Add function to generate QR codes

gists.org

@@ -843,7 +843,7 @@ Based on an answer at the [[https://emacs.stackexchange.com/a/77480/34645][Emacs
   (add-to-list 'my/denote/url-functions #'my/elfeed/entry-url)
 #+end_src
 
-* Using gpg-agent inside Emacs in Termux
+* Using gpg-agent inside Emacs in Termux :emacs:termux:
 :PROPERTIES:
 :URL:      https://emacs.ch/@bram85/111580555195721041
 :END:
@@ -908,6 +908,40 @@ Finally, I attached this hook in three places:
 #+end_src
 
 Which covers my (potential) GPG/SSH usage within Emacs. Now, anytime a I perform a GPG / SSH operation, the $GPG_TTY variable is set properly and if needed, the passhprase prompt shows up in the minibuffer.
+
+* Generate and show QR for the region or minibuffer input :emacs:
+
+#+begin_src elisp :tangle gists/generate-qr.el
+  (defun my/generate-qr (text &optional img)
+    "Generate a QR code from the region or given TEXT.
+
+  If no region is active, the TEXT defaults to the clipboard content.
+
+  When IMG is non-nil, generate an image instead of the default
+  UTF-8 representation.
+
+  This function relies on qrencode(1) being present in your $PATH."
+    (interactive
+     (let ((default-text (if (use-region-p)
+                             (buffer-substring-no-properties (region-beginning) (region-end))
+                           (my/clipboard-get))))
+       (list
+        (read-string (format-prompt "Text" default-text) nil nil default-text)
+        current-prefix-arg)))
+    (with-current-buffer (get-buffer-create "*qr*")
+      ;; in case the buffer still exists and image-mode is active
+      (fundamental-mode)
+      (erase-buffer)
+      (insert text)
+      (let ((file-format
+             (if (equal current-prefix-arg '(4)) "PNG" "UTF8")))
+        (call-process-region nil nil "qrencode" t t nil "-o" "-" "-t" file-format)
+        (when (and (display-graphic-p) (string= file-format "PNG"))
+          (image-mode)))
+      (display-buffer (current-buffer))))
+#+end_src
+
+
 * Meta
 ** License
 

gists/generate-qr.el

@@ -0,0 +1,27 @@
+(defun my/generate-qr (text &optional img)
+  "Generate a QR code from the region or given TEXT.
+
+If no region is active, the TEXT defaults to the clipboard content.
+
+When IMG is non-nil, generate an image instead of the default
+UTF-8 representation.
+
+This function relies on qrencode(1) being present in your $PATH."
+  (interactive
+   (let ((default-text (if (use-region-p)
+                           (buffer-substring-no-properties (region-beginning) (region-end))
+                         (my/clipboard-get))))
+     (list
+      (read-string (format-prompt "Text" default-text) nil nil default-text)
+      current-prefix-arg)))
+  (with-current-buffer (get-buffer-create "*qr*")
+    ;; in case the buffer still exists and image-mode is active
+    (fundamental-mode)
+    (erase-buffer)
+    (insert text)
+    (let ((file-format
+           (if (equal current-prefix-arg '(4)) "PNG" "UTF8")))
+      (call-process-region nil nil "qrencode" t t nil "-o" "-" "-t" file-format)
+      (when (and (display-graphic-p) (string= file-format "PNG"))
+        (image-mode)))
+    (display-buffer (current-buffer))))