[racket] Second display monitor issue

EnumDisplayMonitors() is the way I see to get an HMONITOR, which is
needed for GetMonitorInfo. Is there another way?

At Sat, 26 May 2012 15:03:50 -0600, Kieron Hardy wrote:
> Thanks Matthew for the fix - it seems to work fine - and wow done so
> quickly too!
> 
> Is there a reason you have Windows enumerate the display monitors (with
> EnumDisplayMonitors) and then ask Windows for details for each of those
> monitors (with GetMonitorInfoW)? I am thinking that a more direct approach
> would be to have some sort of in-range step through the monitors in turn
> directly and collecting and processing the data that way. I am probably
> missing something but the enumerate-first approach seems to be doing more
> work than strictly necessary. Admittedly it's a terribly minor quibble,
> it's only a tiny bit more work, what with the small number of monitors and
> the small number of times this needs to be done, am just looking for
> greater understanding.
> 
> Cheers,
> 
> Kieron.
> 
> On Sat, May 26, 2012 at 8:18 AM, Matthew Flatt <mflatt at cs.utah.edu> wrote:
> 
> > Thanks! I've pushed a change that should solve the problem; let me know
> > if it still doesn't work.
> >
> > At Sat, 26 May 2012 05:45:52 -0600, Kieron Hardy wrote:
> > > So it seems that for some reason (Older Dell laptop, ATI video, Windows 7
> > > using generic drivers) the Windows system call to return the list of
> > > monitors is returning them to Racket in a different order (primary
> > display
> > > monitor last) than expected (primary display monitor first).
> > >
> > > The code for get-all-screen-rects (in
> > > collects/mred/private/wx/win32/frame.rkt) assumes monitor 0 is the
> > primary
> > > display monitor and is the first item in the list returned by
> > > EnumDisplayDevices. My tests show that at least sometimes the primary
> > > display monitor is not the first item in the list (also noted on SO at
> > >
> > http://stackoverflow.com/questions/2600255/how-can-i-retrieve-monitor-information
> > > ).
> > >
> > > An alternative solution to getting monitor information would be to use
> > > GetMonitorInfo passing a MONITORINFO or MONITORINFOEX structure for each
> > of
> > > the values in the range 0 .. GetSystemMetrics (SM_CMONITORS) and used in
> > > Racket perhaps sorted by the monitor name returned in the szDevice field
> > of
> > > the MONITORINFOEX structure.
> > >
> > > If Racket needs to designate monitor 0 as the primary monitor then
> > > get-all-screen-rects must enumerate the display monitors and then perform
> > > some processing to sort them so that the primary monitor is returned as
> > the
> > > first item in the list.
> > >
> > > Cheers,
> > >
> > > Kieron.
> > > ____________________
> > >   Racket Users list:
> > >   http://lists.racket-lang.org/users
> >