High Resolution Video Modes & Calculating Text Resolution

ID: Q71263

The information in this article applies to:

The C Run-Time (CRT), included with:
- Microsoft C for MS-DOS, versions 5.1, 6.0, 6.0a, and 6.0ax
- Microsoft C/C++ for MS-DOS, version 7.0
- Microsoft Visual C++ for Windows, version 1.0

When using the graphics library to write text to the screen, the number of rows and columns of text to be displayed is based on the capabilities of the video resolution with which you are working. There are basically two fonts built into the VGA BIOS. They are both 8 pixels wide and either 8 or 16 pixels high (8x8 and 8x16). These character sizes are used to calculate the number of rows and columns that you can display on a graphics screen. The formula is:


             screen height
    rows =  ----------------
            character height

                screen width
    columns =  ---------------
               character width

In C versions 5.1, 6.0, 6.0a 6.0ax, the maximum supported resolution is 640x480. Using the 8x8 character set, the corresponding text resolution is 60 rows by 80 columns. C/C++ version 7.0 and later support video modes of up to 1280x1024. Using the 8x8 character set, the corresponding maximum text resolution is 128 rows by 160 columns. For more information on video modes, see the documention for the _setvideomode() function.

Additional query words: kbinf 5.10 6.00 6.00a 6.00ax 7.00 1.00


Keywords          : kb16bitonly 
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Last Reviewed: July 20, 1999