I generally use TikZ or Inkscape, or occasionally Asymptote, depending on the context.
Some quick notes about your app:
- No touch zoom/pan. Apart from that it worked okay on a Galaxy Note phone with the pen.
- I managed to make a shape vanish by (I think) rotating it quickly. I couldn't repeat that.
- The polyline selection seems quite broken. Draw a shape, then draw a polyline around it. Now you can't select the first shape, even though it's not obscured by anything.
Some quick notes about your app:
- No touch zoom/pan. Apart from that it worked okay on a Galaxy Note phone with the pen.
- I managed to make a shape vanish by (I think) rotating it quickly. I couldn't repeat that.
- The polyline selection seems quite broken. Draw a shape, then draw a polyline around it. Now you can't select the first shape, even though it's not obscured by anything.