Hi! I understand it is intended to be simple, but it must have some functions.
What features would you like to have in this activity?

demo

Excellent your demonstration. This is a very good starting point. What children like from Tuxpaint is the 'stamps' feature. There are many little images that the children can use as a brush. For this one task is to create a gallery selector as it can be reused in the vector drawing animation.

• color selector
• brush size selector
• brush type selector (like bluring) (skip if it's too hard to implement)
• flood fill
• eraser (follows brush size and type)
• rectangle
• line
• text. The text can be changed until the image is saved.
• clear all
• undo / redo
• image gallery selector
• save / load (need to implement T1497: Saving / Loading of children's creation)

For the gallery it makes sense to open another task. In the gallery items are grouped by category. In the main interface we must see the current item selected in the gallery.

Not all have to be implemented in a single shot, this is like a wish list and we may find better options during the development.

As stated in duplicate task T7405 , work has been started in gsoc-tuxPaint branch.

Will be completing this activity as discussed in the proposal(https://www.dropbox.com/s/79jq0ltkg4rv8ir/GSoC_KDE_amit.pdf?dl=0) :)

work branch --> https://cgit.kde.org/gcompris.git?h=gsoc_asagtani_paint

After all the work I did last year to complete this activity, it works quite good on desktop (Linux at least, not tested on windows yet), but there is weird bug on Android that prevents using it properly.
(some kind of issues when loading canvas... to investigate further).

When that bug on android is fixed, there will be a few other minor things to fix and it should be ready to merge finally.