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#include <stdinc.h>#include <xyio.h>image *xyopen(handle, name, mode, naxis, axes)int handle, naxis, axes[naxis];string name, mode; void xyclose(handle)int handle; void xyclose(handle)int handle; void xyread(handle, index, array)int handle, index;real array[]; void xywrite(handle, index, array)int handle, index;real array[]; void xysetpl(handle, naxis, nsize)int handle, naxis, nsize[]; Descriptionxyopen opens an image file. For an input file, it determines the size of each axis. For a output file, it writes out this info. name is the name of the file to be opened, mode the access mode. It can be "r" or "w" to open the file in read or write mode, although the strings "old" and "new" are also supported. naxis is the maximum number of axes that the calling program can handle. For an input file, if the data file has fewer than naxis axes, the higher dimensions are treated as having only one element. If the data file has more than naxis axes, and the higher dimensions are more than 1 element deep, xyopen will call error and die. axes is an input array when writing and output for reading. It gives the number of elements along each axis. xyopen returns a handle of the file, which is used in subsequent operations. xyclose closes a previously opened image file. xyread reads a single row from an image. This accesses the plane given by the last call to xysetpl(see below). index is the row number to read. This varies from 0 to axes[1]-1. array is the read row. axes[0] elements are returned. xywrite is the inverse of xyread. xysetpl sets up which (hyper) plane of a cube is to be accessed. By default, if not called, the first plane will be accessed. naxis is the size of the modified nsize array. nsize gives the indices, along the 3rd, 4th, 5th, etc dimensions, of the plane that is to be accessed. nsize[0] corresponds to the index along the 3rd dimension, and can take values from 0 to axes[2]-1 etc. ExampleThe following example shows how to sum all the pixel values in an an image: real *data, sum=0; int i, j, k, h, axes[3]; xyopen(&h,"ccd","r",3,axes); data = (real *) allocate(axes[0] * sizeof(real); for(k=0; k<axes[2]; k++) { xysetpl(h,1,&k); for(j=0; j<axes[1]; j++) { xyread(h,j,data); for(i=0; i<axes[0]; i++) sum += data[i]; } } printf("Sum = %g0,sum);

~/src/image/ioxyio.c

15-may-92V1.0 CreatedPJT 7-jan-99V1.1 Fixed documentation bugPJT