Another CLI UI strangeness:

[Jake Shadle]

Another CLI UI strangeness:

        --out-fmt <out-fmt>                       
            The format to save the generated image as.
            
            NOTE: this will only apply when stdout is specified via `-o -`, otherwise the image format is determined by
            the file extension of the path provided to `-o` [default: png]

Explicit command-line option should override any sort of auto-detection.

Originally posted by @vi in #20 (comment)

[Tomasz Stachowiak]

... or rename the switch to --stdout-fmt 😛

[Tomasz Stachowiak]

Otherwise it's probably weird if you specify foo.png as output, yet it ends up being a JPEG with a .png extension because you used --out-fmt jpg (or it gets renamed to foo.jpg, thus disagreeing with the value for the -o switch)

[Jake Shadle]

Yah, that's what I was going to do, because it would indeed be very confusing to have the mismatch, which is why it currently operates this way.

[Vitaly Shukela]

This "explicit command line overrides filename extension" rule is mostly for scripting, not for manual invocation.

Filename may be user-specified, texture-synthesis result is just some intermediate output. If filename is out.jpg it may still end up as JPG, but not from texture-synthesis, rather at some later stage.

Current option --out-fmt indeed works as if it were --stdout-fmt:

$ texture-synthesis  --out-fmt png  --out qqq generate q.png 
[00:00:22] ######################################## 100%
 stage   6 ######################################## 100%
error: Unsupported image format image/""

I expect command-line tools to work with filenames like /tmp/tmp.HpdW5bEo1g if format is explicitly specified.

[Jake Shadle]

So in the scenario you just described, would you be ok if it worked like

#!/bin/bash

out_file=$(mktemp)
texture-synthesis --stdout-fmt bmp --out - generate imgs/1.jpg > $out_file`
echo "$(file $out_file)"

That way the "normal" case of the user using the file extension to determine the output format still works, and gives an error if it's an unrecognized/unsupported output format, but in a more advanced scripting scenario where you want more control, you have to write to stdout and do whatever redirection or piping you need afterwards.

[Vitaly Shukela]

With --stdout-fmt instead of --out-fmt it is at least not contradictory and not unexpected.

Problems may arise if we would need to ouput multiple images. Typically there's only one stdout.

[Jake Shadle]

Sure, but such a change would drastically change the CLI entirely, so should be fine for now.