The LayoutEditShape provides the shapes of the code element pointed to by index along with any surrounding code elements as defined by the ShapeContextSize layout value of the layout object defined by layout_object. the LayoutEditShape functions are intended to be used when performing editing operations on a single code element, e.g. insertion or deletion of a single code element. The LayoutTransform function should be used when doing string shaping. The LayoutEditShape function does not affect any state maintained by the LayoutTransform functions.
When the LayoutEdiShape funtions completes without errors a zero is returned, index and InpSize return the minimum set of code elements required to be redrawn, and if OutBuf is not NULL the respective shaped code elements are written into OutBuf. Any portion of the the InpBuf may be indicated as needing to be redrawn/shaped. Otherwise, if an error occurs a non-zero value is returned and any output values depend on the error code.