Touch support

[ozwaldorf]

The current touch support is poor, tested on wayland. Dragging a finger around doesn't draw a line as expected, but instead starts zooming the canvas.

[vishisht-dubey]

hey @ozwaldorf i would like to work on this issue please assign this to me

[kkoomen]

@ozwaldorf Hi. You are right that the support is very poor, because this is simply my own personal project that I open sourced. I only use a wacom drawing tablet when using this, maybe a touchpad or mouse, but that happens rarely, and to clarify, I haven't planned on adding support for anything else than a PC/laptop. Maybe in the future.

That being said, I just added basic touch support for you, you should be able to draw right now. Let me know if it works as you expect and what you are missing that would like to be added. If you are quick in responding I can immediately work on it, because I have all the time this week to work on the project.

[ozwaldorf]

Thanks for the fast response. I'm able to draw successfully with the latest commits, although it still has a side effect of zooming in and out while touching

[kkoomen]

@ozwaldorf Alright, I guess you want a two-finger pinch zoom to zoom in/out, right?

EDIT: @ozwaldorf I just created pinch touch support inside the master branch. Please have a look and see if zooming in/out with two fingers works as expected and let me know. I don't have touch devices, so I somewhat simulated it. Hope it works.