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References: 7. Ellipse & Polygon Drawing

  1. Ellipse - Wikipedia - Covers the geometric definition of an ellipse, its two independent axes, and how a circle is the special case where those axes are equal. Grounds the chapter's xradius/yradius parameters and the "circle as special ellipse" concept.

  2. Polygon - Wikipedia - Explains vertices, edges, closed polygonal chains, and the distinction between convex and non-convex (concave) polygons. Directly supports the point array, polygon vertex, closed polygon path, and convex/concave concepts built around fb.poly().

  3. Spatial anti-aliasing - Wikipedia - Describes why raster displays produce jagged "staircase" edges on curves and how anti-aliasing techniques blend boundary pixels to smooth them. Explains the root cause behind this chapter's anti-aliasing limitation section.

  4. Computer Graphics: Principles and Practice (3rd Edition) - John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley - Addison-Wesley Professional - The standard graphics reference; its chapters on rasterization, curve approximation with line segments, and polygon filling underpin the ellipse and poly methods taught here.

  5. Computational Geometry: Algorithms and Applications (3rd Edition) - Mark de Berg, Otfried Cheong, Marc van Kreveld, and Mark Overmars - Springer - Formalizes polygon vertices, convexity testing, and simple closed paths with rigorous algorithms, giving a deeper theoretical grounding for the convex/concave polygon distinction introduced in this chapter.

  6. FrameBuffer - MicroPython Library Documentation - MicroPython Official Docs - Official reference for FrameBuffer.ellipse() and FrameBuffer.poly(), including the fill flag and quadrant bitmask argument. The primary technical source for every method call used in this chapter.

  7. Midpoint ellipse drawing algorithm - GeeksforGeeks - Walks through how ellipses are rasterized on a pixel grid by computing one quadrant and mirroring it with 4-way symmetry. Connects directly to the chapter's quadrant fill code, which exposes that same quadrant structure as a bitmask.

  8. Convex Polygon: Definition, Properties, Formulas, and Examples - GeeksforGeeks - Defines convex polygons by interior angle and contrasts them with concave (dented) polygons, with worked examples. Reinforces the convex/concave classification used when designing eyebrow and mouth shapes with fb.poly().

  9. Ellipse - Math Is Fun - Math Is Fun - A visual, beginner-friendly explanation of ellipses, their foci, and major/minor axes, including the note that a circle is just an ellipse with equal axes. A gentler on-ramp than the Wikipedia article for students new to the shape.

  10. Polygons - Math Is Fun - Math Is Fun - Introduces polygons, naming conventions by side count, and the convex-versus-concave distinction in plain language with diagrams. Useful companion reading for students building point arrays for the first time.