Re: Link preview generation with new link preview property

["Björn Bidar" <bjorn.bidar@thaodan.de>]

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Ihor Radchenko <yantar92@posteo.net> writes:

> Karthik Chikmagalur <karthikchikmagalur@gmail.com> writes:
>
>> ...
>> Considering this, it might be better to just split
>> `org-link-preview-file' into two public functions, where the "inside"
>> function accepts an image instead of a file.
>
> Agree.
> Would you be interested to create a patch?

Did you think of something like this?


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From a3c682a7d730b0ae9492407d080ba8549a19e02d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Bidar?= <bjorn.bidar@thaodan.de>
Date: Fri, 20 Dec 2024 01:00:46 +0200
Subject: [PATCH] org-link: Split link preview into two functions

* lisp/ol.el (org-link-preview-file,
org-link-preview-image-data): Split up the actual preview part into
a separate function.  The new preview function can be called by
:preview handler to display the image according to the correct alignment
for the link to be previewed.
---
 lisp/ol.el | 45 ++++++++++++++++++++++++++-------------------
 1 file changed, 26 insertions(+), 19 deletions(-)

diff --git a/lisp/ol.el b/lisp/ol.el
index 032610bad..dd6b07152 100644
--- a/lisp/ol.el
+++ b/lisp/ol.el
@@ -2177,27 +2177,34 @@ (defun org-link-preview-file (ov path link)
                 ((string-match-p (image-file-name-regexp) file))
                 ((file-exists-p file)))
       (let* ((width (org-display-inline-image--width link))
-	     (align (org-image--align link))
-             (image (org--create-inline-image file width)))
-        (when image            ; Add image to overlay
-	  ;; See bug#59902.  We cannot rely
-          ;; on Emacs to update image if the file
-          ;; has changed.
-          (image-flush image)
-	  (overlay-put ov 'display image)
-	  (overlay-put ov 'face 'default)
-	  (overlay-put ov 'keymap image-map)
-          (when align
-            (overlay-put
-             ov 'before-string
-             (propertize
-              " " 'face 'default
-              'display
-              (pcase align
-                ("center" `(space :align-to (- center (0.5 . ,image))))
-                ("right"  `(space :align-to (- right ,image)))))))
+             (image-data (org--create-inline-image file width)))
+        (when image-data
+	  (org-link-preview-image-data ov image-data link)
           t)))))
 
+(defun org-link-preview-image-data (ov image-data link)
+  "Display image data IMAGE-DATA in overlay OV for link.
+
+This intended to be used by functions which provide the :preview link property
+of links such as in `org-link-preview-file'"
+  (let ((align (org-image--align link)))
+    ;; See bug#59902.  We cannot rely
+    ;; on Emacs to update image if the file
+    ;; has changed.
+    (image-flush image-data)
+    (overlay-put ov 'display image-data)
+    (overlay-put ov 'face 'default)
+    (overlay-put ov 'keymap image-map)
+    (when align
+      (overlay-put
+       ov 'before-string
+       (propertize
+        " " 'face 'default
+        'display
+        (pcase align
+          ("center" `(space :align-to (- center (0.5 . ,image-data))))
+          ("right"  `(space :align-to (- right ,image-data)))))))))
+
 ;;;; "help" link type
 (defun org-link--open-help (path _)
   "Open a \"help\" type link.
-- 
2.45.2