[contains fix] With no output filename given, output format of scans ignores -x / --compression option and is solely determined by -m / --mode where -m color produces JPGs and -m gray produces PNGs

[luke]

I have tried this with 3.17.11 which I've been running until now and have installed (latest) 3.18.6 today where the issue persists.

When no output file is specified (-o), the output file format isn't picked according to the compression chosen but according to the mode (color or gray).

----------------------------------------

$ hp-scan -m gray -x jpeg
will produce a PNG file.

Output:

Mode: gray
Compression: JPEG
...
Setting output format to PNG for greyscale mode.

----------------------------------------

$ hp-scan -m gray
will produce a PNG file.

Output:

Mode: gray
Compression: JPEG
...
Setting output format to PNG for greyscale mode.

----------------------------------------

$ hp-scan -m color -x raw
will produce a JPEG file.

Output:

Mode: color
Compression: None
...
Setting output format to JPEG for color/lineart mode.

----------------------------------------

$ hp-scan -m color
will produce a JPEG file.

Mode: color
Compression: JPEG
...
Setting output format to JPEG for color/lineart mode.

----------------------------------------

This is confusing.

I went over to `/usr/share/hplip/scan.py` and the mistake seems to be here:

----------------------------------------

        if 'file' in dest and not output:
            log.warn("File destination enabled with no output file specified.")

            if adf:
               log.info("Setting output format to PDF for ADF mode.")
               output = utils.createSequencedFilename("hpscan", ".pdf")
               output_type = 'pdf'
            else:
               if scan_mode == 'gray':
                  log.info("Setting output format to PNG for greyscale mode.")
                  output = utils.createSequencedFilename("hpscan", ".png")
                  output_type = 'png'
               else:
                  log.info("Setting output format to JPEG for color/lineart mode.")
                  output = utils.createSequencedFilename("hpscan", ".jpg")
                  output_type = 'jpeg'

            log.warn("Defaulting to '%s'." % output)

        else:
            try:
               output_type = os.path.splitext(output)[1].lower()[1:]
               if output_type == 'jpg':
                  output_type = 'jpeg'
            except IndexError:
               output_type = ''

----------------------------------------

To get PNG files in colour mode I *have to* specify an output filename with .png extension manually.

The -x/--compression option has virtually no effect, because the output filename solely relies on either the -o option or the -m option.

In the above code this:

----------------------------------------

               if scan_mode == 'gray':
                  log.info("Setting output format to PNG for greyscale mode.")
                  output = utils.createSequencedFilename("hpscan", ".png")
                  output_type = 'png'
               else:
                  log.info("Setting output format to JPEG for color/lineart mode.")
                  output = utils.createSequencedFilename("hpscan", ".jpg")
                  output_type = 'jpeg'

----------------------------------------

should be changed so something like this

----------------------------------------

               if scanner_compression == 'jpeg':
                  log.info("Setting output format to JPEG.")
                  output = utils.createSequencedFilename("hpscan", ".jpg")
                  output_type = 'jpeg'
               else:
                  log.info("Setting output format to PNG.")
                  output = utils.createSequencedFilename("hpscan", ".png")
                  output_type = 'png'

----------------------------------------

Which I have tested and works.

[srinivas (srinivas5)]

Hi Luke,

Thanks for your analysis. we will try to incorporate your suggestions on the compression(-x) in our future releases.
Yes currently we should specify the hp-scan command in the below way to get respective output file formats.
hp-scan --adf --mode=color/gray --filetype=png/jpg/pdf

Thanks,
Srinivas Teja.

[Bill Yikes (yik3s)]

Just wanted to say I was stung by this bug despite a patch submission 6 years ago. I’m running version 3.22.10 and it’s still a disaster. It behaves just as Luke described.

The docs are also still inconsistent with the behaviour, man page as well as this web doc:

https://developers.hp.com/hp-linux-imaging-and-printing/tech_docs/man_pages/scan?language=zh-hans

In the very least there should be a loud “KNOWN BUGS” section added to the docs until it gets fixed so other people don’t waste too much time in frustration.

[luke (jlw)]

It's been a while since I posted this. Unfortunate that this is still in there.

From what I remember what I posted completely fixes it as well. It's a really minor thing. Just needs to be changed in the code. Would be good if someone with the permissions could actually do that now.