Add example file for creating normal distribution

Author: tekktrik

Diff for: examples/displayio_cartesion_fillarea.py

@@ -0,0 +1,60 @@
+# SPDX-FileCopyrightText: 2021 Stefan Krüger
+#
+# SPDX-License-Identifier: MIT
+#############################
+"""
+This is a basic demonstration of a Cartesian widget for line-ploting
+"""
+
+import time
+import board
+import displayio
+import random
+from displayio_cartesian import Cartesian
+
+# create the display on the PyPortal or Clue or PyBadge(for example)
+display = board.DISPLAY
+# otherwise change this to setup the display
+# for display chip driver and pinout you have (e.g. ILI9341)
+
+# Generate data - here we'll make a normal distribution
+X_LOWER_BOUND = 0
+X_UPPER_BOUND = 10
+raw_data = []
+data = []
+
+for _ in range(100):
+    data_point = int(10 * random.random(X_LOWER_BOUND, X_UPPER_BOUND + 1))
+    raw_data.append(data_point)
+
+y_upper_bound = 0
+for value in range(len(X_UPPER_BOUND + 1)):
+    value_count = raw_data.count(value)
+    data.append(value_count)
+    y_upper_bound = max(y_upper_bound, value_count)
+
+# pybadge display:  160x128
+# Create a Cartesian widget
+# https://circuitpython.readthedocs.io/projects/displayio-layout/en/latest/api.html#module-adafruit_displayio_layout.widgets.cartesian
+my_plane = Cartesian(
+    x=15,  # x position for the plane
+    y=2,  # y plane position
+    width=140,  # display width
+    height=105,  # display height
+    xrange=(X_LOWER_BOUND, X_UPPER_BOUND),  # x range
+    yrange=(0, y_upper_bound),  # y range
+    fill_area=True
+)
+
+my_group = displayio.Group()
+my_group.append(my_plane)
+display.show(my_group)  # add high level Group to the display
+
+print("examples/displayio_layout_cartesian_fillarea.py")
+
+for x, y in data:
+    my_plane.add_plot_line(x, y)
+    time.sleep(0.5)
+
+while True:
+    pass