Jeff Epler's blog

Time to finish that languishing clock project!

A leap second has been announced at the end of June 2012.

It's gratifying when the compiler is right

I've been playing with clang because I'd like to use its static analyzer on the code at $DAY_JOB. Unfortunately, it frequently bombs while building our code. Fortuately, many of the bombs are due to our bugs, not theirs. Here's one example:

Need another reminder to steer clear of non-Free software?

It's played out over and over again on proprietary platforms: the vendor decides that this or that component should be deleted from user machines, and as if by magic it happens, without regard to the fact that user systems will encounter reduced functionality as a result.

Well, through its "Partner" archive, Ubuntu is in the unenviable position of doing the same thing.

Ingrid's Canadian Rockies Photos

(M)(L)

A beautiful reflection in Lake Annette

Photos that Ingrid took on our August 2011 trip to the Canadian Rockies, including Banff and Jasper National Parks

New Site Look

I recently decided it was time for a new look on my website. The new design is based on twitter bootstrap for css and a bit of javascript. I hope the result is a new look which is still light and simple but which also fits better with the sensibilities of today's web.

Cheeseball Barley Wine

(adapted from the Horn Dog Barley Wine recipe in Clone Brews; Clone Brews offers mini-mash and all-grain versions of this recipe)

My half-batch came out very dark and not at all hoppy. The original recipe calls for 9 months of bottle conditioning, but I found it to be very pleasant after just 2 months. I prefer to split a (12oz) bottle with a friend. This is quite enough to lend a pleasant feeling of warmth. It's said to keep at cellar temperatures for 2 years, but I doubt this has ever been experimentally proven.

Pairs well with left-over ginger triple-chocolate wedding cake.

Style: English Barley Wine
OG: 1.103-1.104
FG: 1.023-1.024
Est ABV: 10.2%

Recipe for 5 gallons:

csql: perform sql queries on csv data

The websites I operate are flat-file based, so when I want to store data it's easiest to write it in csv format. But it's not particularly easy to make queries on this data without additional software.

I'd rather not fire up Open Office or try to figure out how to make awk parse a quoted excel-format file, so I wrote 'csql', which reads a csv file into an in-memory sql database, performs a query, and then writes the result also in csv format.

A short example:

rsvp.csv:

Buffy Summers,false,0
Xander Harris,true,2
Willow Rosenberg,true,1

rsvp.cols:

name text
attend boolean
count integer

Performing queries:

$ csql rsvp.csv 'select sum(count) from t where attend="true"'
3
$ csql rsvp.csv 'select name from t where attend="true"'
Xander Harris
Willow Rosenberg

Files currently attached to this page:

csql

3.4kB

Source: USB Stacker for EOS Cameras

I promised to post the code I wrote to do focus stacking. Here it is, in the form of a patch to pyptp.

The code is lightly tested on my Canon EOS 7D.

It's necessary to change the shutter release button so that a half-press does not autofocus. (this is somewhere in the C.Fn. menus) If your camera doesn't have this custom function, I don't think this code will work for you.

Manually focus the lens at the far end of the range, set lens to autofocus, plug in the usb cable, and run the program. You may have to fiddle with the "--stepsize=" argument in order to get an appropriate amount of movement between each shot and of course "--count=" to capture enough frames to cover your subject. For a list of other other options, run 'python stack.py --help'.

Files currently attached to this page:

pyptp-canon-stacker.patch

17.0kB

Focus Stacking Success

I've finally had success with focus stacking!

Inspired by the focus stacking assistant, I wrote a Python program using pyptp that does something similar with a Canon EOS tethered to a Linux PC. (I intend to release this in a bit, but it's very much "under construction" code at this time)

I then aligned the images in hugin and stitched with enblend.

There's still some tinkering to do with tunable parameters, but it looks pretty good! In the thumbnail you can see that all of the table cloth is in focus; view the medium or large versions to see more detail.

tnef2mime: automatically extract parts from winmail.dat

In her professional life, my fiancée routinely gets emails with attachments in the 'winmail.dat' aka application/ms-tnef format. It does her no good to berate these prisoners of proprietary software, so I set out to provide her with an easy-to-use solution that would work on her end. Now, prompted by this blog entry I am posting it for others to use.

There are a number of programs that can rescue data from this proprietary attachment format, but I was not aware of a program that would automatically convert the winmail.dat attachment to (a series of) regular mime attachments. (it appears that ytnef_smtpd may be such a program)

So I wrote one, tnef2mime.py. tnef2mime reads a message on standard input, combs it for ms-tnef attachments, and uses the tnef(1) program to extract their contents. Then it takes the extracted files, adds them as new MIME parts, and prints the whole resulting message.

This is suitable for use in e.g. procmail:

:0fw
| tnef2mime

Several steps are taken in order to minimize the chances for data loss: Just in case it did an imperfect job, it leaves the existing ms-tnef attachment intact. If any problem is encountered, the unmodified message is written.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

Files currently attached to this page:

tnef2mime.py

3.1kB