| Andrew Cooke | Contents | Latest | RSS | Twitter | Previous | Next


Welcome to my blog, which was once a mailing list of the same name and is still generated by mail. Please reply via the "comment" links.

Always interested in offers/projects/new ideas. Eclectic experience in fields like: numerical computing; Python web; Java enterprise; functional languages; GPGPU; SQL databases; etc. Based in Santiago, Chile; telecommute worldwide. CV; email.

Personal Projects

Lepl parser for Python.

Colorless Green.

Photography around Santiago.

SVG experiment.

Professional Portfolio

Calibration of seismometers.

Data access via web services.

Cache rewrite.

Extending OpenSSH.

C-ORM: docs, API.

Last 100 entries

China Gamifies Real Life; Can't Help Thinking It's Thoughtcrime; Mefi Quotes; Spray Painting Bike Frame; Weeks 10 + 11; Change: No Longer Possible To Merge Metadata; Books on Old Age; Health Tree Maps; MRA - Men's Rights Activists; Writing Good C++14; Risk Assessment - Fukushima; The Future of Advertising and Surveillance; Travelling With Betaferon; I think I know what I dislike so much about Metafilter; Weeks 8 + 9; More; Pastamore - Bad Italian in Vitacura; History Books; Iraq + The (UK) Governing Elite; Answering Some Hard Questions; Pinochet: The Dictator's Shadow; An Outsider's Guide To Julia Packages; Nobody gives a shit; Lepton Decay Irregularity; An Easier Way; Julia's BinDeps (aka How To Install Cairo); Good Example Of Good Police Work (And Anonymity Being Hard); Best Santiago Burgers; Also; Michael Emmerich (Vibrator Translator) Interview (Japanese Books); Clarice Lispector (Brazillian Writer); Books On Evolution; Looks like Ara (Modular Phone) is dead; Index - Translations From Chile; More Emotion in Chilean Wines; Week 7; Aeon Magazine (Science-ish); QM, Deutsch, Constructor Theory; Interesting Talk Transcripts; Interesting Suggestion Of Election Fraud; "Hard" Books; Articles or Papers on depolarizing the US; Textbook for "QM as complex probabilities"; SFO Get Libor Trader (14 years); Why Are There Still So Many Jobs?; Navier Stokes Incomplete; More on Benford; FBI Claimed Vandalism; Architectural Tessellation; Also: Go, Blake's 7; Delusions of Gender (book); Crypto AG DID work with NSA / GCHQ; UNUMS (Universal Number Format); MOOCs (Massive Open Online Courses); Interesting Looking Game; Euler's Theorem for Polynomials; Weeks 3-6; Reddit Comment; Differential Cryptanalysis For Dummies; Japanese Graphic Design; Books To Be Re-Read; And Today I Learned Bugs Need Clear Examples; Factoring a 67 bit prime in your head; Islamic Geometric Art; Useful Julia Backtraces from Tasks; Nothing, however, is lost with less discomfort than that which, when lost, cannot be missed; Article on Didion; Cost of Living by City; British Slavery; Derrida on Metaphor; African SciFi; Traits in Julia; Alternative Japanese Lit; Pulic Key as Address (Snow); Why Information Grows; The Blindness Of The Chilean Elite; Some Victoriagate Links; This Is Why I Left StackOverflow; New TLS Implementation; Maths for Physicists; How I Am 8; 1000 Word Philosophy; Cyberpunk Reading List; Detailed Discussion of Message Dispatch in ParserCombinator Library for Julia; FizzBuzz in Julia w Dependent Types; kokko - Design Shop in Osaka; Summary of Greece, Currently; LLVM and GPUs; See Also; Schoolgirl Groyps (Maths); Japanese Lit; Another Example - Modular Arithmetic; Music from United; Python 2 and 3 compatible alternative.; Read Agatha Christie for the Plot; A Constructive Look at TempleOS; Music Thread w Many Recommendations; Fixed Version; A Useful Julia Macro To Define Equality And Hash; k3b cdrom access, OpenSuse 13.1; Week 2

© 2006-2015 Andrew Cooke (site) / post authors (content).

Some Notes on OGL with wxPython

From: "andrew cooke" <andrew@...>

Date: Thu, 8 Jan 2009 17:57:41 -0300 (CLST)

WxPython, the Python binding for WxWindows, whicah calls GTK on Linux, and
which gives fairly nice-looking GUIs, includes a little-documented module
called ogl.

The documentation generated from source is at
http://www.wxpython.org/docs/api/wx.lib.ogl-module.html and there's some
additional notes at http://wiki.wxpython.org/index.cgi/wxOGL

Here's a few more details I just learnt:

- Kind of obvious, but things are drawn in the order provided to
canvas.AddShape(), so supply "top" things last.

- To generate text use a ogl.TextShape.  This is like a RectangleShape, in
that it has a width and height - these form the clipping area.  Add text
to the shape using AddText(...).  You can also add text to other shapes,
but it will be clipped by the boundary (TextShape's boundary is

- To add a line, use ogl.LineShape().  The exact sequence of calls is
tricky, but this seems to work:
  line = ogl.LineShape()
  line.MakeControlPoints(2) # has to be at least 2
  line.SetEnds(x1, y1, x2, y2) # sets the first + last control points
  line.InsertControlPoint(x, y) # see below
  line.SetSplit(True) # for a spline
The InsertControlPoint() adds an additional point in the list of control
points; it is always inserted just before the end (ie (x2, y2) above), so
repeatedly calling this "fills in" the line from start to end.


More wxPython and OGL

From: "andrew cooke" <andrew@...>

Date: Mon, 12 Jan 2009 15:00:51 -0300 (CLST)

Still don't completely "get" this, but here's some more details:

By default, it's possible to drag shapes around on the canvas (mouse left
click and drag).  If a line is from shapeA to shapeB then
  shapeA.AddLine(line, shapeB)
attaches them, so that dragging is coherent (note that the shapes must
already be drawn; the line is drawn "underneath").

Dragging can be disabled by using

Response to clocking etc is mediated via the ShapeEvtHandler.  However
there's something odd with the architecture - Shape inherits from this
class but also has an instance (Shape._eventhandler).  As far as I can
tell the inherited handler is unused and you override fucntinality (to
intercept events etc) by setting the instance handler

However, you cannot just set the handler with a subclass, you must also
define the "previous" event handler to be what was already defined.  In
other words:
  myEventHandler = ....

Whether an object responds to a click or not is defined by the sensitivity
filter.  If the object is insensitive then the event is propagated to the
parent.  This means that if you have one shape on top of another (in my
case, overwritten text) then you can make sure that events detected by the
top layer shape are forwarded by:
  lowerShape = ...
  upperShape = ...

The event handler associated with the lower shape will then receive events
as expected.


Comment on this post