Q:

How to rotate two rectangle widgets independently on single screen in kivy?

I am learning programming in python and working on one simple gaming application in which I need to rotate two rectangles on click on them on single screen but what's happening is when I am clicking on one of them both the rectangles rotate along the origin of that rectangle that is being clicked but this is not the case with another rectangle, in fact its position is not also that that is supposed to be and when clicking on the assigned position(where that rectangle is not present) it gets rotated without rotating both the rectangles. I just need to rotate both the rectangles on clicking independently. 
    It is difficult to explain it so please try to execute the code and find whats happening.
from kivy.app import App
from kivy.graphics import Rotate, Rectangle, Ellipse, Color
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen, CardTransition
from kivy.uix.widget import Widget
from kivy.properties import ObjectProperty, NumericProperty, ReferenceListProperty, ListProperty
from kivy.uix.floatlayout import FloatLayout

Builder.load_string('''

<Stage_2>:
    object2: Object2
    object3: Object3

    Object2:
        id: Object2
        center: self.rotate_origin

    Object3:
        id: Object3
        center: self.rotate_origin

<Manager>:
    id: screen_manager

    Screen:
        name:"P"
        FloatLayout:

            Button:
                pos_hint:{"x":0.2,"y":0.05}
                size_hint: 0.6, 0.2
                font_size: (root.width**2 + root.height**2) / 13**4
                text: "Play"
                background_color: 255,0,1,1
                on_release:
                    root.transition.direction = "up"        
                    root.current = "stage2"

    Screen:
        name: 'stage2'
        Stage_2:
            id:s2

''')

class Object2(Widget):
    def __init__(self, *args, **kwargs):
        Widget.__init__(self, *args, **kwargs)
        self.rect_pos_x = 500
        self.rect_pos_y = 425
        self.rect_pos = self.rect_pos_x, self.rect_pos_y
        self.rect_width = 150
        self.rect_height = 30
        self.rect_size = self.rect_width, self.rect_height
        self.rotate_origin_x = self.rect_pos_x + self.rect_width / 2
        self.rotate_origin_y = self.rect_pos_y + self.rect_height / 2
        self.rotate_origin = self.rotate_origin_x, self.rotate_origin_y
        self.angle = 135
        print('rect 1')
        with self.canvas:
            Rotate(origin=self.rotate_origin, angle=self.angle)
            Color(rgb=(0,197,68))
            Rectangle(pos=self.rect_pos, size=self.rect_size)

    def rotate(self):
        self.canvas.clear()
        self.angle += 90
        if (self.angle > 315):
            self.angle = 225
        with self.canvas:
            Rotate(origin=self.rotate_origin, angle=self.angle)
            Color(rgb=(0, 255, 100))
            Rectangle(pos=self.rect_pos, size=self.rect_size)

    def on_touch_up(self, touch):
        if self.collide_point(*touch.pos):
            self.rotate()
            print(self.angle)
class Object3(Widget):
    def __init__(self, *args, **kwargs):
        Widget.__init__(self, *args, **kwargs)
        self.rect_pos_x = 500
        self.rect_pos_y = 250
        self.rect_pos = self.rect_pos_x, self.rect_pos_y
        self.rect_width = 150
        self.rect_height = 30
        self.rect_size = self.rect_width, self.rect_height
        self.rotate_origin_x = self.rect_pos_x + self.rect_width / 2
        self.rotate_origin_y = self.rect_pos_y + self.rect_height / 2
        self.rotate_origin = self.rotate_origin_x, self.rotate_origin_y
        self.angle = 135
        print('rect 2')
        with self.canvas:
            Rotate(origin=self.rotate_origin, angle=self.angle)
            Color(rgb=(1,255,0))
            Rectangle(pos=self.rect_pos, size=self.rect_size)

    def rotate(self):
        self.canvas.clear()
        self.angle += 90
        if (self.angle > 315):
            self.angle = 225
        with self.canvas:
            Rotate(origin=self.rotate_origin, angle=self.angle)
            Color(rgb=(0, 255, 100))
            Rectangle(pos=self.rect_pos, size=self.rect_size)

    def on_touch_up(self, touch):
        if self.collide_point(*touch.pos):
            self.rotate()
            print(self.angle)

class Stage_2(Widget):
    object2 = ObjectProperty(None)
    object3 = ObjectProperty(None)

class Manager(ScreenManager):
    pass

sm = Manager()

class ScreensApp(App):
    def build(self):
        return sm

if __name__ == '__main__':
    ScreensApp().run()

A:

If you include PushMatrix() and PopMatrix() in your canvas instructions, then only the current Widget will be affected. And then, if you adjust the Widget size and pos to that of the Rectangle, you should get better (but not perfect) collide_point performance:
    with self.canvas:
        PushMatrix()
        Rotate(origin=self.rotate_origin, angle=self.angle)
        Color(rgb=(1,255,0))
        Rectangle(pos=self.rect_pos, size=self.rect_size)
        PopMatrix()
        self.pos = self.rect_pos
        self.size = self.rect_size

This needs to be done whenever you use with self.canvas that involves Rotation, Scale, or Translate. The collide_point() will still be looking at the Widget size and pos, not the Rectangle, but at least the centers of the Widget and its Rectangle should coincide.

