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

C[omp]ute

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

Calling C From Fortran 95; Bjork DJ Set; Z3 Example With Python; Week 1; Useful Guide To Starting With IJulia; UK Election + Media; Review: Reinventing Organizations; Inline Assembly With Julia / LLVM; Against the definition of types; Dumb Crypto Paper; The Search For Quasi-Periodicity...; Is There An Alternative To Processing?; CARDIAC (CARDboard Illustrative Aid to Computation); The Bolivian Case Against Chile At The Hague; Clear, Cogent Economic Arguments For Immigration; A Program To Say If I Am Working; Decent Cards For Ill People; New Photo; Luksic And Barrick Gold; President Bachelet's Speech; Baltimore Primer; libxml2 Parsing Stream; configure.ac Recipe For Library Path; The Davalos Affair For Idiots; Not The Onion: Google Fireside Chat w Kissinger; Bicycle Wheels, Inertia, and Energy; Another Tax Fraud; Google's Borg; A Verion That Redirects To Local HTTP Server; Spanish Accents For Idiots; Aluminium Cans; Advice on Spray Painting; Female View of Online Chat From a Male; UX Reading List; S4 Subgroups - Geometric Interpretation; Fucking Email; The SQM Affair For Idiots; Using Kolmogorov Complexity; Oblique Strategies in bash; Curses Tools; Markov Chain Monte Carlo Without all the Bullshit; Email Para Matias Godoy Mercado; The Penta Affair For Idiots; Example Code To Create numpy Array in C; Good Article on Bias in Graphic Design (NYTimes); Do You Backup github?; Data Mining Books; SimpleDateFormat should be synchronized; British Words; Chinese Govt Intercepts External Web To DDOS github; Numbering Permutations; Teenage Engineering - Low Price Synths; GCHQ Can Do Whatever It Wants; Dublinesque; A Cryptographic SAT Solver; Security Challenges; Word Lists for Crosswords; 3D Printing and Speaker Design; Searchable Snowden Archive; XCode Backdoored; Derived Apps Have Malware (CIA); Rowhammer - Hacking Software Via Hardware (DRAM) Bugs; Immutable SQL Database (Kinda); Tor GPS Tracker; That PyCon Dongle Mess...; ASCII Fluid Dynamics; Brandalism; Table of Shifter, Cassette and Derailleur Compatability; Lenovo Demonstrates How Bad HTTPS Is; Telegraph Owned by HSBC; Smaptop - Sunrise (Music); Equation Group (NSA); UK Torture in NI; And - A Natural Extension To Regexps; This Is The Future Of Religion; The Shazam (Music Matching) Algorithm; Tributes To Lesbian Community From AIDS Survivors; Nice Rust Summary; List of Good Fiction Books; Constructing JSON From Postgres (Part 2); Constructing JSON From Postgres (Part 1); Postgres in Docker; Why Poor Places Are More Diverse; Smart Writing on Graceland; Satire in France; Free Speech in France; MTB Cornering - Where Should We Point Our Thrusters?; Secure Secure Shell; Java Generics over Primitives; 2014 (Charlie Brooker); How I am 7; Neural Nets Applied to Go; Programming, Business, Social Contracts; Distributed Systems for Fun and Profit; XML and Scheme; Internet Radio Stations (Curated List); Solid Data About Placebos; Half of Americans Think Climate Change Is a Sign of the Apocalypse; Saturday Surf Sessions With Juvenile Delinquents; Ssh, tty, stdout and stderr; Feathers falling in a vacuum; Santiago 30m Bike Route

© 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
invisible).

- 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.Initialise()
  line.SetSplit(True) # for a spline
  canvas.AddShape(line)
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.

Andrew

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
  shape.SetDraggable(False)

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
(Shape.SetEventHandler).

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 = ....
  myEventHandler.SetPreviousHandler(shape.GetEventHandler())
  shape.SetEventHandler(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 = ...
  canvas.AddShape(lowerShape)
  upperShape = ...
  canvas.AddShape(upperShape)
  upperShape.SetParent(lowerShape)
  upperShape.SetSensitivityFilter(0)

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

Andrew

Comment on this post