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;