Hi there!

When I recently tried to use some of the POVRay options for partial 
rendering output (-SC, -EC, -SR, -ER), I experienced a strange 
phenomenon - the selected rectangle was rendered correctly, but was 
shifted to the upper edge of the (mainly black) output image (horizontal 
position seemed ok). Furthermore, when trying to read a PNG thus created 
using Java's imageio package, the program exited reporting an Exception. 
(I apologize for not having written down the exact error message... 
something like "ImageFormatException in PNGInputStream"...sorry!)

I wonder if anyone else has realized this or a similar issue. Or perhaps 
somebody even knows how to circumvent this problem...?

Regards -

	Torsten

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On Fri, 16 May 2003 13:21:55 +0200, Torsten Crass <tor### [at] eBiologyde>
wrote:
> When I recently tried to use some of the POVRay options for partial 
> rendering output (-SC, -EC, -SR, -ER), I experienced a strange 
> phenomenon - the selected rectangle was rendered correctly, but was 
> shifted to the upper edge of the (mainly black) output image (horizontal 
> position seemed ok).

AFAIK it is expected behaviour. But perhaps I misunderstand your problem.

> Furthermore, when trying to read a PNG thus created 
> using Java's imageio package, the program exited reporting an Exception. 
> (I apologize for not having written down the exact error message... 
> something like "ImageFormatException in PNGInputStream"...sorry!)

Verify with at least a few other applications reading of it. I would not trust
Java based application in bug reporting.

ABX

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Torsten Crass wrote:
> 
> Hi there!
> 
> When I recently tried to use some of the POVRay options for partial
> rendering output (-SC, -EC, -SR, -ER), I experienced a strange
> phenomenon - [...]

See the threads:

Subject: Partial Output Options
Date: Tue, 21 Jan 2003 11:07:03 EST

Newsgroups: povray.general

Subject: Povray writes wrong PNG image size info to partially rendered
images
Date: Tue, 1 Apr 2003 00:18:40 -0500
From: "George Pantazopoulos" <the### [at] attbicom*KILLSPAM*>
Newsgroups: povray.general

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 28 Feb. 2003 _____./\/^>_*_<^\/\.______

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Hi Christoph,

> See the threads:

thanks a lot, apparently I am not the only one... (Sorry for not having 
discovered these threads before - but for some reason I didn't manage to 
acces the web interface's search engine, so I used my newsreader to 
check only the last 500 mails in a couple of groups...)

Anyway - be this the desired behaviour or not, I definitely agree that 
it is worth being mentioned in section 5.2.2.1.2...

Thanks again, and a nice weekend -

       Torsten

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When making the PicPender.exe (the Program that puts the tiles together) I
found that problem.

If you just want to make those tiles into one Image, you can get the
SMPOV-Package and use picpend.exe for that.

Its an Windows-Executable and will put all those tiles properly into one
image.



Theo Gottwald

Tel. +49 ((0)7 21) 9 66 33-00

Fax +49 ((0)7 21) 9 66 33-99

E-Mail: the### [at] it-beraterorg



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"Torsten Crass" <tor### [at] eBiologyde> schrieb im Newsbeitrag
news:3ec4c9d3$1@news.povray.org...
> Hi there!
>
> When I recently tried to use some of the POVRay options for partial
> rendering output (-SC, -EC, -SR, -ER), I experienced a strange
> phenomenon - the selected rectangle was rendered correctly, but was
> shifted to the upper edge of the (mainly black) output image (horizontal
> position seemed ok). Furthermore, when trying to read a PNG thus created
> using Java's imageio package, the program exited reporting an Exception.
> (I apologize for not having written down the exact error message...
> something like "ImageFormatException in PNGInputStream"...sorry!)
>
> I wonder if anyone else has realized this or a similar issue. Or perhaps
> somebody even knows how to circumvent this problem...?
>
> Regards -
>
> Torsten
>

Post a reply to this message

Hi Theo,

 > If you just want to make those tiles into one Image, you can get the
 > SMPOV-Package and use picpend.exe for that.


<sigh>No, just like many other people about which I read in the above 
mentioned threads I nee to render different versions of a _small_ part 
of the scene, so I thought using the partial output options and 
overlaying a standard image with the resulting fragments would have been 
a good idea... but apparently I was mistaken.</sigh> Maybe passing the 
povray output through some tolerant image conversion program prior to 
further Java-based processing might help...

Thanx anyway -

         Torsten

Post a reply to this message

On Fri, 16 May 2003 15:31:52 +0200, Torsten Crass <tor### [at] eBiologyde>
wrote:
> <sigh>No, just like many other people about which I read in the above 
> mentioned threads I nee to render different versions of a _small_ part 
> of the scene, so I thought using the partial output options and 
> overlaying a standard image with the resulting fragments would have been 
> a good idea... but apparently I was mistaken.</sigh> Maybe passing the 
> povray output through some tolerant image conversion program prior to 
> further Java-based processing might help...

There is a small solution to your needs. Instead of using something like:

  +W100 +H100 +SC10 +EC90 +SR20 +ER30

use

  +W80 +H10

with

  "zoomin" include file with +SC.1 +EC.9 +SR.2 +ER.3

where zoomin include file can be found via
http://news.povray.org/search/?s=zoomin
(thought I never tried this way, for sure numbers needs recalculation to yours)

ABX

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>   "zoomin" include file with +SC.1 +EC.9 +SR.2 +ER.3

Hey, thanx!

That looks worth a try! :-)

Have a nice weekend, and happy rendering -

       Torsten

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