Merge

1 files changed, 206 insertions, 0 deletions

diff --git a/events-example3.py b/events-example3.py
new file mode 100755
index 0000000..d21877b
--- /dev/null
+++ b/events-example3.py
@@ -0,0 +1,206 @@
+#!/usr/bin/python
+# events-example3.py
+# Demos timer, mouse, and keyboard events
+
+from tkinter import *
+import math
+import random
+
+class Vector(object):
+    """N-dimensional vector class."""
+    def __init__(self, *components):
+        """Create a vector from its components."""
+        self.components = components
+
+    def __add__(self, other):
+        """Add two vectors."""
+        return self.__class__(
+            *map(lambda xy: xy[0] + xy[1], zip(self.components, other.components))
+        )
+
+    def __sub__(self, other):
+        """Subtract two vectors."""
+        return self.__class__(
+            *map(lambda xy: xy[0] - xy[1], zip(self.components, other.components))
+        )
+
+    def __mul__(self, other):
+        """Multiply a vector by a constant."""
+        return self.__class__(*map(lambda x: x * other, self.components))
+
+    def __rmul__(self, other):
+        """Multiply a constant by a vector."""
+        return self * other
+
+    def __abs__(self):
+        """Return the 2-norm of the vector."""
+        return math.sqrt(sum(map(lambda x: x * x, self.components)))
+
+    def __truediv__(self, scalar):
+        """Return self * 1 / scalar."""
+        return self * (1 / scalar)
+
+    def __eq__(self, other):
+        return self.components == other.components
+
+
+def init(data):
+    data.squareLeft = 50
+    data.squareTop = 0
+    data.squareFill = "red"
+    data.squareSize = 25
+    data.circleCenters = [ ]
+    data.counter = 0
+    data.headingRight = True
+    data.headingDown = True
+    data.isPaused = False
+    data.timerDelay = 50
+
+    data.speed = Vector(10, 0)
+    data.drag = -1
+
+    data.tailAcceleration = Vector(5, 0)
+    data.tailDuration = 2
+    data.tailMoving = False
+    data.tailThreshold = 5
+    data.tailMoveCount = 0
+
+def mousePressed(event, data):
+    newCircleCenter = (event.x, event.y)
+    data.circleCenters.append(newCircleCenter)
+
+def keyPressed(event, data):
+    if (event.char == "d"):
+        if (len(data.circleCenters) > 0):
+            data.circleCenters.pop(0)
+        else:
+            print("No more circles to delete!")
+    elif (event.char == "p"):
+        data.isPaused = not data.isPaused
+    elif (event.char == "s"):
+        doStep(data)
+    if (event.keysym == "Left"):
+        moveLeft(data)
+    elif (event.keysym == "Right"):
+        moveRight(data)
+
+def moveLeft(data):
+    data.squareLeft -= 20
+
+def moveRight(data):
+    data.squareLeft += 20
+
+def moveUp(data):
+    data.squareTop -= 20
+
+def moveDown(data):
+    data.squareTop += 20
+
+def timerFired(data):
+    if (not data.isPaused): doStep(data)
+
+def fixDirection(data, theta=None):
+    if theta is None:
+        theta = random.random() * 2 * math.pi
+    costheta = math.cos(theta)
+    sintheta = math.sin(theta)
+    speedx = data.tailAcceleration.components[0]
+    speedy = data.tailAcceleration.components[1]
+    # From en.wikipedia.org/wiki/Rotation_matrix
+    data.tailAcceleration = Vector(
+        speedx * costheta - speedy * sintheta,
+        speedx * sintheta + speedy * costheta
+    )
+
+def doStep(data):
+    data.counter += 1
+    if random.random() < 1 / 50:
+        fixDirection(data)
+        #print(abs(data.tailAcceleration))
+    data.speed += data.drag * data.speed / abs(data.speed)
+    if abs(data.speed) < data.tailThreshold:
+        data.tailMoving = True
+    if data.tailMoveCount > data.tailDuration:
+        data.tailMoveCount = 0
+        data.tailMoving = False
+    if data.tailMoving:
+        data.speed += data.tailAcceleration
+        data.tailMoveCount += 1
+    data.squareLeft += data.speed.components[0]
+    data.squareTop += data.speed.components[1]
+    if data.squareLeft + data.squareSize > data.width:
+        data.squareLeft = 0
+    if data.squareLeft < 0:
+        data.squareLeft = data.width - data.squareSize
+    if data.squareTop < 0:
+        data.squareTop = data.height - data.squareSize
+    if data.squareTop + data.squareSize > data.height:
+        data.squareTop = 0
+
+def redrawAll(canvas, data):
+    # draw the square
+    canvas.create_rectangle(data.squareLeft,
+                            data.squareTop,
+                            data.squareLeft + data.squareSize,
+                            data.squareTop + data.squareSize,
+                            fill=data.squareFill)
+    # draw the circles
+    for circleCenter in data.circleCenters:
+        (cx, cy) = circleCenter
+        r = 20
+        canvas.create_oval(cx-r, cy-r, cx+r, cy+r, fill="cyan")
+    # draw the text
+    canvas.create_text(150,20,text="events-example3.py")
+    canvas.create_text(150,40,text="Mouse clicks create circles")
+    canvas.create_text(150,60,text="Pressing 'd' deletes circles")
+    canvas.create_text(150,80,text="Pressing 'p' pauses/unpauses timer")
+    canvas.create_text(150,100,text="Pressing 's' steps the timer once")
+    canvas.create_text(150,120,text="Left arrow moves square left")
+    canvas.create_text(150,140,text="Right arrow moves square right")
+    canvas.create_text(150,160,text="Timer changes color of square")
+
+####################################
+# use the run function as-is
+####################################
+
+def run(width=300, height=300):
+    def redrawAllWrapper(canvas, data):
+        canvas.delete(ALL)
+        redrawAll(canvas, data)
+        canvas.update()    
+
+    def mousePressedWrapper(event, canvas, data):
+        mousePressed(event, data)
+        redrawAllWrapper(canvas, data)
+
+    def keyPressedWrapper(event, canvas, data):
+        keyPressed(event, data)
+        redrawAllWrapper(canvas, data)
+
+    def timerFiredWrapper(canvas, data):
+        timerFired(data)
+        redrawAllWrapper(canvas, data)
+        # pause, then call timerFired again
+        canvas.after(data.timerDelay, timerFiredWrapper, canvas, data)
+    # Set up data and call init
+    class Struct(object): pass
+    data = Struct()
+    data.width = width
+    data.height = height
+    data.timerDelay = 100 # milliseconds
+    init(data)
+    # create the root and the canvas
+    root = Tk()
+    canvas = Canvas(root, width=data.width, height=data.height)
+    canvas.pack()
+    # set up events
+    root.bind("<Button-1>", lambda event:
+                            mousePressedWrapper(event, canvas, data))
+    root.bind("<Key>", lambda event:
+                            keyPressedWrapper(event, canvas, data))
+    timerFiredWrapper(canvas, data)
+    # and launch the app
+    root.mainloop()  # blocks until window is closed
+    print("bye!")
+
+run(600, 1000)