READ_XWD function reads the contents of a file created by the
(X Windows Dump) command and returns the image and color table vectors in the form of IDL variables. READ_XWD returns a 2D byte array containing the image. If the file cannot be open or read, the return value is zero.
Note: this function is intended to be used only on files containing 8-bit pixmaps created with
version 6 or later.
This routine is written in the IDL language. Its source code can be found in the file
subdirectory of the IDL distribution.