A very basic, based on the font-size implementation in TinyMCE, plugin to format a element with a given line-height.
This was written for TinyMCE version 4.1.5 (2014-09-09)
https://github.com/tinymce/tinymce/
Copy the plugin into your TinyMCE plugin folder.
Your TinyMCE init() method should contain the following value:
tinymce.init({
...
plugins: 'lineheight',
toolbar: 'lineheightselect'
...
});
Also you could configure the different heights like that:
tinymce.init({
...
lineheight_formats: "8pt 9pt 10pt 11pt 12pt 14pt 16pt 18pt 20pt 22pt 24pt 26pt 36pt",
...
});