emacs-framebuffer

commit e75ca19318dcfaef7750b422baa5463125638e7f
parent dd8128fa30ea2099f000cd3b40a9cc0435f282ae
Author: Tomas Hlavaty <tom@logand.com>
Date:   Sun, 11 Oct 2020 00:04:47 +0200

use framebuffer stride for correct buffer width

Diffstat:
M
emacs-framebuffer.el
 | 
18
+++++++++++++-----

1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/emacs-framebuffer.el b/emacs-framebuffer.el
@@ -85,7 +85,7 @@
      ((string-match "\\.\\(xpm\\|XPM\\)\\'" name) 'xpm)
      )))
 
-(defun framebuffer-virtual-size ()
+(defun framebuffer-virtual-size () ;; TODO rm unused?
   (with-temp-buffer
     ;; TODO which framebuffer if more than one?
     (insert-file-contents "/sys/class/graphics/fb0/virtual_size")
@@ -98,6 +98,12 @@
     (insert-file-contents "/sys/class/graphics/fb0/bits_per_pixel")
     (read (current-buffer))))
 
+(defun framebuffer-stride ()
+  (with-temp-buffer
+    ;; TODO which framebuffer if more than one?
+    (insert-file-contents "/sys/class/graphics/fb0/stride")
+    (read (current-buffer))))
+
 (defun framebuffer-size ()
   (if (and framebuffer-width framebuffer-height)
       (cons framebuffer-width framebuffer-height)
@@ -635,6 +641,7 @@
       (destructuring-bind (x1 y1 x2 y2) (window-edges (get-buffer-window) t)
         (let* ((fw (frame-width))
                (fh (frame-height))
+	       (stride (framebuffer-stride))
                (cw (floor fbw fw))
                (ch (floor fbh fh))
                (wx (* x1 cw))
@@ -647,7 +654,7 @@
             (ecase (framebuffer-bits-per-pixel)
               (32
                (dotimes (y wh)
-                 (goto-char (+ (point-min) (* 4 vw (+ y wy)) (* 4 wx)))
+                 (goto-char (+ (point-min) (* stride (+ y wy)) (* 4 wx)))
                  (dotimes (x ww)
                    (delete-char 4)
                    (insert (mod x 256))
@@ -671,6 +678,7 @@
         (set-buffer-multibyte nil)
         (insert-file-contents-literally "/dev/fb0")
         (let ((bpp (framebuffer-bits-per-pixel))
+	      (stride (framebuffer-stride))
               (fb (current-buffer)))
           (with-temp-buffer
             (set-buffer-multibyte nil)
@@ -682,7 +690,7 @@
                  (32
                   (dotimes (y h)
                     (with-current-buffer fb
-                      (goto-char (+ (point-min) (* 4 vw y))))
+                      (goto-char (+ (point-min) (* stride y))))
                     (let ((i 0)
                           (n 0))
                       (dotimes (x w)
@@ -711,7 +719,7 @@
                  (32
                   (dotimes (y h)
                     (with-current-buffer fb
-                      (goto-char (+ (point-min) (* 4 vw y))))
+                      (goto-char (+ (point-min) (* stride y))))
                     (dotimes (x w)
                       (let (r g b a)
                         (with-current-buffer fb
@@ -731,7 +739,7 @@
                  (32
                   (dotimes (y h)
                     (with-current-buffer fb
-                      (goto-char (+ (point-min) (* 4 vw y))))
+                      (goto-char (+ (point-min) (* stride y))))
                     (dotimes (x w)
                       (let (r g b a)
                         (with-current-buffer fb