touchdebug: use new Point() and remove_group()

examples/touchdebug.py

@@ -1,34 +1,59 @@
 from kivy.app import App
 from kivy.uix.widget import Widget
 from kivy.uix.label import Label
-from kivy.graphics import Color, Rectangle
+from kivy.graphics import Color, Rectangle, Point
+from random import random
+from math import sqrt
+
+def calculate_points(x1, y1, x2, y2, steps=2):
+    dx = x2 - x1
+    dy = y2 - y1
+    dist = sqrt(dx * dx + dy * dy)
+    if dist < steps:
+        return None
+    o = []
+    m = dist / steps
+    for i in xrange(int(m)):
+        mi = i / m
+        o.extend([x1 + dx * mi, y1 + dy * mi])
+    return o
+
 
 class Touchdebug(Widget):
     def on_touch_down(self, touch):
         win = self.get_parent_window()
         ud = touch.userdata
+        ud['group'] = g = str(touch.uid)
         with self.canvas:
-            ud['color'] = Color(1, 1, 1)
+            ud['color'] = Color(random(), 1, 1, mode='hsv', group=g)
             ud['lines'] = (
-                Rectangle(pos=(touch.x, 0), size=(1, win.height)),
+                Rectangle(pos=(touch.x, 0), size=(1, win.height), group=g),
-                Rectangle(pos=(0, touch.y), size=(win.width, 1)))
+                Rectangle(pos=(0, touch.y), size=(win.width, 1), group=g),
+                Point(points=(touch.x, touch.y), source='particle.png',
+                      pointsize=5, group=g)
+            )
 
         ud['label'] = Label()
         self.update_touch_label(ud['label'], touch)
         self.add_widget(ud['label'])
+        ud['oldtouch'] = touch.x, touch.y
 
     def on_touch_move(self, touch):
         ud = touch.userdata
         ud['lines'][0].pos = touch.x, 0
         ud['lines'][1].pos = 0, touch.y
+
+        oldx, oldy = ud['oldtouch']
+        points = calculate_points(oldx, oldy, touch.x, touch.y)
+        if points:
+            ud['oldtouch'] = touch.x, touch.y
+            ud['lines'][2].points = ud['lines'][2].points + points
         ud['label'].pos = touch.pos
         self.update_touch_label(ud['label'], touch)
 
     def on_touch_up(self, touch):
         ud = touch.userdata
-        self.canvas.remove(ud['color'])
+        self.canvas.remove_group(ud['group'])
-        self.canvas.remove(ud['lines'][0])
-        self.canvas.remove(ud['lines'][1])
         self.remove_widget(ud['label'])
 
     def update_touch_label(self, label, touch):