graphics.zip

# graphics.py """Simple object oriented graphics library The library is designed to make it very easy for novice programmers to experiment with computer graphics in an object oriented fashion. It is written by John Zelle for use with the book "Python Programming: An Introduction to Computer Science" (Franklin, Beedle & Associates). LICENSE: This is open-source software released under the terms of the GPL (http://www.gnu.org/licenses/gpl.html). PLATFORMS: The package is a wrapper around Tkinter and should run on any platform where Tkinter is available. INSTALLATION: Put this file somewhere where Python can see it. OVERVIEW: There are two kinds of objects in the library. The GraphWin class implements a window where drawing can be done and various GraphicsObjects are provided that can be drawn into a GraphWin. As a simple example, here is a complete program to draw a circle of radius 10 centered in a 100x100 window: -------------------------------------------------------------------- from graphics import * def main(): win = GraphWin("My Circle", 100, 100) c = Circle(Point(50,50), 10) c.draw(win) win.getMouse() # Pause to view result win.close() # Close window when done main() -------------------------------------------------------------------- GraphWin objects support coordinate transformation through the setCoords method and pointer-based input through getMouse. The library provides the following graphical objects: Point Line Circle Oval Rectangle Polygon Text Entry (for text-based input) Image Various attributes of graphical objects can be set such as outline-color, fill-color and line-width. Graphical objects also support moving and hiding for animation effects. The library also provides a very simple class for pixel-based image manipulation, Pixmap. A pixmap can be loaded from a file and displayed using an Image object. Both getPixel and setPixel methods are provided for manipulating the image. DOCUMENTATION: For complete documentation, see Chapter 4 of "Python Programming: An Introduction to Computer Science" by John Zelle, published by Franklin, Beedle & Associates. Also see http://mcsp.wartburg.edu/zelle/python for a quick reference""" # Version 4.1 12/29/2009 # * Merged Pixmap and Image class. Old Pixmap removed, use Image. # Version 4.0.1 10/08/2009 # * Modified the autoflush on GraphWin to default to True # * Autoflush check on close, setBackground # * Fixed getMouse to flush pending clicks at entry # Version 4.0 08/2009 # * Reverted to non-threaded version. The advantages (robustness, # efficiency, ability to use with other Tk code, etc.) outweigh # the disadvantage that interactive use with IDLE is slightly more # cumbersome. # * Modified to run in either Python 2.x or 3.x (same file). # * Added Image.getPixmap() # * Added update() -- stand alone function to cause any pending # graphics changes to display. # # Version 3.4 10/16/07 # Fixed GraphicsError to avoid "exploded" error messages. # Version 3.3 8/8/06 # Added checkMouse method to GraphWin # Version 3.2.3 # Fixed error in Polygon init spotted by Andrew Harrington # Fixed improper threading in Image constructor # Version 3.2.2 5/30/05 # Cleaned up handling of exceptions in Tk thread. The graphics package # now raises an exception if attempt is made to communicate with # a dead Tk thread. # Version 3.2.1 5/22/05 # Added shutdown function for tk thread to eliminate race-condition # error "chatter" when main thread terminates # Renamed various private globals with _ # Version 3.2 5/4/05 # Added Pixmap object for simple image manipulation. # Version 3.1 4/13/05 # Improved the Tk thread communication so that most Tk calls # do not have to wait for synchonization with the Tk thread. # (see _tkCall and _tkExec) # Version 3.0 12/30/04 # Implemented Tk event loop in separate thread. Should now work # interactively with IDLE. Undocumented autoflush feature is # no longer necessary. Its default is now False (off). It may # be removed in a future version. # Better handling of errors regarding operations on windows that # have been closed. # Addition of an isClosed method to GraphWindow class. # Version 2.2 8/26/04 # Fixed cloning bug reported by Joseph Oldham. # Now implements deep copy of config info. # Version 2.1 1/15/04 # Added autoflush option to GraphWin. When True (default) updates on # the window are done after each action. This makes some graphics # intensive programs sluggish. Turning off autoflush causes updates # to happen during idle periods or when flush is called. # Version 2.0 # Updated Documentation # Made Polygon accept a list of Points in constructor # Made all drawing functions call TK update for easier animations # and to make the overall package work better with # Python 2.3 and IDLE 1.0 under Windows (still some issues). # Removed vestigial turtle graphics. # Added ability to configure font for Entry objects (analogous to Text) # Added setTextColor for Text as an alias of setFill # Changed to class-style exceptions # Fixed cloning of Text objects # Version 1.6 # Fixed Entry so StringVar uses _root as master, solves weird # interaction with shell in Idle # Fixed bug in setCoords. X and Y coordinates can increase in # "non-intuitive" direction. # Tweaked wm_protocol so window is not resizable and kill box closes. # Version 1.5 # Fixed bug in Entry. Can now define entry before creating a # GraphWin. All GraphWins are now toplevel windows and share # a fixed root (called _root). # Version 1.4 # Fixed Garbage collection of Tkinter images bug. # Added ability to set text atttributes. # Added Entry boxes. import time, os, sys try: # import as appropriate for 2.x vs. 3.x import tkinter as tk except: import Tkinter as tk ########################################################################## # Module Exceptions class GraphicsError(Exception): """Generic error class for graphics module exceptions.""" pass OBJ_ALREADY_DRAWN = "Object currently drawn" UNSUPPORTED_METHOD = "Object doesn't support operation" BAD_OPTION = "Illegal option value" DEAD_THREAD = "Graphics thread quit unexpectedly" _root = tk.Tk() _root.withdraw() def update(): _root.update() ############################################################################ # Graphics classes start here class GraphWin(tk.Canvas): """A GraphWin is a toplevel window for displaying graphics.""" def __init__(self, title="Graphics Window", width=200, height=200, autoflush=True): master = tk.Toplevel(_root) master.protocol("WM_DELETE_WINDOW", self.close) tk.Canvas.__init__(self, master, width=width, height=height) self.master.title(title) self.pack() master.resizable(0,0) self.foreground = "black" self.items = [] self.mouseX = None self.mouseY = None self.bind("<Button-1>", self._onClick) self.height = height self.width = width self.autoflush = autoflush self._mouseCallback = None self.trans = None self.closed = False master.lift() if autoflush: _root.update() def __checkOpen(self): if self.closed: raise GraphicsError("window is closed") def setBackground(self, color): """Set background color of the window""" self.__checkOpen() self.config(bg=color) self.__autoflush() def setCoords(self, x1, y1, x2, y2): """Set coordinates of window to run from (x1,y1) in the lower-left corner to (x2,y2) in the upper-right corner.""" self.trans = Transform(s