header for image mode

1 files changed, 30 insertions, 1 deletions

diff --git a/init.el b/init.el
index 9cd6822..511af25 100644
--- a/init.el
+++ b/init.el
@@ -1719,11 +1719,40 @@
 ;;;; protobuf
 (use-package protobuf-mode :ensure t)
 
-;;; Graphics
+;;; Graphics / images
 (setq image-use-external-converter t
       image-cache-eviction-delay 120)
 (setq widget-image-enable nil)
 
+;; stolen from
+;; https://emacs.dyerdwelling.family/emacs/20260430074958-emacs--a-tiny-header-line-tweak:-image-dimensions-in-image-mode/
+
+(defun jao-image-mode-show-dimensions ()
+  "Display the open image's pixel dimensions and file size in the header line."
+  (when (and (derived-mode-p 'image-mode)
+             buffer-file-name
+             (file-exists-p buffer-file-name))
+    (condition-case err
+        (let* ((image (or (image-get-display-property)
+                          (create-image buffer-file-name)))
+               (size (image-size image t))
+               (width (car size))
+               (height (cdr size))
+               (bytes (file-attribute-size
+                       (file-attributes buffer-file-name))))
+          (setq header-line-format
+                (format " %d x %d px   %s"
+                        width height
+                        (file-size-human-readable bytes))))
+      (error
+       (setq header-line-format
+             (format " image dimensions unavailable: %S" err))))))
+
+(add-hook 'image-mode-hook #'jao-image-mode-show-dimensions)
+(add-hook 'image-mode-new-window-functions
+          (lambda (&rest _) (jao-image-mode-show-dimensions)))
+
+
 ;;; Network
 ;;;; r2e