wxPython/wx/lib/floatcanvas/__init__.py

   1 """
   2 This is the floatcanvas package. It provides two primary modules, and a
   3 support module.
   4
   5 FloatCanvas.py contains the main FloatCanvas class, and its supporting
   6 classes.  NavCanvas.py contains a wrapper for the FloatCanvas that
   7 provides the canvas and a toolbar with tools that allow you to navigate
   8 the canvas (zooming, panning, etc.)  Resources.py is a module that
   9 contains a few resources required by the FloatCanvas (icons, etc)
  10
  11 The FloatCanvas is a high level window for drawing maps and anything
  12 else in an arbitrary coordinate system.
  13
  14 The goal is to provide a convenient way to draw stuff on the screen
  15 without having to deal with handling OnPaint events, converting to pixel
  16 coordinates, knowing about wxWindows brushes, pens, and colors, etc. It
  17 also provides virtually unlimited zooming and scrolling
  18
  19 I am using it for two things:
  20 1) general purpose drawing in floating point coordinates
  21 2) displaying map data in Lat-long coordinates
  22
  23 If the projection is set to None, it will draw in general purpose
  24 floating point coordinates. If the projection is set to 'FlatEarth', it
  25 will draw a FlatEarth projection, centered on the part of the map that
  26 you are viewing. You can also pass in your own projection function.
  27
  28 It is double buffered, so re-draws after the window is uncovered by
  29 something else are very quick.
  30
  31 It relies on NumPy, which is needed for speed (maybe, I haven't profiled
  32 properly) and convenience.
  33
  34 Bugs and Limitations: Lots: patches, fixes welcome
  35
  36 For Map drawing: It ignores the fact that the world is, in fact, a
  37 sphere, so it will do strange things if you are looking at stuff near
  38 the poles or the date line. so far I don't have a need to do that, so I
  39 havn't bothered to add any checks for that yet.
  40
  41 Zooming: I have set no zoom limits. What this means is that if you zoom
  42 in really far, you can get integer overflows, and get weird results. It
  43 doesn't seem to actually cause any problems other than weird output, at
  44 least when I have run it.
  45
  46 Speed: I have done a couple of things to improve speed in this app. The
  47 one thing I have done is used NumPy Arrays to store the coordinates of
  48 the points of the objects. This allowed me to use array oriented
  49 functions when doing transformations, and should provide some speed
  50 improvement for objects with a lot of points (big polygons, polylines,
  51 pointsets).
  52
  53 The real slowdown comes when you have to draw a lot of objects, because
  54 you have to call the wx.DC.DrawSomething call each time. This is plenty
  55 fast for tens of objects, OK for hundreds of objects, but pretty darn
  56 slow for thousands of objects.
  57
  58 If you are zoomed in, it checks the Bounding box of an object before
  59 drawing it. This makes it a great deal faster when there are a lot of
  60 objects and you are zoomed in so that only a few are shown.
  61
  62 Mouse Events:
  63
  64 There are a full set of custom mouse events. They are just like the
  65 regular mouse events, but include an extra attribute: Event.GetCoords(),
  66 that returns the (x,y) position in world coordinates, as a length-2
  67 NumPy vector of Floats.
  68
  69 There are also a full set of bindings to mouse events on objects, so
  70 that you can specify a given function be called when an object is
  71 clicked, mouse-over'd, etc.
  72
  73 See the Demo for what it can do, and how to use it.
  74
  75 Copyright: Christopher Barker
  76 License: Same as the version of wxPython you are using it with.
  77
  78 TRAC site for some docs and updates:
  79 http://morticia.cs.dal.ca/FloatCanvas/
  80
  81 SVN for latest code:
  82 svn://morticia.cs.dal.ca/FloatCanvas
  83
  84 Mailing List:
  85 http://mail.mithis.com/cgi-bin/mailman/listinfo/floatcanvas
  86
  87 Check for updates or answers to questions, send me an email.
  88 Please let me know if you're using this!!!
  89 Contact me at:
  90
  91 Chris.Barker@noaa.gov
  92
  93 """
  94
  95 __version__ = "0.9.18"
  96
  97