Changing to 50-Row Mode on the VGA

The function vid_vga50() switches the VGA between 25-row mode and 50-row mode. This function operates the same under PCDOS.

To enable 50-row mode, call:

vid_vga50(ON);

After making this call, the screen fonts and physical cursor are changed to those required for the new mode. The appropriate global variables are adjusted to set the environment for the new number of screen columns and rows (including VSROWQ). The Vermont Views global windows are resized to fit the new screen dimensions.

To return to 25-row mode, call:

vid_vga50(OFF);