Ticket #211 (Fixed)Tue Jul 21 14:55:18 UTC 2009

ScrollList_SetFont and TextArea_SetFont don't interpret identifier "" like a NULL pointer.

Details by Christopher Bazley (288):

The TextGadgets module provides two methods ScrollList_SetFont and TextArea_SetFont, which are analogous to the (undocumented) methods that the Window module provides to set the text font for dis`playing gadgets of type ActionButton, RadioButton, DisplayField, WritableField, StringSet or Button.

Unlike the methods provided by the Window module, the TextGadgets module does not interpret an empty string (R4 points to a control character) as equivalent to a NULL string pointer (i.e. the value of R4 is 0). Instead, it passes an empty string straight through to SWI Font_FindFont, which returns a slightly puzzling error " font not found".

This lack of flexibility makes calling these methods via a veneer awkward in languages such as BASIC where there is no representation of a NULL string that is distinct from an empty string. Hence, it is necessary to use a different SYS statement when trying to unset a gadget’s custom font (i.e. revert to using the desktop font).