Options documented.

README.md

@@ -37,11 +37,90 @@ to CSS.  To compile, use a `SassC::Engine`, e.g.:
 SassC::Engine.new(sass, style: :compressed).render
 ```
 
+Here is a more detailed example, which also produces a 
+[source-map](https://docs.google.com/document/d/1U1RGAehQwRypUTovF1KRlpiOFze0b-_2gc6fAH0KY0k):
+
+```ruby
+template = File.read('styles/mystyle.scss')
+
+options = { style:               :compressed,
+            filename:            'mystyle.scss',
+            output_path:         'mystyle.css',
+            source_map_file:     'mystyle.css.map',
+            load_paths:          ['styles'],
+            source_map_contents: true }
+
+engine = SassC::Engine.new(template, options)
+
+css = engine.render
+File.write('styles/mystyle.css', css)
+
+map = engine.source_map
+File.write('styles/mystyle.css.map', map)
+```
+
 **Note**:  If you want to use this library with Rails/Sprockets, check out
 [sassc-rails](https://github.com/bolandrm/sassc-rails).
 
 Additionally, you can use `SassC::Sass2Scss` to convert Sass syntax to Scss syntax.
 
+### Options
+
+Options can be set by passing an option-hash to `SassC::Engine.new` as shown in the examples above.
+
+Available options are:
+
+* **`:syntax`**
+  The syntax of the input file, `:sass` for the indented syntax
+  and `:scss` for the CSS-extension syntax.  
+  Defaults to `:scss`.
+
+* **`:style`**
+  Sets the style of the CSS-output.
+  Can be `:nested`, `:compact`, `:compressed`, or `:expanded`.
+  See the [SASS_REFERENCE](http://sass-lang.com/documentation/file.SASS_REFERENCE.html#output_style)
+  for details.  
+  Defaults to `:nested`.
+
+* **`:filename`**
+  The name of the file being rendered. 
+  This is used for reporting errors and to reference the main source-file in the _source-map_.   
+  Defaults to `"stdin"`.
+
+* **`:output_path`**
+  The path to which the CSS-output will be written to. This value will be used to reference 
+  the generated CCS-file in the _source-map_.   
+  When no value is provided, the _libsass_ library will try to guess this value using the value given in `:filename`.
+
+* **`:source_map_file`**
+  The URI of the _source-map_. This information will be written into the compiled CSS-file.
+  Omitting this information causes no _source-map_ to be generated at all.  
+
+* **`:load_paths`**
+  An array of filesystem-paths which should be searched for Sass-partials.
+
+* **`:precision`**
+  Sets the precision factor used in numeric output.
+
+* **`:source_map_contents`**
+  When set to _true_ the full source text will be included in the _source-map_.
+  Useful for debugging in situations where the server cannot access the original source files.
+
+* **`:source_map_embed`**
+  Includes the _source-map_ as a [Data URI](https://en.wikipedia.org/wiki/Data_URI_scheme) into the generated CSS-file.   
+  Note: for security reasons, newer versions of Chrome- (60+) and Firefox- (61+) browsers now block web-pages from navigating
+  to _data URIs_ so that this option has become rather obsolete.  
+
+* **`:omit_source_map_url`**
+  When set to _true_ no reference to the _source-map_ file will be emitted into the CSS-file. 
+
+* **`:line_comments`**
+  When set to _true_ causes the line number and filename of the source be emitted into the compiled CSS-file. 
+  Useful for debugging when the _source-map_ is not available. 
+
+* **`:quiet`**
+  When set to _true_ a call to `Engine.render` will not produce any output.
+
 ## Credits
 
 This gem is maintained by [Ryan Boland](https://ryanboland.com)