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authorMaxim Cournoyer <maxim.cournoyer@gmail.com>2022-08-12 11:23:29 -0400
committerMaxim Cournoyer <maxim.cournoyer@gmail.com>2022-08-28 22:10:20 -0400
commit42fee6d0f176aea5d208e3e6d8b5270abcf4173c (patch)
treeeabc7202187ee4ccda3e7e28c3223f5f9c9345ca /gnu/build
parent697b797160f8145f282767cedd66be2d7297fe1e (diff)
build: marionette: Add support for Tesseract OCR.
* gnu/build/marionette.scm (invoke-ocrad-ocr): New procedure. (invoke-tesseract-ocr): Likewise. (marionette-screen-text): Rename the #:ocrad argument to #:ocr. Dispatch the matching OCR invocation procedure. (wait-for-screen-text): Rename the #:ocrad argument to #:ocr. * gnu/tests/base.scm (run-basic-test): Adjust accordingly. * gnu/tests/install.scm (enter-luks-passphrase): Likewise. (enter-luks-passphrase-for-home): Likewise.
Diffstat (limited to 'gnu/build')
-rw-r--r--gnu/build/marionette.scm67
1 files changed, 39 insertions, 28 deletions
diff --git a/gnu/build/marionette.scm b/gnu/build/marionette.scm
index 24170bbd30..06b699bd7b 100644
--- a/gnu/build/marionette.scm
+++ b/gnu/build/marionette.scm
@@ -268,39 +268,50 @@ Monitor\")."
;; The "quit" command terminates QEMU immediately, with no output.
(unless (string=? command "quit") (wait-for-monitor-prompt monitor)))))
-(define* (marionette-screen-text marionette
- #:key
- (ocrad "ocrad"))
- "Take a screenshot of MARIONETTE, perform optical character
-recognition (OCR), and return the text read from the screen as a string. Do
-this by invoking OCRAD (file name for GNU Ocrad's command)"
- (define (random-file-name)
- (string-append "/tmp/marionette-screenshot-"
- (number->string (random (expt 2 32)) 16)
- ".ppm"))
-
- (let ((image (random-file-name)))
+(define* (invoke-ocrad-ocr image #:key (ocrad "ocrad"))
+ "Invoke the OCRAD command on image, and return the recognized text."
+ (let* ((pipe (open-pipe* OPEN_READ ocrad "-i" "-s" "10" image))
+ (text (get-string-all pipe)))
+ (unless (zero? (close-pipe pipe))
+ (error "'ocrad' failed" ocrad))
+ text))
+
+(define* (invoke-tesseract-ocr image #:key (tesseract "tesseract"))
+ "Invoke the TESSERACT command on IMAGE, and return the recognized text."
+ (let* ((output-basename (tmpnam))
+ (output-basename* (string-append output-basename ".txt")))
(dynamic-wind
(const #t)
(lambda ()
- (marionette-control (string-append "screendump " image)
- marionette)
-
- ;; Tell Ocrad to invert the image colors (make it black on white) and
- ;; to scale the image up, which significantly improves the quality of
- ;; the result. In spite of this, be aware that OCR confuses "y" and
- ;; "V" and sometimes erroneously introduces white space.
- (let* ((pipe (open-pipe* OPEN_READ ocrad
- "-i" "-s" "10" image))
- (text (get-string-all pipe)))
- (unless (zero? (close-pipe pipe))
- (error "'ocrad' failed" ocrad))
- text))
+ (let ((exit-val (status:exit-val
+ (system* tesseract image output-basename))))
+ (unless (zero? exit-val)
+ (error "'tesseract' failed" tesseract))
+ (call-with-input-file output-basename* get-string-all)))
(lambda ()
- (false-if-exception (delete-file image))))))
+ (false-if-exception (delete-file output-basename))
+ (false-if-exception (delete-file output-basename*))))))
+
+(define* (marionette-screen-text marionette #:key (ocr "ocrad"))
+ "Take a screenshot of MARIONETTE, perform optical character
+recognition (OCR), and return the text read from the screen as a string. Do
+this by invoking OCR, which should be the file name of GNU Ocrad's
+@command{ocrad} or Tesseract OCR's @command{tesseract} command."
+ (define image (string-append (tmpnam) ".ppm"))
+ ;; Use the QEMU Monitor to save an image of the screen to the host.
+ (marionette-control (string-append "screendump " image) marionette)
+ ;; Process it via the OCR.
+ (cond
+ ((string-contains ocr "ocrad")
+ (invoke-ocrad-ocr image #:ocrad ocr))
+ ((string-contains ocr "tesseract")
+ (invoke-tesseract-ocr image #:tesseract ocr))
+ (else (error "unsupported ocr command"))))
(define* (wait-for-screen-text marionette predicate
- #:key (timeout 30) (ocrad "ocrad"))
+ #:key
+ (ocr "ocrad")
+ (timeout 30))
"Wait for TIMEOUT seconds or until the screen text on MARIONETTE matches
PREDICATE, whichever comes first. Raise an error when TIMEOUT is exceeded."
(define start
@@ -312,7 +323,7 @@ PREDICATE, whichever comes first. Raise an error when TIMEOUT is exceeded."
(let loop ((last-text #f))
(if (> (car (gettimeofday)) end)
(error "'wait-for-screen-text' timeout" 'ocr-text: last-text)
- (let ((text (marionette-screen-text marionette #:ocrad ocrad)))
+ (let ((text (marionette-screen-text marionette #:ocr ocr)))
(or (predicate text)
(begin
(sleep 1)