[XeTeX] Size of JPEG graphics

[Jonathan Kew]

On 8 Sep 2004, at 2:25 pm, Bruno Voisin wrote:

> I have just been faced with a strange behaviour of XeTeX compared with 
> pdfTeX, and it took some time to reduce the observed behaviour to a 
> simple fact: for a JPEG file that I created using Adobe Illustrator 
> (opening an EPS file in Illustrator, modifying it, and saving the 
> result as a JPEG file), and included in a TeX file, the size of the 
> JPEG image in the PDF output is different depending on whether pdfTeX 
> or XeTeX is used. (By size here I mean the size in centimeters (or 
> inches!) on the page, not the size of the file.)

A little experimentation with resizing a JPEG in Photoshop seems to 
show that XeTeX measures the JPEG as if it were a 72dpi image in all 
cases, whereas pdfTeX pays proper attention to the resolution of the 
image. I consider this a XeTeX bug and will look into fixing it.

Note, however, that this will cause the layout of existing documents to 
change if they include non-72dpi images; users, take note that at this 
point in XeTeX's life, I'm not promising absolute document stability!

BTW, does the same problem occur if the image is in a different format 
such as TIFF, PNG, BMP, etc.?

JK