clipka <ano### [at] anonymousorg> wrote:

> What you forget about is that...
>
> (1) JPEG having no gamma chunk means that it will indeed probably show
> identical in all apps on /your/ computer, but that doesn't mean it will
> look like that on /other/ computers.

Good point. (Actually, I thought that a .png image would *showcase* these kinds
of discrepancies in an even worse way; but apparently not, which is good to
know.)

Ken

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clipka <ano### [at] anonymousorg> wrote:
> Am 25.04.2010 23:20, schrieb Alain:

> >> How about changing the default output file type for both Windows and
> >> Unix version to PNG?
> >
> > Why not for all versions?
>
> With me having not much of an idea about Macs anyway, I pass that
> question on to any Mac experts listening right now...

Probably not an expert, but everything I've used on the Mac can read/write all
the POV-Ray output filetypes (apart from HDR). I'd say your arguments hold for
the Mac platform as well as Win/Unix.

(oh, and I vote PNG too; not sure about Win7 but XP certainly had no clue what
to do with TGAs, and I object to BMP on moral and aesthetic grounds ;) JPEG is
out of the question for your stated reasons. 2 of my English pence :))

Bill

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Am 26.04.2010 10:20, schrieb Bill Pragnell:

> (oh, and I vote PNG too; not sure about Win7 but XP certainly had no clue what
> to do with TGAs, and I object to BMP on moral and aesthetic grounds ;) JPEG is
> out of the question for your stated reasons. 2 of my English pence :))

I think BMP (which is the current default for POV-Ray for Windows) has 
also become a poor choice for technical reasons, as POV-Ray's 
implementation can only write uncompressed BMPs, making it a major waste 
of space without any gain. (It would of course be possible to implement 
compressed BMP output, but then again, why bother when there are better 
alternatives around nowadays.)

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> Yes, I do see the need for that. But as a practical matter, I wonder if 
> there is
> a discernable visual difference between a .png file and one saved as a
> highest-quality .jpeg? (I suppose that's open to debate.)

FWIW I had a model of the golden gate bridge and the red vertical cables 
never worked with JPEG.

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clipka <ano### [at] anonymousorg> wrote:
> (It would of course be possible to implement
> compressed BMP output, but then again, why bother when there are better
> alternatives around nowadays.)

Um...because it would be free of embedded gamma? ;-) (Sorry, I can't seem to let
this poor old horse die a peaceful death.)  Actually, I didn't know that a
compressed BMP image was even possible.

In re-reading the posts here, I get the impression that one of the reasons for
choosing .png as a default is that it's a smaller file size (compared to BMP,
for example.) In the old days--when hard-drive memory was at more of a
premium--that would have been a legitimate argument. But it's an issue that has
far less importance now. (ALTHOUGH, for uploading onto the 'net, a compressed
image is preferable; no argument there. And .png might well be the right choice,
for the reasons given.)

I guess a basic question (or some further food for thought) would be this:
Should the choice of POV's default file type be 'driven' by the needs of the
'net? I would estimate that the ratio of my own POV images (between JPEG/PNG and
BMP) is less than 1%. In other words, I only compress an image when I have to.
No compelling reason to do otherwise.

Although I work on a Windows platform, I actually hadn't considered BMP as an
alternative to the PNG 'default' idea. (It's the POV default anyway, on that
platform.) But it does have one compelling virtue: The majority of computer
users work on Windows--and it's an easy step to convert BMP to JPEG (or PNG!) in
any image app--assuming that everyone who works with POV-Ray *has* another image
app to do that with. (Who doesn't??) Yet, I don't know how/if Macs work with BMP
images; I assume they can handle it.

But in the final analysis, I guess there's nothing wrong with PNG as the
default, if it's implemented and documented well.

Ken

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Slime <fak### [at] emailaddress> wrote:
> I don't think the default file type should be one that uses lossy 
> compression.

  I didn't know that POV-Ray even supported lossy formats as output...

-- 
                                                          - Warp

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On 04/25/2010 06:44 AM, clipka wrote:
> How about changing the default output file type for both Windows and
> Unix version to PNG?

I'm in favor of this as that's the most common format I use ... but that
doesn't make it correct. Everyone has made compelling pro and con
arguments, but I think it's rather like asking a painter what medium
they like to work with ... acrylics or oil. Personal choice right? If
something other than png is ultimately the choice ... no worries for me
as the format I like to use is just a command line option away!

Jim

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Am 26.04.2010 15:01, schrieb Warp:
> Slime<fak### [at] emailaddress>  wrote:
>> I don't think the default file type should be one that uses lossy
>> compression.
>
>    I didn't know that POV-Ray even supported lossy formats as output...

Contrary to rumors, POV-Ray can output JPEG.

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clipka <ano### [at] anonymousorg> wrote:
> Am 26.04.2010 15:01, schrieb Warp:
> > Slime<fak### [at] emailaddress>  wrote:
> >> I don't think the default file type should be one that uses lossy
> >> compression.
> >
> >    I didn't know that POV-Ray even supported lossy formats as output...

> Contrary to rumors, POV-Ray can output JPEG.

  Is that new in POV-Ray 3.7? How do you fine-tune the compression options?

-- 
                                                          - Warp

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On 04/26/2010 02:34 PM, Warp wrote:
> clipka <ano### [at] anonymousorg> wrote:
>> Am 26.04.2010 15:01, schrieb Warp:
>>> Slime<fak### [at] emailaddress>  wrote:
>>>> I don't think the default file type should be one that uses lossy
>>>> compression.
>>>
>>>    I didn't know that POV-Ray even supported lossy formats as output...
> 
>> Contrary to rumors, POV-Ray can output JPEG.
> 
>   Is that new in POV-Ray 3.7? How do you fine-tune the compression options?
> 
http://wiki.povray.org/content/Documentation:Reference_Section_1.1#Output_File_Type

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