diff options
Diffstat (limited to 'src/Fl_x.cxx')
| -rw-r--r-- | src/Fl_x.cxx | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/src/Fl_x.cxx b/src/Fl_x.cxx index 68f746033..6668fcf43 100644 --- a/src/Fl_x.cxx +++ b/src/Fl_x.cxx @@ -1586,6 +1586,35 @@ int fl_handle(const XEvent& thisevent) if ((Atom)(data[0]) == WM_DELETE_WINDOW) { event = FL_CLOSE; } else if (message == fl_XdndEnter) { + /* + Excerpt from the XDND protocol at https://www.freedesktop.org/wiki/Specifications/XDND/ : + - data.l[0] contains the XID of the source window. + - data.l[1]: + Bit 0 is set if the source supports more than three data types. + The high byte contains the protocol version to use (minimum of the source's and + target's highest supported versions). The rest of the bits are reserved for future use. + - data.l[2,3,4] contain the first three types that the source supports. Unused slots are set + to None. The ordering is arbitrary. + + If the Source supports more than three data types, bit 0 of data.l[1] is set. This tells the + Target to check the property XdndTypeList on the Source window for the list of available + types. This property should contain all the available types. + + BUT wayland gnome apps (e.g., gnome-text-editor) set bit 0 of data.l[1] + even though their source supports 2 data types (UTF8 text + a gnome-specific type) + and put None (==0) in each of data.l[2,3,4]. + The same gnome apps run in X11 mode (GDK_BACKEND=x11) clear bit 0 of data.l[1] + and support only UTF8 text announced in data.l[2]. + FLTK wayland apps set bit 0 of data.l[1] and support only UTF8 text. + + Overall, the correct procedure is + if (bit 0 of data.l[1] is set) { + get the XdndTypeList property + use all the data types it returns which can be in any number ≥ 1 + } else { + the source supports 1, 2 or 3 data types available at data.l[2,3,4] + } + */ #if FLTK_CONSOLIDATE_MOTION fl_xmousewin = window; #endif // FLTK_CONSOLIDATE_MOTION |