HOWTO: How to Determine If a Device Is Palette Capable (72387)


The information in this article applies to:

  • Microsoft Windows Software Development Kit (SDK) 3.1
  • Microsoft Win32 Application Programming Interface (API), when used with:
    • Microsoft Windows NT Server 3.5
    • Microsoft Windows NT Server 3.51
    • Microsoft Windows NT Server 4.0
    • Microsoft Windows NT Workstation 3.5
    • Microsoft Windows NT Workstation 3.51
    • Microsoft Windows NT Workstation 4.0
This article was previously published under Q72387

SUMMARY

On a device that supports the Windows palette management function, an application can create a logical palette, select the palette into a Device Context (DC), and realize the palette, which maps its colors into the system (hardware) palette. The GetDeviceCaps() API informs an application whether a given device is capable of performing palette manipulation and, if so, the size of the palette. This article discusses the GetDeviceCaps() API and how it is used.

MORE INFORMATION

To determine whether a device can perform palette operations, call the GetDeviceCaps() API with the RASTERCAPS parameter. If the RC_PALETTE bit of the return is set, the device supports the palette management functions.

To determine how many colors in the system palette are available for the application to use, the following parameters can be used in a GetDeviceCaps() call: 
   Parameter      Description
   ---------      -----------
   SIZEPALETTE    Total number of entries in the system palette
   NUMRESERVED    Number of reserved (static) colors in the system palette
This functionality is demonstrated in the MyPal sample code that is included on the Windows version 3.x Software Development Kit (SDK) Source Code 2 disk. For a demonstration, start MyPal and click the right mouse button.

The reserved colors are entries in the system palette that are used by Windows and cannot be changed by an application [except by using SetSystemPaletteUse(), which is not recommended]. The reserved colors are used for the following purposes: 
   Active border
   Active caption
   Background color MDI applications
   Desktop background color
   Push button faces
   Push button edges
   Push button text
   Caption text
   Disabled (gray) text
   Highlight color in controls (to highlight items in the control)
   Highlight text color
   Inactive border
   Inactive caption
   Inactive caption text (new to Windows version 3.1)
   Menu background
   Menu text
   Scroll-bar gray area
   Window background
   Window frame
   Window text
Modification Type:MinorLast Reviewed:2/11/2005
Keywords:kbhowto KB72387
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