{-# OPTIONS -Wall #-}

--------------------------------------------------------------------------------
-- |
-- Module      :  Wumpus.Tree
-- Copyright   :  (c) Stephen Tetley 2010
-- License     :  BSD3
--
-- Maintainer  :  Stephen Tetley <stephen.tetley@gmail.com>
-- Stability   :  highly unstable
-- Portability :  GHC
--
--------------------------------------------------------------------------------

module Wumpus.Tree
  (
  -- * The type of rendered trees
    TreePicture

  , ScaleFactors
  , uniformScaling
  , scaleFactors

  , drawTreePicture
  , drawFamilyTreePicture

  -- * Output to file
  , writeEPS_TreePicture
  , writeSVG_TreePicture

  -- * Drawing nodes
  , charNode
  , textNode
  , circleNode
  , diskNode

  )
  where

import Wumpus.Tree.Base
import Wumpus.Tree.Design
import Wumpus.Tree.Draw

import Wumpus.Basic.Dots.AnchorDots             -- package: wumpus-basic
import Wumpus.Basic.Graphic

import Wumpus.Core                              -- package: wumpus-core

import Data.Tree hiding ( drawTree )

-- | Output a 'TreePicture', generating an EPS file.
--
writeEPS_TreePicture :: FilePath -> TreePicture -> IO ()
writeEPS_TreePicture = writeEPS_latin1

-- | Output a 'TreePicture', generating a SVG file.
--
writeSVG_TreePicture :: FilePath -> TreePicture -> IO ()
writeSVG_TreePicture = writeSVG_latin1


-- | Customize the size of the printed tree.
--
-- A tree is /designed/ with a height of 1 unit between 
-- parent and child nodes.
--
-- The y-scaling factor multiplies the unit height, a scaling 
-- factor of 30 represents 30 /points/.
--
-- In the horizontal, 1 unit is the smallest possible distance 
-- between child nodes.
--
type ScaleFactors = ScalingContext Double Int Double




-- | Build uniform x- and y-scaling factors, i.e. @ x == y @.
--
uniformScaling :: Double -> ScaleFactors
uniformScaling u = ScalingContext (\x -> u * x)
                                  (\y -> u * fromIntegral y) 

scaleFactors :: Double -> Double -> ScaleFactors
scaleFactors sx sy = ScalingContext (\x -> sx * x)
                                    (\y -> sy * fromIntegral y)	


-- | 'drawTreePicture' : @ draw_fun * attr * scale_factors * tree -> TreePicture @
--
-- The rendering function.
-- 
-- @draw_fun@ renders the individual nodes. Usually 'charNode', 
-- 'circleNode'
--
-- @attr@ is the font size (translates to node size), stroke 
-- colour, fill colour.
--
-- @scale_factors@ scales the distances between parent and child 
-- (y-scale) and sibling nodes (x-scale).
--
-- @tree@ is the input tree to be rendered.
--
--
drawTreePicture :: (a -> TreeNode) 
                -> DrawingContext
                -> ScaleFactors 
                -> Tree a 
                -> TreePicture
drawTreePicture drawF dctx sfactors tree = 
    liftToPictureU $ drawTree drawF dctx $ design sfactors tree




drawFamilyTreePicture :: (a -> TreeNode) 
                -> DrawingContext
                -> ScaleFactors 
                -> Tree a 
                -> TreePicture
drawFamilyTreePicture drawF dctx sfactors tree = 
    liftToPictureU $ drawFamilyTree drawF dctx $ design sfactors tree

--------------------------------------------------------------------------------
-- Drawing functions

-- | Render tree nodes with a single character.
--
--  Useful for rendering @ Data.Tree Char @.
--
charNode :: Char -> TreeNode
charNode = dotChar


-- | Tree nodes with a text label.
--
-- Useful for rendering @ Data.Tree String @.
--
-- Note the width of the label is not accounted for in the 
-- /design/ of the tree. Labels with long texts may overlap.
-- Also, only a single line of text is printed - any text after 
-- the first newline character will be dropped.
--
textNode :: String -> TreeNode
textNode = dotText . uptoNewline
  where
    uptoNewline = takeWhile (/='\n')

-- | Tree nodes with a stroked circle.
--
-- Suitable for printing the shape of a tree, ignoring the data.
--
circleNode :: RGBi -> (a -> TreeNode)
circleNode rgb = \_ pt -> localize (strokeColour rgb) (dotCircle pt)


-- | Tree nodes with a filled circle.
--
-- Suitable for printing the shape of a tree, ignoring the data.
--
diskNode :: RGBi -> (a -> TreeNode)
diskNode rgb = \_ pt -> localize (fillColour rgb) (dotDisk pt)