Is that a good thing...? Maybe > not, but it met user needs, and the Web would not have been as successful > without it. But, here's the question: how easy is it to get audio and video > to work reliably (or at all) across browsers, without using some proprietary > technology like Quicktime, Real, or Flash? So, even though HTML took a step > toward supporting those things in some fashion (through the flawed "object" > element), they still don't work 6 years after the HTML 4.01 Specification > came out, because they were underspecified. SVG is inherently a multimedia > language (raster, vector, and animation support were mandated from the > original charter), and video is a natural extension of that mandate; it > seems silly to leave out audio from that, doesn't it? SVG has worked to > serve as a host language for the relevant parts of SMIL (since SMIL is only > a hosted language), and these capabilities certainly make more sense in a > graphics language than a text-document format. > > The case for network interfaces is less compelling, I agree... but it makes > sense in a historical context. The SVG WG realized the need for innovation > to help drive the creation of standards-based WebApps, and no other working > group was chartered to do this work. DOM had lain fallow for years; in fact, > it is only because of the initiative of the SVG WG in coordination with > other forward-thinking groups (one of my favorites, XForms, included) that > the new WebAPI working group was chartered to take up these necessary > improvements to the existing DOM. As the WebAPI group takes on the task of > such things as Cross-Domain XHR, the SVG Spec will defer to that > specification instead, as it intends to do for the Wheel event (another > long-unspecified bit of necessary Web infrastructure). > > Vladimir cites an "exhaustive" 4 bullets worth of existing documentation for > SVG, leaving off svg.org and wiki.svg.org... > > Without trying to sound too bitter or unfair, while I am sure he knows > canvas very well, he doesn't seem to know much about SVG. > > Finally, I note that they use the "<canvas>" affectation for Canvas, which > obfuscates that it is, in fact, not XML, not DOM-based, and not intuitive or > compatible with existing Web technologies. > > </rant> > > Okay, now that I've defused that little bomb of a presentation, let me state > my real position on Canvas. > > I think Canvas is fine. I've seen some neat stuff done in Canvas, and look > forward to seeing more. The Web is large, and I think that there is room for > a variety of approaches to solving user needs, even if they overlap a bit. > For one thing, Canvas does 3D, which SVG does only grudgingly, by design. I > don't think this has to turn into a religious war, when it could be a set of > complementary technologies. After all, they are both implemented natively in > the same set of browsers, so everybody wins. > > In short, I don't see Canvas as competition to SVG.... after all, it doesn't > have a Networking IO, and what's a graphics format without a Networking IO?? > > Regards- > Doug > > > Jeff Schiller wrote: > | > | http://people.mozilla.com/~vladimir/xtech2006/ > | > | About 5 slides on SVG and 14 on <canvas> (including some stuff on > | Canvas3D). > | > | What got me about this presentation is the slide-pack has about 8 > | slides with some really cool-looking <canvas> demos: a video game, a > | plush web-stat chart, funky animations, colourful borders, widgets. > | And in the whole slide-pack, only one single SVG example: a very > | crude-looking chart made from the Dojo toolkit that looks like it was > | produced by Excel 2.0. > | > | Where's the SVG love here? > | > | In my mind, the potential uses for SVG vastly outweighs those of > | <canvas>, yet SVG seems to be losing mindshare left and right. Will > | there be any mindshare left for SVG when WPF arrives? > | > | For my own sanity, can we get a list of cool SVG demos and experiments > | that are out in the wild? I'd like links to these demos in one > | central place (not multiple emails in a newsgroup) so we can point > | people to one URL and say: Look, here are some cool examples of what > | SVG can do. For this reason, I've started the "SVG Roadshow" post at > | GetSVG.com: http://www.getsvg.com/general/announcements/svg_roadshow > | > | Thanks, > | Jeff > ------------------------ Yahoo! Groups Sponsor --------------------~--> Get to your groups with one click. Know instantly when new email arrives http://us.click.yahoo.com/.7bhrC/MGxNAA/yQLSAA/1U_rlB/TM --------------------------------------------------------------------~-> ----- To unsubscribe send a message to: [EMAIL PROTECTED] -or- visit http://groups.yahoo.com/group/svg-developers and click "edit my membership" ---- Yahoo! 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