Archive for June, 2009

Improvements to TwitToday

Wednesday, June 10th, 2009

I’ve been doing too much Java at work recently, so in the interest of keeping my hand in with some low-level C++, I picked up the code for my mobile twitter client, TwitToday, again.

I originally wrote it at a hackday, but I’ve since come back to tweak it a couple of times to get it to spawn background worker threads, add SIP on-screen keyboard support, and improve support for sending special and accented characters.

After another evening of tweaking, I’ve added a few new minor features:

Transparent text box

When not in use, the text box is now transparent. When it has focus, it is coloured in white as usual.

A few people commented that a bright white text box could dominate a dark Today screen too much, so this is hopefully a nice aesthetic improvement.

I did this by creating a custom windows procedure for the text box.

The windows procedure needed to handle a couple of events:

Handling WM_PAINT by using SetBkMode to make the text box TRANSPARENT

Handling WM_ERASEBKGND by using TODAYM_DRAWWATERMARK to draw the background over the text control’s rectangle.

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How to customise the NavigationToolbar2 toolbar in matplotlib

Saturday, June 6th, 2009

My CurrentCost desktop software is written in Python, and uses the matplotlib library for plotting graphs.

I am a big fan of matplotlib – you can create some very cool graphs with it. It’s not without it’s issues… for example, I’ve still yet to work out how to do realtime graphing with it that isn’t massively inefficient and resource intensive. But that’s for another post 🙂

One of the nice things that you get with it is a toolbar that lets the user switch between different modes that the mouse supports – zooming, panning, and so on.

Adding the toolbar is straightforward – I create an object of the class NavigationToolbar2Wx and add it to a sizer which in turn I add to the graph Plot.

self.toolbar = Toolbar(self.canvas)
self.toolbar.Realize()
sizer = wx.BoxSizer(wx.VERTICAL)
sizer.Add(self.canvas, 1, wx.EXPAND)
sizer.Add(self.toolbar, 0 , wx.LEFT | wx.EXPAND)
self.SetSizer(sizer)

The NavigationToolbar2 toolbar provides a number of features but it doesn’t exactly meet my needs so last night I had a go at customising it.

I wanted to:

  • remove the configure subplots button – as I don’t use subplots in my graphs
  • add a couple of new buttons – for different navigation abilities

I couldn’t find this documented clearly anywhere, so thought it was worth sharing the code that I came up with.

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