[Solved] Mouse Position incorrect after resolution scaling.

[ImBored]

I have had this issue before with previous projects and it is something to do with how I am scaling my game to full screen.

The code for how I scale my game is given below:

application_surface_draw_enable(false);

window_set_fullscreen(true);

MonitorW = display_get_width();
MonitorH = display_get_height();

GameW = 960;
GameH = 540;

Mult = floor(MonitorW / GameW);

global.XOffset = (MonitorW - (GameW * Mult)) / 2;
global.YOffset = (MonitorH - (GameH * Mult)) / 2;

var Set = true;
var Room = room_next(room);
while (Set)
{
    room_set_view(Room, 0, true, 0, 0, GameW, GameH, 0, 0, GameW, GameH, 0, 0, -1, -1, -1);
    room_set_view_enabled(Room, true);
    if (Room == room_last)
    {
        Set = false;
    }
    else
    {
        Room = room_next(Room);
    }
}

surface_resize(application_surface, GameW * Mult, GameH * Mult);
display_set_gui_size(MonitorW, MonitorH);
global.GuiHeight = display_get_gui_height();
global.GuiWidth = display_get_gui_width();

I then draw the application surface in a post draw event:

draw_surface_ext(application_surface, global.XOffset, global.YOffset, 1, 1, 0, c_white, 1);

The problem that happens is that the mouse_x coordinate is set at 0 at the left side of the screen and the mouse_x coordinate is set at 960 at the far right of the screen. I want it to be 0 on the left of application surface and 960 on the right of the application surface. Same for the y coordinates.