The READ_GIF procedure reads the contents of a GIF format image file and returns the image and color table vectors (if present) in the form of IDL variables.
Although the GIF format allows files to contain multiple images, READ_GIF only reads in the first image in a file. Only 8-bit images are supported, and local colormaps are not supported.
This routine is written in the IDL language. Its source code can be found in the file
subdirectory of the IDL distribution.
Set this keyword to close any open files. The CLOSE keyword is only useful if a file containing multiple images (as specified by the MULTIPLE keyword) is in use. Note that you do not need to specify the normal arguments to READ_GIF ( Filename , Image , etc.) when using this keyword.
Set this keyword to read files that contain multiple images. Each call to READ_GIF returns the next image, with the file remaining open between calls. The Filename argument is ignored and may be omitted after the first call. Reading past the last image returns a scalar value of -1 in the variable specified in the Image argument, and closes the file. R, G, and B color vectors are returned only once, along with the first image.