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Q73674: Icon and Cursor Size Determined by Display Driver

Article: Q73674
Product(s): Microsoft Windows Software Development Kit
Version(s): WINDOWS:3.0,3.1
Operating System(s): 
Keyword(s): 
Last Modified: 06-NOV-1999

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The information in this article applies to:

- Microsoft Windows Software Development Kit (SDK) versions 3.0, 3.1 
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SUMMARY
=======

The display driver determines the display size of an icon or a cursor. Display
drivers for Microsoft Windows operating system version 3.0 specify icon- and
cursor-compression factors, which are used to determine the size for a
particular icon or cursor. Under Windows version 3.1, the method that the
display driver uses for storing icon and cursor dimensions is different. The
text below details the two methods of storing icon and cursor dimensions.

MORE INFORMATION
================

Each compression factor is the ratio of 64 to the icon or cursor size. In other
words, the icon-width compression factor is 64 divided by the final width of an
icon. Because each factor must be a whole number, the height or the width of an
icon or a cursor must be 64, 32, or 16 pixels.

Four compression factors are stored as a resource in each display driver. The
following table shows typical values:

  Display             Icon/Cursor        Compression Factors
  Drivers             Dimensions         Width       Height
  ----------------------------------------------------------
  CGA                  32 x 16             2           4
  EGA, VGA, 8514       32 x 32             2           2

In Windows version 3.1, the display driver stores the actual icon dimensions.
Therefore, for an icon 32 pixels wide, the driver stores 32 instead of 2. This
removes the limitation that 64 by 64 is the largest possible icon size.

Display drivers for versions of Windows earlier than version 3.0 will continue to
be supported. If Windows encounters an icon dimension less than 11, it treats
the dimension as a compression factor and calculates the dimension accordingly.

Additional query words: 3.00 3.10

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Keywords          :  
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK300 kbWinSDK310
Version           : WINDOWS:3.0,3.1

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