bug#22549: 25.0.50; Tooltips placed outside of screen limits

[martin rudalics <rudalics@gmx.at>]

 > I don't think that performance considerations are applicable here. About
 > compromising the one monitor case: in theory, the monitor's geometry is
 > always the right thing to use for calculating the tooltip position, not
 > x_display_pixel_width/height. For instance: it is possible to configure
 > X for having a desktop area larger than the monitor's resolution, IIRC.

But ‘x_display_pixel_height’ returns the value of 'HeightOfScreen' which
is what we need for the one monitor case.

 >> There's no guarantee that ‘x-display-monitor-attributes-list’ works on
 >> all systems, especially on those where neither Xinerama nor XRandr are
 >> installed.  IIRC older versions of the latter might also have problems
 >> when a monitor is added/removed during a session.  The fallback should
 >> always give the same results as the present code, but who knows ...
 >
 > See the attached patch. If we can't use the monitor's geometry, we
 > default to the old code.

My concern was less that ‘x-display-monitor-attributes-list’ would not
assign a value to max_y.  My concern was that that value could be wrong.

Anyway.  Better install your initial patch then.  It's cleaner and we'll
see soon enough whether it causes any problems.

 >> And just to make sure: Can we rely on the fact that XQueryPointer always
 >> gives reliable results with multiple monitors and its present arguments?
 >
 > Dunno. I know nothing about X Windows.

Have you tried with a frame that spans both monitors?

martin