Created attachment 4509
X.Org xeyes application view
Like it os done in X.Org application (see the attached image).
Created attachment 4510
Currently (xfce-extra/xfce4-eyes-plugin-4.4.1-r1) the both pupils behaviour looks to be managed by the left one.
Example in opposite to requested behaviour is attached.
Implemented in http://git.xfce.org/panel-plugins/xfce4-eyes-plugin/commit/?id=c5f5e0484d8fbcb68ed28732dc240935be336782, fixed in http://git.xfce.org/panel-plugins/xfce4-eyes-plugin/commit/?id=8164b087d1d2d5650c6835f89b4a46bc3d0426ca.
Created attachment 4945
Patch implementing eye position calculations in 3D coords
Current behavior is better but it still feels unnatural. This is mostly because the eye balls are in the same x-y plane as the mouse pointer.
The attached patch calculates 3D angles of the eye sight as if the eye ball was slightly behind the screen (at the moment the distance is hardcoded to 3x eyeball radius). Smaller z distance makes the eyeballs more independent, larger - increases the (x-y) tracking distance (the eyes remain in their center position longer).
A comment, possibly invalid:
The very first time I tried the plugin from master branch (in a deskbar mode) it calculated the eye ball position as if the eye ball was shifted to the left by ~30-40px (to the left edge of the plugin).
After rebuilding the plugin and restarting the panel this issue went away, so it might have been some setup problem on my side.
Thanks, this is indeed an improvement. Tested with all themes, works fine. The 3x distance seems to be a good default.
Fixed in 4.4.2.