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Explain vector display

Short answer

A vector display draws images as sets of line segments, steering the electron beam directly between endpoints. Only the drawn parts are refreshed from a display list of commands (MOVE, LINE). It offers high resolution but poor colour/shading and flickers with complex images.

Explain about vector display.

A vector display (random scan, calligraphic or stroke display) draws a picture as a series of straight line segments. The electron beam is deflected directly from one end point to the other, so only the parts of the screen that contain the picture are drawn.

CPU <-> System memory
   |        (display file / list)
   v
Display processor --> Deflection --> CRT
(reads commands,         circuits
 refresh ~30-60 Hz)

Working

  1. The application program and graphics package store the picture as line-drawing commands (e.g. MOVE, LINE) in a display list (refresh display file).
  2. The display processor (display controller) reads the commands in turn and moves the beam along each line.
  3. Because the phosphor glows only for a short time, the whole list is redrawn 30 to 60 times per second to refresh.

Features

  • Small memory (only commands stored).
  • Very high resolution, smooth lines without staircase effect.
  • Flicker appears if the display list is long.
  • Poor for filled areas, shading and many colours.
  • Used in early CAD, plotters and radar-type displays; now largely replaced by raster displays.

✓ Answer checked by Claude Opus 5.5 (high effort)

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