Output Devices

Theory of Computation & Computer Graphics — Introduction of Computer Graphics, NEC licence examination syllabus (Nepal Engineering Council).

Output Devices

Where does the finished image actually go, beyond the screen?

🖨️ Printers and Plotters

PrintersProduce a physical copy of an image/document, pixel by pixel (like inkjet/laser printers).

PlottersDraw using continuous pen strokes rather than a pixel grid — historically used for precise engineering/architectural drawings.

💡 One-liner: "How does a plotter's drawing method differ fundamentally from a printer's?" → A plotter draws continuous lines with a physical pen (vector-style); a printer builds up an image from a grid of dots (raster-style) — the same conceptual split as vector vs raster displays.

The same raster–vector split, in physical form

A printer and a plotter differ exactly as a raster and a vector display do, which is why the pairing is worth learning once rather than twice.

A printer composes an image from a grid of dots and can therefore reproduce photographs, with quality described by dots per inch — the print equivalent of screen resolution. A plotter moves a physical pen along continuous paths, so it draws precise unbroken lines at any size but cannot fill a photographic image at all.

The consequence follows directly: plotters survived in engineering and architecture because a technical drawing is line work, must be dimensionally exact, and is often produced at very large sizes where a dot grid would either lose precision or require an impractical amount of data.

💡 Resolution terminology differs by medium and examiners test it: screens are described in pixels (total grid) and printers in dots per inch (density). A larger screen at the same resolution has bigger pixels; a printer at higher DPI puts more dots in the same physical inch.

Syllabus points

Printers, plotters

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