Coloured faces: 740 bytes is too much.

Coloured faces: 740 bytes is too much.

[Gaute B Strokkenes]

[-- Attachment #1: Type: text/plain, Size: 652 bytes --]

I recently received some advice on gnu.emacs.gnus on how to get this
working.  However, I believe that the specification of the Face:
header is wrong in one respect.  It states that, because of
limitations on how large a news/mail header can be and the base64
encoding that is used, the png image can be at most 740 bytes long.

As luck would have it, the 10-colour version of the 9-colour image
that I have in this image is precisely 739 bytes.  When I base64
encode it I get a header that is too long.  A suitably modified
version of the make-face shell script seems to agree with me as well.

It seems that the calculations here need to be redone.


[-- Attachment #2: My pretty face --]
[-- Type: image/png, Size: 739 bytes --]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #3: Not just a pretty face --]
[-- Type: text/x-sh, Size: 826 bytes --]

#!/bin/bash

png1=$1
png2=$2

if [ "$png1" = "" -o "$png2" = "" ]; then
   echo "Usage: make-face <PNG-FILE> <BASE64-FILE>"
   exit
fi

quant=16
found=false
tmp=/tmp/make-face.$$.tmp
tmp2=/tmp/mak-face2.$$.tmp

while [ "$found" = "false" ]; do
    echo -n "Trying quantization $quant ($jpg)..."
    pngtopnm "$png1"\
	| ppmnorm\
	| pnmscale -width 48 -height 48\
	| ppmquant $quant\
	| pnmtopng > $tmp2
    size=`ls -l $tmp2 | awk '{ print $5; }'`
    echo "Size of png is  $size"
    cat "$tmp2" \
	| mimencode > $tmp
    size=`ls -l $tmp | awk '{ print $5; }'`
    if [ $size -lt 999 ]; then
	echo -n "Face:" > "$png2"
	for i in `cat $tmp`; do
	    echo -n " " >> "$png2"
	    echo "$i" >> "$png2"
	done
	rm $tmp
	rm $tmp2
	found=true
	echo "done"
    else
	quant=`expr $quant - 2`
	echo "too big ($size)"
    fi
done

    

[-- Attachment #4: Type: text/plain, Size: 101 bytes --]



-- 
Big Gaute                               http://www.srcf.ucam.org/~gs234/
Are we on STRIKE yet?

Re: Coloured faces: 740 bytes is too much.

[Lars Magne Ingebrigtsen]

Gaute B Strokkenes <gs234@cam.ac.uk> writes:

> As luck would have it, the 10-colour version of the 9-colour image
> that I have in this image is precisely 739 bytes.  When I base64
> encode it I get a header that is too long. 

Oops.  A miscalculation on my part.  I calculated 33% + newlines, but
there needs to be a space on the beginning of each line as well.  The
real limit is 726 bytes, and I've now updated the web page.

-- 
(domestic pets only, the antidote for overdose, milk.)
   larsi@gnus.org * Lars Magne Ingebrigtsen

Re: Coloured faces: 740 bytes is too much.

[Gaute B Strokkenes]

On 15 apr 2003, larsi@gnus.org wrote:
>Gaute B Strokkenes <gs234@cam.ac.uk> writes:
>
>>As luck would have it, the 10-colour version of the 9-colour image
>>that I have in this image is precisely 739 bytes.  When I base64
>>encode it I get a header that is too long. 
>
>Oops.  A miscalculation on my part.  I calculated 33% + newlines, but
>there needs to be a space on the beginning of each line as well.  The
>real limit is 726 bytes, and I've now updated the web page.

That's execellent--but let's not forget the obvious patch to
gnus-fun.el:

Index: gnus-fun.el
===================================================================
RCS file: /usr/local/cvsroot/gnus/lisp/gnus-fun.el,v
retrieving revision 6.44
diff -u -r6.44 gnus-fun.el
--- gnus-fun.el	16 Apr 2003 13:20:01 -0000	6.44
+++ gnus-fun.el	16 Apr 2003 17:10:36 -0000
@@ -115,7 +115,7 @@
 	       (format gnus-convert-image-to-face-command
 		       (shell-quote-argument (expand-file-name file))
 		       quant)))
-	(if (> (length attempt) 740)
+	(if (> (length attempt) 726)
 	    (progn
 	      (setq quant (- quant 2))
 	      (message "Length %d; trying quant %d"
@@ -155,10 +155,10 @@
 (defun gnus-convert-png-to-face (file)
   "Convert FILE to a Face.
 FILE should be a PNG file that's 48x48 and smaller than or equal to
-740 bytes."
+726 bytes."
   (mm-with-unibyte-buffer
     (insert-file-contents file)
-    (when (> (buffer-size) 740)
+    (when (> (buffer-size) 726)
       (error "The file is %d bytes long, which is too long"
 	     (buffer-size)))
     (gnus-face-encode)))


-- 
Big Gaute                               http://www.srcf.ucam.org/~gs234/
I decided to be JOHN TRAVOLTA instead!!