Resize long expressions in LaTeX to prevent overflow

code/drasil-printers/lib/Language/Drasil/TeX/Helpers.hs

@@ -25,10 +25,7 @@ import Data.List (isSuffixOf)
 -- | Helper for adding fencing symbols.
 br, sq, parens, quote :: D -> D
 -- | Curly braces.
-br x = lb <> x <> rb
-  where
-  lb = pure $ text "{"
-  rb = pure $ text "}"
+br x = lbrace <> x <> rbrace
 -- | Square brackets.
 sq x = ls <> x <> rs
   where
@@ -45,6 +42,12 @@ quote x = lq <> x <> rq
   lq = pure $ text "``"
   rq = pure $ text "''"
 
+lbrace, rbrace :: D
+-- | Helper for opening curly brace.
+lbrace = pure $ text "{"
+-- | Helper for closing curly brace.
+rbrace = pure $ text "}"
+
 -- | 0-argument command.
 command0 :: String -> D
 command0 s = pure $ H.bslash TP.<> text s
@@ -276,8 +279,21 @@ useTikz = usepackage "luatex85" $+$ command0 "def" <>
 -- on Monad...
 
 -- | toEqn is special; it switches to 'Math', but inserts an equation environment.
-toEqn :: D -> D
-toEqn (PL g) = equation $ PL (\_ -> g Math)
+-- The 'scale' parameter determines the maximum width of the equation based on
+-- the corresponding scaling command.
+toEqn :: ExprScale -> D -> D
+toEqn scale (PL g) = equation $ command2D "resizeExpression" (PL (\_ -> g Math)) (command0 (show scale))
+
+-- | Represents the scaling factor for an equation.
+-- 'InDef' and 'OutDef' correspond to predefined scaling commands.
+-- Commands are defined in 'Preamble.hs'
+data ExprScale = InDef | OutDef
+
+-- | Provides a string representation for 'ExprScale' values.
+-- Used to convert 'ExprScale' to the corresponding command string.
+instance Show ExprScale where
+  show InDef  = "inDefScale"
+  show OutDef = "outDefScale"
 
 -----------------------------------------------------------------------------
 -- | Helper(s) for String-Printing in TeX where it varies from HTML/Plaintext.

code/drasil-printers/lib/Language/Drasil/TeX/Monad.hs

@@ -109,6 +109,10 @@ vpunctuate x = tpRunPrint (TP.vcat . TP.punctuate x)
 -- Combine 'TP.hcat' and 'TP.punctuate'.
 hpunctuate :: TP.Doc -> [D] -> D
 hpunctuate x = tpRunPrint (TP.hcat . TP.punctuate x)
+
+-- | Nest a 'D' by a specified indentation level.
+nest :: Int -> D -> D
+nest i (PL f) = PL $ \ctx -> TP.nest i (f ctx)
 --------
 -- | MathContext operations.
 lub :: MathContext -> MathContext -> MathContext

code/drasil-printers/lib/Language/Drasil/TeX/Preamble.hs

@@ -3,10 +3,12 @@ module Language.Drasil.TeX.Preamble (genPreamble) where
 
 import Data.List (nub)
 
+import Text.PrettyPrint (text)
 import Language.Drasil.Printing.LayoutObj (LayoutObj(..))
-import Language.Drasil.TeX.Monad (D, vcat, (%%))
+import Language.Drasil.TeX.Monad (D, vcat, (%%), nest)
 import Language.Drasil.TeX.Helpers (docclass, command, command1o, command2, command3,
-  usepackage)
+  usepackage, command0, lbrace, rbrace, ExprScale(InDef, OutDef))
+import Language.Drasil.Printing.Helpers (sq, brace)
 
 import Language.Drasil.Config (hyperSettings, fontSize, bibFname)
 
@@ -35,6 +37,8 @@ data Package = AMSMath      -- ^ Improves information structure for mathematical
              | EnumItem     -- ^ Contol basic list environments.
              | SVG          -- ^ For rendering svg diagrams.
              | Float        -- ^ For enhanced control over placement of figures and tables.
+             | Graphicx     -- ^ Resizebox for large expressions.
+             | Calc         -- ^ Perform arithmetic operation in LaTeX commands.
              deriving Eq
 
 -- | Adds a 'Package' to the LaTeX document.
@@ -66,6 +70,8 @@ addPackage Unicode   = usepackage "unicode-math"
 addPackage EnumItem  = usepackage "enumitem"
 addPackage SVG       = usepackage "svg"
 addPackage Float     = usepackage "float"
+addPackage Graphicx  = usepackage "graphicx"
+addPackage Calc      = usepackage "calc"
 
 -- | Common LaTeX commands.
 data Def = Bibliography
@@ -74,6 +80,10 @@ data Def = Bibliography
          | SetMathFont
          | SymbDescriptionP1
          | SymbDescriptionP2
+         | SaveBox
+         | InDefScale
+         | OutDefScale
+         | ResizeExpr
          deriving Eq
 
 -- | Define common LaTeX commands.
@@ -84,6 +94,21 @@ addDef LessThan      = command2 "newcommand" "\\lt" "\\ensuremath <"
 addDef SetMathFont   = command "setmathfont" "Latin Modern Math"
 addDef SymbDescriptionP1 = command3 "newlist" "symbDescription" "description" "1"
 addDef SymbDescriptionP2 = command1o "setlist" (Just "symbDescription") "noitemsep, topsep=0pt, parsep=0pt, partopsep=0pt"
+addDef SaveBox       = command "newsavebox" "\\mybox"
+addDef InDefScale    = command0 "def" <> command (show InDef)  "0.8"
+addDef OutDefScale   = command0 "def" <> command (show OutDef) "1.0"
+addDef ResizeExpr = vcat [
+    command "newcommand" "\\resizeExpression" <> pure (sq "2") <> lbrace,
+    nest 2 $ vcat [
+        command2 "savebox" "\\mybox" "$#1$",
+        command0 "ifdim" <> command0 "wd" <> command0 "mybox" <> pure (text ">#2") <> command0 "linewidth",
+        nest 2 $ command3 "resizebox" "#2\\textwidth" "!" ("\\usebox" ++ brace "\\mybox"),
+        command0 "else",
+        nest 2 $ command "usebox" "\\mybox",
+        command0 "fi"
+      ],
+    rbrace
+  ]
 
 -- | Generates LaTeX document preamble.
 genPreamble :: [LayoutObj] -> D
@@ -117,6 +142,6 @@ parseDoc los' =
     parseDoc' Header{}     = ([], [])
     parseDoc' Paragraph{}  = ([], [])
     parseDoc' List{}       = ([EnumItem], [])
-    parseDoc' EqnBlock{}   = ([], [])
+    parseDoc' EqnBlock{}   = ([Graphicx, Calc], [InDefScale, OutDefScale, SaveBox, ResizeExpr])
     parseDoc' Cell{}       = ([], [])
     parseDoc' CodeBlock{}  = ([], [])

code/drasil-printers/lib/Language/Drasil/TeX/Print.hs

@@ -33,7 +33,7 @@ import Language.Drasil.TeX.Helpers (author, bold, br, caption, center, centering
   empty, enumerate, externalref, figure, fraction, includegraphics, item, item',
   itemize, label, maketitle, maketoc, mathbb, mkEnv, mkEnvArgBr, mkEnvArgSq,
   mkMinipage, newline, newpage, parens, quote, sec, snref, sq, superscript,
-  symbDescription, texSym, title, toEqn)
+  symbDescription, texSym, title, toEqn, ExprScale(InDef, OutDef))
 import Language.Drasil.TeX.Monad (D, MathContext(Curr, Math, Text), (%%), ($+$),
   hpunctuate, lub, runPrint, switch, toMath, toText, unPL, vcat, vpunctuate)
 import Language.Drasil.TeX.Preamble (genPreamble)
@@ -62,7 +62,7 @@ lo :: LayoutObj -> PrintingInformation -> D
 lo (Header d t l)         _ = sec d (spec t) %% label (spec l)
 lo (HDiv _ con _)        sm = print sm con -- FIXME ignoring 2 arguments?
 lo (Paragraph contents)   _ = toText $ newline (spec contents)
-lo (EqnBlock contents)    _ = makeEquation contents
+lo (EqnBlock contents)    _ = makeEquation contents OutDef
 lo (Table _ rows r bl t)  _ = toText $ makeTable rows (spec r) bl (spec t)
 lo (Definition _ ssPs l) sm = toText $ makeDefn sm ssPs $ spec l
 lo (List l)               _ = toText $ makeList l
@@ -76,10 +76,22 @@ lo (Graph ps w h c l)    _  = toText $ makeGraph
 lo (Cell _) _               = empty
 lo (CodeBlock _) _          = empty
 
+-- | Helper for converting layout objects into a more printable form.
+-- This function is specific to definitions.
+lo' :: LayoutObj -> PrintingInformation -> D
+lo' (HDiv _ con _)      sm = printDef sm con
+lo' (EqnBlock contents) _  = makeEquation contents InDef
+lo' obj                 sm = lo obj sm
+
 -- | Converts layout objects into a document form.
 print :: PrintingInformation -> [LayoutObj] -> D
 print sm = foldr (($+$) . (`lo` sm)) empty
 
+-- | Converts layout objects into a document form.
+-- Specific to Definitions.
+printDef :: PrintingInformation -> [LayoutObj] -> D
+printDef sm = foldr (($+$) . (`lo'` sm)) empty
+
 -- | Determine wether braces and brackets are opening or closing.
 data OpenClose = Open | Close
 
@@ -345,17 +357,18 @@ makeDefTable sm ps l = mkEnvArgBr "tabular" (col rr colAwidth ++ col (rr ++ "\\a
 
 -- | Helper that makes the rows of a definition table.
 makeDRows :: PrintingInformation -> [(String,[LayoutObj])] -> D
-makeDRows _  []         = error "No fields to create Defn table"
-makeDRows sm ls    = foldl1 (%%) $ map (\(f, d) -> dBoilerplate %%  pure (text (f ++ " & ")) <> print sm d) ls
-  where dBoilerplate = pure $ dbs <+> text "\\midrule"
+makeDRows _  []      = error "No fields to create Defn table"
+makeDRows sm ls      = foldl1 (%%) $ map (\(f, d) -> 
+  pure (dbs <+> text "\\midrule") %% 
+  pure (text (f ++ " & ")) <> printDef sm d) ls
 
 -----------------------------------------------------------------
 ------------------ EQUATION PRINTING------------------------
 -----------------------------------------------------------------
 
--- | Prints an equation.
-makeEquation :: Spec -> D
-makeEquation contents = toEqn (spec contents)
+-- | Prints an equation with a maximum width determined by the given scale.
+makeEquation :: Spec -> ExprScale -> D
+makeEquation contents scale = toEqn scale (spec contents)
 
   --TODO: Add auto-generated labels -> Need to be able to ensure labeling based
   --  on chunk (i.e. "eq:h_g" for h_g = ...