Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!uunet!microsoft!chrisg
From: chrisg@microsoft.UUCP (Chris GUZAK)
Newsgroups: comp.windows.ms.programmer
Subject: Re: WinApps detecting 24-bit Video Drivers
Message-ID: <58843@microsoft.UUCP>
Date: 6 Nov 90 18:18:59 GMT
References: <599@nih-csl.nih.gov>
Reply-To: chrisg@microsoft.UUCP (Chris GUZAK)
Organization: Microsoft Corp., Redmond WA
Lines: 17

In article <599@nih-csl.nih.gov> bert@helix.nih.gov (Bert Tyler) writes:
>How should a WinApp check for the presence of a 24-bit (IE, > 256 colors)
>video driver?

24 bit and 16 bit displays will return -1 for NUMCOLORS (since
GetDeviceCaps() only returns 16 bits.  You can also check
NUMPLANES * BITSPIXEL > 8 also indicates a > 256 color device.

Palettes will be mapped to nearest colors on these devices so
you will get what you expect.

People should be careful with the returns from NUMPLANES and
BITSPIXEL.  Improper use of these parameters are almost always
the cause of regular windows programs not running on 24 bit
displays.

Chris Guzak