readpixels(3G) readpixels(3G)
NAME
readpixels - returns values of specific pixels
SPECIFICATION
C long readpixels(n, colors)
short n;
Colorindex colors[];
FORTRAN integer*4 function readpi(n, colors)
integer*4 n
integer*2 colors(n)
DESCRIPTION
readpixels attempts to read up to n pixel values from the
bitplanes in color map mode. It reads them into the array
colors starting from the current character position along a
single scan line (constant y) in the direction of increasing
x. readpixels returns the number of pixels actually read,
which is the number requested if the starting point is at
least that many away from the edge of the screen. The
values of pixels read outside the screen are undefined.
readpixels updates the current character position to one
pixel to the right of the last one read; the current
character position is undefined if the new position is
outside the viewport.
In double buffer mode, only the back buffer is read. Use
readRGB to read pixels in RGB mode.
SEE ALSO
readRGB, writepixels
Programming Guide, Section 3.9, Writing and Reading Pixels
NOTE
This routine is available only in immediate mode.
Page 1 (printed 8/20/87)