QBasic Tutorial 26 - Screen Coordinates - QB64


Screen 13 will be used within this tutorial. Screen 13 has a resolution of 320 x 200. This tutorial will show the screen coordinates.

The tutorial in the old QBasic Tutorial Series, regarding coordinates, was wrong. The old tutorial had screen coordinates of:

(0, 0)
(0, 200)
(320, 200)
(320, 0)

Since the starting coordinate is 0,0 that means that the math equation of n - 1 needs to be used. So, the farthest coordinate for Screen 13 is (320 - 1, 200 - 1) which gives us (319, 199).

The correct coordinates for each corner, of Screen 13, is:

(0, 0)
(0, 199)
(319, 199)
(319, 0)

PSET will place a pixel at a specified coordinate and color.

Code Download
QBT26_1.BAS - Incorrect Coordinates
QBT26_2.BAS - Correct Coordinates 



QBasic / QB64 Links

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QB64 Wiki & Manual is found at qb64.com/wiki.html

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QBasic 1.1 needs DOSBox to run on Windows Vista and greater, Mac, and Linux.
DosBox is a free download at www.dosbox.com

Free QB64/QBasic Code

QBasic.Net - www.qbasic.net

Pete's QBasic Site - www.petesqbsite.com/index.php

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