cap_touch_demo: do not use global ctx

python_payload/apps/cap_touch_demo.py

@@ -3,18 +3,34 @@ import math
 import time
 
 import hardware
-from st3m import utils
+from st3m import utils, application
 
-ctx = hardware.get_ctx()
 
+class Dot:
+    def __init__(self, size, imag, real):
+        self.size = size
+        self.imag = imag
+        self.real = real
 
-def init():
-    pass
+    def draw(self, i, ctx):
+        imag = self.imag
+        real = self.real
+        size = self.szie
 
+        col = (1.0, 0.0, 1.0)
+        if i % 2:
+            col = (0.0, 1.0, 1.0)
+        ctx.rgb(*col).rectangle(
+            -int(imag - (size / 2)), -int(real - (size / 2)), size, size
+        ).fill()
 
-def run():
-    ctx.rgb(0, 0, 0).rectangle(-120, -120, 240, 240).fill()
-    time.sleep_ms(30)
+
+class CapTouchDemo(application.Application):
+    def on_init(self):
+        self.dots = []
+
+    def main_foreground(self):
+        self.dots = []
         for i in range(10):
             size = (hardware.get_captouch(i) * 4) + 4
             size += int(
@@ -28,20 +44,13 @@ def run():
             x += (hardware.captouch_get_petal_phi(i) / 600) * 1j
             rot = cmath.exp(2j * math.pi * i / 10)
             x = x * rot
-        col = (1.0, 0.0, 1.0)
-        if i % 2:
-            col = (0.0, 1.0, 1.0)
-        ctx.rgb(*col).rectangle(
-            -int(x.imag - (size / 2)), -int(x.real - (size / 2)), size, size
-        ).fill()
-    hardware.display_update()
-
 
-def foreground():
-    pass
+            self.dots.append(Dot(size, x.imag, x.real))
 
+    def on_draw(self, ctx):
+        ctx.rgb(0, 0, 0).rectangle(-120, -120, 240, 240).fill()
+        for i, dot in enumerate(self.dots):
+            dot.draw(i, ctx)
 
-from st3m.application import Application
 
-app = Application("cap touch")
-app.main_foreground = run
+app = CapTouchDemo("cap touch")
\ No newline at end of file