[XeTeX] strange case of overlapping graphics

Fri Jun 11 00:13:26 CEST 2021

Hi Zdenek,

On 11 Jun 2021, at 6:49 am, Zdenek Wagner <zdenek.wagner at gmail.com<mailto:zdenek.wagner at gmail.com>> wrote:

Yes, it is what I saw in pdflatex as well. Now I see the reason, I have not read my exiftool output carefully. It says:

X Resolution                    : 25
Y Resolution                    : 7

Yes, that does look a bit weird, doesn’t it.
One would expect it to be the same in both directions, unless specifically
set to be different for a special effect.

Notice that it also says    Resolution Unit: inches .
Surely not!  unless it needs ~100 units for the inch.
Further down there are  Pixel units of meters.
Very strange.

Thanks in advance for any lessons on how to properly read/interpret this info.

So the culprit need not be XeTeX after all.

All the best.

Ross

So, pdftex as well as viewers used by Phil honour the resolution in both directions and the output is tall. Gwenview, gimp and ocular just honour the size in pixels. Xelatex probably calculates the dimensions correctly taking into account X/Y resolutions, generated the commands for PNG inclusion but xdvipdfmx honours the pixels only, not the resolutions.

Zdeněk Wagner
http://ttsm.icpf.cas.cz/team/wagner.shtml<http://ttsm.icpf.cas.cz/team/wagner.shtml>

čt 10. 6. 2021 v 22:37 odesílatel Ross Moore <ross.moore at mq.edu.au<mailto:ross.moore at mq.edu.au>> napsal:
Hi Janusz, and others

For me, using  pdftex, the only issue is that the aspect ratio isn’t correct.
<Screen Shot 2021-06-11 at 6.24.10 am.png>
XeTeX gets it wrong:

<Screen Shot 2021-06-11 at 6.31.43 am.png>
Notice the apparent lack of centering with respect to the caption.
It’s as if the width has been read incorrectly by XeTeX, for positioning
the 2 instances of the image.

Explicitly specifying a more realistic width fixes this, with both engines.
Examining the information in GraphicConverter  (on MacOS)
I cannot see anything amiss.  (see image)

<Screen Shot 2021-06-11 at 6.21.21 am.png>

So to me, this looks like a XeTeX issue after all.

Hope this helps.

Ross

On 11 Jun 2021, at 2:12 am, Janusz S. Bień <jsbien at mimuw.edu.pl<mailto:jsbien at mimuw.edu.pl>> wrote:

On Thu, Jun 10 2021 at 11:04 -05, Herbert Schulz wrote:
>> On Jun 10, 2021, at 10:58 AM, Zdenek Wagner <zdenek.wagner at gmail.com<mailto:zdenek.wagner at gmail.com>> wrote:
>>
>> čt 10. 6. 2021 v 17:09 odesílatel Philip Taylor
>> <P.Taylor at hellenic-institute.uk<mailto:P.Taylor at hellenic-institute.uk>> napsal:
>>>
>>> In both Windows Preview and in Adobe Illustrator CC, the PNG file
>>> is roughly twice as tall (relative to its width) as it appears in
>>> the PDF.
>>> --
>> So this means that the PNG contains something strange which is
>> interpreted by some programs and ignored by other programs. Maybe
>> different vertical and horizontal resolutions? I do not have a tool to
>> analyze it further.

Tomorrow I will make more tests and submit the problem to ddjvu
author(s).

> Howdy,
>
> And
>
> \includegraphics[width=1.3cm]{Zaborowski_MBC_page19y42_a}
> \includegraphics[width=1.3cm]{Zaborowski_MBC_page19y42_a}
>
> works fine (not exactly the same size but that can be adjusted).

Yes. It's great you have found a way to circumvent the problem!

On the other hand this make the problem more misterious...

Best regards

Janusz

--
,
Janusz S. Bien
emeryt (emeritus)
https://sites.google.com/view/jsbien<https://sites.google.com/view/jsbien>

Dr Ross Moore
Department of Mathematics and Statistics
12 Wally’s Walk, Level 7, Room 734
Macquarie University, NSW 2109, Australia
T: +61 2 9850 8955  |  F: +61 2 9850 8114
M:+61 407 288 255  |  E: ross.moore at mq.edu.au<mailto:ross.moore at mq.edu.au>
http://www.maths.mq.edu.au<http://www.maths.mq.edu.au/>
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Dr Ross Moore
Department of Mathematics and Statistics
12 Wally’s Walk, Level 7, Room 734
Macquarie University, NSW 2109, Australia
T: +61 2 9850 8955  |  F: +61 2 9850 8114
M:+61 407 288 255  |  E: ross.moore at mq.edu.au<mailto:ross.moore at mq.edu.au>
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