branch: externals/doc-toc
commit ae455b486327205e5e6df786d42af188bddd8fa5
Author: Daniel Nicolai <dalanico...@gmail.com>
Commit: Daniel Nicolai <dalanico...@gmail.com>
Implement language customization for OCR
---
README.org | 3 ++-
toc-mode.el | 37 ++++++++++++++++++++++++++++++-------
2 files changed, 32 insertions(+), 8 deletions(-)
diff --git a/README.org b/README.org
index 8e268b752e..86a38c2d93 100644
--- a/README.org
+++ b/README.org
@@ -45,7 +45,8 @@ toc-extract-pages-ocr= if doc has no text layer or text layer
is bad, and answer
the subsequent prompts by entering the pagenumbers for the first and the last
page each followed by =RET=. *For PDF extraction with OCR, currently it is
required*
*to view all contents pages once before extraction* (toc-mode uses the cached
file
-data).
+data). Also the languages used for tesseract OCR can be customized via the
+`toc-ocr-languages' variable.
[[toc-mode-extract.gif]]
diff --git a/toc-mode.el b/toc-mode.el
index 3ce807deb5..d2dbfa279a 100644
--- a/toc-mode.el
+++ b/toc-mode.el
@@ -48,11 +48,12 @@
;; text layer is bad, and answer the subsequent prompts by entering the
;; pagenumbers for the first and the last page each followed by RET. For PDF
;; extraction with OCR, currently it is required to view all contents pages
once
-;; before extraction (toc-mode uses the cached file data). A buffer with the,
-;; somewhat cleaned up, extracted text will open in TOC-cleanup mode. Prefix
-;; command with the universal argument (C-u) to omit clean and get the raw
text.
-;; 2. TOC-Cleanup In this mode you can further cleanup the contents to create a
-;; list where each line has the structure:
+;; before extraction (toc-mode uses the cached file data). Also the languages
+;; used for tesseract OCR can be customized via the `toc-ocr-languages'
+;; variable. A buffer with the, somewhat cleaned up, extracted text will open
in
+;; TOC-cleanup mode. Prefix command with the universal argument (C-u) to omit
+;; clean and get the raw text. 2. TOC-Cleanup In this mode you can further
+;; cleanup the contents to create a list where each line has the structure:
;; TITLE (SOME) PAGENUMBER
@@ -167,6 +168,14 @@ For DJVU the old DJVU file is replaced by default"
:type 'file
:group 'toc)
+(defcustom toc-ocr-languages nil
+ "Languages used for extraction with ocr.
+Should be one or multiple language codes as recognized
+by tesseract -l flag, e.g. eng or eng+nld. Use
+\\[execute-extended-command] `toc-list-languages' to list the
+available languages."
+ :type 'string
+ :group 'toc)
;;;; toc-extract and cleanup
;;; toc-cleanup
@@ -311,6 +320,15 @@ text."
(toc--cleanup startpage)))
(message "Buffer not in pdf-view- or djvu-read-mode"))))
+(defun toc-list-languages ()
+ "List languages available for ocr.
+For use in `toc-ocr-languages'."
+ (interactive)
+ (let ((print-length nil))
+ (message (format "%s" (seq-subseq
+ (split-string
+ (shell-command-to-string "tesseract --list-langs"))
+ 5)))))
;;;###autoload
(defun toc-extract-pages-ocr (arg)
@@ -327,7 +345,10 @@ unprocessed text."
(read-string "Enter end-pagenumber for extraction:
")))
(source-buffer (current-buffer))
(ext (url-file-extension (buffer-file-name (current-buffer))))
- (buffer (file-name-sans-extension (buffer-name))))
+ (buffer (file-name-sans-extension (buffer-name)))
+ (args (list "stdout" "--psm" "6")))
+ (when toc-ocr-languages
+ (setq args (append args (list "-l" toc-ocr-languages))))
(while (<= page (+ endpage))
(let ((file (cond ((string= ".pdf" ext)
(make-temp-file "pageimage"
@@ -340,7 +361,9 @@ unprocessed text."
nil
(number-to-string page)
(image-property djvu-doc-image
:data))))))
- (call-process "tesseract" nil (list buffer nil) nil file
"stdout" "--psm" "6")
+ (apply 'call-process
+ (append (list "tesseract" nil (list buffer nil) nil file)
+ args))
(setq page (1+ page))))
(switch-to-buffer buffer)
(toc-cleanup-mode) ;; required before setting local variable
