Examples: adding simple touch button example

examples/touch_buttons.py

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+from presto import Presto
+from touch import Button
+
+presto = Presto()
+display = presto.display
+WIDTH, HEIGHT = display.get_bounds()
+
+# Couple of colours for use later
+WHITE = display.create_pen(255, 255, 255)
+RED = display.create_pen(230, 60, 45)
+GREEN = display.create_pen(9, 185, 120)
+BLACK = display.create_pen(0, 0, 0)
+
+# We'll need this for the touch element of the screen
+touch = presto.touch
+
+CX = WIDTH // 2
+CY = HEIGHT // 2
+BUTTON_WIDTH = 100
+BUTTON_HEIGHT = 50
+
+# Create a touch button and set the touch region.
+# Button(x, y, width, height)
+button_1 = Button(10, 35, BUTTON_WIDTH, BUTTON_HEIGHT)
+button_2 = Button(10, 95, BUTTON_WIDTH, BUTTON_HEIGHT)
+button_3 = Button(10, 155, BUTTON_WIDTH, BUTTON_HEIGHT)
+
+while True:
+
+    # Check for touch changes
+    touch.poll()
+
+    # Clear the screen and set the background colour
+    display.set_pen(WHITE)
+    display.clear()
+    display.set_pen(BLACK)
+
+    # Title text
+    display.text("Touch Button Demo", 23, 7)
+
+    # Finding the state of a touch button is much the same as a physical button
+    # calling '.is_pressed()' on your button object will return True or False
+    if button_1.is_pressed():
+        display.set_pen(GREEN)
+        display.text("You Pressed\nButton 1!", (button_1.x + button_1.w) + 20, button_1.y + 3, 100, 2)
+    else:
+        display.set_pen(RED)
+
+    # We've defined our touch Button object but we need a visual representation of it for the user!
+    # We can use the '.bounds' property of our Button object to set the X, Y, WIDTH and HEIGHT
+    display.rectangle(*button_1.bounds)
+
+    if button_2.is_pressed():
+        display.set_pen(GREEN)
+        display.text("You Pressed\nButton 2!", (button_2.x + button_2.w) + 20, button_2.y + 3, 100, 2)
+    else:
+        display.set_pen(RED)
+
+    display.rectangle(*button_2.bounds)
+
+    if button_3.is_pressed():
+        display.set_pen(GREEN)
+        display.text("You Pressed\nButton 3!", (button_3.x + button_3.w) + 20, button_3.y + 3, 100, 2)
+    else:
+        display.set_pen(RED)
+
+    display.rectangle(*button_3.bounds)
+
+    # Finally, we update the screen so we can see our changes!
+    presto.update()