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Task/Bitmap-Midpoint-circle-algorithm/Haskell/bitmap-midpoint-circle-algorithm-2.hs

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+module CircleArrayExample where
+
+import Circle
+
+-- A surface is just a 2d array of characters for the purposes of this example
+type Colour = Char
+type Surface = Array (Int, Int) Colour
+
+-- Returns a surface of the given width and height filled with the colour
+blankSurface :: Int -> Int -> Colour -> Surface
+blankSurface width height filler = listArray bounds (repeat filler)
+  where
+    bounds = ((0, 0), (width - 1, height - 1))
+
+-- Generic plotting function. Plots points onto a surface with the given colour.
+plotPoints :: Surface -> Colour -> [Point] -> Surface
+plotPoints surface colour points = surface // zip points (repeat colour)
+
+-- Draws a circle of the given colour on the surface given a center and radius
+drawCircle :: Surface -> Colour -> Point -> Int -> Surface
+drawCircle surface colour center radius
+  = plotPoints surface colour (generateCirclePoints center radius)
+
+-- Converts a surface to a string
+showSurface image = unlines [[image ! (x, y) | x <- xRange] | y <- yRange]
+  where
+    ((xLow, yLow), (xHigh, yHigh)) = bounds image
+    (xRange, yRange) = ([xLow..xHigh], [yLow..yHigh])
+
+-- Converts a surface to a string and prints it
+printSurface = putStrLn . showSurface