kivy/examples/canvas/lines.py

from kivy.app import App
from kivy.properties import OptionProperty, NumericProperty, ListProperty, \
        BooleanProperty
from kivy.uix.floatlayout import FloatLayout
from kivy.lang import Builder
from kivy.clock import Clock
from math import cos, sin

Builder.load_string('''
<LinePlayground>:
    canvas:
        Color:
            rgba: .4, .4, 1, root.alpha
        Line:
            points: self.points
            joint: self.joint
            cap: self.cap
            width: self.linewidth
            close: self.close
        Color:
            rgba: .8, .8, .8, root.alpha_controlline
        Line:
            points: self.points
            close: self.close
        Color:
            rgba: 1, .4, .4, root.alpha
        Line:
            points: self.points2
            joint: self.joint
            cap: self.cap
            width: self.linewidth
            close: self.close

    GridLayout:
        cols: 2
        size_hint: 1, None
        height: 44 * 5

        GridLayout:
            cols: 2

            Label:
                text: 'Alpha'
            Slider:
                value: root.alpha
                on_value: root.alpha = float(args[1])
                min: 0.
                max: 1.
            Label:
                text: 'Alpha Control Line'
            Slider:
                value: root.alpha_controlline
                on_value: root.alpha_controlline = float(args[1])
                min: 0.
                max: 1.
            Label:
                text: 'Width'
            Slider:
                value: root.linewidth
                on_value: root.linewidth = args[1]
                min: 1
                max: 40
            Label:
                text: 'Cap'
            GridLayout:
                rows: 1
                ToggleButton:
                    group: 'cap'
                    text: 'none'
                    on_press: root.cap = self.text
                ToggleButton:
                    group: 'cap'
                    text: 'round'
                    on_press: root.cap = self.text
                ToggleButton:
                    group: 'cap'
                    text: 'square'
                    on_press: root.cap = self.text
            Label:
                text: 'Joint'
            GridLayout:
                rows: 1
                ToggleButton:
                    group: 'joint'
                    text: 'none'
                    on_press: root.joint = self.text
                ToggleButton:
                    group: 'joint'
                    text: 'round'
                    on_press: root.joint = self.text
                ToggleButton:
                    group: 'joint'
                    text: 'miter'
                    on_press: root.joint = self.text
                ToggleButton:
                    group: 'joint'
                    text: 'bevel'
                    on_press: root.joint = self.text

            Label:
                text: 'Close'
            ToggleButton:
                text: 'Close line'
                on_press: root.close = self.state == 'down'

        AnchorLayout:
            GridLayout:
                cols: 1
                size_hint: None, None
                size: self.minimum_size
                ToggleButton:
                    size_hint: None, None
                    size: 100, 44
                    text: 'Animate'
                    on_state: root.animate(self.state == 'down')
                Button:
                    size_hint: None, None
                    size: 100, 44
                    text: 'Clear'
                    on_press: root.points = root.points2 = []

''')


class LinePlayground(FloatLayout):
    alpha_controlline = NumericProperty(1.0)
    alpha = NumericProperty(0.5)
    close = BooleanProperty(False)
    points = ListProperty([500, 500, 300, 300, 500, 300, 500, 400, 600, 400])
    points2 = ListProperty([])
    joint = OptionProperty('none', options=('round', 'miter', 'bevel', 'none'))
    cap = OptionProperty('none', options=('round', 'square', 'none'))
    linewidth = NumericProperty(10.0)
    dt = NumericProperty(0)

    def on_touch_down(self, touch):
        if super(LinePlayground, self).on_touch_down(touch):
            return True
        touch.grab(self)
        self.points = self.points + list(touch.pos)
        return True

    def on_touch_move(self, touch):
        if touch.grab_current is self:
            self.points[-2:] = list(touch.pos)
            return True
        return super(LinePlayground, self).on_touch_move(touch)

    def on_touch_up(self, touch):
        if touch.grab_current is self:
            touch.ungrab(self)
            return True
        return super(LinePlayground, self).on_touch_up(touch)

    def animate(self, do_animation):
        if do_animation:
            Clock.schedule_interval(self.update_points_animation, 0)
        else:
            Clock.unschedule(self.update_points_animation)

    def update_points_animation(self, dt):
        cy = self.height * 0.6
        cx = self.width * 0.1
        w = self.width * 0.8
        step = 20
        points = []
        points2 = []
        self.dt += dt
        for i in xrange(int(w / step)):
            x = i * step
            points.append(cx + x)
            points.append(cy + cos(x / w * 8. + self.dt) * self.height * 0.2)
            points2.append(cx + x)
            points2.append(cy + sin(x / w * 8. + self.dt) * self.height * 0.2)
        self.points = points
        self.points2 = points2


class TestLineApp(App):
    def build(self):
        return LinePlayground()


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