Since we are at it

[andu]

A little something to share: this is a script which reads the width and 
height in a given JPEG file. I was planing to enable some weblog cgi 
scripts I made to handle photos and set the width and height parameters in 
html so that the images even if they are slightly bigger they will fit into 
a given rectangle and be scaled proportionally. True scaling of images 
usually requires extra software present on a server.
Put this in a button:

on mouseUp
  answer file ""
  put url ("binfile:" & it) into rawFile
  put length(rawFile) into tLen
  put offset(numtochar("255")&numtochar("217"), rawFile) into eoj
  if eoj+2>=tLen then put  0 into tCount
  else put  eoj into tCount
  repeat while tCount<tLen
    put offset(numtochar("255"), rawFile,tCount) into tOff
    put chartonum(char tCount+tOff+1 of rawFile)  into tChar
    if tChar is among the items of  "192,193,194,195" then
      put char (tCount+tOff+5) to (tCount+tOff+8) of rawFile into rawSize
      put baseconvert(chartonum(char 1 of rawSize),10,16)\ 
&baseconvert(chartonum(char 2 of rawSize),10,16) into hSize
      put baseconvert(chartonum(char 3 of rawSize),10,16)\ 
&baseconvert(chartonum(char 4 of rawSize),10,16) into wSize
      put "H="&baseconvert(hSize,16,10) & space &\ 
"W="&baseconvert(wSize,16,10) into dimensions
      exit repeat
    end if
    add tOff to tCount
  end repeat
  put  dimensions
end mouseUp

I'm sure it can be optimized but my knowledge of binary data is less then 
minimal. One thing the script doesn't check is if the file is a true JPEG.
A similar process can read/extract the thumbnail image if the JPEG has one 
and/or the exif data if it exists but I have a family to feed and my time 
for playing is over;-).


Regards, Andu Novac