wxPython/demo/GraphicsContext.py

   1
   2 import wx
   3 import colorsys
   4 from math import cos, sin, radians
   5
   6 #----------------------------------------------------------------------
   7
   8 BASE  = 80.0    # sizes used in shapes drawn below
   9 BASE2 = BASE/2
  10 BASE4 = BASE/4
  11
  12
  13 class TestPanel(wx.Panel):
  14     def __init__(self, parent, log):
  15         self.log = log
  16         wx.Panel.__init__(self, parent, -1)
  17
  18         self.Bind(wx.EVT_PAINT, self.OnPaint)
  19
  20     def OnPaint(self, evt):
  21         dc = wx.PaintDC(self)
  22         try:
  23             gc = wx.GraphicsContext.Create(dc)
  24         except NotImplementedError:
  25             dc.DrawText("This build of wxPython does not support the wx.GraphicsContext "
  26                         "family of classes.",
  27                         25, 25)
  28             return
  29
  30         font = wx.SystemSettings.GetFont(wx.SYS_DEFAULT_GUI_FONT)
  31         font.SetWeight(wx.BOLD)
  32         gc.SetFont(font)
  33
  34         # make a path that contains a circle and some lines, centered at 0,0
  35         path = gc.CreatePath()
  36         path.AddCircle(0, 0, BASE2)
  37         path.MoveToPoint(0, -BASE2)
  38         path.AddLineToPoint(0, BASE2)
  39         path.MoveToPoint(-BASE2, 0)
  40         path.AddLineToPoint(BASE2, 0)
  41         path.CloseSubpath()
  42         path.AddRectangle(-BASE4, -BASE4/2, BASE2, BASE4)
  43
  44
  45         # Now use that path to demonstrate various capbilites of the grpahics context
  46         gc.PushState()             # save current translation/scale/other state
  47         gc.Translate(60, 75)       # reposition the context origin
  48
  49         gc.SetPen(wx.Pen("navy", 1))
  50         gc.SetBrush(wx.Brush("pink"))
  51
  52         # show the difference between stroking, filling and drawing
  53         for label, PathFunc in [("StrokePath", gc.StrokePath),
  54                                 ("FillPath",   gc.FillPath),
  55                                 ("DrawPath",   gc.DrawPath)]:
  56             if "wxGTK" in wx.PlatformInfo:
  57                 w, h = dc.GetTextExtent(label) # NYI in Cairo context
  58             else:
  59                 w, h = gc.GetTextExtent(label)
  60
  61             gc.DrawText(label, -w/2, -BASE2-h)
  62             PathFunc(path)
  63             gc.Translate(2*BASE, 0)
  64
  65
  66         gc.PopState()              # restore saved state
  67         gc.PushState()             # save it again
  68         gc.Translate(60, 200)      # offset to the lower part of the window
  69
  70         gc.DrawText("Scale", 0, -BASE2)
  71         gc.Translate(0, 20)
  72
  73         # for testing clipping
  74         #gc.Clip(0, 0, 100, 100)
  75         #rgn = wx.RegionFromPoints([ (0,0), (75,0), (75,25,), (100, 25),
  76         #                            (100,100), (0,100), (0,0)  ])
  77         #gc.ClipRegion(rgn)
  78         #gc.ResetClip()
  79
  80         gc.SetBrush(wx.Brush(wx.Colour(178,  34,  34, 128)))   # 128 == half transparent
  81         for cnt in range(8):
  82             gc.Scale(1.08, 1.08)    # increase scale by 8%
  83             gc.Translate(5,5)
  84             gc.DrawPath(path)
  85
  86
  87         gc.PopState()              # restore saved state
  88         gc.PushState()             # save it again
  89         gc.Translate(400, 200)
  90         gc.DrawText("Rotate", 0, -BASE2)
  91
  92         gc.Translate(0, 75)
  93         for angle in range(0, 360, 30):
  94             gc.PushState()         # save this new current state so we can pop back to
  95                                    # it at the end of the loop
  96             r, g, b = [int(c * 255) for c in colorsys.hsv_to_rgb(float(angle)/360, 1, 1)]
  97             gc.SetBrush(wx.Brush(wx.Colour(r, g, b, 64)))
  98
  99             # use translate to artfully reposition each drawn path
 100             gc.Translate(1.5 * BASE2 * cos(radians(angle)),
 101                          1.5 * BASE2 * sin(radians(angle)))
 102
 103             # use Rotate to rotate the path
 104             gc.Rotate(radians(angle))
 105
 106             # now draw it
 107             gc.DrawPath(path)
 108             gc.PopState()
 109
 110         gc.PopState()
 111
 112
 113 #----------------------------------------------------------------------
 114
 115 def runTest(frame, nb, log):
 116     win = TestPanel(nb, log)
 117     return win
 118
 119 #----------------------------------------------------------------------
 120
 121
 122
 123 overview = """<html><body>
 124 <h2><center>wx.GraphicsContext and wx.GraphicsPath</center></h2>
 125
 126 The new advanced 2D drawing API is implemented via the
 127 wx.GraphicsContext and wx.GraphicsPath classes.  They wrap GDI+ on
 128 Windows, Cairo on wxGTK and CoreGraphics on OS X.  They allow
 129 path-based drawing with alpha-blending and anti-aliasing, and use a
 130 floating point cooridnate system.
 131
 132 <p>When viewing this sample pay attention to how the rounded edges are
 133 smoothed with anti-aliased drawing, and how the shapes on the lower
 134 half of the window are partially transparent, allowing you to see what
 135 was drawn before.
 136
 137 </body></html>
 138 """
 139
 140
 141
 142 if __name__ == '__main__':
 143     import sys,os
 144     import run
 145     run.main(['', os.path.basename(sys.argv[0])] + sys.argv[1:])
 146