main 26807f1c 2/3: Flush preview images when leaving previews visible

[Arash Esbati]

branch: main
commit 26807f1cfdb8573bad60765b47ca2b70723d5262
Author: Paul Nelson <ultrono@gmail.com>
Commit: Arash Esbati <arash@gnu.org>

    Flush preview images when leaving previews visible
    
    * preview.el (preview-replace-active-icon): When
    `preview-leave-open-previews-visible' is t, flush the current
    image spec before mutating it in place.  Without this flush,
    Emacs might still show the cached previous image (see Emacs
    bug#59902 for related discussion).  (bug#78627)
---
 preview.el | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/preview.el b/preview.el
index 7f1027dc..3b3f63ac 100644
--- a/preview.el
+++ b/preview.el
@@ -1,6 +1,6 @@
 ;;; preview.el --- embed preview LaTeX images in source buffer  -*- 
lexical-binding: t; -*-
 
-;; Copyright (C) 2001-2024  Free Software Foundation, Inc.
+;; Copyright (C) 2001-2025  Free Software Foundation, Inc.
 
 ;; Author: David Kastrup
 ;; Keywords: tex, text, convenience
@@ -1204,12 +1204,6 @@ is located."
 
   (cons 'image (cdr icon)))
 
-(defsubst preview-replace-active-icon (ov replacement)
-  "Replace the active Icon in OV by REPLACEMENT, another icon."
-  (let ((img (overlay-get ov 'preview-image)))
-    (setcdr (car img) (cdar replacement))
-    (setcdr img (cdr replacement))))
-
 (defcustom preview-leave-open-previews-visible nil
   "Whether to leave previews visible when they are opened.
 If nil, then the TeX preview icon is used when the preview is opened.
@@ -1223,6 +1217,16 @@ ready.  This behavior suppresses flicker in the 
appearance."
   :group 'preview-appearance
   :type 'boolean)
 
+(defsubst preview-replace-active-icon (ov replacement)
+  "Replace the active Icon in OV by REPLACEMENT, another icon."
+  (let ((img (overlay-get ov 'preview-image)))
+    (when (and preview-leave-open-previews-visible
+               (consp img))
+      ;; No "TeX icon" has been shown, so we flush manually.
+      (image-flush (car img) t))
+    (setcdr (car img) (cdar replacement))
+    (setcdr img (cdr replacement))))
+
 (defun preview-gs-place (ov snippet box run-buffer tempdir ps-file _imagetype)
   "Generate an image placeholder rendered over by Ghostscript.
 This enters OV into all proper queues in order to make it render