Archive for Graphics

Why the manual step?

One of the consequences of buying a new camera is that your current photo processing software may not be fully equipped for the job of handling the images that it creates. This is a particular issue with raw image files and Adobe Photoshop Elements 5 was unable to completely handle DNG files made with my Pentax K10D until I upgraded to version 7. Yes, I do realise that upgrading camera should been in order but I only lost the white balance adjustments so I could with things as they until upgrading gained a more compelling case.

As things stood, Elements 7 was unable to import CR2 files from my Canon PowerShot G11 into the Organiser so it was off to the appropriate page on the Adobe website for a Camera Raw updater. I picked up the latest release of Camera Raw (5.6 at the time of writing) even though it was found in the Elements 8 category (don’t be put by this because release notes address the version compatibility question more extensively). Strangely, the updater doesn’t complete everything because you still need to copy Camera Raw.8bi from the zip archive and backup the original. Quite why this couldn’t have been more automated, even with user prompts for file names and locations, is beyond me but that is how it is. However, once all was in place, CR2 files were handled by Elements without missing a beat.

Converting from CGM to Postscript

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

A certain lack of speed

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?

8?

It now seems that we have a new version of Photoshop Elements from Adobe for every year unless you’re a Mac user. Version 7 convinced me to splash out and that gained me Camera Raw recognition of my Pentax K10D along with subtly enhanced image processing power that I have been putting to good use to get more pleasing results than I ever got before. What can be achieved by using levels, curves and the shadow/highlight adjustment tool for exposure correction has amazed me recently. Quick selection functionality has allowed me to treat skies differently from everything else in landscape photos, a flexible graduated filter if you like. It seems to work on Windows 7 along with Vista and XP so I plan to stick with it for a while yet. As you may have gathered from this, it would take some convincing to make me upgrade and, for me, version 8 doesn’t reach that mark. All in all, it seems that it is a way of giving Mac users a new release with added goodness after having to stay with 6 for so long; yes, there are new features like autotagging in the image organiser but they just don’t grab me. Given that they already have Aperture from Apple and Windows users seem to get more releases, it’s a wonder that any Mac user would toy with Elements anyway. Maybe, that’s Adobe’s suspicion too.

Enabling DVD playback in Ubuntu 9.04

This information is scattered about the web but I decided to collect something together in one place in case it helps anyone else. Here are two commands that appeared to do the deed for me:

sudo apt-get install ubuntu-restricted-extras totem-xine libxine1-ffmpeg libdvdread4

sudo /usr/share/doc/libdvdread4/install-css.sh

The libdvdread piece is what sorts out encrypted disks and needs a two stage installation, hence the second command. For non-encrypted disks, ubuntu-restricted-extras might be all that’s needed if my experience is typical. Taking things further, Wim Wenders’ Buena Vista Social Club (Region 2 disk) worked when I tried it too. In the interests of completeness, I tried the command combination on a virgin 9.04 installation with restricted and multiverse repositories enabled. Along the way, I spied a whole raft of helper components being set in place and things worked like I would have expected with the aforementioned DVD afterwards. As with anything related to computing, your mileage may vary and, for more information, you can take a look here.

Anquet and VirtualBox Shared Folders

For a while now, I have had Anquet installed in a virtual machine instance of Windows XP but it has been throwing errors continuously on start up. Perhaps surprisingly, it only dawned upon me recently what might have been the cause. A bit of fiddling revealed that my storing the mapping data Linux side and sharing it into the VM wasn’t helping and copying it to a VM hard drive set things to rights. This type of thing can also cause problems when it comes getting Photoshop to save files using VirtualBox’s Shared Folders feature too. Untangling the situation is a multi-layered exercise. On the Linux side, permissions need to be in order and that involves some work with chmod (775 is my usual remedy) and chgrp to open things up to the vboxusers group. Adding in Windows’ foibles when it comes to networked drives and their mapping to drive letters brings extra complexity; shared folders are made visible to Windows as \\vboxsvr\shared_folder_name\. The solution is either a lot of rebooting, extensive use of the net use command or both. It induces the sort of toing and froing that makes copying things over and back as needed look less involved and more sensible if a little more manual than might be liked.

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