Joe Lanman

Inkscape is one of the most successful and usable open-source applications around – it’s a drawing app, useful for designing icons and logos, or laying out posters and leaflets. I used it to design my pocket calendar cards.

I fired it up recently to design a leaflet for my Mum’s guest house, featuring lots of photos of the local area. I’d previously rotated them to some jaunty angles and needed to straighten them up. I couldn’t find anything in the interface to do this (boo) but then remembered that one great feature of Inkscape is that it stores the state of the document as an editable SVG file. Even if there wasn’t a way to remove the rotations in the interface, I could do it by editing the data directly (hooray!), it’s a sort of View Source for illustration/page layout.

1. Open the Edit menu, select XML Editor
2. Select the image you’d like to straighten on the page
3. In the XML Editor, click Transform attribute, and click the Delete Attribute button above

Boom – straight images.

Obviously, it would be nice to have a button to do this (maybe there is – feel free to let me know in the comments), but I like that the use of an open image format, and the tools to edit the data directly allows me to achieve what I need to do. Do you have any Inkscape tips?

Transport for London have recently started offering a very handy cycle journey planner on their site, great – but it’d be much more handy in interactive form on my Android phone. Here’s a quick guide on how to do that:

1) Plan your route, then click upload to GPS device (top right). This will give you a GPX file to download.

2) Download RMaps – this is what we’re going to use to view the route on Android, and its a fantastic map app to have anyway, its main advantage over Google Maps being it can cache maps offline for you – if you happen to be hiking out of mobile range for instance.

3) Transfer your GPX file to your phone. I used the Android Dropbox app, but you could just use USB, or a couple of floppies.

4) Open the route with RMaps – in RMaps, press Menu ->More -> Tracks. Now press Menu again -> Import, and select your GPX file. The route name should now appear on the screen, tap it to get a tick – it is now displayed on the map screen.

5) And you’re done – press Back until you see the map screen – if you zoom in you should see your route highlighted in purple.

I’m a big fan of applications that do a simple thing well; jsFiddle.net is an innovative environment to work on HTML, CSS and JavaScript in the browser. Coded by Piotr Zalewa and designed by Oskar Krawczyk, it’s a tool I’ve found really useful for me and my team – the simple four-pane layout is brilliantly suited to front-end development:
(more…)

There are two out-of-the-box methods for multiple selection in HTML: checkboxes and the <select> tag. Neither are perfect – I’ll be discussing why, and proposing a sort of mashup of the best aspects of both, using jQuery.

(more…)

I ran into an issue today while trying to implement image uploads. It’s a very basic implementation: taking files from a POST request, copying them to a local folder, and then making thumbnails of them.

I started with the file upload tutorial in the web.py cookbook.

The problem I was getting was that the Python Image library (PIL) was failing to make the thumbnails, with the error ‘image file is truncated’.

(more…)

After looking at Web.py’s own templating system, and considering Cheetah, I’ve ended up going with Mako for now. So far I’ve found it very straightforward, with some powerful-looking features to expand into in the future.

One of the great features is template inheritance – but I hit an issue recently with passing a variable from a child template to a parent. It’s not immediately obvious how to do this, but I found the answer on the Mako Google Groups archive (link here):

Child:

<%inherit file="meta.html"/>

<%def name="vars()">

	<% return (meta.id,) %>

</%def>

Parent:

<% (id,) = self.vars() %>

On a side note, I found out today that two of the Python libraries I’m using, Mako and SQLAlchemy, were coded by the same guy – Michael Bayer. Clever chap – not only are the libraries pretty impressive, but they are both well documented and he regularly contributes to the mailing lists for both projects. And he doesn’t even have a big internet head like some developers – though I tracked his blog down here:

http://techspot.zzzeek.org/

Should that be ‘a’ or ‘an’ SQLAlchemy object?

My current CMS project is based on creating templates in the back-end, and then using these to produce ‘inherited’ objects with the same attributes.

I quickly found that it’s surprisingly tricky to grab a template object using SQLAlchemy, and copy it into a similar, but separate, entity. Using the Python ‘copy’ function confuses SQLAlchemy – when you try to save it, it thinks it is merely a representation of the original (template) object.

Here’s how I create separate ‘clones’ from my template objects, defining a function on the object itself:

(more…)

Only a day after complaining about my ATI card running under Ubuntu, I seem to have a solved a lot of the issues. Slightly embarrassing. To recap – my system is set up like this:

HP 8510p laptop with an ATI HD 2600 mobility card running Ubuntu 8.04 with a 1680×1050 screen, often connected to an external monitor (same resolution).

My ideal setup would be like this:

• ‘Big desktop’ mode when plugged into an external monitor, allowing windows to be dragged between screens.
• When the monitor is unplugged, to continue working on the laptop screen, without restarting Xorg.
• Compiz-fusion providing ‘expose’ functionality amongst other things.
• Generally not having crashes would be nice.

(more…)

They do things in Windows there.*

So I’m making a valiant effort to move to Linux, and stay in Linux.  I like how easy it is to install development stuff (servers, compilers, libraries) and I like the ethos of open source software. I installed Ubuntu a few months ago, and again on my new HP laptop. Everything is snappy and responsive, but I have had a few problems…

(more…)

The Python language has useful string methods to search for prefixes and suffixes:

my_string.startswith('pre')

The same thing can be achieved in Javascript using the rather powerful search and replace methods.

(more…)