The register

Everything on this site, in one table

Every entry is one problem the grid created and somebody solved. 21 entries across 5 sections, with the problem each one answered.

	Entry	What it covers	Length
	The framebuffer	A block of memory where every pixel has an address is what made painting on a screen possible at all.	Long read
	Bresenham's line	A straight line rarely agrees with the grid, so an algorithm has to decide which pixels it lands on using only integers.	Long read
	Anti-aliasing	A hard edge on a grid produces a stair, and softening the boundary trades one artefact for a less objectionable one.	Medium
	SuperPaint	Richard Shoup's system at Xerox PARC was the first that let a person paint into a framebuffer and see it immediately.	Long read
	Sampling	Everything on a grid is a measurement taken at intervals, and what falls between the intervals is gone.	Short

	Entry	What it covers	Length
	Sketchpad	Ivan Sutherland's 1963 system let someone draw on a screen with a light pen, and the drawing was made of objects rather than marks.	Long read
	Constraints	Telling the drawing that two lines must stay perpendicular is a different idea from drawing them perpendicular, and it is the older ancestor of modern tools.	Medium
	The light pen	It does not draw; it detects when the screen's beam passes under it, which is why it only worked on the displays of its day.	Medium
	Vector displays	Some screens drew lines directly rather than filling a grid, and they were sharp in a way rasters took years to match.	Short

	Entry	What it covers	Length
	Bézier	Pierre Bézier published the curve for car bodywork, and it survives because four points describe a smooth path that is easy to compute and easy to drag.	Long read
	de Casteljau	The algorithm that evaluates the curve by repeated straight-line subdivision, worked out at a rival firm and unpublished for years.	Medium
	The control polygon	The handles are not on the curve; they pull it, which is why the interface feels the way it does.	Medium
	Splines	The name comes from the flexible strip a draughtsman bent through fixed points, and the mathematics describes the same behaviour.	Short

	Entry	What it covers	Length
	RGB and CMYK	One adds light and the other subtracts it, and neither can describe the whole of what the other can.	Long read
	Gamut	The set of colours a device can actually produce is a shape, and converting between devices means deciding what to do with everything outside it.	Medium
	CIE 1931	A model of what the eye responds to, built from experiments on a small number of observers, that still underpins every colour system in use.	Long read
	Test charts	A known reference in the frame is the only way to find out what a device is actually doing to colour.	Short

	Entry	What it covers	Length
	The RAND Tablet	An early digitising tablet that let a stylus position be read directly, years before anything like it was affordable.	Long read
	Stylus pressure	Reading how hard the pen is pressed turns a position into a gesture, and it is what made digital drawing feel like drawing.	Medium
	The mouse	A relative pointing device is bad at drawing and good at everything else, which is why both survived.	Medium
	Screens	The display is a measuring instrument you are also looking at, and it drifts.	Short