graphics.py

# 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)

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.

DOCUMENTATION: For complete documentation, see Chapter 5 of "Python
Programming: An Introduction to Computer Science" by John Zelle,
published by Franklin, Beedle & Associates.  """

# 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
#     Fix Garbage collection of Tkinter images bug.
#     Add ability to set text atttributes.
#     Add Entry boxes.


import Tkinter
tk = Tkinter

from copy import copy

import exceptions

class GraphicsError(exceptions.Exception):
    """Generic error class for graphics module exceptions."""
    def __init__(self, args=None):
        self.args=args

OBJ_ALREADY_DRAWN = "Object currently drawn"
UNSUPPORTED_METHOD = "Object doesn't support operation"
BAD_OPTION = "Illegal option value"


# create an invisible global main root for all windows
_root = tk.Tk()
_root.withdraw()

class GraphWin(tk.Canvas):

    """A GraphWin is a toplevel window for displaying graphics."""
    
    def __init__(self, title="Graphics Window", width=200, height=200):
        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._mouseCallback = None
        self.trans = None
        _root.update()
        
    def setBackground(self, color):
        """Set background color of the window"""
        self.config(bg=color)
        
    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(self.width, self.height, x1, y1, x2, y2)
        
    def close(self):
        """Close the window"""
        self.master.destroy()
        self.quit()
        _root.update()
    
    def plot(self, x, y, color="black"):
        """Set pixel (x,y) to the given color"""
        xs,ys = self.toScreen(x,y)
        self.create_line(xs,ys,xs+1,ys, fill=color)
        _root.update()
        
    def plotPixel(self, x, y, color="black"):
        """Set pixel raw (independent of window coordinates) pixel
        (x,y) to color"""
    	self.create_line(x,y,x+1,y, fill=color)
    	_root.update()
    	
    def flush(self):
        """Update drawing to the window (deprecated)"""
        self.update_idletasks()
        
    def getMouse(self):
        """Wait for mouse click and return Point object representing
        the click"""
        self.mouseX = None
        self.mouseY = None
        while self.mouseX == None or self.mouseY == None:
            self.update()
        x,y = self.toWorld(self.mouseX, self.mouseY)
        return Point(x,y)
    
    def getHeight(self):
        """Return the height of the window"""
        return self.height
        
    def getWidth(self):
        """Return the width of the window"""
        return self.width
    
    def toScreen(self, x, y):
        trans = self.trans
        if trans:
            return self.trans.screen(x,y)
        else:
            return x,y
                      
    def toWorld(self, x, y):
        trans = self.trans
        if trans:
            return self.trans.world(x,y)
        else:
            return x,y
        
    def setMouseHandler(self, func):
        self._mouseCallback = func
        
    def _onClick(self, e):
        self.mouseX = e.x
        self.mouseY = e.y
        if self._mouseCallback:
            self._mouseCallback(Point(e.x, e.y)) 
                      
class Transform:

    """Internal class for 2-D coordinate transformations"""
    
    def __init__(self, w, h, xlow, ylow, xhigh, yhigh):
        # w, h are width and height of window
        # (xlow,ylow) coordinates of lower-left [raw (0,h-1)]
        # (xhigh,yhigh) coordinates of upper-right [raw (w-1,0)]
        xspan = (xhigh-xlow)
        yspan = (yhigh-ylow)
        self.xbase = xlow
        self.ybase = yhigh
        self.xscale = xspan/float(w-1)
        self.yscale = yspan/float(h-1)
        
    def screen(self,x,y):
        # Returns x,y in screen (actually window) coordinates
        xs = (x-self.xbase) / self.xscale
        ys = (self.ybase-y) / self.yscale
        return int(xs+0.5),int(ys+0.5)
        
    def world(self,xs,ys):
        # Returns xs,ys in world coordinates
        x = xs*self.xscale + self.xbase
        y = self.ybase - ys*self.yscale
        return x,y


# Default values for various item configuration options. Only a subset of
#   keys may be present in the configuration dictionary for a given item
DEFAULT_CONFIG = {"fill":"",
		  "outline":"black",
		  "width":"1",
		  "arrow":"none",
		  "text":"",
		  "justify":"center",
                  "font": ("helvetica", 12, "normal")}

class GraphicsObject:

    """Generic base class for all of the drawable objects"""
    # A subclass of GraphicsObject should override _draw and
    #   and _move methods.
    
    def __init__(self, options):
        # options is a list of strings indicating which options are
        # legal for this object.
        
        # When an object is drawn, canvas is set to the GraphWin(canvas)
        #    object where it is drawn and id is the TK identifier of the
        #    drawn shape.
        self.canvas = None
        self.id = None

        # config is the dictionary of configuration options for the widget.
        config = {}
        for option in options:
            config[option] = DEFAULT_CONFIG[option]
        self.config = config
        
    def setFill(self, color):
        """Set interior color to color"""
        self._reconfig("fill", color)
        
    def setOutline(self, color):
        """Set outline color to color"""
        self._reconfig("outline", color)
        
    def setWidth(self, width):
        """Set line weight to width"""
        self._reconfig("width", width)

    def draw(self, graphwin):

        """Draw the object in graphwin, which should be a GraphWin
        object.  A GraphicsObject may only be drawn into one
        window. Raises an error if attempt made to draw an object that
        is already visible."""

        if self.canvas: raise GraphicsError, OBJ_ALREADY_DRAWN
        self.canvas=graphwin
        self.id = self._draw(graphwin, self.config)
        _root.update()

    def undraw(self):

        """Undraw the object (i.e. hide it). Returns silently if the
        object is not currently drawn."""
        
        if not self.canvas: return
        self.canvas.delete(self.id)
        self.canvas = None
        self.id = None
        _root.update()
        
    def move(self, dx, dy):

        """move object dx units in x direction and dy units in y
        direction"""
        
        self._move(dx,dy)
        canvas = self.canvas
        if canvas:
            trans = canvas.trans
            if trans:
                x = dx/ trans.xscale 
                y = -dy / trans.yscale
            else:
                x = dx
                y = dy
            self.canvas.move(self.id, x, y)
        _root.update()
           
    def _reconfig(self, option, setting):
        # Internal method for changing configuration of the object
        # Raises an error if the option does not exist in the config
        #    dictionary for this object
        if not self.config.has_key(option):
            raise GraphicsError, UNSUPPORTED_METHOD
        options = self.config
        options[option] = setting
        if self.canvas: self.canvas.itemconfig(self.id, options)
        _root.update()

    def _draw(self, canvas, options):
        """draws appropriate figure on canvas with options provided
        Returns Tk id of item drawn"""
        pass # must override in subclass

    def _move(self, dx, dy):
        """updates internal state of object to move it dx,dy units"""
        pass # must override in subclass
         
class Point(GraphicsObject):
    def __init__(self, x, y):
        GraphicsObject.__init__(self, ["outline", "fill"])
        self.setFill = self.setOutline
        self.x = x
        self.y = y
        
    def _draw(self, canvas, options):
        x,y = canvas.toScreen(self.x,self.y)
        return canvas.create_rectangle(x,y,x+1,y+1,options)
        
    def _move(self, dx, dy):
        self.x = self.x + dx
        self.y = self.y + dy
        
    def clone(self):
        other = Point(self.x,self.y)
        other.config = self.config
        return other
                
    def getX(self): return self.x
    def getY(self): return self.y

class _BBox(GraphicsObject):
    # Internal base class for objects represented by bounding box
    # (opposite corners) Line segment is a degenerate case.
    
    def __init__(self, p1, p2, options=["outline","width","fill"]):
        GraphicsObject.__init__(self, options)
        self.p1 = p1.clone()
	self.p2 = p2.clone()

    def _move(self, dx, dy):
        self.p1.x = self.p1.x + dx
        self.p1.y = self.p1.y + dy
        self.p2.x = self.p2.x + dx
        self.p2.y = self.p2.y  + dy
                
    def getP1(self): return self.p1

    def getP2(self): return self.p2
    
    def getCenter(self):
        p1 = self.p1
        p2 = self.p2
        return Point((p1.x+p2.x)/2.0, (p1.y+p2.y)/2.0)
    
class Rectangle(_BBox):
    
    def __init__(self, p1, p2):
        _BBox.__init__(self, p1, p2)
    
    def _draw(self, canvas, options):
        p1 = self.p1
        p2 = self.p2
        x1,y1 = canvas.toScreen(p1.x,p1.y)
        x2,y2 = canvas.toScreen(p2.x,p2.y)
        return canvas.create_rectangle(x1,y1,x2,y2,options)
        
    def clone(self):
        other = Rectangle(self.p1, self.p2)
        other.config = self.config
        return other
        
class Oval(_BBox):
    
    def __init__(self, p1, p2):
        _BBox.__init__(self, p1, p2)
        
    def clone(self):
        other = Oval(self.p1, self.p2)
        other.config = self.config
        return other
   
    def _draw(self, canvas, options):
        p1 = self.p1
        p2 = self.p2
        x1,y1 = canvas.toScreen(p1.x,p1.y)
        x2,y2 = canvas.toScreen(p2.x,p2.y)
        return canvas.create_oval(x1,y1,x2,y2,options)
    
class Circle(Oval):
    
    def __init__(self, center, radius):
        p1 = Point(center.x-radius, center.y-radius)
        p2 = Point(center.x+radius, center.y+radius)
        Oval.__init__(self, p1, p2)
        self.radius = radius
        
    def clone(self):
        other = Circle(self.getCenter(), self.radius)
        other.config = self.config
        return other
        
    def getRadius(self):
        return self.radius
              
class Line(_BBox):
    
    def __init__(self, p1, p2):
        _BBox.__init__(self, p1, p2, ["arrow","fill","width"])
        self.setFill(DEFAULT_CONFIG['outline'])
        self.setOutline = self.setFill
   
    def clone(self):
        other = Line(self.p1, self.p2)
        other.config = self.config
        return other
	
    def _draw(self, canvas, options):
        p1 = self.p1
        p2 = self.p2
        x1,y1 = canvas.toScreen(p1.x,p1.y)
        x2,y2 = canvas.toScreen(p2.x,p2.y)
        return canvas.create_line(x1,y1,x2,y2,options)
        
    def setArrow(self, option):
        if not option in ["first","last","both","none"]:
            raise GraphicsError, BAD_OPTION
        self._reconfig("arrow", option)
        

class Polygon(GraphicsObject):
    
    def __init__(self, *points):
        # if points passed as a list, extract it
        if len(points) == 1 and type(points[0] == type([])):
            points = points[0]
        self.points = map(Point.clone, points)
        GraphicsObject.__init__(self, ["outline", "width", "fill"])
        
    def clone(self):
        other = apply(Polygon, self.points)
        other.config = self.config
        return other

    def getPoints(self):
        return map(Point.clone, self.points)

    def _move(self, dx, dy):
        for p in self.points:
            p.move(dx,dy)
   
    def _draw(self, canvas, options):
        args = [canvas]
        for p in self.points:
            x,y = canvas.toScreen(p.x,p.y)
            args.append(x)
            args.append(y)
        args.append(options)
        return apply(GraphWin.create_polygon, args) 

class Text(GraphicsObject):
    
    	def __init__(self, p, text):
    		GraphicsObject.__init__(self, ["justify","fill","text","font"])
    		self.setText(text)
    		self.anchor = p.clone()
    		self.setFill(DEFAULT_CONFIG['outline'])
                self.setOutline = self.setFill
    		
    	def _draw(self, canvas, options):
    		p = self.anchor
    		x,y = canvas.toScreen(p.x,p.y)
    		return canvas.create_text(x,y,options)
    		
    	def _move(self, dx, dy):
    		self.anchor.move(dx,dy)
    		
    	def clone(self):
    		other = Text(self.anchor, self.config['text'])
    		other.config = self.config
    		return other

    	def setText(self,text):
    		self._reconfig("text", text)
    		
    	def getText(self):
    		return self.config["text"]
    	    	
    	def getAnchor(self):
    		return self.anchor.clone()

        def setFace(self, face):
            if face in ['helvetica','arial','courier','times roman']:
                f,s,b = self.config['font']
                self._reconfig("font",(face,s,b))
            else:
                raise GraphicsError, BAD_OPTION

        def setSize(self, size):
            if 5 <= size <= 36:
                f,s,b = self.config['font']
                self._reconfig("font", (f,size,b))
            else:
                raise GraphicsError, BAD_OPTION

        def setStyle(self, style):
            if style in ['bold','normal','italic', 'bold italic']:
                f,s,b = self.config['font']
                self._reconfig("font", (f,s,style))
            else:
                raise GraphicsError, BAD_OPTION

        def setTextColor(self, color):
            self.setFill(color)


class Entry(GraphicsObject):

    def __init__(self, p, width):
        GraphicsObject.__init__(self, [])
        self.anchor = p.clone()
        #print self.anchor
        self.width = width
        self.text = tk.StringVar(_root)
        self.text.set("")
        self.fill = "gray"
        self.color = "black"
        self.font = DEFAULT_CONFIG['font']
        self.entry = None

    def _draw(self, canvas, options):
        p = self.anchor
        x,y = canvas.toScreen(p.x,p.y)
        frm = tk.Frame(canvas.master)
        self.entry = tk.Entry(frm,
                              width=self.width,
                              textvariable=self.text,
                              bg = self.fill,
                              fg = self.color,
                              font=self.font)
        self.entry.pack()
        self.setFill(self.fill)
        return canvas.create_window(x,y,window=frm)

    def getText(self):
        return self.text.get()

    def _move(self, dx, dy):
        self.anchor.move(dx,dy)

    def getAnchor(self):
        return self.anchor.clone()

    def clone(self):
        other = Entry(self.anchor, self.width)
        other.config = self.config
        other.text = tk.StringVar()
        other.text.set(self.text.get())
        other.fill = self.fill
        return other

    def setText(self, t):
        self.text.set(t)
            
    def setFill(self, color):
        self.fill = color
        if self.entry:
            self.entry.config(bg=color)

    def _setFontComponent(self, which, value):
        font = list(self.font)
        font[which] = value
        self.font = tuple(font)
        if self.entry:
            self.entry.config(font=self.font)

    def setFace(self, face):
        if face in ['helvetica','arial','courier','times roman']:
            self._setFontComponent(0, face)
        else:
            raise GraphicsError, BAD_OPTION

    def setSize(self, size):
        if 5 <= size <= 36:
            self._setFontComponent(1,size)
        else:
            raise GraphicsError, BAD_OPTION

    def setStyle(self, style):
        if style in ['bold','normal','italic', 'bold italic']:
            self._setFontComponent(2,style)
        else:
            raise GraphicsError, BAD_OPTION

    def setTextColor(self, color):
        self.color=color
        if self.entry:
            self.entry.config(fg=color)

    		
class Image(GraphicsObject):

    idCount = 0
    imageCache = {}  # keep images here to avoid gc
    
    def __init__(self, p, file=None):
        GraphicsObject.__init__(self, [])
        self.file = file
        self.anchor = p.clone()
        self.imageId = Image.idCount
        Image.idCount = Image.idCount + 1
    		
    def _draw(self, canvas, options):
        p = self.anchor
        x,y = canvas.toScreen(p.x,p.y)
        img = tk.PhotoImage(file=self.file, master=canvas)
        self.imageCache[self.imageId] = img  # save in cache to avoid gc 
        return canvas.create_image(x,y,image=img)
    
    def _move(self, dx, dy):
        self.anchor.move(dx,dy)

    def undraw(self):
        del self.imageCache[self.imageId]  # allow gc of tk photoimage
        GraphicsObject.undraw(self)

    def getAnchor(self):
        return self.anchor.clone()
    		
    def clone(self):
        other = Image(self.anchor, self.file)
        other.config = self.config
        return other
        
def color_rgb(r,g,b):
    """r,g,b are intensities of red, green, and blue in range (0-255)
    Returns color specifier string for the resulting color"""
    return "#%02x%02x%02x" % (r,g,b)

def test():
    win = GraphWin()
    win.setCoords(0,0,10,10)
    t = Text(Point(5,5), "Centered Text")
    t.draw(win)
    p = Polygon(Point(1,1), Point(5,3), Point(2,7))
    p.draw(win)
    e = Entry(Point(5,6), 10)
    e.draw(win)
    win.getMouse()
    p.setFill("red")
    p.setOutline("blue")
    p.setWidth(2)
    s = ""
    for pt in p.getPoints():
        s = s + "(%0.1f,%0.1f) " % (pt.getX(), pt.getY())
    t.setText(e.getText())
    e.setFill("green")
    e.setText("Spam!")
    e.move(2,0)
    win.getMouse()
    p.move(2,3)
    s = ""
    for pt in p.getPoints():
        s = s + "(%0.1f,%0.1f) " % (pt.getX(), pt.getY())
    t.setText(s)
    win.getMouse()
    p.undraw()
    e.undraw()
    t.setStyle("bold")
    win.getMouse()
    t.setStyle("normal")
    win.getMouse()
    t.setStyle("italic")
    win.getMouse()
    t.setStyle("bold italic")
    win.getMouse()
    t.setSize(14)
    win.getMouse()
    t.setFace("arial")
    t.setSize(20)
    win.getMouse()
    win.close()

if __name__ == "__main__":
    test()