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)

Pascal
function readpixels(n: longint; var colors: Colorindex): longint;

DESCRIPTION

readpixels attempts to read up to n pixel values from the bitplanes.  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 current viewport.  The values of pixels read outside the current viewport are undefined.  readpixels updates the current character position to one pixel to the right of the last one read; it does not define it 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 IRIS Graphics Programming, Section 3.9, Writing and Reading Pixels

NOTE

This routine is available only in immediate mode. 

Version 2.5r1  —  October 29, 1986