Added -center option for text, soon to be used for stamps too.

cpdf.ml

@@ -1694,6 +1694,7 @@ type position =
   | Right of float
   | Diagonal
   | ReverseDiagonal
+  | Centre
 
 let string_of_position = function
   | PosCentre (a, b) -> Printf.sprintf "PosCentre %f %f" a b
@@ -1709,6 +1710,7 @@ let string_of_position = function
   | Right a -> Printf.sprintf "Right %f" a
   | Diagonal -> "Diagonal"
   | ReverseDiagonal -> "Reverse Diagonal"
+  | Centre -> "Centre"
 
 type orientation =
   | Horizontal
@@ -1719,25 +1721,25 @@ type justification = LeftJustify | CentreJustify | RightJustify
 
 (* Given the mediabox, calculate an absolute position for the text. *)
 let calculate_position ignore_d w (xmin, ymin, xmax, ymax) orientation pos =
-  (*i Printf.printf "calculate_position %b %f %f %f %f %f %b\n" ignore_d w xmin ymin xmax ymax shorterside; i*)
   let rot = if orientation = VerticalDown then rad_of_deg 270. else 0. in
     match pos with
+    | Centre ->
+        (xmin +. xmax) /. 2. -. w /. 2.,
+        (ymin +. ymax) /. 2.,
+        rot
     | Diagonal ->
         let angle = atan ((ymax -. ymin) /. (xmax -. xmin))
         in let cx, cy = (xmax +. xmin) /. 2., (ymax +. ymin) /. 2. in
           let dl = w /. 2. in
             let dx = dl *. cos angle
             in let dy = dl *. sin angle in
-                (*i Printf.printf "Diagonal: angle = %f, cx = %f, cy = %f, dx = %f, dy = %f\n" angle cx cy dx dy; i*)
               cx -. dx, cy -. dy, angle
     | ReverseDiagonal ->
-          (*flprint "REVERSE DIAGONAL IN CALCULATE POSITION\n";*)
         let angle = atan ((ymax -. ymin) /. (xmax -. xmin))
         in let cx, cy = (xmax +. xmin) /. 2., (ymax +. ymin) /. 2. in
           let dl = w /. 2. in
             let dx = dl *. cos angle
             in let dy = dl *. sin angle in
-                (*Printf.printf "Diagonal: angle = %f\n" (deg_of_rad angle);*)
               cx -. dx, (ymax +. ymin) -. (cy -. dy), angle -. ((2. *. pi) -. ((pi -. (2. *. angle)) *. 2.) /. 2.) +. pi
     | PosLeft (x, y) -> xmin +. x, ymin +. y, rot
     | PosCentre (x, y) -> xmin +. x -. (w /. 2.), ymin +. y, rot
@@ -1861,7 +1863,7 @@ let find_justification_offsets longest_w w position = function
   | LeftJustify ->
       begin match position with
       | TopLeft _ | Left _ | PosLeft _ | BottomLeft _ -> 0.
-      | Top _ | PosCentre _ | Bottom _ -> (longest_w -. w) /. 2.
+      | Top _ | PosCentre _ | Bottom _ | Centre -> (longest_w -. w) /. 2.
       | TopRight _ | BottomRight _ | PosRight _ | Right _ -> longest_w -. w
       | Diagonal -> 0.
       | ReverseDiagonal -> 0.
@@ -1869,7 +1871,7 @@ let find_justification_offsets longest_w w position = function
   | RightJustify ->
       begin match position with
       | TopLeft _ | Left _ | PosLeft _ | BottomLeft _ -> ~-.(longest_w -. w)
-      | Top _ | PosCentre _ | Bottom _ -> ~-.((longest_w -. w) /. 2.)
+      | Top _ | PosCentre _ | Bottom _ | Centre -> ~-.((longest_w -. w) /. 2.)
       | TopRight _ | BottomRight _ | PosRight _ | Right _ -> 0.
       | Diagonal -> 0.
       | ReverseDiagonal -> 0.
@@ -1877,7 +1879,7 @@ let find_justification_offsets longest_w w position = function
   | CentreJustify ->
       begin match position with
       | TopLeft _ | Left _ | PosLeft _ | BottomLeft _ -> ~-.((longest_w -. w) /. 2.)
-      | Top _ | PosCentre _ | Bottom _ -> 0.
+      | Top _ | PosCentre _ | Bottom _ | Centre -> 0.
       | TopRight _ | BottomRight _ | PosRight _ | Right _ -> (longest_w -. w) /. 2.
       | Diagonal -> 0.
       | ReverseDiagonal -> 0.

cpdf.mli

@@ -232,6 +232,7 @@ type position =
   | Right of float
   | Diagonal
   | ReverseDiagonal
+  | Centre
 
 (** Produce a debug string of a [position] *)
 val string_of_position : position -> string

cpdfcommand.ml

@@ -932,9 +932,12 @@ let setreversediagonal n =
   args.position <- Cpdf.ReverseDiagonal;
   args.justification <- Cpdf.CentreJustify
 
-(* FIXME: We will add a center option to text positioning, which can be used for this too *)
 let setcenter n =
-  args.position <- Cpdf.Diagonal;
+  args.position <- Cpdf.Centre;
+  args.justification <- Cpdf.CentreJustify
+
+let setscalecenter n =
+  args.position <- Cpdf.ReverseDiagonal;
   args.justification <- Cpdf.CentreJustify
 
 let setbates n =
@@ -1331,8 +1334,8 @@ and specs =
    ("-scale-contents",
       Arg.Float setscalecontents,
       "  Scale Contents by the given factor");
-   ("-center",
+   ("-scale-center",
-      Arg.Float setcenter,
+      Arg.Float setscalecenter,
       "  Scale contents around center");
    ("-scale-to-fit-scale",
       Arg.Float setscaletofitscale,
@@ -1510,6 +1513,9 @@ and specs =
    ("-reverse-diagonal",
       Arg.Unit setreversediagonal,
       " Place text diagonally across page from top left");
+   ("-center",
+      Arg.Unit setcenter,
+      " Place text in the center of the page");
    ("-justify-left",
       Arg.Unit setjustifyleft,
       " Justify multiline text left");

cpdfmanual.tex

@@ -1276,6 +1276,7 @@ The starting point can be set with the \texttt{-bates} option. For example:
       \small\verb!-right 10! & Right of baseline 10 pts in from the center right \\
       \small\verb!-diagonal! & Diagonal, bottom left to top right, centered on page\\
       \small\verb!-reverse-diagonal! & Diagonal, bottom right to top left, centered on page\\    
+      \small\verb!-center! & Centered on page\\
     \end{tabular}
   \end{framed}