[bug#57151,2/2] gnu: tesseract-ocr: Make the default install minimally useful.
Commit Message
* gnu/packages/ocr.scm (tesseract-ocr)
[phases]{adjust-TESSDATA_PREFIX-macro}: New phase.
{install-minimal-tessdata}: New phase.
[native-inputs]: Add tesseract-ocr-tessdata-fast.
[search-paths]: New field.
[description]: Mention how to add support for more languages.
---
gnu/packages/ocr.scm | 33 ++++++++++++++++++++++++++++++---
1 file changed, 30 insertions(+), 3 deletions(-)
@@ -132,6 +132,15 @@ (define-public tesseract-ocr
(substitute* "configure.ac"
(("AC_SUBST\\(\\[XML_CATALOG_FILES])")
""))))
+ (add-after 'unpack 'adjust-TESSDATA_PREFIX-macro
+ (lambda _
+ ;; Use a deeper TESSDATA_PREFIX hierarchy so that a more
+ ;; specific search-path than '/share' can be specified. The
+ ;; build system uses CPPFLAGS for itself, so we can't simply set
+ ;; a make flag.
+ (substitute* "Makefile.am"
+ (("-DTESSDATA_PREFIX='\"@datadir@\"'")
+ "-DTESSDATA_PREFIX='\"@datadir@/tesseract-ocr\"'"))))
(add-after 'build 'build-training
(lambda* (#:key parallel-build? #:allow-other-keys)
(define n (if parallel-build? (number->string
@@ -140,7 +149,18 @@ (define n (if parallel-build? (number->string
(invoke "make" "-j" n "training")))
(add-after 'install 'install-training
(lambda _
- (invoke "make" "training-install"))))))
+ (invoke "make" "training-install")))
+ (add-after 'install 'install-minimal-tessdata
+ ;; tesseract-ocr cannot be used without its trained models data;
+ ;; install the English language as a minimal base which can be
+ ;; extended via TESSDATA_PREFIX.
+ (lambda* (#:key native-inputs inputs #:allow-other-keys)
+ (define eng.traineddata
+ "/share/tesseract-ocr/tessdata/eng.traineddata")
+ (install-file (search-input-file (or native-inputs inputs)
+ eng.traineddata)
+ (dirname (string-append #$output
+ eng.traineddata))))))))
(native-inputs
(list asciidoc
autoconf
@@ -152,13 +172,18 @@ (define n (if parallel-build? (number->string
libtool
libxml2 ;for XML_CATALOG_FILES
libxslt
- pkg-config))
+ pkg-config
+ tesseract-ocr-tessdata-fast))
(inputs
(list cairo
icu4c
leptonica
pango
python-wrapper))
+ (native-search-paths (list (search-path-specification
+ (variable "TESSDATA_PREFIX")
+ (files (list "share/tesseract-ocr/tessdata"))
+ (separator #f)))) ;single value
(home-page "https://github.com/tesseract-ocr/tesseract")
(synopsis "Optical character recognition engine")
(description
@@ -166,7 +191,9 @@ (define n (if parallel-build? (number->string
high accuracy. It supports many languages, output text formatting, hOCR
positional information and page layout analysis. Several image formats are
supported through the Leptonica library. It can also detect whether text is
-monospaced or proportional.")
+monospaced or proportional. Support for the English language is included by
+default. To add support for more languages, the
+@code{tesseract-ocr-tessdata-fast} package should be installed.")
(license license:asl2.0)))
(define-public gimagereader