diff --git a/LICENSE b/LICENSE new file mode 100644 --- /dev/null +++ b/LICENSE @@ -0,0 +1,30 @@ +Copyright Liam O'Connor (c) 2015 + +All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + + * Redistributions in binary form must reproduce the above + copyright notice, this list of conditions and the following + disclaimer in the documentation and/or other materials provided + with the distribution. + + * Neither the name of Liam O'Connor nor the names of other + contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. diff --git a/Setup.hs b/Setup.hs new file mode 100644 --- /dev/null +++ b/Setup.hs @@ -0,0 +1,2 @@ +import Distribution.Simple +main = defaultMain diff --git a/latex-formulae-image.cabal b/latex-formulae-image.cabal new file mode 100644 --- /dev/null +++ b/latex-formulae-image.cabal @@ -0,0 +1,52 @@ +name: latex-formulae-image +version: 0.1.0.0 +synopsis: A library for rendering LaTeX formulae as images using an actual LaTeX installation +description: This library provides the basic infrastructure necessary to convert LaTeX formulae into images, using a real + LaTeX installation. This is useful in particular for showing formulae on websites, where using alternatives + like MathJax is not an option (e.g, when you want to use various LaTeX packages that MathJax doesn't support). + . + This library requires @latex@, @dvips@ and ImageMagick's @convert@ to be present in the system. @convert@ + needs to understand PostScript files. + . + We also + use a few tricks to compute where the baseline is in the image, so these images can be effectively typeset inline + with other text. + . + The companion library to this, @latex-formulae-pandoc@, provides useful tools to integrate this library with pandoc, + when generating HTML documents. +homepage: http://github.com/liamoc/latex-formulae#readme +license: BSD3 +license-file: LICENSE +author: Liam O'Connor +maintainer: liamoc@cse.unsw.edu.au +copyright: Liam O'Connor, 2015 +category: Image +build-type: Simple +-- extra-source-files: +cabal-version: >=1.10 +source-repository head + type: git + location: https://github.com/liamoc/latex-formulae +flag old-base + description: if building with older base versions + default: False + +library + hs-source-dirs: src + exposed-modules: Image.LaTeX.Render + if flag(old-base) + build-depends: base >= 4.7 && < 4.8 + , transformers-compat >= 0.4 && < 0.5 + else + build-depends: base >= 4.8 && < 4.9 + build-depends: JuicyPixels >= 3.2 && < 3.3, errors >= 2.0 && < 2.1 + , temporary >= 1.2 && < 1.3 + , transformers >= 0.3 && < 0.5 + , directory >= 1.2 && < 1.3 + , process >= 1.2 && < 1.3 + , filepath >= 1.3 && < 1.5 + default-language: Haskell2010 + +source-repository head + type: git + location: https://github.com/liamoc/latex-formulae-image diff --git a/src/Image/LaTeX/Render.hs b/src/Image/LaTeX/Render.hs new file mode 100644 --- /dev/null +++ b/src/Image/LaTeX/Render.hs @@ -0,0 +1,169 @@ +{-# LANGUAGE FlexibleContexts, RecordWildCards #-} +module Image.LaTeX.Render + ( -- * Rendering Formulas + imageForFormula + , Formula, Baseline + -- * Errors + , RenderError (..) + -- * Options + -- ** Environment Options + , EnvironmentOptions (..) + , defaultEnv + , TempDirectoryHandling (..) + -- ** Formula Options + , FormulaOptions (..) + , displaymath + , math + ) + where + +import Codec.Picture +import Data.Maybe +import Control.Error.Util +import Data.List +import System.IO.Temp +import System.FilePath +import System.Process +import System.Directory +import Control.Monad.Trans.Except +import Control.Monad +import System.Exit +import Control.Exception +import Control.Arrow(second) +import Control.Applicative +import Data.Monoid +import Prelude + +-- | This type contains all possible errors than can happen while rendering an equation. +-- It includes all IO errors that can happen as well as more specific errors. +data RenderError = ImageIsEmpty -- ^ The equation produced an empty image + | CannotDetectBaseline -- ^ The baseline marker could not be found + | LaTeXFailure String -- ^ @latex@ returned a nonzero error code + | DVIPSFailure String -- ^ @dvips@ returned a nonzero error code + | IMConvertFailure String -- ^ @convert@ returned a nonzero error code + | IOException IOException -- ^ An 'IOException' occurred while managing the temporary files used to convert the equation + | ImageReadError String -- ^ The PNG image from ImageMagick could not be read by JuicyPixels. + deriving (Show) + + +data TempDirectoryHandling = UseSystemTempDir { nameTemplate :: String } + -- ^ A temporary directory with a name based on the given template will be created in the system temporary files location + | UseCurrentDir { nameTemplate :: String } + -- ^ A temporary directory with a name based on the given template will be created in the current directory + +data EnvironmentOptions + = EnvironmentOptions { latexCommand :: String -- ^ Command to use for @latex@, default is @latex@ + , dvipsCommand :: String -- ^ Command to use for @dvips@, default is @dvips@ + , imageMagickCommand :: String -- ^ Command to use for ImageMagick's @convert@, default is @convert@ + , latexArgs :: [String] -- ^ Any additional arguments for @latex@ + , dvipsArgs :: [String] -- ^ Any additional arguments for @dvips@ + , imageMagickArgs :: [String] -- ^ Any additional arguments for @convert@ + , tempDir :: TempDirectoryHandling -- ^ How to handle temporary files + , tempFileBaseName :: String -- ^ The base name to use for the temporary files. + } + +data FormulaOptions + = FormulaOptions { preamble :: String -- ^ LaTeX preamble to use. Put your @\usepackage@ commands here.@ commands here. + , environment :: String -- ^ LaTeX environment in which the equation will be typeset, usually @math@ or @displaymath@ + , dpi :: Int -- ^ DPI for the image to be rendered at. ~200 is good for retina displays, ~100 works OK for non-retina displays. + } + +-- | Use the @amsmath@ package, the @displaymath@ environment, and 200dpi. +displaymath :: FormulaOptions +displaymath = FormulaOptions "\\usepackage{amsmath}" "displaymath" 200 + +-- | Use the @amsmath@ package, the @math@ environment, and 200dpi. +math :: FormulaOptions +math = FormulaOptions "\\usepackage{amsmath}\\usepackage{amsfonts}\\usepackage{stmaryrd}" "math" 200 + +-- | Sensible defaults for system environments. Works if @dvips@, @convert@, and @latex@ are recent enough and in your @$PATH@. +defaultEnv :: EnvironmentOptions +defaultEnv = EnvironmentOptions "latex" "dvips" "convert" [] [] [] (UseSystemTempDir "latex-eqn-temp") "working" + +-- | A LaTeX formula, e.g @x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}@ for the quadratic formula. Do not include any @$@s to denote the environment, just +-- specify the environment in the 'FormulaOptions' instead. +type Formula = String + +-- | Number of pixels from the bottom of the image to the typesetting baseline. Useful for setting your formulae inline with text. +type Baseline = Int + + + +-- | Convert a formula into a JuicyPixels 'DynamicImage', also detecting where the typesetting baseline of the image is. +imageForFormula :: EnvironmentOptions -> FormulaOptions -> Formula -> IO (Either RenderError (Baseline, DynamicImage)) +imageForFormula (EnvironmentOptions {..}) (FormulaOptions {..}) eqn = + bracket getCurrentDirectory setCurrentDirectory $ const $ withTemp $ \temp -> runExceptT $ do + let doc = mconcat ["\\nonstopmode\n", + "\\documentclass[12pt]{article}\n", + "\\pagestyle{empty}\n", preamble, + "\\begin{document}\n", + "\\begin{", environment, "}\n", + ".",eqn, + "\\end{", environment, "}\n", + "\\end{document}\n"] + io $ writeFile (temp tempFileBaseName <.> "tex") doc + io $ setCurrentDirectory temp + (c,o,e) <- io $ flip (readProcessWithExitCode latexCommand) "" $ latexArgs ++ [tempFileBaseName <.> "tex"] + io $ removeFile (tempFileBaseName <.> "tex") + io $ removeFile (tempFileBaseName <.> "aux") + when (c /= ExitSuccess) $ do + io $ removeFile (tempFileBaseName <.> "dvi") + throwE $ LaTeXFailure (o ++ "\n" ++ e) + (c',o',e') <- io $ flip (readProcessWithExitCode dvipsCommand) "" $ dvipsArgs ++ ["-q", "-E", "-o", tempFileBaseName <.> "ps", tempFileBaseName <.> "dvi"] + io $ removeFile (tempFileBaseName <.> "dvi") + when (c' /= ExitSuccess) $ throwE $ DVIPSFailure (o' ++ "\n" ++ e') + (c'', o'', e'') <- io $ flip (readProcessWithExitCode imageMagickCommand) "" $ + [ "-density", show dpi + , "-bordercolor", "none" + , "-border", "1x1" + , "-trim" + , "-background", "none" + , "-splice","1x0" + ] ++ imageMagickArgs ++ + [ tempFileBaseName <.> "ps", tempFileBaseName <.> "png" ] + io $ removeFile (tempFileBaseName <.> "ps") + when (c'' /= ExitSuccess) $ throwE $ IMConvertFailure (o'' ++ "\n" ++ e'') + imgM <- io $ readImage (tempFileBaseName <.> "png") + img <- withExceptT ImageReadError $ hoistEither imgM + io $ removeFile $ tempFileBaseName <.> "png" + hoistEither $ postprocess img + where + io = withExceptT IOException . tryIO + withTemp a = case tempDir of + UseSystemTempDir f -> withSystemTempDirectory f a + UseCurrentDir f -> withTempDirectory "." f a + +postprocess :: DynamicImage -> Either RenderError (Int, DynamicImage) +postprocess (ImageY8 i) = second ImageY8 <$> postprocess' i (pixelAt i 0 0) +postprocess (ImageY16 i) = second ImageY16 <$> postprocess' i (pixelAt i 0 0) +postprocess (ImageYF i) = second ImageYF <$> postprocess' i (pixelAt i 0 0) +postprocess (ImageYA8 i) = second ImageYA8 <$> postprocess' i (pixelAt i 0 0) +postprocess (ImageYA16 i) = second ImageYA16 <$> postprocess' i (pixelAt i 0 0) +postprocess (ImageRGB8 i) = second ImageRGB8 <$> postprocess' i (pixelAt i 0 0) +postprocess (ImageRGB16 i) = second ImageRGB16 <$> postprocess' i (pixelAt i 0 0) +postprocess (ImageRGBF i) = second ImageRGBF <$> postprocess' i (pixelAt i 0 0) +postprocess (ImageRGBA8 i) = second ImageRGBA8 <$> postprocess' i (pixelAt i 0 0) +postprocess (ImageRGBA16 i) = second ImageRGBA16 <$> postprocess' i (pixelAt i 0 0) +postprocess (ImageYCbCr8 i) = second ImageYCbCr8 <$> postprocess' i (pixelAt i 0 0) +postprocess (ImageCMYK8 i) = second ImageCMYK8 <$> postprocess' i (pixelAt i 0 0) +postprocess (ImageCMYK16 i) = second ImageCMYK16 <$> postprocess' i (pixelAt i 0 0) + + +postprocess' :: (Eq a, Pixel a) => Image a -> a -> Either RenderError (Int, Image a) +postprocess' img bg + = do startX <- note ImageIsEmpty $ listToMaybe $ dropWhile isEmptyCol [0.. imageWidth img - 1] + let (dotXs, postXs) = break isEmptyCol [startX .. imageWidth img] + postX <- note CannotDetectBaseline $ listToMaybe postXs + let postY = (+ 2) $ average $ dotXs >>= (\x -> takeWhile (not . isEmpty x) (dropWhile (isEmpty x) [0..imageHeight img - 1])) + average = uncurry div . foldl' (\(s,c) e -> (e+s,c+1)) (0,0) + newHeight = imageHeight img + newWidth = imageWidth img - postX + 3 + baseline = imageHeight img - postY + let image = generateImage (pixelAt' . (+ postX)) newWidth newHeight + return (baseline, image) + where + isEmptyCol x = all (isEmpty x) [0.. imageHeight img - 1] + isEmpty x = (== bg) . pixelAt img x + pixelAt' x y | x < imageWidth img && y < imageHeight img = pixelAt img x y + | otherwise = bg +