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Joined 2026-09-21 Message
Incoming links: Bresenham's line algorithm
Jack Elton Bresenham 2026-10-31
Three advantages of integer arithmetic for raster graphics are:
- Cheap, fast operations. Historically, integer addition, subtraction and shifts needed much less hardware and execution time than floating-point arithmetic, especially on machines without a floating-point unit. An incremental Bresenham's line algorithm needs only a few additions and a decision per pixel.
- Exact decisions. Provided integer overflow is excluded, the scaled midpoint line decision is exact. There is no accumulated rounding error that can move a decision across a half-pixel boundary; equality has a reproducible tie rule.
- Simple storage and hardware. Integer coordinates already identify pixels. An implementation can keep coordinates and decision variables in ordinary registers and use a small add/compare datapath, avoiding conversion between floating-point numbers and integer screen addresses.