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(slib.info)Portable Image Files

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Portable Image Files
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  `(require 'pnm)'

 - Function: pnm:type-dimensions path
     The string PATH must name a "portable bitmap graphics" file.
     `pnm:type-dimensions' returns a list of 4 items:
       1. A symbol describing the type of the file named by PATH.

       2. The image width in pixels.

       3. The image height in pixels.

       4. The maximum value of pixels assume in the file.

     The current set of file-type symbols is:
    pbm
    pbm-raw
          Black-and-White image; pixel values are 0 or 1.

    pgm
    pgm-raw
          Gray (monochrome) image; pixel values are from 0 to MAXVAL
          specified in file header.

    ppm
    ppm-raw
          RGB (full color) image; red, green, and blue interleaved
          pixel values are from 0 to MAXVAL


 - Function: pnm:image-file->array path array
     Reads the "portable bitmap graphics" file named by PATH into
     ARRAY.  ARRAY must be the correct size and type for PATH.  ARRAY
     is returned.

 - Function: pnm:image-file->array path
     `pnm:image-file->array' creates and returns an array with the
     "portable bitmap graphics" file named by PATH read into it.


 - Procedure: pnm:array-write type array maxval path
     Writes the contents of ARRAY to a TYPE image file named PATH.  The
     file will have pixel values between 0 and MAXVAL, which must be
     compatible with TYPE.  For `pbm' files, MAXVAL must be `1'.