Another option is wxMathPlot which is wxWidgets based.
From it's website:
wxMathPlot main features:
- Completely mouse-driven view control: pan, zoom, scroll, box
positioning.
- Printing class.
- Screenshot saving of plot window (BMP, PNG and JPEG formats).
- Overlay movable boxes with legend or mouse coordinate display.
- Can set margins to avoid plots to cover axis labels.
- Flexible axis positioning
- A series of useful layer to directly plot data from STL vector, movable objects, covariance ellipse, bitmaps, etc.
- Multi-platform: runs everywhere wxWidgets does.
