On Tue, May 14, 2013 at 12:43 AM, Jonathan Wilkes <jancsika@yahoo.com> wrote:
I just noticed that svg isn't allowed as a "media type" in Wordpress by default. I'd imagine the same is probably true for forums, too, making it less flexible than, say, exporting a patch to png or something. (And png has a "comment" section of essentially arbitrary length that I could abuse to store the pd-file along with the png.)On 05/13/2013 02:56 PM, András Murányi wrote:
On Sun, May 12, 2013 at 1:02 AM, Jonathan Wilkes <jancsika@yahoo.com> wrote:
>From: s p <sebpiq@gmail.com>
>To: Jonathan Wilkes <jancsika@yahoo.com>
>Cc: PD List <pd-list@iem.at>
>Sent: Saturday, May 11, 2013 4:37 PM
>Subject: Re: [PD] pd -> svg
>
>Thanks Jonathan,
>
>I don't really have the time to take care about this those days, but I'll fix it as soon as possible, and post here when that'll be done.
>
>Cheers,
>
>Sébastien
Here's an idea...
Suppose I build a Pd gui-plugin that exports a Pd file to svg. It takes the toplevel patch and makes the drawing instructions like my example in the OP. But it also draws a little navigation bar at the bottom with 1) a little image with id="source patchname", 2) a play button with id = "webpd-play patchname", 3) a stop button with id = "webpd-stop patchname"
The image with id="source patchname" is the base64-encoded source of the patch. This would be neat because:
a) Anyone could export to svg and get a file that can be displayed in any modern browser (with searchable/selectable text in most of them).
b) Since the drawing instructions Pd uses are so simple the svg will probably display on mobile devices (even older ones).
c) Since the source is embedded in the file, webpd js could just listen for clicks to any webpd-play buttons in the page, and when it catches one it looks for an svg image with id "source" plus the same patchname as the webpd-play button. It then decodes the image, loads it and plays it until it receives a "webpd-stop" button click.
This method has the benefit of degrading gracefully; that is, if someone using NoScript wants to read a forum with pd patch svg images in it, they will still be able to view the image. Moreover, a forum admin or blog owner can post the svgs simply to show pictures of patches; then later when the audio api becomes more common than just firefox nightly they can add the webpd code once and all their images will now feature audio.
-Jonathan
This sounds extremely appealing to me.
About the HTML side, be careful with using the ID field because it can be used only once and then other uses become impossible. Also, it has to be unique which would effectively prevent the same patch from being embedded more than once.
You might want to consider the CLASS field instead which can hold an unlimited number (theoretically; the practical limit is around 2000) of classes, and classes are already used deliberately to signify different attributes of HTML elements.
I'd also recommend prepending the string with something constant that will allow the automatic discovery of such strings among other, non-pd-parseable strings (versus having plain base64-encoded strings, which are not detectable by themselves, or, at least, must be decoded before recognized). For separating the prepended part from the base64 part, CSS allows for any ISO 10646 character higher than U+00A1 to be used, or even lower characters when escaped with backslash. (I don't recommend an escaped character because the backslash might "disappear" while the HTML get processed by various scripts here and there.)
For example: <img src="mypatch.svg" class="thisclass thatclass pd-source_ABC123BASE64STRING" /> would be a nice extendable format.
Still, the fact that you can zoom in losslessly on a svg is very appealing. If I grouped the drawing instructions for each object with <g> and put the name + args somewhere in there, it'd be pretty easy to convert the svg to pd file (at least for simple patches... subpatches might pose a problem). I like the idea of the source being available within the diagram itself, it'd make it much less work to do stuff like a presentation through a browser, and later adding audio to it. (And even later, taking those groups and manipulating them with the mouse.)
Thanks for the info on CSS, I'll look into it further. I just started researching all this stuff, and everything has many ways to solve the same problem (i.e., html5 canvas, svg, css, not to mention all the javascript libraries to manipulate all of those).
-Jonathan
The Wordpress problem is easy to come around by a plugin (http://wordpress.org/extend/plugins/scalable-vector-graphics-svg/) or an addition to the functions.php file in the template (http://wordpress.org/support/topic/svg-upload-not-allowed?replies=9).
I imagine the play button and co would be drawn by a wrapper (Javascript) too. That's how I actually imagine backwards compatibility: where not supported, only the image of the patch is displayed.
I'd love to discuss this further with you, and willing to put work into it. I'm pretty confident when it comes to browsers and CMSs ;)
András