C/DOS Teleradiology Application

Below is a screenshot of a C/DOS teleradiology app I wrote in 1993.  This was before any GUI libraries existed for DOS (as far as I know).  As a result, my 16-bit C code had to write directly to the VGA card's framebuffer VRAM via "far"  C pointers. The code wrote every pixel of the mouse arrow cursor, the font pixels, the UI widgets, and the imagery.   All images were stored in Expanded Memory (XMS) and paged into a 64K address window in the 0-1MB DOS address space for read/write access to the data in higher memory addresses.

This screenshot shows the original images on the left, and enhanced images on the right, the result of the CLAHE algorithm (Contrast Limited Adaptive Histogram Equalization).