Besides defining a default size of the editor window you can also change the size of a CKEditor instance on the fly.
To achieve this, use the resize function to define the dimensions of the editor interface, assigning the window a width and height value in pixels or CSS-accepted units.
// Set editor width to 100% and height to 350px. editor.resize( '100%', '350' )
While setting the height value, use the isContentHeight
parameter to decide whether the value applies to the whole editor interface or just the editing area.
// The height value now applies to the editing area. editor.resize( '100%', '350', true )