Gang

I am using POV 3.5 under XP Professional.
I am rendering the woodenbox demo at 640 x 480.
When I look at the generated woodenbox.bmp everything is A-OK.

I then move my mouse and select a center region from the rendered image.
I then render it again.
When I look at the woodbox.bmp the background is all black as I had hoped.
But the region I selected is not in the center of the woodenbox.bmp.

The dimensions are correct. and the X offset is correct. But the Y offset is
0 so it is shifted
up against the top of the BMP.

I looked at the MESSAGES window and it said

"Output Options
  Image resolution 640 by 480 (rows 94 to 306, columns 188 to 423)."

The values are correct but the resulting BMP is incorrect.

Is this a bug or am I doing something wrong?

Bob

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In article <3fd3895a$1@news.povray.org> , "Bob Zigon" 
<nos### [at] iquestnet> wrote:
> Gang

Please do not multipost messages.  Cross-post instead.

> The dimensions are correct. and the X offset is correct. But the Y offset is
> 0 so it is shifted
> up against the top of the BMP.
>
> I looked at the MESSAGES window and it said
>
> "Output Options
>   Image resolution 640 by 480 (rows 94 to 306, columns 188 to 423)."
>
> The values are correct but the resulting BMP is incorrect.
>
> Is this a bug or am I doing something wrong?

As POV-Ray always writes the whole image, whatever you are seeing is correct
and your expectation is incorrect.  I don't really get what you expect
versus what you see, but POV-Ray will render the selected area and leave the
whole image empty around it.  Thus, this sounds a lot like you are making an
incorrect selection for the area you are up to.

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

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news:3fd3a86f$1@news.povray.org...
> and your expectation is incorrect.  I don't really get what you expect
> versus what you see, but POV-Ray will render the selected area and leave
the
> whole image empty around it.  Thus, this sounds a lot like you are making
an
> incorrect selection for the area you are up to.

It's simple, though: he just wants the selected area to be where he asked it
to be and where it's expected (right in the middle for instance). As anyone
who ever rendered a partial BMP file knows, the rendered area *** always ***
shows up on top of the file but, strangely, with the correct horizontal
(column) position.

G.

-- 
**********************
http://www.oyonale.com
**********************
- Graphic experiments
- POV-Ray and Poser computer images
- Posters

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> but POV-Ray will render the selected area and leave the
> whole image empty around it.

What POV-Ray does, and what he's talking about, is renders the selected area
in the wrong area of the output image.

For instance, if you select a square at the center of your image, the
outputted file will be black everywhere but the *top* middle, where your
selected render will appear. One would expect blackness everywhere but the
*center*, which is where your selection was.

It's hard to explain exactly. If you haven't seen it before, then take any
old image, select a small square to render somewhere near the center of the
image, and then view the output image (not just POV-Ray's display), and note
the difference between the output image and what POV-Ray displayed.

 - Slime
 [ http://www.slimeland.com/ ]

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Gilles

Thank you for verifying what I saw. It sounds to me like you have done a
partial rendering
with the windows version.

Any idea how to solve it?

Bob

"Gilles Tran" <gitran_nospam_@wanadoo.fr> wrote in message
news:3fd3afd8@news.povray.org...

> news:3fd3a86f$1@news.povray.org...
> > and your expectation is incorrect.  I don't really get what you expect
> > versus what you see, but POV-Ray will render the selected area and leave
> the
> > whole image empty around it.  Thus, this sounds a lot like you are
making
> an
> > incorrect selection for the area you are up to.
>
> It's simple, though: he just wants the selected area to be where he asked
it
> to be and where it's expected (right in the middle for instance). As
anyone
> who ever rendered a partial BMP file knows, the rendered area *** always
***
> shows up on top of the file but, strangely, with the correct horizontal
> (column) position.
>
> G.
>
> --
> **********************
> http://www.oyonale.com
> **********************
> - Graphic experiments
> - POV-Ray and Poser computer images
> - Posters
>
>

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3fd3afd8@news.povray.org...
> As anyone
> who ever rendered a partial BMP file knows, the rendered area *** always
***
> shows up on top of the file but, strangely, with the correct horizontal
> (column) position.


Oh yes but it is certainly the expected behaviour isn't it? ;-)
If POV behaves this way, sure it is intended.
We should at least feel happy that the rendered area is inside the output
file!

Marc

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On Sun, 7 Dec 2003 20:55:55 -0500, "Bob Zigon" <nos### [at] iquestnet>
wrote:
> Any idea how to solve it?

I never investigated it deeply but I suppose there is nothing to solve because
it looks to me more as feature than as buggy behaviour. There is plenty of
applications which can read images and then glue them first above second. IMO
having top-bottom margins included in images it would be much harder becuase
it would require crop which is harder to maintain in automated batch mode.

ABX

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In article <3fd3b45f$1@news.povray.org> , "Slime" <fak### [at] emailaddress> 
wrote:

> What POV-Ray does, and what he's talking about, is renders the selected area
> in the wrong area of the output image.
>
> For instance, if you select a square at the center of your image, the
> outputted file will be black everywhere but the *top* middle, where your
> selected render will appear. One would expect blackness everywhere but the
> *center*, which is where your selection was.

No, you are wrong interpreting what you are seeing.  POV-Ray simply outputs
only the rows which contains the rendered area.  However, the image is
specified to have a certain height and width.  What you see outside the
rendered area when viewing this image is completely up to your image viewing
program.

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

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news:3fd3da27
> Thank you for verifying what I saw. It sounds to me like you have done a
> partial rendering
> with the windows version.
> Any idea how to solve it?

Not really, as the wrong positioning of the rendered part was never an issue
in the first place, which is why I never considered it to be a "real" bug.
True, there are cases where having the exact position would be handy (when
pasting the re-rendered part on the original image, particularly, this would
make the positioning much easier). However, I'd prefer to have the partial
rendering saved in a file with the exact dimensions of the rendered part:
when re-rendering bits of large images, that would save me the trouble of
having to manage temporary 90Mb image files.
In any case, when they're fast enough and fit on the screen, I just don't
save partial renderings: I just make a screen capture and then crop and
paste the result.

G.
-- 

**********************
http://www.oyonale.com
**********************
- Graphic experiments
- POV-Ray and Poser computer images
- Posters

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Thorsten Froehlich wrote:
>In article <3fd3b45f$1[at]news.povray.org> , "Slime" <fak### [at] emailaddress>
>wrote:
>
>> What POV-Ray does, and what he's talking about, is renders the selected area
>> in the wrong area of the output image.
>>
>> For instance, if you select a square at the center of your image, the
>> outputted file will be black everywhere but the *top* middle, where your
>> selected render will appear. One would expect blackness everywhere but the
>> *center*, which is where your selection was.
>
>No, you are wrong interpreting what you are seeing.  POV-Ray simply outputs
>only the rows which contains the rendered area.  However, the image is
>specified to have a certain height and width.  What you see outside the
>rendered area when viewing this image is completely up to your image viewing
>program.
>
>    Thorsten
>
>____________________________________________________
>Thorsten Froehlich, Duisburg, Germany
>e-mail: tho### [at] trfde
>
>Visit POV-Ray on the web: http://mac.povray.org
>

Just to settle my over thanking mind here how would an image view know where
the first pixel bytes of a BMP should be located with in the header
specified size of the image. If the BMP only has the pixel data to the
region selected in povray but a total image size of say 640x480 I do not
see any way of knowing where the for example 30x30 of data should be placed
with in the 640x480. No matter what program is used outside of povray the
available pixels in the bmp will be loaded at the first pixel. I have had a
little trouble with this my self. Photoshop refuses to load the files.
AcdSee will load them and save a fixed size for the image. Is there a
viewer that is able to load these partial renders in reference to the
images size given in the header?

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