input - Calculating rotation degrees based on delta x,y movement of touch or mouse -

i have object in 2d space want rotate based on how input in 2d space moves. basically, think move finger or mouse around on screen either clockwise or counter clockwise, , object rotates relative how rotate finger. position of object not matter @ all, meaning rotation translated object finger movement, , there no relation between object's position , finger movement position.

i using libgdx , x , y delta movement (positive , negative integers depending on direction of movement) in call method "touchdragged".

how can use delta x , y calculate degrees of movement can apply object. preferably i'd add radian or degree value.

i can work fine if using 1 axis. i.e. if move finger or down, or rotates either clock-wise or counter-clockwise. problem getting work result of both x , y movement.

ps: did bit of looking around before posting question , know there similar questions couldn't figure out based on them. don't know why seemed different questions tackling different use cases each 1 different mine.

[edit: stated barodapride, libgdx provide vector2 api vector2.angle(vector2 reference) returns float angle value you, it's know what's going on under hood]

use cartesian polar coordinates, axis position gonna 0,0 in cartesian plane, can't test can idea following code wrote, take @ this futher reference:

public boolean touchdragged(inputevent event, float posx, float posy, int pointer){     //declare , position of axis (in screen coords, can camera.project()     float axisx,axisy;     axisx = getaxisx();     axisy = getaxisy();     //transform clicked position cartesian plane given axis     float cartesianx,cartesiany;     cartesianx = posx-axisx;     cartesiany = posy-axisy;     //calculate de radius     float radius = math.sqrt( cartesianx * cartesianx + cartesiany * cartesiany );     //get angle in radians     float angleinradians = math.acos( cartesianx / radius );     //get angle in degrees     float angleindegrees = angleinradians *57.2958;     return true; } 

the inverse, x,y given radius , angle:

double x = getaxisx() + math.cos( angleinradians ) * radius; double y = getaxisy() + math.sin( angleinradians ) * radius;