modal help proposal

[Phil Blundell]

Traditional "mouse-over" tooltips often don't work when your input
device is a touchpanel, since it may not be possible to move the pointer
without generating a click event.  In the GPE project we've been using a
modal help system based on the protocol below.

A panel button or hotkey is used to enter help mode.  In this mode, the
help application grabs all mouse clicks, suspending normal UI
operation.  Any click event is interpreted as a request for help on the
widget that was clicked.  The tooltip text is passed back to the help
application which displays it in a pop-up.

It'd be cool to see something like this supported directly by the widget
toolkits.  It's fairly easy to hook this kind of functionality into at
least the existing GtkTooltip class.

p.

--

Simple Modal Help Protocol
--------------------------

Windows which support interactive help should set a
_GPE_INTERACTIVE_HELP property on themselves. 

When a mouse click happens in help mode, the help application will
send a ClientMessage event to the appropriate window, with type
_GPE_INTERACTIVE_HELP, empty event mask, and payload:

l[0]	a Window
l[1]	x coordinate of mouse click relative to destination window
l[2]	y coordinate of mouse click relative to destination window
l[3]	an Atom

The receiving program should respond to this message by setting the
desired help text as the contents of a STRING property named by the
Window and Atom specified in the clientmessage.