Use height + vertical margin instead of outerHeight for cellHeight

app/assets/javascripts/player/renderers/base.js.coffee

@@ -23,7 +23,8 @@ class AsciiIo.Renderer.Base extends Backbone.View
     sample = $('<span class="font-sample"><span class="line"><span>M</span></span></span>')
     @$el.parent().append(sample)
     @cellWidth = sample.width()
-    @cellHeight = sample.find('span span').outerHeight()
+    span = sample.find('span span')
+    @cellHeight = span.height() + span.css('padding-top') + span.css('padding-bottom')
     sample.remove()
     @fixTerminalElementSize()
     @fixPlayerContainerSize()