Radio Shack TRS-80 - Page 90

Operation Manual
Computer Graphics
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Functions
POINT
Reads Pixel Value at Current Coordinates
POINT returns the OFF/ON pixel value at current x and y
coor~inate as specified by SETXY or SETXYR. If the point is
not in the current viewport, POINT returns -1.
Example
K=POINT(M)
Sample Program (see PSET)
FVIEW
Reads Viewport's Parameters
FVIEW returns the specified viewport parameter:
~ = returns the left X-coordinate
1 = returns the left Y-coordinate
2 = returns the right X-coordinate
3 = returns the right Y-coordinate
Example
I=FVIEW(~)
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