112 lines
3.2 KiB
Python
112 lines
3.2 KiB
Python
"""
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BufferedCanvas -- flicker-free canvas widget
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Copyright (C) 2005, 2006 Daniel Keep, 2011 Duane Johnson
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To use this widget, just override or replace the draw method.
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This will be called whenever the widget size changes, or when
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the update method is explicitly called.
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Please submit any improvements/bugfixes/ideas to the following
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url:
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http://wiki.wxpython.org/index.cgi/BufferedCanvas
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2006-04-29: Added bugfix for a crash on Mac provided by Marc Jans.
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"""
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# Hint: try removing '.sp4msux0rz'
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__author__ = 'Daniel Keep <daniel.keep.sp4msux0rz@gmail.com>'
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__license__ = """
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This file is part of the Printrun suite.
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Printrun is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Printrun is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with Printrun. If not, see <http://www.gnu.org/licenses/>.
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"""
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__all__ = ['BufferedCanvas']
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import wx
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class BufferedCanvas(wx.Panel):
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"""
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Implements a flicker-free canvas widget.
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Standard usage is to subclass this class, and override the
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draw method. The draw method is passed a device context, which
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should be used to do your drawing.
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If you want to force a redraw (for whatever reason), you should
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call the update method. This is because the draw method is never
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called as a result of an EVT_PAINT event.
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"""
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# These are our two buffers. Just be aware that when the buffers
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# are flipped, the REFERENCES are swapped. So I wouldn't want to
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# try holding onto explicit references to one or the other ;)
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buffer = None
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backbuffer = None
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def __init__(self,
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parent,
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ID=-1,
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pos = wx.DefaultPosition,
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size = wx.DefaultSize,
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style = wx.NO_FULL_REPAINT_ON_RESIZE|wx.WANTS_CHARS):
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wx.Panel.__init__(self, parent, ID, pos, size, style)
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# Bind events
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self.Bind(wx.EVT_PAINT, self.onPaint)
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# Disable background erasing (flicker-licious)
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def disable_event(*pargs,**kwargs):
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pass # the sauce, please
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self.Bind(wx.EVT_ERASE_BACKGROUND, disable_event)
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##
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## General methods
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##
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def draw(self, dc, w, h):
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"""
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Stub: called when the canvas needs to be re-drawn.
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"""
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pass
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def update(self):
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"""
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Causes the canvas to be updated.
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"""
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self.Refresh()
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def getWidthHeight(self):
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width, height = self.GetClientSizeTuple()
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if width == 0:
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width = 1
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if height == 0:
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height = 1
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return (width, height)
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##
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## Event handlers
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##
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def onPaint(self, event):
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# Blit the front buffer to the screen
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w, h = self.GetClientSizeTuple()
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if not w or not h:
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return
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else:
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dc = wx.BufferedPaintDC(self)
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self.draw(dc, w, h)
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