Add example for colorwheel effect

Author: tekktrik

examples/displayio_effects_colorwheel.py

@@ -0,0 +1,58 @@
+# SPDX-FileCopyrightText: 2021 GaryZ, Alec Delaney
+# SPDX-FileCopyrightText: Copyright (c) 2022 Alec Delaney for CircuitPython Organization
+#
+# SPDX-License-Identifier: Unlicense
+#############################
+"""
+Use the random fluctuation effect for the Dial.
+"""
+
+import time
+import board
+import displayio
+import terminalio
+from displayio_dial import Dial
+from displayio_effects import WidgetType, colorwheel_effect
+
+# Fonts used for the Dial tick labels
+tick_font = terminalio.FONT
+
+display = board.DISPLAY  # create the display on the PyPortal or Clue (for example)
+# otherwise change this to setup the display
+# for display chip driver and pinout you have (e.g. ILI9341)
+
+
+# Define the minimum and maximum values for the dial
+minimum_value = 0
+maximum_value = 100
+
+# Hook in the throttle effect for the Dial widget
+colorwheel_effect.hook_colorwheel_effect(Dial, WidgetType.DIAL)
+
+# Create a Dial widget
+my_dial = Dial(
+    x=20,  # set x-position of the dial inside of my_group
+    y=20,  # set y-position of the dial inside of my_group
+    width=180,  # requested width of the dial
+    height=180,  # requested height of the dial
+    padding=25,  # add 25 pixels around the dial to make room for labels
+    start_angle=-120,  # left angle position at -120 degrees
+    sweep_angle=240,  # total sweep angle of 240 degrees
+    min_value=minimum_value,  # set the minimum value shown on the dial
+    max_value=maximum_value,  # set the maximum value shown on the dial
+    tick_label_font=tick_font,  # the font used for the tick labels
+    tick_label_scale=2.0,  # the scale factor for the tick label font
+)
+
+my_group = displayio.Group()
+my_group.append(my_dial)
+
+display.show(my_group)  # add high level Group to the display
+
+# Set the dial to the value before turning on the fluctuation effect
+my_dial.value = 50
+
+while True:
+
+    my_dial.update_colorwheel()
+    time.sleep(0.01)