adding new example showing the progress bar feature to change color programmatically

docs/examples.rst

@@ -6,3 +6,13 @@ Ensure your device works with this simple test.
 .. literalinclude:: ../examples/progressbar_simpletest.py
     :caption: examples/progressbar_simpletest.py
     :linenos:
+
+
+Color Scale
+------------
+
+Example showing how to change the progressbar color while updating the values
+
+.. literalinclude:: ../examples/progressbar_displayio_blinka_color_scale.py
+    :caption: examples/progressbar_displayio_blinka_color_scale.py
+    :linenos:

examples/progressbar_displayio_blinka_color_scale.py

@@ -0,0 +1,82 @@
+#!/usr/bin/env python3
+
+# SPDX-FileCopyrightText: 2021 Hugo Dahl for Adafruit Industries
+# SPDX-FileCopyrightText: 2021 Jose David M.
+# SPDX-License-Identifier: MIT
+
+# Before you can run this example, you will need to install the
+# required libraries identifies in the `requirements.txt` file.
+# You can do so automatically by using the "pip" utility.
+
+"""
+Shows the ability of the progress bar to change color on the fly.
+This example is and adaptation from the progressbar_displayio_blinka test
+"""
+
+import time
+import adafruit_fancyled.adafruit_fancyled as fancy
+import displayio
+from blinka_displayio_pygamedisplay import PyGameDisplay
+from adafruit_progressbar.horizontalprogressbar import (
+    HorizontalProgressBar,
+    HorizontalFillDirection,
+)
+
+display = PyGameDisplay(width=320, height=240, auto_refresh=False)
+splash = displayio.Group(max_size=10)
+display.show(splash)
+
+# Setting up the grayscale values, You could use a different scale, and add more entries
+# to have detailed transitions
+# see learning guide regarding the FancyLed library
+# https://learn.adafruit.com/fancyled-library-for-circuitpython/palettes
+grad = [
+    (0.0, 0x000000),
+    (0.20, 0x333333),
+    (0.40, 0x666666),
+    (0.60, 0x999999),
+    (0.80, 0xCCCCCC),
+    (1.0, 0xEEEEEE),
+]
+
+# Creating the grayscale Palette using the FancyLed Library
+palette = fancy.expand_gradient(grad, 50)
+
+colors = list()
+
+# We create an equal space palette. This is done for convenience and clarity as we use
+# a value from 0 to 100 in our ProgressBar
+for i in range(99):
+    color = fancy.palette_lookup(palette, i / 100)
+    colors.append(color.pack())
+
+# Background creation
+color_bitmap = displayio.Bitmap(display.width, display.height, 1)
+color_palette = displayio.Palette(1)
+color_palette[0] = 0x2266AA  # Teal-ish-kinda
+
+bg_sprite = displayio.TileGrid(color_bitmap, pixel_shader=color_palette, x=0, y=0)
+splash.append(bg_sprite)
+
+
+horizontal_bar = HorizontalProgressBar(
+    (10, 80),
+    (180, 40),
+    fill_color=0x990099,
+    outline_color=0x0000FF,
+    bar_color=0x00FF00,
+    direction=HorizontalFillDirection.LEFT_TO_RIGHT,
+)
+splash.append(horizontal_bar)
+
+# List of step values for the progress bar
+test_value_range_1 = [i for i in range(99)]
+
+# Must check display.running in the main loop!
+while display.running:
+    print("\nDemonstration of values between 0 and 100 - Horizontal")
+    for val in test_value_range_1:
+        horizontal_bar.value = val
+        horizontal_bar.bar_color = colors[val]
+        display.refresh()
+        time.sleep(0.1)

examples/requirements.txt

@@ -9,3 +9,4 @@
 Adafruit-Blinka
 adafruit-blinka-displayio
 blinka-displayio-pygamedisplay
+adafruit-circuitpython-fancyled