Changing custom crop area is very slow

[Michał Sawicz]

Steps to reproduce:
* scan a page
* select "Custom" from Crop options
* drag the crop area around

Expected results:
* changing the crop area is a minimum effort to the CPU

Current results
* CPU over 30% and the selection is very slow / choppy

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: simple-scan 3.9.4.1-0ubuntu1
ProcVersionSignature: Ubuntu 3.11.0-2.5-generic 3.11.0-rc5
Uname: Linux 3.11.0-2-generic x86_64
NonfreeKernelModules: wl nvidia
ApportVersion: 2.12.1-0ubuntu2
Architecture: amd64
Date: Tue Aug 20 15:23:11 2013
DriverPackageVersions:
 libsane 1.0.23-0ubuntu3
 libsane-extras N/A
 hplip 3.13.8-0ubuntu1
 hpoj N/A
MachineType: Dell Inc. Latitude E6420
MarkForUpload: True
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.11.0-2-generic root=/dev/mapper/username--laptop-ubuntu--root ro rootflags=subvol=@ splash quiet vt.handoff=7
SourcePackage: simple-scan
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/11/2012
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A14
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA14:bd07/11/2012:svnDellInc.:pnLatitudeE6420:pvr01:rvnDellInc.:rn:rvr:cvnDellInc.:ct9:cvr:
dmi.product.name: Latitude E6420
dmi.product.version: 01
dmi.sys.vendor: Dell Inc.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.