hp-scan segfaults when lineart selected

[Tim Waugh]

When using "hp-scan -r 2400 -m lineart", hp-scan segfaults.

It seems to happen inside python-pillow due to incorrect parameters:

hp-scan[30127]: debug: PPL=20400 lines=28064 depth=1 BPL=2550 pad=0 total=71563200

  lines=28064
  pixels_per_line=20400
  total=71563200
  buf = bytearray(total)
  im = Image.frombuffer('RGBA', (pixels_per_line, lines), buf, 'raw', 'RGBA', 0, 1).convert('L')
(segfaults, or gives a traceback with newer versions of python-pillow)

Based on the idea that 'RGBA' is the wrong parameter -- isn't the scanner giving us bw bitmap data? -- I tried this change:

diff -up hplip-3.14.6/scan.py.lineart hplip-3.14.6/scan.py
--- hplip-3.14.6/scan.py.lineart 2014-07-23 12:30:52.361517852 +0100
+++ hplip-3.14.6/scan.py 2014-07-23 12:32:17.052940000 +0100
@@ -977,8 +977,8 @@ try:
                         try:
                             pixels_per_line = bytes_per_line * 8 # Calculation of pixels_per_line for Lineart must be 8 time of bytes_per_line
                                                                           # Otherwise, scanned image will be corrupted (slanted)
- im = Image.frombuffer('RGBA', (pixels_per_line, lines), buffer.read(),
- 'raw', 'RGBA', 0, 1).convert('L')
+ im = Image.frombuffer('1', (pixels_per_line, lines), buffer.read(),
+ 'raw', '1', 0, 1).convert('L')
                         except ValueError:
                             log.error("Did not read enough data from scanner (I/O Error?)")
                             sys.exit(1)

But that also fails and seem to consume a large amount of memory in doing so.

HPLIP 3.14.6 on Fedora 20.

Original bug report:
  https://bugzilla.redhat.com/show_bug.cgi?id=1076954

[goutam (goutamkk)]

Hi Tim,

Thank you for reporting this issue. We will take a look at it.
Can you tell us on which device you are able to produce this issue ?

Thanks,
goutam

[Tim Waugh (twaugh)]

From the original bug report:

"Printer is an HP Deskjet 3510, connected both as USB 2 and wifi. I'd like to use the faster connection, but the choices presented by hp-scan don't indicate which is USB, and which is Wifi."