SCROLL_CB
Called when some manipulation is made to the scrollbar. The canvas is automatically redrawn only if this callback is NOT defined.
Callback
int function(Ihandle *ih, int op, float posx, float posy);ih: identifier of the element that activated the
event.
op: indicates the operation performed on the
scrollbar.
If the manipulation was made on the vertical scrollbar, it can have the following values:
IUP_SBUP - line up
IUP_SBDN - line down
IUP_SBPGUP - page up
IUP_SBPGDN - page down
IUP_SBPOSV - vertical positioning
IUP_SBDRAGV - vertical drag If it was on the horizontal scrollbar, the following values are valid:
IUP_SBLEFT - column left
IUP_SBRIGHT - column right
IUP_SBPGLEFT - page left
IUP_SBPGRIGHT - page right
IUP_SBPOSH - horizontal positioning
IUP_SBDRAGH - horizontal dragposx, posy: the same as the ACTION canvas callback (corresponding to the values of attributes POSX and POSY).
Notes
Line and page operations are reported in Win32, Motif, GTK, Qt, WinUI, Cocoa and Haiku; the drag operations IUP_SBDRAGH/IUP_SBDRAGV only in Win32, Motif and Haiku (the others use IUP_SBPOSH/IUP_SBPOSV during a drag). GTK 4, FLTK, EFL and iOS report only IUP_SBPOSH/IUP_SBPOSV. For portability prefer reading POSX and POSY.