Merge pull request #114 from FayCarsons/flip-y-axis

Flip y axis

examples/quadtree.ml

@@ -5,8 +5,7 @@ let size = 800.
 let half_size = size /. 2.
 let max_leaf_points = 4
 let clusters = 32
-let point_size  = 1
-
+let point_size = 1
 let box_color = (0, 0, 0)
 let point_color = (255, 1, 1)
 
@@ -41,7 +40,6 @@ let cluster _ =
 (* Axis aligned bounding box *)
 type box = { min : point; max : point }
 
-
 let box min max = { min; max }
 
 (* Returns the middle point of the box *)
@@ -57,14 +55,13 @@ let quarters ({ min; max } as box) =
   (lu, ru, rd, ld)
 
 (* Checks whether point is within bounds of box *)
-let contains { min; max }  ({ x; y }: point) =
+let contains { min; max } ({ x; y } : point) =
   x > min.x && x < max.x && y > min.y && y < max.y
 
 (* Quadtree and utils *)
 
 (* 2-tuple of bounding box * 'a list of elts whose positions are within that box *)
 type 'a leaf = box * 'a list
-
 type 'a tree = Leaf of 'a leaf | Node of 'a tree list
 
 (* Constructs tree from root *)
@@ -96,7 +93,7 @@ let build () =
 
 (* Converts our constructed tree into a flat list of shapes for rendering *)
 let to_flat_shapes tree =
-  let open Joy in 
+  let open Joy in
   (* Converts box into rectangle *)
   let rect_of_bb bb =
     rectangle ~c:(midpoint bb)

lib/joy.ml

@@ -4,7 +4,6 @@ include Transform
 include Color
 
 let context = Context.context
-
 let set_line_width = Context.set_line_width
 
 let init ?(background = Color.white) ?(line_width = 2) ?(size = (500, 500))

lib/joy.mli

@@ -13,7 +13,7 @@ val polygon : float point list -> shape
 val complex : shapes -> shape
 val with_stroke : color -> shape -> shape
 val with_fill : color -> shape -> shape
-val no_stroke : shape -> shape 
+val no_stroke : shape -> shape
 val no_fill : shape -> shape
 val rotate : int -> transformation
 val translate : int -> int -> transformation

lib/render.ml

@@ -11,7 +11,7 @@ let draw_circle ctx ({ c; radius; stroke; fill } : circle) =
     set_color fill;
     Cairo.fill_preserve ctx.ctx
   in
-  Cairo.arc ctx.ctx c.x c.y ~r:radius ~a1:0. ~a2:(Float.pi *. 2.);
+  Cairo.arc ctx.ctx c.x (Float.neg c.y) ~r:radius ~a1:0. ~a2:(Float.pi *. 2.);
   Option.iter stroke_circle stroke;
   Option.iter fill_circle fill;
   Cairo.Path.clear ctx.ctx
@@ -42,7 +42,9 @@ let draw_ellipse ctx { c; rx; ry; stroke; fill } =
     set_color fill;
     Cairo.fill_preserve ctx.ctx
   in
-  let start, curve_one, curve_two = create_control_points (c, rx, ry) in
+  let start, curve_one, curve_two =
+    create_control_points (c, rx, Float.neg ry)
+  in
   Cairo.move_to ctx.ctx start.x start.y;
   let x1, y1, x2, y2, x3, y3 = curve_one in
   Cairo.curve_to ctx.ctx x1 y1 x2 y2 x3 y3;
@@ -55,9 +57,9 @@ let draw_ellipse ctx { c; rx; ry; stroke; fill } =
 let draw_line ctx { a; b; stroke } =
   set_color stroke;
   let { x; y } = a in
-  Cairo.move_to ctx.ctx x y;
+  Cairo.move_to ctx.ctx x (Float.neg y);
   let { x; y } = b in
-  Cairo.line_to ctx.ctx x y;
+  Cairo.line_to ctx.ctx x (Float.neg y);
   Cairo.stroke ctx.ctx
 
 let draw_polygon ctx { vertices; stroke; fill } =
@@ -75,14 +77,13 @@ let draw_polygon ctx { vertices; stroke; fill } =
       let { x = x1; y = y1 }, { x = x2; y = y2 } =
         (List.nth pair 0, List.nth pair 1)
       in
-      Cairo.move_to ctx.ctx x1 y1;
-      Cairo.line_to ctx.ctx x2 y2)
+      Cairo.move_to ctx.ctx x1 (Float.neg y1);
+      Cairo.line_to ctx.ctx x2 (Float.neg y2))
     points;
   Option.iter stroke_rect stroke;
   Option.iter fill_rect fill;
   Cairo.Path.clear ctx.ctx
 
-
 (* Validates context before rendering *)
 let show shapes =
   let rec render ctx = function

lib/shape.ml

@@ -50,10 +50,7 @@ let rectangle ?(c = center) width height =
   let y = c.y -. (h /. 2.) in
   polygon
     [
-      { x; y };
-      { x; y = y +. h };
-      { x = x +. w; y = y +. h };
-      { x = x +. w; y };
+      { x; y }; { x; y = y +. h }; { x = x +. w; y = y +. h }; { x = x +. w; y };
     ]
 
 let ellipse ?(c = center) rx ry =
@@ -81,20 +78,20 @@ let rec with_fill fill = function
       print_endline "lines do not have a fill field!";
       line'
 
-let rec no_stroke = function 
-    | Circle circle' -> Circle { circle' with stroke = None }
-    | Ellipse ellipse' -> Ellipse { ellipse' with stroke = None }
-    | Polygon polygon' -> Polygon { polygon' with stroke = None }
-    | Complex complex' -> Complex (List.map no_stroke complex')
-    | _ as line' -> 
+let rec no_stroke = function
+  | Circle circle' -> Circle { circle' with stroke = None }
+  | Ellipse ellipse' -> Ellipse { ellipse' with stroke = None }
+  | Polygon polygon' -> Polygon { polygon' with stroke = None }
+  | Complex complex' -> Complex (List.map no_stroke complex')
+  | _ as line' ->
       print_endline "Cannot remove stroke from lines";
       line'
 
-let rec no_fill = function 
-      | Circle circle' -> Circle { circle' with fill = None }
-      | Ellipse ellipse' -> Ellipse { ellipse' with fill = None }
-      | Polygon polygon' -> Polygon { polygon' with fill = None }
-      | Complex complex' -> Complex (List.map no_fill complex')
-      | _ as line' -> 
-        print_endline "Lines do not have a fill field!";
-        line'
+let rec no_fill = function
+  | Circle circle' -> Circle { circle' with fill = None }
+  | Ellipse ellipse' -> Ellipse { ellipse' with fill = None }
+  | Polygon polygon' -> Polygon { polygon' with fill = None }
+  | Complex complex' -> Complex (List.map no_fill complex')
+  | _ as line' ->
+      print_endline "Lines do not have a fill field!";
+      line'

lib/transform.ml

@@ -31,6 +31,7 @@ let rec translate dx dy = function
   | Complex shapes -> Complex (List.map (translate dx dy) shapes)
 
 let scale_length fact len = len *. fact
+
 let rec scale factor = function
   | Circle circle' ->
       Circle
@@ -52,7 +53,8 @@ let rec scale factor = function
       Polygon
         {
           polygon' with
-          vertices = List.map (Util.pmap (scale_length factor)) polygon'.vertices;
+          vertices =
+            List.map (Util.pmap (scale_length factor)) polygon'.vertices;
         }
   | Complex shapes -> Complex (List.map (scale factor) shapes)
 
@@ -95,7 +97,6 @@ let repeat n op shape =
   in
   Complex (repeat' (n, []))
 
-
 (** Takes a function and a shape and returns a new shape with the 
     function applied to the original's color *)
 let rec map_stroke f = function

lib/util.ml

@@ -1,5 +1,6 @@
 (* point -> point arithmetic *)
 open Shape
+
 let ( /~ ) p1 p2 = { x = p1.x /. p2.x; y = p1.x /. p2.x }
 
 (* point -> scalar arithmetic *)
@@ -30,10 +31,7 @@ let rec partition n ?(step = 0) lst =
   | [] -> []
   | lst' ->
       let taken, _ = take n lst in
-      if List.length taken = n then
-        taken
-        ::
-       partition n ~step (List.tl lst')
+      if List.length taken = n then taken :: partition n ~step (List.tl lst')
       else []
 
 (* Misc *)