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XBM images sometimes inverted on Windows
From: |
Neil Roberts |
Subject: |
XBM images sometimes inverted on Windows |
Date: |
Fri, 30 Nov 2007 12:42:26 +0000 |
User-agent: |
Mutt/1.5.16 (2007-06-09) |
Hi,
I've noticed that when running Emacs under Windows, if you create an
XBM image where the :data keyword is set to a string containing the
actual bits of the bitmap then the foreground and background colours
are swapped. If you use the same image but set the :data keyword to an
XBM image string then the swapping does not occur. The swapping
doesn't occur either way under X. Is this a bug?
Please eval the following code snippet to demonstrate. Under X, both
smilies look the same, but under Windows the bottom smiley is
white-on-black, and the top smiley is black-on-white.
(defconst smiley-data '(#x00 #x00 #x24 #x00 #x00 #x24 #x18 #x00))
(defun smiley-from-xbm-data ()
;; Make an XBM image from the smiley data
(list 'image :type 'xbm :ascent 100 :data
(concat "#define smiley_width 8\n"
"#define smiley_height 8\n"
"static unsigned char smiley_bits[] = {\n"
" "
(mapconcat (lambda (byte) (format "0x%02x" byte))
smiley-data ", ")
" };")))
(defun smiley-from-xbm-bytes ()
;; Make an image using the bytes directly in a string
(list 'image :type 'xbm :ascent 100 :width 8 :height 8
:data (apply 'string smiley-data)))
(save-excursion
(set-buffer (get-buffer-create "*Smiley demo*"))
(erase-buffer)
(insert "Smiley created from XBM image: "
(propertize ":)" 'display (smiley-from-xbm-data)) "\n"
"Smiley created from the actual bytes: "
(propertize ":)" 'display (smiley-from-xbm-bytes)) "\n")
(pop-to-buffer (current-buffer)))
Thanks,
- Neil
- XBM images sometimes inverted on Windows,
Neil Roberts <=