__init__.py

'''A round menu that appears on a long touch
'''
from kivy.uix.widget import Widget
from kivy.uix.label import Label
from kivy.uix.behaviors import ButtonBehavior
from kivy.lang import Builder
from kivy.clock import Clock
from kivy.animation import Animation
from kivy.properties import (
    NumericProperty, ListProperty, ObjectProperty, DictProperty)
from kivy.app import App

from functools import partial
from copy import copy

KV = '''
#:import pi math.pi
#:import cos math.cos
#:import sin math.sin
#:import V kivy.vector.Vector

<ModernMenu>:
    canvas.before:
        Color:
            rgba: 1, 0, 0, .4
        Ellipse:
            pos: self.center_x - self.radius, self.center_y - self.radius
            size: self.radius * 2, self.radius * 2
            angle_start: 0
            angle_end: self.circle_progress * 360 * self.creation_direction
        Color:
            rgba: self.color
        Line:
            circle:
                (
                self.center_x, self.center_y,
                self.radius, 0, self.circle_progress * 360 * self.creation_direction
                )
            width: self.line_width
    on_touch_down:
        V(args[1].pos).distance(self.center) < self.radius and (
        self.back() if self.choices_history else self.dismiss())

<ModernMenuLabel>:
    size: self.texture_size
    padding: 5, 5
    on_press: self.callback and self.callback(self)

    canvas.before:
        Color:
            rgba: .1, .4, .4, .9
        Rectangle:
            pos: self.pos
            size: self.size
        Line:
            points:
                (
                self.center_x, self.center_y,
                self.parent.center_x + cos(
                self.opacity * self.index * 2 * pi / self.siblings
                ) * self.parent.radius,
                self.parent.center_y + sin(
                self.opacity * self.index * 2 * pi / self.siblings
                ) * self.parent.radius
                ) if self.parent else []
            width: self.parent.line_width if self.parent else 1

    center:
        (
        self.parent.center_x +
        cos(self.opacity * self.index * 2 * pi / self.siblings) * self.radius,
        self.parent.center_y +
        sin(self.opacity * self.index * 2 * pi / self.siblings) * self.radius
        ) if (self.size and self.parent and self.parent.children) else (0, 0)
'''


def dist((x1, y1), (x2, y2)):
    return ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 5


class ModernMenuLabel(ButtonBehavior, Label):
    index = NumericProperty(0)
    radius = NumericProperty(100)
    siblings = NumericProperty(1)
    callback = ObjectProperty(None)

    def on_parent(self, *args):
        if self.parent:
            self.parent.bind(children=self.update_siblings)

    def update_siblings(self, *args):
        if self.parent:
            self.siblings = max(0, len(self.parent.children))
        else:
            self.siblings = 1


class ModernMenu(Widget):
    radius = NumericProperty(50)
    circle_width = NumericProperty(5)
    line_width = NumericProperty(2)
    color = ListProperty([.3, .3, .3, 1])
    circle_progress = NumericProperty(0)
    creation_direction = NumericProperty(1)
    creation_timeout = NumericProperty(1)
    choices = ListProperty([])
    item_cls = ObjectProperty(ModernMenuLabel)
    item_args = DictProperty({'opacity': 0})
    animation = ObjectProperty(Animation(opacity=1, d=.5))
    choices_history = ListProperty([])

    def start_display(self, touch):
        touch.grab(self)
        a = Animation(circle_progress=1, d=self.creation_timeout)
        a.bind(on_complete=self.open_menu)
        touch.ud['animation'] = a
        a.start(self)

    def open_menu(self, *args):
        self.clear_widgets()
        for i in self.choices:
            kwargs = copy(self.item_args)
            kwargs.update(i)
            ml = self.item_cls(**kwargs)
            self.animation.start(ml)
            self.add_widget(ml)

    def open_submenu(self, choices, *args):
        self.choices_history.append(self.choices)
        self.choices = choices
        self.open_menu()

    def back(self, *args):
        self.choices = self.choices_history.pop()
        self.open_menu()

    def on_touch_move(self, touch, *args):
        if (
            touch.grab_current == self and
            dist(touch.pos, touch.opos) > self.radius and
            self.parent and
            self.circle_progress < 1
        ):
            self.parent.remove_widget(self)

        return super(ModernMenu, self).on_touch_move(touch, *args)

    def on_touch_up(self, touch, *args):
        if (
            touch.grab_current == self and
            self.parent and
            self.circle_progress < 1
        ):
            self.parent.remove_widget(self)
        return super(ModernMenu, self).on_touch_up(touch, *args)

    def dismiss(self):
        a = Animation(opacity=0)
        a.bind(on_complete=self._remove)
        a.start(self)

    def _remove(self, *args):
        if self.parent:
            self.parent.remove_widget(self)


class MenuSpawner(Widget):
    timeout = NumericProperty(0.1)
    menu_cls = ObjectProperty(ModernMenu)
    cancel_distance = NumericProperty(10)
    menu_args = DictProperty({})

    def on_touch_down(self, touch, *args):
        t = partial(self.display_menu, touch)
        touch.ud['menu_timeout'] = t
        Clock.schedule_once(t, self.timeout)
        return super(MenuSpawner, self).on_touch_down(touch, *args)

    def on_touch_move(self, touch, *args):
        if (
            touch.ud['menu_timeout'] and
            dist(touch.pos, touch.opos) > self.cancel_distance
        ):
            Clock.unschedule(touch.ud['menu_timeout'])
        return super(MenuSpawner, self).on_touch_move(touch, *args)

    def on_touch_up(self, touch, *args):
        if touch.ud.get('menu_timeout'):
            Clock.unschedule(touch.ud['menu_timeout'])
        return super(MenuSpawner, self).on_touch_up(touch, *args)

    def display_menu(self, touch, dt):
        menu = self.menu_cls(center=touch.pos, **self.menu_args)
        self.add_widget(menu)
        menu.start_display(touch)


Builder.load_string(KV)

TESTAPP_KV = '''
FloatLayout:
    ScrollView:
        BoxLayout:
            orientation: 'vertical'
            size_hint_y: None
            height: 1000
            Button:
                text: 'test1'
            Label:
                text: 'label1'
            Button:
                text: 'test2'
            Label:
                text: 'label2'
            Button:
                text: 'test3'
            Label:
                text: 'label3'

    MenuSpawner:
        timeout: .8
        menu_args:
            dict(
            creation_direction=-1,
            radius=30,
            creation_timeout=.4,
            choices=[
            dict(text='submenu 1', index=1, callback=app.callback1),
            dict(text='action 1', index=2, callback=app.callback2),
            dict(text='action 2', index=3, callback=app.callback3),
            dict(text='submenu 2', index=4, callback=app.callback4),
            dict(text='action 3', index=5, callback=app.callback5),
            ])
'''


class ModernMenuApp(App):
    def build(self):
        return Builder.load_string(TESTAPP_KV)

    def callback1(self, *args):
        print "test 1"
        args[0].parent.open_submenu(
            choices=[
                dict(text='action 1', index=1, callback=self.callback2),
                dict(text='action 2', index=2, callback=self.callback2),
                dict(text='action 3', index=3, callback=self.callback2),
            ])

    def callback2(self, *args):
        print "test 2"
        args[0].parent.dismiss()

    def callback3(self, *args):
        print "test 3"
        args[0].parent.dismiss()

    def callback4(self, *args):
        print "test 4"
        args[0].parent.open_submenu(
            choices=[
                dict(text='hey', index=1, callback=self.callback2),
                dict(text='oh', index=2, callback=self.callback2),
            ])

    def callback5(self, *args):
        print "test 5"
        args[0].parent.dismiss()


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