Computer graphics techniques and tradeoffs in avionics displays

EFIS displays present significant computer graphics challenges. To meet the requirements set forth for airborne multipurpose electronic displays, not only must display quality be high, but also the refresh rate must be sufficient to provide smooth animation. In addition, display quality and speed must be weighed against memory requirements, which are often highly constrained for avionics displays. This paper presents techniques that may be leveraged to produce fast, high-quality graphics on low-resolution displays. The memory implications and tradeoffs associated with these techniques are also discussed. The paper begins with a brief background on antialiasing, supersampling, and area sampling. Antialiasing algorithms are then described for various graphics elements, including lines, polygons, small circle arcs, and great circle arcs. The paper also outlines a weighted area sampling approach for pre-computing antialiased lookup tables near the edges and endpoints of lines, as well as near the edge of a region. Finally, a supersampling approach is discussed for quickly rendering rotated bitmaps.