15. Screen Class

Exercise

Design a screen class that keeps track of the brightness of all pixels on the 5 by 5 LED display of the microbit.
Initialize the class instance with all pixels at 0 brightness.
Create a method to reset all pixels to 0 brightness.
Create a method to set all pixels to a given brightness.
Create a method to set all pixels to a random brightness.
Create a method to show the screen using the pixel brightness values.
Create a method to set a pixel brightness like the standard set_pixel method: .set_pixel(x, y, value).
Create a method to get a pixel brightness like the standard set_pixel method: .get_pixel(x, y, value).
Create a method to set the pixel brightness for a row.
Create a method to set the pixel brightness for a column.
Create a method to set the pixel brightness for a random row.
Create a method to set the pixel brightness for a random column.
Create a method to set the pixel brightness for a random pixel.
Create a method to set a random pixel brightness for a given pixel.
Create a method to set a random pixel brightness for a random pixel.
Create a method that returns the number of pixels with brightness greater than 0.
Create a method that returns the number of pixels with brightness greater than a specified value.
Create a method that returns the number of pixels with brightness of a specified value.

Exercise solution

Q1

Design a screen class.

from microbit import *
import random

class Screen:
    def __init__(self):
        self.pixels = [[0 for _ in range(5)] for _ in range(5)]

    def reset(self, showpix=True):
        self.pixels = [[0 for _ in range(5)] for _ in range(5)]
        if showpix:
            self.show()

    def set_all(self, brightness, showpix=True):
        self.pixels = [[brightness for _ in range(5)] for _ in range(5)]
        if showpix:
            self.show()

    def set_all_random(self, showpix=True):
        self.pixels = [[random.randint(0, 9) for _ in range(5)] for _ in range(5)]
        if showpix:
            self.show()

    def show(self):
        for x in range(5):
            for y in range(5):
                display.set_pixel(x, y, self.pixels[x][y])

    def set_row(self, row, brightness, showpix=True):
        self.pixels[row] = [brightness for _ in range(5)]
        if showpix:
            self.show()

    def set_column(self, col, brightness, showpix=True):
        for i in range(5):
            self.pixels[i][col] = brightness
        if showpix:
            self.show()

    def set_random_row(self, brightness, showpix=True):
        self.pixels[random.randint(0, 4)] = [brightness for _ in range(5)]
        if showpix:
            self.show()

    def set_random_column(self,  brightness, showpix=True):
        rany = random.randint(0, 4)
        for x in range(5):
            self.pixels[x][rany] = brightness
        if showpix:
            self.show()

    def set_pixel(self, x, y, brightness, showpix=True):
        self.pixels[x][y] = brightness
        if showpix:
            self.show()

    def set_random_pixel(self, brightness, showpix=True):
        x, y = random.randint(0, 4), random.randint(0, 4)
        self.pixels[x][y] = brightness
        if showpix:
            self.show()

    def set_random_brightness(self, x, y, showpix=True):
        self.pixels[x][y] = random.randint(0, 9)
        if showpix:
            self.show()

    def set_random_pixel_random_brightness(self, showpix=True):
        x, y = random.randint(0, 4), random.randint(0, 4)
        self.pixels[x][y] = random.randint(0, 9)
        if showpix:
            self.show()

    def get_pixel_brightness(self, x, y):
        return self.pixels[x][y]

    def count_pixels_greater_than_zero(self):
        return sum(pixel > 0 for row in self.pixels for pixel in row)

    def count_pixels_greater_than(self, brightness):
        return sum(pixel > brightness for row in self.pixels for pixel in row)

    def count_pixels_of_value(self, brightness):
        return sum(pixel == brightness for row in self.pixels for pixel in row)

Exercise

Design some tests to make sure that the screen class is working as expected.

Exercise solution