-- | A module for rendering lines as an HTML5 file containing an SVG image.
-- This can be used to visualize the denotational semantics of a MiniLogo
-- program.
--
-- NOTE: You should not change the definitions in this file!
--
module Render (Point,Line,toHTML,toGridHTML) where
import Data.List (intercalate)
-- | A point is a cartesian pair (x,y).
type Point = (Int,Int)
-- | A line is defined by its endpoints.
type Line = (Point,Point)
-- | Output a list of lines as an HTML5 file containing an SVG image.
toHTML :: [Line] -> IO ()
toHTML ls = writeFile "MiniMiniLogo.html" (header ++ content ls ++ footer)
-- | Alternate version of 'toHTML' that adds a grid to the background.
toGridHTML :: [Line] -> IO ()
toGridHTML ls = writeFile "MiniMiniLogo.html" (header ++ grid ++ content ls ++ footer)
--
-- Private definitions. All definitions below this point will not be visible
-- from within a module that imports this module.
--
scale, margin, width, height :: Int
scale = 10
margin = 10
width = 800
height = 400
gridStep = 5
maxX = width `div` scale
maxY = height `div` scale
gridStyle = "fill:none;stroke:lightgrey;stroke-width:1"
drawStyle = "fill:none;stroke:red;stroke-width:2"
title = "MiniLogo Semantics Viewer"
view = "","",""]
grid = unlines (map (poly gridStyle) lines)
where lines = [ [(x,0), (x,maxY)] | x <- [0,gridStep..maxX] ]
++ [ [(0,y), (maxX,y)] | y <- [0,gridStep..maxY] ]
content :: [Line] -> String
content = unlines . map (poly drawStyle) . chunk
-- | A canvas-adjusted point as a string.
point :: Point -> String
point (x,y) = show xp ++ "," ++ show yp
where xp = x*scale + margin
yp = height - y*scale + margin
-- | Chunk a bunch of lines into sequences of connected points.
chunk :: [Line] -> [[Point]]
chunk [] = []
chunk [(p,q)] = [[p,q]]
chunk ((p,q):ls) | q == head ps = (p:ps) : pss
| otherwise = [p,q] : ps : pss
where (ps:pss) = chunk ls
-- | Draw a sequence of connected points.
poly :: String -> [Point] -> String
poly style ps = ""