[Sugar-devel] [karma] early draft of karma presentation

[Lucian Branescu]

You could send strings for function blocks that can later be eval-ed.
But the eval itself might slow things down a lot. You can also send
JSON objects between workers. Some browsers serialise the JSON to
string and then re-eval it, others send the actual object.

About shared data, try to stay away from it anyway. Message passing is
desirable most of the time.

2009/8/25 Felipe López Toledo <zer.subzero at gmail.com>:
> Hi
> in my early post I talked about
> canvas vs SVG (slide #28)
> why not processingJS? (slide #28)
> here some technical stuff:
> ---
> Browser Optimization (slide #29)
> Karma lessons must run under the XO-1.
> Default browser: Browse ( based on Gecko )
> Experimental: Surf ( based on webkit )
> No problem with html elements (div, img, ...)
> What about canvas content?
> Under a normal browser clearing and redrawing the canvas objects may not be
> a problem, but remember that the XO has not that kind of normal resources.
> We must use them efficiently.
> If we have no option, it's preferable to spend cpu than spend memory.
> We emphasize rendering speed over quality
> image-rendering / firefox 3.6 alpha
> webkit has nothing
> Quadrilaterals (http://karma.sugarlabs.org/quadrilaterals/)
> how does it work?
> 2 canvases
> the first for temporal drawing of the current line
> cleared and re drawn when "mousemove"
> the second has the drawn polygon, background, etc..
> Quadrilaterals under Browse has a severe lag problem (unusable)
> Quadrilaterals under Surf works nice
> Surf-106 is faster than Browse-102, should we use Webkit or Gecko?
> --
> Web Workers (slide #30)
> We tried to use web workers to handle animations: an animation core.
> The animation core would be running as a worker thread: doing the neccesary
> calculations for the animated objects and sending messages to the root
> document to manipulate (update) the neccesary html elements (canvas...)
> We try to combine actions with predictable behaviour.
> Problems:
> it's not possible to send functions as worker messages, so, it's hard to use
> callbacks.
> how to share memory (variables) between the root document and the worker
> thread without copying that data?
> --
> 2009/8/21 Christoph Derndorfer <christoph.derndorfer at gmail.com>
>>
>> Hey guys,
>> I basically agree with the points raised here so far and have a couple to
>> add myself:
>> slide #11: I would also mentioned that you had tried eToys/Squeak
>> slide #24: I'm not sure we agreed on each lesson having to include a
>> tutorial and an exercise. Of course this is a good goal but the question is
>> whether we should really make that a requirement?
>> slide #32: "i81n";-)
>> slide #43: add link to Karma blog at http://karmaproject.wordpress.com/,
>> add at least one e-mail address for direct contact, add link to Sugar
>> mailing-list (http://lists.sugarlabs.org/listinfo/sugar-devel)
>> That's all I can think of for now...
>> Christoph
>> 2009/8/21 Felipe López Toledo <zer.subzero at gmail.com>
>>>
>>> Hi guys
>>>
>>> Joshua, Bryan has talked Christoph and me about you, thanks for writing
>>> :)
>>>
>>>> * I would update the slide "Nobody Wants to Help", to something like,
>>>> "Flash is a poor longterm solution." I would drop the claim "Flash Devs
>>>> don't like to share." I would
>>>>   - Despite the great work of the free software community on projects
>>>> like Gnash and the GameSWF library, there is very little in terms of sharing
>>>> and collaboration of free software Flash projects.
>>>
>>> +1
>>>>
>>>>   - There is no free software Flash development tool,
>>>
>>> mmm, I remember MTASC http://www.mtasc.org/
>>>>
>>>> instead almost all Flash development is done through the proprietary
>>>> software created by Macromedia.
>>>
>>> +1
>>>
>>> Bryan, really good draft, here some initial feedback:
>>>
>>> 1. SVG vs canvas
>>> I used RaphalJS (http://raphaeljs.com/) demos to test SVG animatios using
>>> Browse and Surf,
>>> results:
>>> under surf: the XO crashed several times :(
>>> under Browse: the animations look really good, but the performance is
>>> really bad (you will get a several lag when clicking something, etc...)
>>>
>>> canvas is low level so, canvas drawing is faster than SVG drawing.
>>> about manipulation, well, It's really easy to manipulate SVG Objects
>>> (everything you draw is an object) but canvas is just a box where you can
>>> draw, Karma provides (some of) that objects.
>>>
>>> 2. why not processingjs?
>>> processingjs by default uses processing language, then if you want to use
>>> it you'll need to learn processing syntax... to support that syntax,
>>> processingjs uses a parser, so, it's slower than simple JS.
>>> in fact, you can use javascript to access processingjs objects, but.. the
>>> actual processingjs library is not designed to work under the XO, neither to
>>> work as a jQuery plugin.
>>> I think jresig doesn't encourage to use processing (syntax), he just take
>>> processing because processing was there (looking for the reference)
>>>
>>> I will add more info on the technical stuff.
>>>
>>> regards
>>>
>>> On Thu, Aug 20, 2009 at 7:57 PM, Joshua Gay <jgay at ck12.org> wrote:
>>>>
>>>> Bryan,
>>>>
>>>> This is looking good so far. Here are some initial thoughts,
>>>>
>>>> * It would be good to have a handout that puts all this info on a single
>>>> double side sheet of paper (a suggestion taken from Edward Tufte's essay
>>>> "The Cognitive Style of Powerpoint) for people to read along with and to
>>>> look at afterward.
>>>> * I think overall it can be trimmed down abit when it is being pitched
>>>> to specific groups (e.g., JS crowd).
>>>> * I would update the slide "Nobody Wants to Help", to something like,
>>>> "Flash is a poor longterm solution." I would drop the claim "Flash Devs
>>>> don't like to share." I would
>>>>   - Despite the great work of the free software community on projects
>>>> like Gnash and the GameSWF library, there is very little in terms of sharing
>>>> and collaboration of free software Flash projects.
>>>>   - There is no free software Flash development tool, instead almost all
>>>> Flash development is done through the proprietary software created by
>>>> Macromedia.
>>>> * I would introduce some more lucid examples of the kinds of things you
>>>> would like to use this library to create.
>>>>
>>>>
>>>> I had some other thoughts on the internationalization parts, too. I will
>>>> try to respond later with them. The short of it is that I think the examples
>>>> you gave me (in our phone call) about gettext being an overly-burdonsome
>>>> approach for JS made a lot of sense and I think it would also help to
>>>> explain that you are looking for the JS equivalent of gettext; kind of
>>>> abstract this part away from your specific needs as an organization, and
>>>> talk about how this could benefit projects in general.
>>>>
>>>> -Josh
>>>>
>>>> On Thu, Aug 20, 2009 at 12:51 PM, Bryan Berry <bryan at olenepal.org>
>>>> wrote:
>>>>>
>>>>> josh, kcd, subzero
>>>>>
>>>>> 1st off, let me introduce Josh Gay, a js dev and free textbook guru. He
>>>>> is interested to make a presentation about karma to the JS devs group
>>>>> in
>>>>> Boston on Aug 27th.
>>>>>
>>>>> here is a more technically-oriented presentation for karma
>>>>>
>>>>> It is long on introduction and short on technical details. Much of the
>>>>> first part could be cut out depending on the target audience. I made it
>>>>> longer and more general for my first draft.
>>>>>
>>>>> It lacks a lot of technical detail on what we need help w/ for
>>>>> animation, i18n, web workers, localstorage
>>>>>
>>>>> --
>>>>> Bryan W. Berry
>>>>> Technology Director
>>>>> OLE Nepal, http://www.olenepal.org
>>>>
>>>
>>>
>>>
>>> --
>>> Felipe López Toledo
>>>
>>> _______________________________________________
>>> Sugar-devel mailing list
>>> Sugar-devel at lists.sugarlabs.org
>>> http://lists.sugarlabs.org/listinfo/sugar-devel
>>>
>>
>>
>>
>> --
>> Christoph Derndorfer
>> co-editor, olpcnews
>> url: www.olpcnews.com
>> e-mail: christoph at olpcnews.com
>
>
>
> --
> Felipe López Toledo
>
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