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;;; "pnm.scm" Read PNM image files.
; Copyright 2000 Aubrey Jaffer
;
;Permission to copy this software, to modify it, to redistribute it,
;to distribute modified versions, and to use it for any purpose is
;granted, subject to the following restrictions and understandings.
;
;1. Any copy made of this software must include this copyright notice
;in full.
;
;2. I have made no warrantee or representation that the operation of
;this software will be error-free, and I am under no obligation to
;provide any services, by way of maintenance, update, or otherwise.
;
;3. In conjunction with products arising from the use of this
;material, there shall be no use of my name in any advertising,
;promotional, or sales literature without prior written consent in
;each case.
(require 'scanf)
(require 'printf)
(require 'array)
(require 'array-for-each)
(require 'byte)
(require 'line-i/o)
(define (pnm:read+integer port)
(define uint #f)
(do ((chr (peek-char port) (peek-char port)))
((not (and (char? chr) (or (char-whitespace? chr) (eqv? #\# chr)))))
(if (eqv? #\# chr)
(read-line port)
(read-char port)))
(if (eof-object? (peek-char port))
(peek-char port)
(and (eqv? 1 (fscanf port " %u" uint)) uint)))
(define (pnm:type-dimensions port)
(if (input-port? port)
(let* ((c1 (read-char port))
(c2 (read-char port)))
(cond
((and (eqv? #\P c1)
(char? c2)
(char-numeric? c2)
(char-whitespace? (peek-char port)))
(let* ((format (string->symbol (string #\p c2)))
(width (pnm:read+integer port))
(height (pnm:read+integer port))
(ret
(case format
((p1) (list 'pbm width height 1))
((p4) (list 'pbm-raw width height 1))
((p2) (list 'pgm width height (pnm:read+integer port)))
((p5) (list 'pgm-raw width height (pnm:read+integer port)))
((p3) (list 'ppm width height (pnm:read+integer port)))
((p6) (list 'ppm-raw width height (pnm:read+integer port)))
(else #f))))
(and (char-whitespace? (read-char port)) ret)))
(else #f)))
(call-with-input-file port pnm:type-dimensions)))
(define (pnm:read-binary! array port)
(array-map! array (lambda () (read-byte port))))
(define (pnm:image-file->array path . array)
(set! array (and (not (null? array)) (car array)))
(call-with-input-file path
(lambda (port)
(apply (lambda (type width height max-pixel)
(define (read-binary)
(pnm:read-binary! array port)
(if (eof-object? (peek-char port)) array
(slib:error type 'not 'at 'file 'end)))
(define (read-text)
(array-map! array (lambda () (pnm:read+integer port)))
(if (eof-object? (pnm:read+integer port)) array
(slib:error type 'not 'at 'file 'end)))
(define (read-pbm)
(array-map! array (lambda () (eqv? 1 (pnm:read+integer port))))
(if (eof-object? (pnm:read+integer port)) array
(slib:error type 'not 'at 'file 'end)))
(case type
((pbm)
(or array
(set! array (make-array #t height width)))
(read-pbm))
((pgm)
(or array
(set! array (make-array max-pixel height width)))
(read-text))
((ppm)
(or array
(set! array (make-array max-pixel height width 3)))
(read-text))
((pbm-raw)
(or array
(set! array (make-array #t height (quotient width 8))))
(read-binary))
((pgm-raw)
(or array
(set! array (make-array max-pixel height width)))
(read-binary))
((ppm-raw)
(or array
(set! array (make-array max-pixel height width 3)))
(read-binary))))
(pnm:type-dimensions port)))))
(define (pnm:image-file->uniform-array path . array)
(fluid-let ((make-array make-uniform-array)
(pnm:read-binary!
(lambda (ra port)
(if (array? ra #t)
(error 'pnm:image-file->array
"pbm-raw support unimplemented")
(let ((bytes (apply make-uniform-array #\a
(array-dimensions ra))))
(uniform-array-read! bytes port)
(array-map! ra char->integer bytes))))))
(apply pnm:image-file->array path array)))
;; ARRAY is required to be zero-based.
(define (pnm:array-write type array maxval port)
(define (write-header type height width maxval)
(let ((magic
(case type
((pbm) "P1")
((pgm) "P2")
((ppm) "P3")
((pbm-raw) "P4")
((pgm-raw) "P5")
((ppm-raw) "P6")
(else (error 'pnm:array-write "bad type" type)))))
(fprintf port "%s\n%d %d" magic width height)
(if maxval (fprintf port "\n%d" maxval))))
(define (write-pixels type array maxval)
(let* ((shp (array-dimensions array))
(height (car shp))
(width (cadr shp)))
(case type
((pbm-raw)
(newline port)
(if (array? array #t)
(uniform-array-write array port)
(error 'pnm:array-write "expected bit-array" array)))
((pgm-raw ppm-raw)
(newline port)
;;; (let ((bytes (apply make-uniform-array #\a shp)))
;;; (array-map! bytes integer->char array)
;;; (uniform-array-write bytes port))
(uniform-array-write array port))
((pbm)
(do ((i 0 (+ i 1)))
((>= i height))
(do ((j 0 (+ j 1)))
((>= j width))
(display (if (zero? (remainder j 35)) #\newline #\space) port)
(display (if (array-ref array i j) #\1 #\0) port)))
(newline port))
((pgm)
(do ((i 0 (+ i 1)))
((>= i height))
(do ((j 0 (+ j 1)))
((>= j width))
(display (if (zero? (remainder j 17)) #\newline #\space) port)
(display (array-ref array i j) port)))
(newline port))
((ppm)
(do ((i 0 (+ i 1)))
((>= i height))
(do ((j 0 (+ j 1)))
((>= j width))
(display (if (zero? (remainder j 5)) #\newline " ") port)
(display (array-ref array i j 0) port)
(display #\space port)
(display (array-ref array i j 1) port)
(display #\space port)
(display (array-ref array i j 2) port)))
(newline port)))))
(if (output-port? port)
(let ((rnk (array-rank array))
(shp (array-dimensions array)))
(case type
((pbm pbm-raw)
(or (and (eqv? 2 rnk)
(integer? (car shp))
(integer? (cadr shp)))
(error 'pnm:array-write "bad shape" type array))
(or (eqv? 1 maxval)
(error 'pnm:array-write "maxval supplied not 1" type))
(write-header type (car shp) (cadr shp) #f)
(write-pixels type array 1))
((pgm pgm-raw)
(or (and (eqv? 2 rnk)
(integer? (car shp))
(integer? (cadr shp)))
(error 'pnm:array-write "bad shape" type array))
(write-header type (car shp) (cadr shp) maxval)
(write-pixels type array maxval))
((ppm ppm-raw)
(or (and (eqv? 3 rnk)
(integer? (car shp))
(integer? (cadr shp))
(eqv? 3 (caddr shp)))
(error 'pnm:array-write "bad shape" type array))
(write-header type (car shp) (cadr shp) maxval)
(write-pixels type array maxval))
(else (error 'pnm:array-write type 'unrecognized 'type))))
(call-with-output-file port
(lambda (port)
(pnm:array-write type array maxval port)))))
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