Re-drawing a line updating its orientation as mouse movement

Builder
1

Hi, I’m a newbie to psychopy and I’m planning to run an online experiment.
My experiment is simple; observers see a random dot motion, and report the direction of motion they saw by mouse.

My question is here in the response phase:
I’m trying to present a line which is re-drawn by the mouse movement in every frame until making a click so that the observers can see the orientation of line to report the direction they saw.
The line orientation is from 0 to 360 degree.
If observers decide to report a specific orientation of line, they click a mouse button to confirm their response.

I’m a new here so I’d like to make this experiment by builder.
Is it possible to make it by builder? Any comments will be vey helpful!
Thanks in advance.

2

Hi Meg,

I’m not very familiar with the draw component in the builder, but i think that what you want to achive can still be done in the builder with a little bit of coding.

My solution would be:

  • Create a “line” (a very tall and narrow rectangle)
  • Create a point (a very small circle) at the centre of the screen and of the line, the same color of the line so it is invisible
  • Set the orientation of the line as a variable to be updated every frame (e.g. $myOri)
  • Create a code component and place it at the top of the list of componets
  • In the “begin routine” tab set the orientation (myOri) you want the line to be at the beginning (like vertical, orizontal or even random)
  • In the “every frame” tab calculate the position of the mouse with mouse.getPos() when the mouse is clicked
  • With a little bit of geometry calculate the orientation the line should have to connect the mouse and the point in the middle and set myOri accordingly
  • Finally, you can have the routine end when a keyboard button is pressed and have the final myOri saved with thisExp.addData()

tandy

1 Like
3

Hi Tandy,

Thanks for your kind reply, and sorry for a little late response!
Thanks to your suggestion, I’ve almost done to make the experiment.
I didn’t know how much I could make with Builder and what I couldn’t make, but thanks to your suggestion, I figured out them.

Thanks again and hope you having great holiday!
Meg