I'm trying to make a horizontal slider that controls the movement of one of my characters. It will control the zoom-in, zoom-out feature of the camera position.

My problem is trying to get the initial position of the slider to be in the center of the variable spread, so if I move it to the left, the variable is negative, and if I move to the right, the variable is positive. The only problem is the bmap in the hslider function always starts at the extreme left. Is there a way to make it start in the center of the variable spread, so the number can decrease or increase, not just increase?

look at this :

hslider = 11,90,100,cursor_map,1,3,var_slide;

If i start with var var_slide = 1; the cursor start at left

If i start with var var_slide = 2; the cursor start at middle

If i start with var var_slide = 3; the cursor start at right

You can't use negative value but you can write :
val_zoom = var_slide -2;