Legacy GM Simple Question about screen_save_part()

[Zechevalier]

screen_save_part() doesn't seem to work the way it's supposed to, and i just want to know if anyone else has had the same experience.

Code from documentation:

screen_save_part(fname,x,y,w,h);

But my problem is with the (w,h) part, it seems to act more like (x2, y2)

so my original code looked like this:

screen_save_part("image.jpg", var_x, var_y, var_pic_w, var_pic_h)

And didn't work as expected.

Until i changed it to this:

screen_save_part("image.jpg", var_x, var_y, var_x+var_pic_w, var_y+var_pic_h)

I hope you get what i'm saying, if anyone has had the same experience let me know.