Karma/Specifications

Introduction

Two main goals should be kept in mind when creating Karma lessons:

they should be easy to adapt
they should run on as much hardware as possibe with OLPC's XO-1 laptop representing the baseline

General Notes

Hardware constraints

Since a large percentage (if not the majority) of Karma users are envisioned to be using OLPC XO-1 laptops, netbooks, older hardware or generally relatively slow systems there are several performance constraints that need to be taken into account when designing Karma lessons.

CPU/Memory: The baseline regarding available performance is the XO-1 laptop which comes with an AMD Geode LX 433MHz CPU and 256MB RAM (full specifications). This limits the use of high-resolution multimedia, animations and videos to some degree.
Display: Karma lessons should work well on displays with a resolution of 1024*768 (whereby a part of the display may be taken up by browser UI elements!).
Mass storage: Since especially the XO-1 laptop only has very limited local mass storage (1GB) lessons should be kept reasonably small.
Connectivity: Karma lessons must not assume constant connectivity with a locally (e.g. XS) or globally available server. Support for storing data locally will be provided by Karma.

Accessibility

Follow best practices for accessibility (e.g. example of a checklist), especially with regard to colorblindness.

HTML

<!DOCTYPE HTML>

JavaScript

...

Animations

Format(s): TBD
Recommended tools: TBD
Notes: TBD

The Karma animations are created using JavScript and the Karma plugin. At this moment we haven't defined a mechanism to "export" (and "import") one animation. But copying and pasting the code (of the animation) will be enough in most cases.

Images

Format(s): JPEG, PNG, SVG (Note 1, 2 and 3)
Recommended tools: Inkscape, GIMP, Adobe Illustrator (non-free), CorelDRAW (non-free)
Max. resolution: 1200*900 px
Notes:

To handle SVG files will be necessary to create a parser svg2canvas in order to introduce them as objects inside canvas element.
Animated SVG content will be hard to reproduce using canvas.
SVG animations seems slow under the XO-1 (Tested with RaphaelJS and Browse)

Sound

Format(s): OGG Vorbis (Note 1)
Bit rate: TBD
Max. size per lesson: 3~4MB
Recommended tools: Audacity
Notes:

https://developer.mozilla.org/En/Media_formats_supported_by_the_audio_and_video_elements

Video

Format(s): TBD (Note 1)
Recommended tools: TBD
Notes: TBD

https://developer.mozilla.org/En/Media_formats_supported_by_the_audio_and_video_elements