main.ml: always center, compare zoom > 0 instead of 1

main.ml

@@ -1101,10 +1101,7 @@ let act cmds =
      if n = 0
      then (
        let y = (getpagey pageno) + truncate y0 in
-       let x =
-         if (!S.x < - truncate x0) || (!S.x > !S.winw - truncate x1)
-         then !S.winw/2 - truncate (x0 /. 2. +. x1 /. 2.)
-         else !S.x
+       let x = !S.x
        in
        addnav ();
        gotoxy x y;
@@ -3038,7 +3035,7 @@ let setautoscrollspeed step goingdown =
 let canpan () =
   match conf.columns with
   | Csplit _ -> true
-  | Csingle _ | Cmulti _ -> !S.x != 0 || conf.zoom > 1.0
+  | Csingle _ | Cmulti _ -> !S.x != 0 || conf.zoom > 0.0
 
 let existsinrow pageno (columns, coverA, coverB) p =
   let last = ((pageno - coverA) mod columns) + columns in
@@ -3386,7 +3383,11 @@ let viewkeyboard key mask =
      end
   | Ascii ' ' -> nextpage ()
   | Delete -> prevpage ()
-  | Ascii '=' -> showtext ' ' (describe_layout !S.layout);
+  | Ascii '=' ->
+     if conf.zoom = 1.0
+     then gotoxy 0 !S.y
+     else setzoom 1.0;
+     reqlayout conf.angle FitPage
   | Ascii 'w' ->
      begin match !S.layout with
      | [] -> ()
@@ -3417,7 +3418,7 @@ let viewkeyboard key mask =
   | Ascii 'c' when !S.mode = View ->
      if Wsi.withalt mask
      then (
-       if conf.zoom > 1.0
+       if conf.zoom > 0.0
        then
          let m = (!S.winw - !S.w) / 2 in
          gotoxy m !S.y