RE: Pixmap practical size limitation?

["Harold Hunt" <huntharo at msu dot edu>]

Jerry,

This is a Cygwin/XFree86-specific mailing list.  Your question about whether
40 MB to 80 MB pixmaps are allowed is a general XFree86/X question that
should be asked and answered by general XFree86/X mailing lists or
documentation.

Please check out these websites for more information and mailing list
addresses:
http://xfree86.org/
http://www.x.org/

You might also want to look in books, etc. for an answer.

Sorry we can't help,

Harold

> -----Original Message-----
> From: cygwin-xfree-owner@cygwin.com
> [mailto:cygwin-xfree-owner@cygwin.com]On Behalf Of Jerry Miller
> Sent: Thursday, April 18, 2002 2:57 PM
> To: cygwin-xfree@cygwin.com
> Subject: Pixmap practical size limitation?
>
>
> In modifying an existing application, which contained
> one (scrolled) DrawingArea and two (scrolled) Text
> widgets, I wanted to use multicolor text and decided
> to use two more DrawingArea widgets to accomplish
> this.  However, only the 2000x2000 original Pixmap
> is reliably written for the refreshment of the original
> DrawingArea.
>
> In order to accommodate the potentially long and/or
> wide range of text in the emulated Text widgets, I
> created a Pixmap of size 5000x4000 and 10000x2000,
> respectively.  To be sure it wasn't something in the
> rendition of the text strings that was at fault in their
> unpredictable behavior, I drew a black 20x100
> rectangle in the upper left corner of each Pixmap
> immediately after creation.  Only the one for the
> 2000x2000 Pixmap appears in the associated
> DrawingArea window.
>
> Other than their sizes (and the variable names,
> of course), there is virtually no difference between
> these Pixmaps.  In fact, if I temporarily change
> the dimensions of the other two to 2000x2000,
> I find that their behavior becomes reliable once
> again.
>
> None of the X documentation mentions any
> size limitations for the Pixmap, whose datatype
> is "opaque."  (Thanks a lot, MIT!)  Even if
> there were one, it should generate a predictable
> error message, rather than an unpredictable
> behavior.  Anyway, even if "unsigned int"
> referred to 16 bits on my computer (which it
> does not), these dimensions would still be
> within range - for that matter, they would even
> be accommodated by "signed short"!
>
> Is this a known bug?  If so, can I get around it,
> albeit kludgily, by declaring 21 variables of type
> Pixmap and doing redundant XDrawString()
> calls to be sure that any that might fall withing
> the bounds of the write will be updated, or is
> there a limit on the _total_ amount of memory
> available for Pixmap data?
>
> I am running under Windows NT4, SP3, with
> the Hummingbird Window Manager, v.6.1.
> (The window manager supplied with cygwin
> is impractical for any sophisticated applications.)
>
>