GameMaker Having right mouse offset for surface_getpixel

[kerim]

Hello,
i'm using an surface and i do want to get any color from where i tap on the surface, but it doesn't work with pure mouse_x and mouse_y because surface_getpixel gets the color from called x,y inside of surface.
my surface is drawed at 960,256 and width: 768, height: 192

thanks for any help

 

[SoVes]

you just do mouse_x-surface_x