modal help proposal

Phil Blundell pb at
Sat Jul 26 23:01:01 EEST 2003

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.



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.

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