JKQTPlotter
an extensive Qt4/Qt5 Plotter framework (including a fast variant and a LaTeX equation renderer!), written fully in C/C++ and without external dependencies

Modules  
Basic Line/Scatter Graphs  
Function Graphs  
Parametrized Line/Scatter Graphs  
Parsed Function Graphs  
This group assembles graphs that show their data with symbols and optionally with connecting lines in diferent styles: