[#315607] Benq 5250C: saned scans only 1/4 of the image

Date:
2017-01-24 20:32 Priority:
3

State:
Open

Submitted by:
Boris Lytochkin (lytboris-guest) Assigned to:
Oliver Schwartz (oliver-guest)

Category:
backends (drivers) Group:
None

Resolution:
None

Summary:
Benq 5250C: saned scans only 1/4 of the image

Detailed description
With 1.0.25 and no patches saned (snapscan backend) scans exactly 1/4 of the image. If I patch snapscan-options.c doubling ranges for this scanner: ============= >diff -u snapscan-options.c~ snapscan-options.c --- snapscan-options.c~ 2015-09-01 03:31:54.000000000 +0300 +++ snapscan-options.c 2017-01-24 23:12:03.724027000 +0300 @@ -119,11 +119,11 @@ /* ranges / static const SANE_Range x_range_fb = { - SANE_FIX (0.0), SANE_FIX (216.0), 0 + SANE_FIX (0.0), SANE_FIX (432.0), 0 }; / mm / static const SANE_Range y_range_fb = { - SANE_FIX (0.0), SANE_FIX (297.0), 0 + SANE_FIX (0.0), SANE_FIX (594.0), 0 }; / mm / / default TPO range (shortest y_range ============= most of the image is scanned (white is only rightmost 1/4 of the image) but 3/4 has color broken. Any ideas how to fix this?

Followups: Sort comments antichronologically

Message
Date: 2017-01-29 12:24 Sender: Olaf Meeuwissen Looks like this is in the backend but it'd be nice to know whether you also see this when scanning over USB.
Date: 2017-01-29 19:41 Sender: Boris Lytochkin Yeah, scanning though scanimage gives the same thing. I just noticed that the image with patched snapscan is scanned completely, but right half of the image has colors broken in two different ways.
Date: 2017-01-29 20:14 Sender: Boris Lytochkin And grayscale is even more broken (still patched backend to scan whole image)
Date: 2017-01-30 08:17 Sender: Oliver Schwartz Is the scan range wrong for all resolutions? A better place to adjust the scan area is snapscan_scsi.c, around line 977, where the scan area is calculated from the physical dimensions. You could try to adjust pos_factor there and see if that delivers better results.
Date: 2017-02-04 15:31 Sender: Boris Lytochkin --- snapscan-scsi.c~ 2017-01-29 22:58:31.000000000 +0300 +++ snapscan-scsi.c 2017-02-04 18:04:05.355844000 +0300 @@ -974,7 +974,7 @@ case PRISA5000: case PRISA5000E: case PRISA5150: - pos_factor = (pss->res > 600) ? 1200 : 600; + pos_factor = 1200; //(pss->res > 600) ? 1200 : 600; break; case PERFECTION1270: case PERFECTION1670: does the same trick - image is scanned 100% but colors are still broken and gray mode has broken line alignment. If I scan Gray and 1200dpi - image itself is not distorted but is seen as if you take 5250c-fullpage.png and make it gray-scale. halftone with patched snapscan-scsi.c is even more broken (150 dpi attached, 300 and 1200 are the same but the angle of color stripes is different).

Attached Files:

Attachments:

Size	Name	Date	By	Download
1.46 MiB	5250c-fullpage.png	2017-01-24 20:32	lytboris-guest	5250c-fullpage.png
1.22 MiB	out-gray.png	2017-01-29 20:14	lytboris-guest	out-gray.png
6.4 MiB	150-ht.tiff	2017-02-04 15:31	lytboris-guest	150-ht.tiff

Changes:

Field	Old Value	Date	By
File Added	7345: 150-ht.tiff	2017-02-04 15:31	lytboris-guest
File Added	7335: out-gray.png	2017-01-29 20:14	lytboris-guest
assigned_to	none	2017-01-29 12:24	olaf-guest
File Added	7334: 5250c-fullpage.png	2017-01-24 20:32	lytboris-guest