Basic computer language commands

Basic computer programming language

POINT Function

Purpose:

To read the color or attribute value of a pixel from the screen.

Syntax:

POINT(x,y)
POINT(function)

Comments:

In the first syntax, x and y are coordinates of the point to be examined.

If the point given is out of range, the value -1 is returned.

See the COLOR and PALETTE statements for valid color and attribute values.

POINT with one argument allows you to retrieve the current graphics coordinates.

POINT(function) returns the value of the current x or y graphics coordinates as follows:

FunctionReturns
0the current physical x coordinate.
1the current physical y coordinate.
2the current logical x coordinate if WINDOW is active; otherwise, it returns the current physical x coordinate as in 0 above.
3the current logical y coordinate if WINDOW is active; otherwise, it returns the current physical y coordinate as in 1 above.

Example 1:

10 SCREEN 1
20 FOR C=0 TO 3
30 PSET (10, 10),C
40 IF POINT(10, 10)<>C THEN PRINT "BROKEN BASIC="
50 NEXT C

Example 2:

The following inverts the current state of a point:

10 SCREEN 2
20 IF POINT(I, I)<>0 THEN PRESET(I, I) ELSE PSET(I, I)

Example 3:

The following is another way to invert a point:

20 PSET (I, I), 1-POINT(I, I)

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