wxPython/wx/lib/colourchooser/pycolourslider.py

   1 """
   2 wxPyColourChooser
   3 Copyright (C) 2002 Michael Gilfix
   4
   5 This file is part of wxPyColourChooser.
   6
   7 You should have received a file COPYING containing license terms
   8 along with this program; if not, write to Michael Gilfix
   9 (mgilfix@eecs.tufts.edu) for a copy.
  10
  11 This version of wxPyColourChooser is open source; you can redistribute it and/or
  12 modify it under the terms listed in the file COPYING.
  13
  14 This program is distributed in the hope that it will be useful,
  15 but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  17 """
  18
  19 import canvas
  20 import colorsys
  21 from wxPython.wx import *
  22
  23 class PyColourSlider(canvas.Canvas):
  24     """A Pure-Python Colour Slider
  25
  26     The colour slider displays transitions from value 0 to value 1 in
  27     HSV, allowing the user to select a colour within the transition
  28     spectrum.
  29
  30     This class is best accompanying by a wxSlider that allows the user
  31     to select a particular colour shade.
  32     """
  33
  34     HEIGHT = 172
  35     WIDTH = 12
  36
  37     def __init__(self, parent, id, colour=None):
  38         """Creates a blank slider instance. A colour must be set before the
  39         slider will be filled in."""
  40         # Set the base colour first since our base class calls the buffer
  41         # drawing function
  42         self.SetBaseColour(colour)
  43
  44         canvas.Canvas.__init__(self, parent, id,
  45                                 size=wxSize(self.WIDTH, self.HEIGHT))
  46
  47     def SetBaseColour(self, colour):
  48         """Sets the base, or target colour, to use as the central colour
  49         when calculating colour transitions."""
  50         self.base_colour = colour
  51
  52     def GetBaseColour(self):
  53         """Return the current colour used as a colour base for filling out
  54         the slider."""
  55         return self.base_colour
  56
  57     def GetValue(self, pos):
  58         """Returns the colour value for a position on the slider. The position
  59         must be within the valid height of the slider, or results can be
  60         unpredictable."""
  61         return self.buffer.GetPixel((0, pos))
  62
  63     def DrawBuffer(self):
  64         """Actual implementation of the widget's drawing. We simply draw
  65         from value 0.0 to value 1.0 in HSV."""
  66         if self.base_colour is None:
  67             return
  68
  69         target_red = self.base_colour.Red()
  70         target_green = self.base_colour.Green()
  71         target_blue = self.base_colour.Blue()
  72
  73         h,s,v = colorsys.rgb_to_hsv(target_red / 255.0, target_green / 255.0,
  74                                     target_blue / 255.0)
  75         v = 1.0
  76         vstep = 1.0 / self.HEIGHT
  77         for y_pos in range(0, self.HEIGHT):
  78             r,g,b = [c * 255.0 for c in colorsys.hsv_to_rgb(h,s,v)]
  79             colour = wxColour(int(r), int(g), int(b))
  80             self.buffer.SetPen(wxPen(colour, 1, wxSOLID))
  81             self.buffer.DrawRectangle((0, y_pos), (15, 1))
  82             v = v - vstep