gistfile1.txt

from pymt import *

class ScaleManipulation(MTWidget):
    
    def init(self):
        self.register_event_type('on_scale')
        self.touches = []
        self.distance = 0

    def on_scale(self, scale):
        self.parent.width *= scale
        self.parent.height *= scale

    def on_touch_down(self, touch):
        if len(self.touches) < 2:
            touch.grab(self)
            self.touches.append(touch)
        if len(self.touches) == 2:
            self.distance = self.touches[0].distance(self.touches[1])

    def on_touch_move(self, touch):
        if len(self.touches) > 1:
            old_distance = self.distance
            self.distance = self.touches[0].distance(self.touches[1])
            self.dispatch_event('on_scale', self.distance/old_distance)

    def on_touch_up(self, touch):
        if touch in self.touches:
            self.touches.remove(touch)

rect = MTRectangularWidget()
rect.add_widget(ScaleManipulation())

runTouchApp(rect)