Better hiding of Org header lines

ha-demos.org

@@ -2,7 +2,7 @@
 #+author: Howard X. Abrams
 #+date:   2024-10-18
 #+filetags: emacs hamacs
-#+lastmod: [2024-10-30 Wed]
+#+lastmod: [2024-11-05 Tue]
 
 A literate programming file for creating and running demonstrations
 
@@ -58,6 +58,29 @@ But I feel I should replace it, and this project encapsulates the following goal
 
 * Presentations with Org
 A demonstration begins with an Org file where the screen shows a /single heading/ with a larger font. Not much more. I have two projects that I like to use.
+** Hiding Blocks
+When showing a presentation, I never want the =#+business= to lines to completely disappear. First attempt turned the foreground color to the background color, but that still leaves a blank, but occupied line. Using the invisible overlays removes them completely:
+
+#+BEGIN_SRC emacs-lisp
+  (defun ha-org-blocks-hide-headers ()
+    "Make the headers and other block metadata invisible.
+  See `ha-org-blocks-show-headers' to return their appearance."
+    (let ((pattern (rx bol (zero-or-more space)
+                       (or ":" "#")
+                       (zero-or-more any) eol)))
+      (save-excursion
+        (goto-char (point-min))
+        (while (re-search-forward pattern nil t)
+          (let* ((start (match-beginning 0)) (end (1+ (match-end 0)))
+                 (ovlay (make-overlay start end)))
+            (overlay-put ovlay 'invisible t))))))
+
+  (defun ha-org-blocks-show-headers ()
+    "Un-invisibilize the headers and other block metadata invisible.
+  In other words, this undoes what `ha-org-blocks-hide-headers' did."
+    (delete-all-overlays))
+#+END_SRC
+
 ** Org Present
 Converted to use [[https://github.com/rlister/org-present][org-present]]. I love the /hooks/ as that makes it easier to handle. My problem with =org-present= is that it doesn’t always display images.
 
@@ -67,24 +90,6 @@ Converted to use [[https://github.com/rlister/org-present][org-present]]. I love
     (defvar ha-org-present-mode-line mode-line-format
       "Cache previous mode-line format state")
 
-    (defun ha-org-blocks-hide-headers ()
-      "Make the headers and other block metadata invisible.
-        See `ha-org-blocks-show-headers'."
-      (let ((pattern (rx bol (zero-or-more space)
-                         (or ":" "#")
-                         (zero-or-more any) eol)))
-        (save-excursion
-          (goto-char (point-min))
-          (while (re-search-forward pattern nil t)
-            (let* ((start (1+ (match-beginning 0))) (end (1+ (match-end 0)))
-                   (ovlay (make-overlay start end)))
-              (overlay-put ovlay 'invisible t))))))
-
-    (defun ha-org-blocks-show-headers ()
-      "Un-invisibilize the headers and other block metadata invisible.
-    In other words, this undoes what `ha-org-blocks-hide-headers' did."
-      (delete-all-overlays))
-
     (defun ha-org-present-start ()
       "Hook to run when starting a presentation.
     This happens _after_ `org-present' has started."
@@ -158,33 +163,32 @@ I’ve used [[https://github.com/takaxp/org-tree-slide][org-tree-slide]] for yea
       "Configure the presentation display.
     See `ha-org-tree-slide-stop' that undoes this."
       (setq org-hide-emphasis-markers t)
-      (set-face-attribute 'org-quote nil
-                          :inherit 'variable-pitch :slant 'italic)
+      (ha-org-blocks-hide-headers)
       (ha-demo-hide-cursor)
-      (ha-demo-presentation-frame)
-      (demo-it--presentation-display-set)
       (ha-demo-hide-mode-line)
-      (git-gutter-mode -1)
+      (ha-demo-presentation-frame)
+      ;; (demo-it--presentation-display-set)
       (text-scale-set 4)
+      (git-gutter-mode -1)
       (flycheck-mode -1)
       (jinx-mode -1))
 
     (defun ha-org-tree-slide-stop ()
       "Reset the display after a presentation.
     See `ha-org-tree-slide-start' for what's set."
-      (demo-it--presentation-display-restore)  ; Restore previous changes
       (setq org-hide-emphasis-markers t)
-      (ha-demo-show-mode-line)
+      (ha-org-blocks-show-headers)
       (ha-demo-show-cursor)
+      (ha-demo-show-mode-line)
       (ha-demo-normalize-frame)
-      (git-gutter-mode)
+      ;; (demo-it--presentation-display-restore)  ; Restore previous changes
       (text-scale-set 0)
+      (git-gutter-mode)
       (flycheck-mode)
       (jinx-mode))
 
     :bind
-    (("S-<f6>" . org-tree-slide-skip-done-toggle)
-     :map org-tree-slide-mode-map
+    (:map org-tree-slide-mode-map
      ("<f5>" . org-tree-slide-move-next-tree)
      ("S-<f5>" . org-tree-slide-move-previous-tree)
      ("M-<f5>" . org-tree-slide-content)
@@ -192,12 +196,9 @@ I’ve used [[https://github.com/takaxp/org-tree-slide][org-tree-slide]] for yea
 
     :general
     (:states 'normal :keymaps 'org-tree-slide-mode-map
-             "c" #'ha-demo-hide-cursor
-             "C" #'ha-demo-show-cursor
+             "C" #'ha-demo-toggle-cursor
              "n" #'org-tree-slide-move-next-tree
-             "j" #'org-tree-slide-move-next-tree
-             "k" #'org-tree-slide-move-previous-tree
-             "p" #'org-tree-slide-move-previous-tree
+             "N" #'org-tree-slide-move-previous-tree
              "Q" (lambda () (interactive) (org-slide-tree-mode -1)))
 
     :hook
@@ -389,6 +390,13 @@ The typical presentation software has an issue for hiding the cursor when workin
       (set-frame-parameter (selected-frame)
                            'cursor-type (nth 5 ha-demo-cursor))
       (setq ha-demo-cursor nil)))
+
+  (defun ha-demo-toggle-cursor ()
+    "Toggles the display of the cursor."
+    (interactive)
+    (if ha-demo-cursor
+        (ha-demo-show-cursor)
+      (ha-demo-hide-cursor)))
     #+END_SRC
 
 ** Hide and Show the Modeline
@@ -469,10 +477,12 @@ All options? Should I use Common Lisp’s =cl-defun= for the keyword parameters?
 
     ;; Step 1: Create a window
     (pcase position
-      ('full )
+      ('above (progn (split-window-vertically)))
+      ('up    (progn (split-window-vertically)))
+      ('left  (progn (split-window-horizontally)))
       ('right (progn (split-window-horizontally) (other-window 1)))
+      ('above (progn (split-window-vertically) (other-window 1)))
       ('below (progn (split-window-vertically) (other-window 1))))
-    ;; We could do :left and :top by not doing the other window bit...
 
     ;; Step 2: Load the file or switch to the buffer:
     (if (file-exists-p filename)
@@ -506,10 +516,7 @@ All options? Should I use Common Lisp’s =cl-defun= for the keyword parameters?
     (unless modeline
       (setq-local mode-line-format nil))
 
-    (when commands (funcall commands))
-    )
-
-  (funcall (lambda () (message "Hello")))
+    (when commands (funcall commands)))
 #+END_SRC
 
 Let try it all together: