Re: Dual head displays

[George Constantinides <gconstantinides(at)mhl.nsw.gov.au>]

I was able to reproduce your problem.
If you set the draw widget to object graphics it works fine,
so it appears to be a limitation with direct graphics.

Draw_2 = WIDGET_DRAW(Base_2, XSIZE = 50, YSIZE = 50, GRAPHICS_LEVEL=2)

Ian Dean wrote:

> Hi,
>  We have been successfully using two X-window displays (on separate
> terminals each with its own IP address) on a DEC??? Alpha running
> OpenVMS 7.1 and using IDL 5.4. The way this is achieved is as follows:
>
>  $ Set display/create/node=ABC/transport=tcpip Display_1
>
> The above VMS command is used to define a second display on "Display_1"
>
> PRO Head_2
>     Base_1 = WIDGET_BASE(XSIZE = 100, YSIZE = 200) ; Base on default
> screen
>     Base_2 = WIDGET_BASE(DISPLAY = 'Display_1', $
>         XSIZE = 100, YSIZE = 200)                  ; Base on second
> screen
>     Text_1 = WIDGET_TEXT(Base_1, VALUE = 'Rubbish')
>     Text_2 = WIDGET_TEXT(Base_2, VALUE = 'More Rubbish')
>     WIDGET_CONTROL, Base_1, /REALIZE
>     WIDGET_CONTROL, Base_2, /REALIZE
> END
>
> This has been working successfully for some years, but up until now,
> only text has been displayed on the second terminal and graphics+text on
> the first terminal.
> However, we now have a requirement to display graphics on the second
> screen. In order to achieve this, the following line was added before
> line 7 above:
>
>     Draw_2 = WIDGET_DRAW(Base_2, XSIZE = 50, YSIZE = 50)
>
> This causes the following error to be reported:
>
> %WIDGET_DRAW: Non-default Display not supported for old graphics.
>
> What exactly does this mean?
> Is OLD graphics direct graphics?
> How can I achieve the desired draw widget on the second terminal?
>
> The above is obviously a cut-down version of the problem. The actual
> software exhibits even more strange effects:
>
> 1) When the package is run using the run command, IDL crashes with an
> access violation - not very helpful.
>
> 2) When stepping through the software, IDL appears to pass the point
> where the crash happens.
>
> 3) AT the point when trying to create the draw widget, IDL does not
> report any errors, but the X windows system does as follows.
>
>     %X windows protocol error: BadDrawable (invalid Pixmap or Window
> parameter)
>
> There must be someone out there who has achieved the effect we are
> looking for. I have e-mailed RSI, but am not holding my breath for a
> quick (or even useful) reply.
>
> Regards,
>  Ian

--
Regards,

George Constantinides
Manly Hydraulics Laboratory
email:  GeorgeC@mhl.nsw.gov.au
URL   http://www.mhl.nsw.gov.au