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         gc = wx.GraphicsContext.Create(dc)
  23
  24         font = wx.SystemSettings.GetFont(wx.SYS_DEFAULT_GUI_FONT)
  25         font.SetWeight(wx.BOLD)
  26         gc.SetFont(font)
  27
  28         # make a path that contains a circle and some lines, centered at 0,0
  29         path = gc.CreatePath()
  30         path.AddCircle(0, 0, BASE2)
  31         path.MoveToPoint(0, -BASE2)
  32         path.AddLineToPoint(0, BASE2)
  33         path.MoveToPoint(-BASE2, 0)
  34         path.AddLineToPoint(BASE2, 0)
  35         path.CloseSubpath()
  36         path.AddRectangle(-BASE4, -BASE4/2, BASE2, BASE4)
  37
  38
  39         # Now use that path to demonstrate various capbilites of the grpahics context
  40         gc.PushState()             # save current translation/scale/other state
  41         gc.Translate(60, 75)       # reposition the context origin
  42
  43         gc.SetPen(wx.Pen("navy", 1))
  44         gc.SetBrush(wx.Brush("pink"))
  45
  46         # show the difference between stroking, filling and drawing
  47         for label, PathFunc in [("StrokePath", gc.StrokePath),
  48                                 ("FillPath",   gc.FillPath),
  49                                 ("DrawPath",   gc.DrawPath)]:
  50             if "wxGTK" in wx.PlatformInfo:
  51                 w, h = dc.GetTextExtent(label) # NYI in Cairo context
  52             else:
  53                 w, h = gc.GetTextExtent(label)
  54
  55             gc.DrawText(label, -w/2, -BASE2-h)
  56             PathFunc(path)
  57             gc.Translate(2*BASE, 0)
  58
  59
  60         gc.PopState()              # restore saved state
  61         gc.PushState()             # save it again
  62         gc.Translate(60, 200)      # offset to the lower part of the window
  63
  64         gc.DrawText("Scale", 0, -BASE2)
  65         gc.Translate(0, 20)
  66
  67         gc.SetBrush(wx.Brush(wx.Colour(178,  34,  34, 128)))   # 128 == half transparent
  68         for cnt in range(8):
  69             gc.Scale(1.08, 1.08)    # increase scale by 8%
  70             gc.Translate(5,5)
  71             gc.DrawPath(path)
  72
  73
  74         gc.PopState()              # restore saved state
  75         gc.PushState()             # save it again
  76         gc.Translate(400, 200)
  77         gc.DrawText("Rotate", 0, -BASE2)
  78
  79         gc.Translate(0, 75)
  80         for angle in range(0, 360, 30):
  81             gc.PushState()         # save this new current state so we can pop back to
  82                                    # it at the end of the loop
  83             r, g, b = [int(c * 255) for c in colorsys.hsv_to_rgb(float(angle)/360, 1, 1)]
  84             gc.SetBrush(wx.Brush(wx.Colour(r, g, b, 64)))
  85
  86             # use translate to artfully reposition each drawn path
  87             gc.Translate(1.5 * BASE2 * cos(radians(angle)),
  88                          1.5 * BASE2 * sin(radians(angle)))
  89
  90             # use Rotate to rotate the path
  91             gc.Rotate(radians(angle))
  92
  93             # now draw it
  94             gc.DrawPath(path)
  95             gc.PopState()
  96
  97         gc.PopState()
  98
  99
 100 #----------------------------------------------------------------------
 101
 102 def runTest(frame, nb, log):
 103     win = TestPanel(nb, log)
 104     return win
 105
 106 #----------------------------------------------------------------------
 107
 108
 109
 110 overview = """<html><body>
 111 <h2><center>wx.GraphicsContext and wx.GraphicsPath</center></h2>
 112
 113 The new advanced 2D drawing API is implemented via the
 114 wx.GraphicsContext and wx.GraphicsPath classes.  They wrap GDI+ on
 115 Windows, Cairo on wxGTK and CoreGraphics on OS X.  They allow
 116 path-based drawing with alpha-blending and anti-aliasing, and use a
 117 floating point cooridnate system.
 118
 119 <p>When viewing this sample pay attention to how the rounded edges are
 120 smoothed with anti-aliased drawing, and how the shapes on the lower
 121 half of the window are partially transparent, allowing you to see what
 122 was drawn before.
 123
 124 </body></html>
 125 """
 126
 127
 128
 129 if __name__ == '__main__':
 130     import sys,os
 131     import run
 132     run.main(['', os.path.basename(sys.argv[0])] + sys.argv[1:])
 133