test/widgets.py

   1 """
   2 --------------------------------------------------------------------------------
   3 widgets.py - S.Fourmanoit <syfou@users.sourceforge.net>, 2005
   4
   5 This shows a simple way to use Python object-orientedness to implement a
   6 simple MVC (Model-View-Control) model, usable with adesklets to implements
   7 easy to use widgets.
   8
   9 The beauty of this code is that, while being compact (the core Widget class
  10 is seventeen lines of code), it gives a way to dynamically create and modify
  11 an arbitrary tree of small graphical elements (widgets) embedding at the
  12 same place all their data and the methods needed to display them.
  13 --------------------------------------------------------------------------------
  14 """
  15 #-------------------------------------------------------------------------------
  16 class Widget(list):
  17     """
  18     Simple class creating a generic widget that can have any numbers
  19     of descendants, storable in a tree-like structure. It implements:
  20
  21     - A breadth first iterator, usable to visit a complete widget tree
  22     or subtree in top to bottom, first to last child order (a widget can
  23     also contain non widget-derived objects -- they will simply be skipped
  24     by the irerator).
  25
  26     - A 'static' config class attribute that can be used to store
  27     a configuration shared by all instances of Widget, or
  28     Widget derivated classes.
  29
  30     - An 'execute' function, that can be used as a shortcut to __iter__
  31     to perform arbitrary code execution on a whole widget tree.
  32
  33     Obviously, this is completely independent from adesklets...
  34     """
  35     __name = None
  36     config = {}
  37
  38     def __init__(self,config=None):
  39         if not config is None:
  40             Widget.config=config
  41
  42     def __iter__(self):
  43         yield self
  44         for elem in list.__iter__(self):
  45             if hasattr(elem,'_Widget__name'):
  46                 for child in elem.__iter__():
  47                     yield child
  48
  49     def execute(self, func, args=[]):
  50         for widget in self:
  51             widget.__getattribute__(func)(*args)
  52
  53 #-------------------------------------------------------------------------------
  54 # Now, as a demonstration, let's create a few very simple classes derived
  55 # from Widget able to specifically deal with adesklets.
  56 #
  57 # Here, we always create a 'draw' method in every one of them, that can be used
  58 # later on to display the element using 'execute' from the root widget element.
  59 # Real-life widgets would probably create at least two methods for this
  60 # (one writing to foreground and the other one to background),
  61 # that would be used appropriately (or arguments would be used).
  62 #
  63 import adesklets
  64
  65 class Box(Widget):
  66     """ Box widget"""
  67     def __init__(self,coords):
  68         Widget.__init__(self)
  69         self.coords=coords
  70     def draw(self):
  71         adesklets.context_set_color(0,0,0,0)
  72         adesklets.context_set_blend(False)
  73         adesklets.image_fill_rectangle(*self.coords)
  74         adesklets.context_set_blend(True)
  75         adesklets.context_set_color(*self.config['box_color'])
  76         adesklets.image_draw_rectangle(*self.coords)
  77
  78 class Text(Widget):
  79     """ Text label widget"""
  80     def __init__(self,coords, text):
  81         Widget.__init__(self)
  82         self.coords=coords
  83         self.text=text
  84     def draw(self):
  85         font=adesklets.load_font(self.config['text_font'])
  86         adesklets.context_set_font(font)
  87         adesklets.context_set_color(*self.config['text_color'])
  88         adesklets.text_draw(self.coords[0],self.coords[1],self.text)
  89         adesklets.free_font(font)
  90     def size(self):
  91         font=adesklets.load_font(self.config['text_font'])
  92         adesklets.context_set_font(font)
  93         result=adesklets.get_text_size(self.text)
  94         adesklets.free_font(font)
  95         return result
  96     def __str__(self):
  97         return "<Text label at %s, being '%s'>" % (self.coords, self.text)
  98
  99 class BoxedText(Widget):
 100     """Compound boxed text widget"""
 101     def __init__(self,coords,text):
 102         Widget.__init__(self)
 103         t=Text(coords,text)
 104         self.append(Box(coords + list(t.size())))
 105         self.append(t)
 106     def draw(self):
 107         pass
 108
 109 class Canva(Widget):
 110     """Root widget"""
 111     def draw(self):
 112         pass
 113
 114 #-------------------------------------------------------------------------------
 115 # Utility functions
 116 #
 117 from signal import pause
 118 from random import randint
 119
 120 def rcoords():
 121     """Iterator generating pseudo-random (x, y) coordinates in [0,100]"""
 122     while 1:
 123         yield [randint(0,100),randint(0,100)]
 124
 125 #-------------------------------------------------------------------------------
 126 # Main routine
 127 # ============
 128
 129 # Here is the configuration: of course, it could as well be an
 130 # adesklets.ConfigFile class or anything else.
 131 #
 132 config = { 'text_font' : 'Vera/20', 'text_color' : [0,255,0,200] ,
 133            'box_color': [255,255,255,200] }
 134
 135 # Create dynamically a bunch of randomly positionned widgets
 136 #
 137 canva=Canva(config)
 138 for coords, caption in zip(rcoords(),'Some text to put on screen'.split()):
 139     canva.append(BoxedText(coords,caption))
 140
 141 # Set up adesklets
 142 #
 143 adesklets.window_resize(150,150)
 144 adesklets.window_set_transparency(True)
 145 adesklets.window_reset(adesklets.WINDOW_MANAGED)
 146 adesklets.window_show()
 147
 148 # Now let's draw everything once...
 149 #
 150 canva.execute('draw')
 151
 152 # ... Printout all existing Text widget properties descending from
 153 # our root 'window' desklet, just to show off...
 154 #
 155 for widget in canva:
 156     if widget.__class__ is Text:
 157         print widget
 158
 159 # ... and finally, sleep forever.
 160 #
 161 pause()
 162
 163 #-------------------------------------------------------------------------------