draggableImages demo for Pythonista on iOS.

draggableImages.py

# http://omz-forums.appspot.com/pythonista/post/5144563366756352

import random, scene
 
sizeInPixels = 100
 
def rectFromPt(inPoint):  # returns a scene.Rect centered on inPoint
    half = sizeInPixels / 2
    return scene.Rect(inPoint.x - half, inPoint.y - half, sizeInPixels, sizeInPixels)
 
class ImageLayer(scene.Layer):
    def __init__(self, inCenter, inImage):
        super(self.__class__, self).__init__(rectFromPt(inCenter))
        self.image = inImage
        
class MyScene(scene.Scene):
    def __init__(self):
        scene.run(self)  # a self running scene

    def setup(self):
        #centerOfScreen = self.bounds.center()
        thePoint = scene.Point(10 + sizeInPixels / 2, 10 + sizeInPixels / 2)
        images = 'Rabbit_Face Mouse_Face Cat_Face Dog_Face Octopus Bear_Face Chicken Cow_Face'
        images = images.split()
        for image in images:
            scene.load_image(image)
        images *= 2 # go from 8 images to 16
        random.shuffle(images)
        for image in images:
            self.add_layer(ImageLayer(thePoint, image))
            thePoint.x += 10 + sizeInPixels / 3
            thePoint.y = thePoint.x
        self.touchedLayer = None
        
    def draw(self):
        scene.background(0, 0, 0)
        self.root_layer.update(self.dt)
        self.root_layer.draw()
 
    def touch_began(self, touch):
        if touch.layer != self.root_layer:
            self.touchedLayer = touch.layer
 
    def touch_moved(self, touch):
        if self.touchedLayer:
            self.touchedLayer.frame = rectFromPt(touch.location)
 
    def touch_ended(self, touch):
        self.touchedLayer = None
 
MyScene()  # a self running scene