27 lines
713 B
Racket
27 lines
713 B
Racket
#lang racket/base
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;;; Portions Copyright (C) 2012 Jose Antonio Ortega Ruiz.
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(require file/convertible
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racket/file
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racket/vector)
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(provide convert-image?
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convert-image)
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;; save-temporary-image : bytes? -> string?
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;;
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;; Write bytes to a temporary file and return "#<Image: filename>".
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(define (save-temporary-image png-bytes)
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(define filename (make-temporary-file "racket-image-~a.png"))
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(with-output-to-file filename #:exists 'truncate
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(λ () (display png-bytes)))
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(format "#<Image: ~a>" filename))
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(define (convert-image? v)
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(convertible? v))
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(define (convert-image v)
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(cond [(and (convertible? v) (convert v 'png-bytes)) => save-temporary-image]
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[else v]))
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