Android Question select canvas to edit

please any hint ?? specially for line

It seems that you are trying to write a kind of CAD program.
The second image looks like a 3D CAD program screen.
It's not an easy task.
You would need to memorize objects (points, lines, shapes etc) with their reference points with all coordinates.
Then when you want to select an object you need to check if the current finger coordinates are close to one componant of the objects.
If yes, you can then edit the object.
Editing graphics with the finger is not that easy.

To have an idea you could have a look at this thread Resize and Crop.

This may give you a start https://www.b4x.com/android/forum/threads/class-screen-hotspots.29592/

Klaus
thanking you for your help , yes its CAD application, this is what I m looking for
Stevel05
I appreciate your support , this really close to my application.