add displaystyle option

README.md

@@ -39,6 +39,7 @@ Turns the LaTeX expression `expr` into an image encoded as a stream.  You can tw
 
 * `dpi`: Dots-per-inch determines the resolution of resulting image.  Default: 300
 * `format`:  Resulting image format. Default `png`
+* `displaystyle`: (boolean) Use display style for forulae, defaults to `false` (inline)
 * `packages`: A list of extra LaTeX packages to include.  Default `["amsmath"]`
 * `macros`: A list of LaTeX preprocessor macros.  Default `""`
 * `pdflatex_path`: A path the `pdflatex` executable.  Default: `pdflatex`

mathmode.js

@@ -15,6 +15,7 @@ module.exports = function(expr, options) {
   }
   var format = options.format || "png";
   var size   = options.dpi    || 300;
+  var ds     = options.displaystyle ? '\\displaystyle' : '';
 
   var package_list = options.packages || [ "amsmath" ];
   var packages = [];
@@ -35,7 +36,7 @@ module.exports = function(expr, options) {
     "\\usepackage{transparent}",
     options.macros || "",
     "\\begin{document}",
-    "\\begin{preview} $",
+    "\\begin{preview} $"+ds,
     sanitize(expr),
     "$ \\end{preview}",
     "\\end{document}"
@@ -60,4 +61,4 @@ module.exports = function(expr, options) {
   tex_stream.pipe(convert.stdin);
 
   return result;
-}
+}

script.js

@@ -0,0 +1,3 @@
+require('./mathmode')('{\\Sigma = \\{0,\\dots, M\\}}', {
+	displaystyle: true
+}).pipe(process.stdout);