Tag Archive for ImageMagick

Solving an upgrade hitch en route to Ubuntu 10.04

May 4, 2010 One comment

After waiting until after a weekend in the Isle of Man, I got to upgrading my main home PC to Ubuntu 10.04. Before the weekend away, I had been updating a 10.04 installation on an old spare PC and that worked fine so the prospects were good for a similar changeover on the main box. That may have been so but breaking a computer hardly is the perfect complement to a getaway.

So as to keep the level of disruption to a minimum, I opted for an in-situ upgrade. The download was left to complete in its own good time and I returned to attend to installation messages asking me if I wished to retain old logs files for the likes of Apache. When the system asked for reboot at the end of the sequence of package downloading, installation and removal, I was ready to leave it do the needful.

However, I met with a hitch when the machine restarted: it couldn’t find the root drive. Live CD’s were pressed into service to shed light on what had happened. First up was an old disc for 9.10 before one for 10.04 Beta 1 was used. That identified a difference between the two that was to prove to be the cause of what I was seeing. 10.04 uses /dev/hd*# (/dev/hda1 is an example) nomenclature for everything including software RAID arrays (“fakeraid”). 9.10 used the /dev/mapper/sil_**************# convention for two of my drives and I get the impression that the names differ according to the chipset that is used.

During the upgrade process, the one thing that was missed was the changeover from /dev/mapper/sil_**************# to /dev/hd*# in the appropriate places in /boot/grub/menu.lst; look for the lines starting with the word kernel. When I did what the operating system forgot, I was greeted by a screen telling of the progress of checks on one of the system’s disks. That process took a while but a login screen followed and I had my desktop much as before. The only other thing that I had to do was run gconf-editor from the terminal to send the title bar buttons to the right where I am accustomed to having them. Since then, I have been working away as before.

Some may decry the lack of change (ImageMagick and UFRaw could do with working together much faster, though) but I’m not complaining; the rough of 9.10 drilled that into me. Nevertheless, I am left wondering how many are getting tripped up by what I encountered, even if it means that Palimpsest (what Ubuntu calls Disk Utility) looks much tidier than it did. Could the same thing be affecting /etc/fstab too? The reason that I don’t know the answer to that question is that I changed all hard disk drive references to UUID a while ago but it’s another place to look if the GRUB change isn’t fixing things for you. If my memory isn’t failing me, I seem to remember seeing /dev/mapper/sil_**************# drive names in there too.

Hardware, Linux, Software

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Converting from CGM to Postscript

November 24, 2009 2 comments

On thing that I recently had to investigate was the possibility of converting CGM vector graphics files into Postscript and from there into PDF. Having used ImageMagick for converting images before, that was an obvious option. However, that cannot process CGM files on its own and needs a delegate or helper application as well. This is the case with raw digital camera files too with UFRaw being the program chosen. For CGM images, the more obscure RALCGM is what’s needed and tracking it down is a bit of an art. The history is that it was developed at the U.K.’s Rutherford Appleton Laboratory but it seems that it was left go off into the wilderness rather than someone keeping an eye on things. With that in mind, here are the installation packages for Windows and Linux (RPM):

Windows Installer

Linux RPM

RALCGM is a handy command line tool that can covert from CGM to Postscript on its own without any need for ImageMagick at all. From what I have seen, fonts on graphical output may look greyer than black but it otherwise does its job well. However, considering that it is a freely available tool, one cannot complain too much. There are other packages for doing vector to raster conversion and the ones that I have seen do have GUI‘s but the freedom to look at for cost software wasn’t mine to have. The required command looks something like the following:

ralcgm -d PS -oL test.cgm test.ps

The switch -d PS uses the software’s Postscript driver and -oL specifies landscape orientation. If you want to find out more, here’s a PDF rendition of the help file that comes with the thing:

RALCGM Documentation

Graphics, Imaging, Software

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Rough?

November 11, 2009 4 comments

Was it because Canonical and friends kept Ubuntu in such a decent state from 8.04 through to 9.04 that things went a little quiet in the blogosphere on the subject of the well-known Linux distribution? If so, 9.10 might be proving more of a talking point and you have to wonder if this is such a good thing with the appearance of Windows 7 on the scene. Looking on the bright side, 10.04 will be an LTS release so there is some chance that any rough edges that are on display now could be resolved by next April. Even so, it might have been better not to see anything so obvious at all.

In truth, Ubuntu always has had its gaps and I have seen a few of their ilk over the last two years. Of these, a few have triggered postings on here. In fact, issues with accessing the BBC iPlayer still bring a goodly number of folk to this website. That may just be a matter of grabbing RealPlayer, now helpfully available as a DEB package, from the requisite place on the web and ensuring that Ubuntu-Restricted-Extras is in place too but you have to know that in the first place. Even so, unexpected behaviours like Palimpsest seeing every partition on a disk as a different drive and SIL Raid mappings being seen for hard drives that used to live on the main home PC that bit the dust earlier this year; it only happens on one of the machines that I have running Ubuntu so it may be hardware thing and newly added hard drive uses none of the SIL mapping either. Perhaps more seriously (is it something that a new user should be encountering?), a misfiring variant of Brasero had me moving to K3b. Then UFRaw was sluggish in batch but that’s nothing that having a Debian VM won’t overcome. Rough edges like these do get you asking if 9.10 was ready for the big time while making you reluctant to recommend it to mainstream users like my brother.

The counterpoint to the above is that 9.10 includes a host of under the bonnet changes like the introduction of Ext4 hard drive formatting, Xsplash to allow the faster system loading to occur unseen and GNOME 2.28. To someone looking in from outside like me, that looks like a lot of work and might explain the ingress of the annoyances that I have seen. Add to that the fact that we are between Debian releases so things like the optimised packaging of ImageMagick or UFRaw may not be so high up the list of the things to do, especially with the more general speed optimisations that were put in place for 9.10. With 10.04 set to be an LTS release so I’d be hoping that consolidation is the order of the day over the next five or six months but it seems to be the inclusion of new features and other such progress that get magazine reviewers giving higher ratings (Linux Format has given it a mark of 9 out of 10). With the mooted inclusion of GNOME 3 and its dramatically different interface in 10.10, they should get their fill of that. However, I’d like to see some restraint for the take of a smooth transition from the familiar GNOME 2.x to the new. If GNOME 3 stays very like its alpha builds, then the question as how users will take to it arises. Of course, there’s some time yet before we see GNOME 3 and, having seen how the Ubuntu developers transformed GNOME 2.28, I wouldn’t be surprised if the impact of any change could be dulled.

In summary, my few weeks with Ubuntu 9.10 as my main OS have thrown up no major roadblocks that would cause me to look at moving elsewhere; Fedora would be tempting if that situation were to arise. The irritations that I have seen are more like signs of a lack of polish and remain peripheral to day-to-day working if you discount CD/DVD burning. To be honest, there always have been roughnesses in Ubuntu but has the lack of sizeable change spoilt us? Whatever about how things feel afterwards, big changes can mean new problems to resolve and inspire blog posts describing any solutions so it’s not all bad. If that’s what Canonical wants to see, they might get it and the year ahead looks as if it is going to be an interesting one after a recent quieter period.

Linux, Software

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A certain lack of speed

November 2, 2009 No comments

A little while, I encountered a problem with ImageMagick processing DNG files in Ubuntu 9.04. Not realising that I could solve me own problem by editing a file named delegates.xml, I took to getting a Debian VM to do the legwork for me. That’s where you’ll find all the commands used when helper software is used by ImageMagick to help it on its way. On its own, ImageMagick cannot deal with DNG files so the command line variant of UFRaw (itself a front end for DCRaw) is used to create a PNM file that ImageMagick can handle. The problem a few months back was that the command in delegates.xml wasn’t appropriate for a newer version of UFRaw and I got it into my head that things like this were hard-wired into ImageMagick. Now, I know better and admit my error.

With 9.1o, it seems that the command in delegates.xml has been corrected but another issue had raised its head. UFRaw 0.15, it seems, isn’t the speediest when it comes to creating PNM files and, while my raw file processing script works after a spot of modification to deal with changes in output from the identify command used, it takes far too long to run. GIMP also uses UFRaw so I wonder if the same problem has surfaced there too but it has been noticed by the Debian team and they have a package for version 0.16 of the software in their unstable branch that looks as if it has sorted the speed issue. However, I am seeing that 0.15 is in the testing branch so I’d be tempted to stick with Lenny (5.x) if any successor turns out to have slower DNG file handling with ImageMagick and UFRaw. In my estimation, 0.13 does what I need so why go for a newer release if it turns out ot be slower?

Graphics, Imaging, Linux, Software, Virtualisation

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A restoration of order

July 12, 2009 No comments

This weekend, I finally put my home computing displacement behind me. My laptop had become my main PC with a combination of external hard drives and an Octigen external hard drive enclosure keeping me motoring in laptop limbo. Having had no joy in the realm of PC building, I decided to go down the partially built route and order a bare bones system from Novatech. That gave me a Foxconn case and motherboard loaded up with an AMD 7850 dual core CPU and 2 GB of RAM. With the motherboard offering onboard sound and video capability, all that was needed was to add drives. I added no floppy drive but instead installed a SATA DVD Writer (not sure that it was a successful purchase, though, but that can be resolved at my leisure) and the hard drives from the old behemoth that had been serving me until its demise. A session of work on the kitchen table and some toing and froing ensued as I inched my way towards a working system.

Once I had set all of the expected hard disks into place, Ubuntu was capable of being summoned to life with the only impediment being an insistence of scanning the 1 TB Western Digital and getting stuck along the way. Not having the patience, I skipped this at start up and later unmounted the drive to let fsck to its thing while I got on with other tasks; the hold up had been the presence of VirtualBox disk images on the drive. Speaking of VirtualBox, I needed to scale back the capabilities of Compiz so things would work as they should. Otherwise, it was a matter of updating various directories with files that had appeared on external drives without making it into their usual storage areas. Windows would never have been so tolerant and, as if to prove the point, I needed to repair an XP installation in one of my virtual machines.

In the instructions that came with the new box, Novatech stated that time was a vital ingredient for a build and they weren’t wrong. The delivery arrived at 09:30 and I later got a shock when I saw the time to be 15:15! However, it was time well spent and I noticed the speed increase when putting ImageMagick through its paces with a Perl script. In time, I might get brave and be tempted to add more memory to get up to 4 GB; the motherboard may only have two slots but that’s not such a problem with my planning on sticking with 32-bit Linux for a while to come. My brief brush with its 64-bit counterpart revealed some roughness that ward me off for a little while longer. For now, I’ll leave well alone and allow things to settle down again. Lessons for the future remain and I may even mull over them in another post…

Hardware, Linux, Software, Virtualisation

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ImageMagick and Ubuntu 9.04

May 5, 2009 One comment

Using a command line tool like ImageMagick for image processing may sound a really counter-intuitive thing to do but there’s no need to do everything on a case by case interactive basis. Image resizing and format conversion come to mind here. Helper programs are used behind the scenes too with Ghostscript being used to create Postscript files, for example.

The subject of helper programs brings me to an issue that has hampered me recently. While I am aware that there are tools like F-Spot available, I am also wont to use a combination of shell scripting (BASH & KSH), Perl and ImageMagick for organising my digital photos. My preference for using Raw camera files (DNG & CRW) means that ImageMagick cannot access these without a little helper. In the case of Ubuntu, it’s UFRaw. However, Jaunty Jackalope appears to have seen UFRaw updated to a version that is incompatible with the included version of ImageMagick (6.4.5 as opposed to 3.5.2 at the time of writing). The result is that the command issued by ImageMagick to UFRaw – issue the command man ufraw-batch to see the details – is not accepted by the included version of the latter, 0.15 if you’re interested. It seems that an older release of UFRaw accepted the output device ppm16 (16-bit PPM files) but this should now be specified as ppm for the output device and 16 for the output depth. In a nutshell, where the parameter output-type did the lot, you now need both output-type and output-depth.

I thought of decoupling things by using UFRaw to create 16-bit PPM files for processing by ImageMagick but to no avail. The identify command wouldn’t return the date on which the image was taken. I even changed the type to 8-bit JPEG’s with added EXIF information but no progress was made. In the end, a mad plan came to mind: creating a VirtualBox VM running Debian. The logic was that if Debian deserves its reputation for solidity, dependencies like ImageMagick and UFRaw shouldn’t be broken and I wasn’t wrong. To make it fly though, I needed to see if I could get Guest Additions installed on Debian. Out of the box, the supported kernel version must be at least 2.6.27 and Debian’s is 2.6.26 so additional work was on the cards. First, GCC, Make and the correct kernel header files need to be installed. Once those are in place, the installation works smoothly and a restart sets the goodies in motion. To make the necessary Shared folder to be available, a command like the following was executed:

mount -t vboxfs [Shared Folder name] [mount point]

Once that deed was done and ImageMagick instated, the processing that I have been doing for new DSLR images was reinstated. Ironically, Debian’s version of ImageMagick, 6.3.7, is even older than Ubuntu’s but it works and that’s the main thing. There is an Ubuntu bug report for this on Launchpad so I hope that it gets fixed at some point in the near future. However, that may mean awaiting 9.10 or Karmic Koala so I’m glad to have the workaround in the meantime.

Graphics, Imaging, Linux, Scripting, Virtualisation

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