Bug 348913

Summary:	Skanlite doesn't draw the page as it's being scanned in, just one black pixel at right edge
Product:	[Applications] Skanlite	Reporter:	Michael <kde>
Component:	general	Assignee:	Kåre Särs <kare.sars>
Status:	REPORTED ---
Severity:	normal	CC:	justin.zobel
Priority:	NOR
Version First Reported In:	2.2.0
Target Milestone:	---
Platform:	Neon
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	Skanlite window as a scan is in progress skanlite scanning but nothing appearing in preview pane skanlite after the scan, showing the result

Description Michael 2015-06-09 06:22:49 UTC

After I start Skanlite with its default settings, then click Scan, the right-hand pane of Skanlite doesn't show a real-time display of the incoming data, just one black pixel marching down the right edge. This happens regardless of the document on the scanner bed.

Reproducible: Always

Steps to Reproduce:
1. Remove the Skanlite configuration file:
$ rm $HOME/.kde/share/config/Skanliterc

2. Run Skanlite:
$ skanlite &

3. Wait for Skanlite to load and find your scanner. It finds mine, the basic "Canon CanoScan LiDE30" model [http://www.usa.canon.com/cusa/support/consumer/scanners/canoscan_series/canoscan_lide_30].

4. Click the Scan button. The scanner will scan the document at the default settings of: color, 8-bit, 600 dpi.

5. Skanlite's right pane shows an white, page-like representation of the scan. As the scan progresses, none of what is being scanned in appears in the white, page-like area, except for one tiny dark pixel marching down the right side of the page-like edge. This is where a real-time display of the incoming data should appear.

6. After the scan has completed, the scan with all of its imagery is only then displayed in a separate preview window with the choice to Close or Save. We can click Close.

Actual Results:
No real-time scan progress is shown in Skanlite's right-most pane, just one dark pixel marching down the right edge.

Expected Results:
In other scanning software, as the document is being scanned, it is slowly being displayed as it comes in, like seeing real-time scanning progress.

Kubuntu Linux x86_64, kernel 3.19.0-18-generic #18-Ubuntu SMP

Skanlite Version: 1.1-0ubuntu1

Comment 1 Michael 2015-06-09 06:25:55 UTC

Created attachment 93087 [details]
Skanlite window as a scan is in progress

Where the pointer shows the dark pixel marching down the right edge of the scan document, even though the paper that was being scanned had much imagery. There is no real-time display of the document being scanned.

Comment 2 Kåre Särs 2015-06-09 20:07:17 UTC

This is unfortunately a bug that I have not been able to reproduce :(

All the scanners (sane-backends) I have produce the image as it is scanned. Here I could need some help to debug the problem...

Comment 3 Michael 2015-06-09 21:28:01 UTC

Okay. Is there some utility that would help me to diagnose the issue from my end?

Comment 4 Michael 2015-06-29 05:41:36 UTC

XSane doesn't have the issue of showing the scan while it is being scanned in, FWIW.

Comment 5 Justin Zobel 2020-11-24 05:20:16 UTC

Thanks for the report, Michael. It's been a while since this report was made.

Can you please test and confirm if this issue is still occurring or if this bug report can be marked as resolved. I've set the bug status to "needsinfo" pending your response, please change back to "reported" or "resolved" when you respond, thanks.

Comment 6 Michael 2020-11-25 03:29:43 UTC

Hello Justin, thank you for checking in. Yes, the bug persists, and this is happening on KDE neon. I've updated the bug report metadata to reflect what I'm testing now, which is Skanlite 2.2.0 and:

Operating System: KDE neon 5.20
KDE Plasma Version: 5.20.3
KDE Frameworks Version: 5.76.0
Qt Version: 5.15.1
Kernel Version: 5.4.0-54-generic
OS Type: 64-bit
Memory: 7.7 GiB of RAM

The testing procedure is almost the same, though now with Frameworks 5, I have to do 

$ rm $HOME/.config/skanliterc

...before 

$ skanlite &

I'm attaching screenshots to show you what I'm seeing. After I hit the Scan button, the preview window is still blank. Afterwards, the preview save window appears, and I finally get to see what I've scanned.

For me, the only way I can get a "live" preview of the paper I'm trying to scan is if I click the Preview button before clicking Scan.

Comment 7 Michael 2020-11-25 03:32:20 UTC

Created attachment 133621 [details]
skanlite scanning but nothing appearing in preview pane

Comment 8 Michael 2020-11-25 03:33:09 UTC

Created attachment 133622 [details]
skanlite after the scan, showing the result