[ka-Map-users] Technical alternatives for SVG on IE

[Pg]

I'm doing experiments with <canvas> too.
In effect I'have an implementation of kaXmlOverlay based on <canvas>.
At the moment there aren't new functinalities (icon rotation and so on).

For IE I used the Emil's library iecanvas, but I had to modify the
code because the original implementation doesn't allow the dynamic
creation of <canvas> nodes as

   document.createElement( 'canvas' )

You can test this alpha version for IE anf Firefox in

  http://85.38.167.230/ka-map/index_kaXmlOverlay.html

Is anyone working with http://sourceforge.net/projects/excanvas/ ?


 - Pg


2006/4/28, Paul Spencer <pspencer at dmsolutions.ca>:
> There is also <canvas> for firefox/safari and a canvas-in-ie that
> wraps canvas syntax around vml for ie (http://me.eae.net/archive/
> 2005/12/29/canvas-in-ie/).  And reading the comments there is also an
> SVG for IE wrapper (http://starkravingfinkle.org/blog/2006/03/svg-in-
> ie/)
>
> Google has also released an open source version of canvas in ie, but
> I haven't tried it (http://excanvas.sourceforge.net/)
>
> Cheers
>
> Paul
>
> On 28-Apr-06, at 10:27 AM, Robert Thau wrote:
>
> > Hi... I've noticed the recent conversation here on SVG overlays.  As a
> > possible point of interest, Internet Explorer can display vector
> > graphics *without* a plugin --- but not in SVG.  Instead, it supports
> > its own, effectively proprietary, XML graphics description language
> > called VML.  (Some Microsoft documentation refers people to a copy of
> > the spec at http://www.w3.org/TR/NOTE-VML --- but that's a discussion
> > draft that the W3C more or less ignored).
> >
> > The advantage of this is, obviously, you aren't requiring users to
> > download a plugin.  The disadvantages are two: you're supporting two
> > vector graphics formats, one of which (VML) does *not* have native
> > support in, say, PostGIS --- and also, the VML engine actually gets
> > kind of slow when there are large numbers of mouse-sensitive overlays
> > on the screen.  But for just, say, putting a few lines or polygons
> > on a map, it's fine.
> >
> > One other point --- I never tried <embed>, but I did try embedded SVG,
> > using <object> tags in Firefox.  The result was behavior which I
> > *think* I've seen described here: the SVG objects seem to "soak up"
> > mouse events, so clicking on them (or dragging over them) doesn't work
> > as you expect.  The reason for this, near as I could tell, was that if
> > you do that, the SVG is considered to be part of a logically separate
> > document, as if it had been loaded into an <iframe>, so mouse events
> > do *not* bubble up from the SVG elements to the <object> tag and its
> > enclosing HTML elements.  To make it work at all, I had to add
> > handlers on the SVG nodes which, in effect, forwarded the mouse events
> > up the chain --- and even then, you got messy visual artifacts while
> > dragging the map.
> >
> > I found inline SVG (just including <svg> tags directly in the body of
> > an HTML document) to work a whole lot better --- event propagation
> > works
> > as you'd expect, and the artifacts don't show up.  However, in Firefox
> > 1.5, this requires the document you're serving to be strict XHTML
> > (and declared as such --- content-type "application/xhtml+xml");
> > in this mode, close tags are mandatory, <br> *must* be typed as <br/>,
> > uppercasing of tag names doesn't work, and so forth.
> >
> > (Brief plug: I've used a mixed inline-SVG/VML approach to graphics
> > overlays in a GPLed project of my own, IvyGIS, which can be loosely
> > described as "PostGIS and Mapserver on Rails and Scriptaculous"; if
> > interested, see http://ivygis.justec.co.in/ for more.  Unfortunately,
> > the demo is a bit slow at the moment due to network difficulties in
> > Tokyo --- however, I'm hosting up the FGS modules containing the code
> > on a server in New York, and installing that goes pretty quick).
> >
> > Robert Thau
> > rst at alum.mit.edu
> > _______________________________________________
> > ka-Map-users mailing list
> > ka-Map-users at lists.maptools.org
> > http://lists.maptools.org/mailman/listinfo/ka-map-users
>
> +-----------------------------------------------------------------+
> |Paul Spencer                           pspencer at dmsolutions.ca   |
> +-----------------------------------------------------------------+
> |Applications & Software Development                              |
> |DM Solutions Group Inc                 http://www.dmsolutions.ca/|
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