John VanSickle <evi### [at] hotmailcom> wrote:
> I think that this is an issue on which there is no substitute for the
> user knowing exactly what he/she is doing.

If the SDL provided a way to specify the intended aspect ratio, then it would be
an easy thing to warn the user if they specify a resolution with a different
aspect ratio.

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clipka wrote:
> John VanSickle <evi### [at] hotmailcom> wrote:
>> I think that this is an issue on which there is no substitute for the
>> user knowing exactly what he/she is doing.
> 
> If the SDL provided a way to specify the intended aspect ratio, then it would be
> an easy thing to warn the user if they specify a resolution with a different
> aspect ratio.
> 
> 
>

#declare aspect_ratio = 4/3;
#if (abs (image_width / image_height - aspect_ratio) < 1e-6)
   #warning concat ("Invalid aspect ratio: expected ",
                    str (aspect_ratio, 1, 3),
                    " got ",
                    str (image_width / image_height, 1, 3),
                    "\n")
#end

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=?ISO-8859-1?Q?=22J=E9r=F4me_M=2E_Berger=22?= <jeb### [at] freefr> wrote:
> #declare aspect_ratio = 4/3;
> #if (abs (image_width / image_height - aspect_ratio) < 1e-6)
>    #warning concat ("Invalid aspect ratio: expected ",
>                     str (aspect_ratio, 1, 3),
>                     " got ",
>                     str (image_width / image_height, 1, 3),
>                     "\n")
> #end

Fine. But why not do this via an SDL statement? The benefits I see would be:

* No cluttering up of the SDL file with yet another macro construction that
still just does some standard thingy

* Providing an official recommended way to deal with aspect ratio that *really*
makes sense (the current recommendation has drawbacks on its own)

* Allowing for additional improvements, like:

- a command line parameter specifying the intended pixel aspect ratio that could
automatically be incorporated into this check (so e.g. specifying an intended
pixel aspect ratio of 2:1 on the command line would suppress the warning when
rendering a 4:3 scene with a resolution of 320x480 pixels) (note that such a
parameter, in turn, could some time become of interest for certain file formats
that natively support pixel aspect ratios other than 1:1)

- providing a shorthand way to set up the camera up/right/direction stuff


Honestly, I see no drawback at all associated with an explicit aspect ratio SDL
parameter. But all existing ways of dealing with aspect ratio *do* have
drawbacks - if only that they're unnecessarily cumbersome.

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