Fix "warning: operation on 'y' may be undefined".

[wxWidgets.git] / wxPython / wx / lib / colourchooser / canvas.py

diff --git a/wxPython/wx/lib/colourchooser/canvas.py b/wxPython/wx/lib/colourchooser/canvas.py
index 829909b48e6685afe0377f97e541cbf4fbe8b687..d505ac344b061785a7bb33178351c550bfae6b92 100644 (file)
--- a/wxPython/wx/lib/colourchooser/canvas.py
+++ b/wxPython/wx/lib/colourchooser/canvas.py
@@ -1,11 +1,130 @@
+"""
+PyColourChooser
+Copyright (C) 2002 Michael Gilfix <mgilfix@eecs.tufts.edu>

 
 

-"""Renamer stub: provides a way to drop the wx prefix from wxPython objects."""
+This file is part of PyColourChooser.

 
 

-__cvsid__ = "$Id$"
-__revision__ = "$Revision$"[11:-2]
+This version of PyColourChooser is open source; you can redistribute it
+and/or modify it under the licensed terms.

 
 

-from wx import _rename
-from wxPython.lib.colourchooser import canvas
-_rename(globals(), canvas.__dict__, modulename='lib.colourchooser.canvas')
-del canvas
-del _rename
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+"""
+
+# 12/14/2003 - Jeff Grimmett (grimmtooth@softhome.net)
+#
+# o 2.5 compatability update.
+#
+# 12/21/2003 - Jeff Grimmett (grimmtooth@softhome.net)
+#
+# o wxPyColorChooser -> PyColorChooser
+# o wxPyColourChooser -> PyColourChooser
+#
+
+import  wx
+
+class BitmapBuffer(wx.MemoryDC):
+    """A screen buffer class.
+
+    This class implements a screen output buffer. Data is meant to
+    be drawn in the buffer class and then blitted directly to the
+    output device, or on-screen window.
+    """
+    def __init__(self, width, height, colour):
+        """Initialize the empty buffer object."""
+        wx.MemoryDC.__init__(self)
+
+        self.width = width
+        self.height = height
+        self.colour = colour
+
+        self.bitmap = wx.EmptyBitmap(self.width, self.height)
+        self.SelectObject(self.bitmap)
+
+        # Initialize the buffer to the background colour
+        self.SetBackground(wx.Brush(self.colour, wx.SOLID))
+        self.Clear()
+
+        # Make each logical unit of the buffer equal to 1 pixel
+        self.SetMapMode(wx.MM_TEXT)
+
+    def GetBitmap(self):
+        """Returns the internal bitmap for direct drawing."""
+        return self.bitmap
+
+class Canvas(wx.Window):
+    """A canvas class for arbitrary drawing.
+
+    The Canvas class implements a window that allows for drawing
+    arbitrary graphics. It implements a double buffer scheme and
+    blits the off-screen buffer to the window during paint calls
+    by the windowing system for speed.
+
+    Some other methods for determining the canvas colour and size
+    are also provided.
+    """
+    def __init__(self, parent, id,
+                 pos=wx.DefaultPosition,
+                 size=wx.DefaultSize,
+                 style=wx.SIMPLE_BORDER):
+        """Creates a canvas instance and initializes the off-screen
+        buffer. Also sets the handler for rendering the canvas
+        automatically via size and paint calls from the windowing
+        system."""
+        wx.Window.__init__(self, parent, id, pos, size, style)
+
+        # Perform an intial sizing
+        self.ReDraw()
+
+        # Register event handlers
+        self.Bind(wx.EVT_SIZE, self.onSize)
+        self.Bind(wx.EVT_PAINT, self.onPaint)
+
+    def MakeNewBuffer(self):
+        size = self.GetSize()
+        self.buffer = BitmapBuffer(size[0], size[1],
+                                   self.GetBackgroundColour())
+
+    def onSize(self, event):
+        """Perform actual redraw to off-screen buffer only when the
+        size of the canvas has changed. This saves a lot of computation
+        since the same image can be re-used, provided the canvas size
+        hasn't changed."""
+        self.MakeNewBuffer()
+        self.DrawBuffer()
+        self.Refresh()
+
+    def ReDraw(self):
+        """Explicitly tells the canvas to redraw it's contents."""
+        self.onSize(None)
+
+    def Refresh(self):
+        """Re-draws the buffer contents on-screen."""
+        dc = wx.ClientDC(self)
+        self.Blit(dc)
+
+    def onPaint(self, event):
+        """Renders the off-screen buffer on-screen."""
+        dc = wx.PaintDC(self)
+        self.Blit(dc)
+
+    def Blit(self, dc):
+        """Performs the blit of the buffer contents on-screen."""
+        width, height = self.buffer.GetSize()
+        dc.BeginDrawing()
+        dc.Blit(0, 0, width, height, self.buffer, 0, 0)
+        dc.EndDrawing()
+
+    def GetBoundingRect(self):
+        """Returns a tuple that contains the co-ordinates of the
+        top-left and bottom-right corners of the canvas."""
+        x, y = self.GetPosition()
+        w, h = self.GetSize()
+        return(x, y + h, x + w, y)
+
+    def DrawBuffer(self):
+        """Actual drawing function for drawing into the off-screen
+        buffer. To be overrideen in the implementing class. Do nothing
+        by default."""
+        pass