DPlot makes use of several publicly-available modules that enhance its functionality:
RunicSoft Function Parser, by Andreas Hartl
A heavily modified version of this DLL is used by the Y=f(X) command and similar commands to generate and/or modify data with a user-defined function.
ZLIB is used to save and read compressed DPlot files. Compression is lossless. Files compressed using this method will have a compression ratio from 2.5:1 to 4:1. Larger files may achieve 12:1 or higher.
FreeImage is a toolkit for for developers interested in supporting a variety of image formats. DPlot uses FreeImage to save BMP, GIF, PNG, JPG, and TIF file formats, and for importing background images.