#!/usr/bin/kivy
__version__ = '1.0'

import kivy
kivy.require('1.0.6')

from kivy.app import App
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.label import Label
from kivy.graphics import Color, Rectangle, Point, GraphicException
from random import random
from math import sqrt


def calculate_points(x1, y1, x2, y2, steps=5):
    dx = x2 - x1
    dy = y2 - y1
    dist = sqrt(dx * dx + dy * dy)
    if dist < steps:
        return None
    o = []
    m = dist / steps
    for i in range(1, int(m)):
        mi = i / m
        lastx = x1 + dx * mi
        lasty = y1 + dy * mi
        o.extend([lastx, lasty])
    return o


class Touchtracer(FloatLayout):

    def on_touch_down(self, touch):
        win = self.get_parent_window()
        ud = touch.ud
        ud['group'] = g = str(touch.uid)
        pointsize = 5
        if 'pressure' in touch.profile:
            ud['pressure'] = touch.pressure
            pointsize = (touch.pressure * 100000) ** 2
        ud['color'] = random()

        with self.canvas:
            Color(ud['color'], 1, 1, mode='hsv', group=g)
            ud['lines'] = [
                Rectangle(pos=(touch.x, 0), size=(1, win.height), group=g),
                Rectangle(pos=(0, touch.y), size=(win.width, 1), group=g),
                Point(points=(touch.x, touch.y), source='particle.png',
                      pointsize=pointsize, group=g)]

        ud['label'] = Label(size_hint=(None, None))
        self.update_touch_label(ud['label'], touch)
        self.add_widget(ud['label'])
        touch.grab(self)
        return True

    def on_touch_move(self, touch):
        if touch.grab_current is not self:
            return
        ud = touch.ud
        ud['lines'][0].pos = touch.x, 0
        ud['lines'][1].pos = 0, touch.y

        index = -1

        while True:
            try:
                points = ud['lines'][index].points
                oldx, oldy = points[-2], points[-1]
                break
            except:
                index -= 1

        points = calculate_points(oldx, oldy, touch.x, touch.y)

        # if pressure changed create a new point instruction
        if 'pressure' in ud:
            if not .95 < (touch.pressure / ud['pressure']) < 1.05:
                g = ud['group']
                pointsize = (touch.pressure * 100000) ** 2
                with self.canvas:
                    Color(ud['color'], 1, 1, mode='hsv', group=g)
                    ud['lines'].append(
                        Point(points=(), source='particle.png',
                              pointsize=pointsize, group=g))

        if points:
            try:
                lp = ud['lines'][-1].add_point
                for idx in range(0, len(points), 2):
                    lp(points[idx], points[idx+1])
            except GraphicException:
                pass

        ud['label'].pos = touch.pos
        import time
        t = int(time.time())
        if t not in ud:
            ud[t] = 1
        else:
            ud[t] += 1
        self.update_touch_label(ud['label'], touch)

    def on_touch_up(self, touch):
        if touch.grab_current is not self:
            return
        touch.ungrab(self)
        ud = touch.ud
        self.canvas.remove_group(ud['group'])
        self.remove_widget(ud['label'])

    def update_touch_label(self, label, touch):
        label.text = 'ID: %s\nPos: (%d, %d)\nClass: %s' % (
            touch.id, touch.x, touch.y, touch.__class__.__name__)
        label.texture_update()
        label.pos = touch.pos
        label.size = label.texture_size[0] + 20, label.texture_size[1] + 20


class TouchtracerApp(App):
    title = 'Touchtracer'
    icon = 'icon.png'

    def build(self):
        return Touchtracer()

    def on_pause(self):
        return True

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