Why is solid fill is harder in random scan display?

Random scan display/Vector scan display means producing images like polygons, geometrical shapes..High resolution, less memory size etc.

Update:

@billrussell42 "because it can draw a square with 4 lines, but to fill it in it has to draw thousands of lines inside the square."don't raster scan display does exactly the same line by line, pixel illumination?So,how is random scan display bad than raster scan display in this issue?

Update 2:

@qrk Raster scan always repaints the whole screen; where is this written. I think raster scan illuminates pixel line by line.

2 Answers

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  • 2 months ago
    Favourite answer

     because it can draw a square with 4 lines, but to fill it in it has to draw thousands of lines inside the square. 

  • qrk
    Lv 7
    2 months ago

    When you talk about random scan, this is a technique used with CRT displays. Fills would require lots of strokes to do a solid fill, thus taking up time that could be better spent updating important data like two planes getting ready to collide. CRTs aren't used for modern displays, thus random scan is a relic in modern design.

    Raster scan always repaints the whole screen, thus, fills do not take up any more time.

    Modern vector graphics files, like SVG, have fill commands, thus fills require a small instruction set to display a fill. This is why SVG files for graphics are small compared to something like a BMP image file.

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