basic splash prototype added

lib/fg42/splash.el

@@ -0,0 +1,58 @@
+;; Vars ------------------------------
+(defvar fg42-logo-image (concat (getenv "FG42_HOME") "/assets/images/logo.png")
+  "Default fg42 logo")
+
+;; Functions -------------------------
+(defun fg42-about-screen ()
+  "Display fancy About screen."
+  (interactive)
+  (let ((frame (fancy-splash-frame)))
+    (save-selected-window
+      (select-frame frame)
+      (switch-to-buffer "*FG42 About*")
+      (setq buffer-undo-list t)
+      (let ((inhibit-read-only t))
+	(erase-buffer)
+	(if pure-space-overflow
+	    (insert pure-space-overflow-message))
+	(fg42-splash-head)
+	(dolist (text fancy-about-text)
+	  (apply #'fancy-splash-insert text)
+	  (insert "\n"))
+	(set-buffer-modified-p nil)
+	(goto-char (point-min))
+	(force-mode-line-update))
+      (use-local-map splash-screen-keymap)
+      (setq-local browse-url-browser-function 'eww-browse-url)
+      (setq tab-width 22)
+      (setq buffer-read-only t)
+      (goto-char (point-min))
+      (forward-line 3))))
+
+
+(defun fg42-splash-head ()
+  "Insert the head part of the splash screen into the current buffer."
+  (let* ((img (create-image fg42-logo-image))
+	 (image-width (and img (car (image-size img))))
+	 (window-width (window-width)))
+    (when img
+      (when (> window-width image-width)
+	;; Center the image in the window.
+	(insert (propertize " " 'display
+			    `(space :align-to (+ center (-0.5 . ,img)))))
+
+	;; Change the color of the XPM version of the splash image
+	;; so that it is visible with a dark frame background.
+	(when (and (memq 'xpm img)
+		   (eq (frame-parameter nil 'background-mode) 'dark))
+	  (setq img (append img '(:color-symbols (("#000000" . "gray30"))))))
+
+	;; Insert the image with a help-echo and a link.
+	(make-button (prog1 (point) (insert-image img)) (point)
+		     'face 'default
+		     'help-echo "mouse-2, RET: Browse http://www.gnu.org/"
+		     'action (lambda (_button) (browse-url "http://www.gnu.org/"))
+		     'follow-link t)
+	(insert "\n\n")))))
+
+(provide 'fg42/splash)