Beginner's Programming Tutorial in QBasic

(Kiana) #1

Displaying graphics


Before you can show graphics images on the screen, you must call the SCREEN command.
SCREEN sets the graphics mode.
The following program uses graphics mode 13 (320x200) to display a line, then returns back to
text mode:
SCREEN 13
' This starts at 10 pixels from the left, 10 from' the top and goes to point (100, 100):
LINE (10, 10)-(100, 100)
WHILE INKEY$ = "": WEND ' Waits until a key is pressed
SCREEN 0 ' Returns to text mode


You can also draw a colored line.
SCREEN 13
LINE (10, 10)-(100, 100), 192 ' Dark green
WHILE INKEY$ = "": WEND
SCREEN 0


To draw a single pixel, use PSET.
SCREEN 13
PSET (160, 100)
WHILE INKEY$ = "": WEND
SCREEN 0


The following displays a circle at (160, 100) with a radius of 50 :
SCREEN 13
CIRCLE (160, 100), 50
WHILE INKEY$ = "": WEND
SCREEN 0

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