From: Daniel Colascione <dancol@dancol.org>
To: Juanma Barranquero <lekktu@gmail.com>
Cc: 10397@debbugs.gnu.org
Subject: bug#10397: [PATCH] Under Remote Desktop, NUMCOLORS is unreliable; workaround
Date: Thu, 29 Dec 2011 19:18:13 -0800 [thread overview]
Message-ID: <4EFD2D75.3030603@dancol.org> (raw)
In-Reply-To: <CAAeL0STqiptDu0iRx1YYzX7dSs-=1fn=GoLVsZr45Q7ernGhKQ@mail.gmail.com>
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On 12/29/11 7:07 PM, Juanma Barranquero wrote:
> On Thu, Dec 29, 2011 at 23:59, Daniel Colascione <dancol@dancol.org> wrote:
>
>> What about this: we'll distrust any NUMCOLORS response less than 256.
>> You'll never use direct color with a bit depth that small, so any answer
>> in that range must be bogus.
>
> Hmm. Shouldn't in fact GetDeviceCaps (hdc, NUMCOLORS) always be <= 256?
>
> According to http://msdn.microsoft.com/en-us/library/dd144877(v=vs.85).aspx
>
> NUMCOLORS
> Number of entries in the device's color table, if the device has a
> color depth of no more than 8 bits per pixel. For devices with greater
> color depths, 1 is returned.
>
> (It says "1", but it's a typo for "-1".)
Good catch. What about this (untested) code?
hdc = GetDC (dpyinfo->root_window);
if (dpyinfo->has_palette)
cap = GetDeviceCaps (hdc, SIZEPALETTE);
else if (dpyinfo->n_cbits <= 8)
/* According to the MSDN, GetDeviceCaps (NUMCOLORS) is valid only
for devices with at most eight bits per pixel. It's supposed
to return -1 for other displays, but because it actually
returns other, incorrect values under some conditions (e.g.,
remote desktop), only use it when we know it's valid. */
cap = GetDeviceCaps (hdc, NUMCOLORS);
else
cap = -1;
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next prev parent reply other threads:[~2011-12-30 3:18 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-29 14:05 bug#10397: [PATCH] Under Remote Desktop, NUMCOLORS is unreliable; workaround Daniel Colascione
2011-12-29 16:13 ` Juanma Barranquero
2011-12-29 16:23 ` Daniel Colascione
2011-12-29 16:27 ` Juanma Barranquero
2011-12-29 16:42 ` Daniel Colascione
2011-12-29 16:45 ` Juanma Barranquero
2011-12-29 22:59 ` Daniel Colascione
2011-12-29 23:10 ` Juanma Barranquero
2011-12-29 23:13 ` Daniel Colascione
2011-12-29 23:18 ` Juanma Barranquero
2011-12-30 3:07 ` Juanma Barranquero
2011-12-30 3:18 ` Daniel Colascione [this message]
2011-12-30 8:51 ` Eli Zaretskii
2011-12-30 9:00 ` Eli Zaretskii
2011-12-30 12:24 ` Juanma Barranquero
2012-08-07 17:13 ` Eli Zaretskii
2012-08-07 17:33 ` Daniel Colascione
2012-08-07 18:07 ` Eli Zaretskii
2016-02-25 6:25 ` Lars Ingebrigtsen
2016-12-13 0:04 ` Glenn Morris
2011-12-30 1:04 ` Jason Rumney
2011-12-30 1:10 ` Daniel Colascione
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