[elpa] externals/scanner c439a01 07/56: add scanner--ensure-init

[Stefan Monnier]

branch: externals/scanner
commit c439a0194d3c52871ca3cfbfa4d1394b3fe72913
Author: Raffael Stocker <address@hidden>
Commit: Raffael Stocker <address@hidden>

    add scanner--ensure-init
---
 scanner.el | 65 +++++++++++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 50 insertions(+), 15 deletions(-)

diff --git a/scanner.el b/scanner.el
index 9b8a68a..95182af 100644
--- a/scanner.el
+++ b/scanner.el
@@ -33,6 +33,7 @@
 
 (require 'dash)
 (require 'cl-lib)
+(require 'subr-x)
 
 (defgroup scanner nil
   "Scan documents and images."
@@ -247,16 +248,23 @@ selection is made."
                 (completing-read "Select scanning device: " choices nil t)
                 "(" t ")")))))
 
-(defun scanner--scanimage-args (outfile format type)
+(defun scanner--scanimage-args (outfile type &optional format)
   "Construct the argument list for scanimage(1).
 OUTFILE is the output filename and FORMAT is the output image
-format.  TYPE is either ‘:image’ or ‘:doc’."
+format.  TYPE is either ‘:image’ or ‘:doc’.
+
+When scanning documents (type :doc), the format argument is
+ignored in favor of ‘scanner-doc-intermediate-format’.  If any of
+the required options from ‘scanner--device-specific-options’ are
+unavailable, they are simply dropped."
   (let ((opts scanner--available-options))
     (-flatten (list (and scanner-device-name
                         (list "-d" scanner-device-name))
-                   (if (eq :image type)
-                       (concat "--format=" format)
-                     (concat "--format=" scanner-doc-intermediate-format))
+                   (concat "--format="
+                           (if (eq :image type)
+                               (or format
+                                   scanner-image-format)
+                             scanner-doc-intermediate-format))
                    "-o" outfile
                    (and (eq :doc type)
                         (-when-let* ((x (car (member "-x" opts)))
@@ -269,7 +277,9 @@ format.  TYPE is either ‘:image’ or ‘:doc’."
                         (concat "--mode=" scanner-scan-mode))
                    (and (member "--resolution" opts)
                         (concat "--resolution=" (number-to-string
-                                                 scanner-doc-resolution)))
+                                                 (if (eq :image type)
+                                                     scanner-image-resolution
+                                                   scanner-doc-resolution))))
                    scanner-scanimage-options))))
 
 (defun scanner--tesseract-args (input output-base)
@@ -298,6 +308,29 @@ selected output options, see ‘scanner-tesseract-outputs’."
     (or (cdr (assoc ext scanner--image-extensions))
        scanner-image-format)))
 
+(defun scanner--sentinel (process event)
+  (message (format "%s: %s" process (string-trim event))))
+
+(defun scanner--ensure-init ()
+  "Ensure that scanning device is initialized.
+If no scanning device has been configured or the configured
+device is not available, attempt auto-detection.  Check for
+availability of required options."
+  (let ((need-autodetect (cond ((null scanner-device-name) t)
+                              ((< 0 (call-process scanner-scanimage-program
+                                                  nil nil nil "-n"
+                                                  "-d" scanner-device-name))
+                               t)
+                              (t nil))))
+    (when need-autodetect
+      (let ((num-devices (length (scanner-detect-devices))))
+       (cond ((eql 0 num-devices)
+              (user-error "No scanning device was found"))
+             ((eql 1 num-devices)
+              (setq scanner-device-name (caar scanner--detected-devices)))
+             (t (scanner-select-device)))))
+    (scanner--check-device-options)))
+
 (defun scanner-scan-document (&optional _filename)
   "Scan a document named FILENAME."
   (interactive)
@@ -315,21 +348,23 @@ selected output options, see ‘scanner-tesseract-outputs’."
   ;; write tests using ert
   )
 
+;; TODO add batch scanning
 (defun scanner-scan-image ()
-  "Scan an image."
+  "Scan an image, reading a file name interactively.
+If ‘scanner-device-name’ is nil or this device is unavailable,
+attempt auto-detection.  If more than one scanning devices are
+available, ask for a selection interactively."
   (interactive)
-  (let* ((filename (read-file-name "Image file: "))
+  (scanner--ensure-init)
+  (let* ((filename (read-file-name "Image file name: "))
         (fmt (scanner--determine-format filename))
         (fname (if (file-name-extension filename)
                    filename
                  (concat (file-name-sans-extension filename) "." fmt)))
-        (args (scanner--scanimage-args fname fmt :image)))
-    (cl-flet ((sentinel (process event)
-                       (message
-                        (format "Scanner: %s" (string-trim event)))))
-      (make-process :name "scanimage"
-                   :command `(,scanner-scanimage-program ,@args)
-                   :sentinel #'sentinel))))
+        (args (scanner--scanimage-args fname :image fmt)))
+    (make-process :name "Scanner"
+                 :command `(,scanner-scanimage-program ,@args)
+                 :sentinel #'scanner--sentinel)))
 
 (provide 'scanner)