adding touch buttons example

Adding an example for user interface buttons. The pressed state of the buttons are tracked based on the touch points.

examples/buttons_example.py

@@ -0,0 +1,83 @@
+# SPDX-FileCopyrightText: 2024 Liz Clark for Adafruit Industries
+# SPDX-License-Identifier: MIT
+
+"""
+Touch buttons example for HX83570 + FT5336 TFT Breakout
+"""
+
+import time
+import board
+import displayio
+from adafruit_hx8357 import HX8357
+from adafruit_button import Button
+import adafruit_ft5336
+import terminalio
+
+displayio.release_displays()
+
+spi = board.SPI()
+# for eyespi bff
+# tft_cs = board.TX
+# tft_dc = board.RX
+# else:
+tft_cs = board.D9
+tft_dc = board.D10
+
+display_bus = displayio.FourWire(spi, command=tft_dc, chip_select=tft_cs)
+# display is rotated to align x, y with touch screen x, y
+display = HX8357(display_bus, width=320, height=480, rotation=270)
+
+i2c = board.I2C()  # uses board.SCL and board.SDA
+touch = adafruit_ft5336.Adafruit_FT5336(i2c)
+
+splash = displayio.Group()
+display.root_group = splash
+
+RED = (255, 0, 0)
+YELLOW = (255, 255, 0)
+GREEN = (0, 255, 0)
+BLUE = (0, 0, 255)
+
+spots = [
+    {'label': "1", 'pos': (10, 10), 'color': RED},
+    {'label': "2", 'pos': (165, 10), 'color': YELLOW},
+    {'label': "3", 'pos': (10, 245), 'color': GREEN},
+    {'label': "4", 'pos': (165, 245), 'color': BLUE},
+    ]
+
+buttons = []
+for spot in spots:
+    button = Button(x=spot['pos'][0], y=spot['pos'][1],
+                    width=145, height=225,
+                    style=Button.ROUNDRECT,
+                    fill_color=spot['color'], outline_color=0xFFFFFF,
+                    label=spot['label'], label_font=terminalio.FONT,
+                    label_color=0x000000)
+    splash.append(button)
+    buttons.append(button)
+
+display.root_group = splash
+
+button_states = [False for _ in buttons]
+
+while True:
+    if touch.touched:
+        t = touch.points
+        print(t)
+        # reset state
+        button_states = [False for _ in buttons]
+        for point in t:
+            for button_index, button in enumerate(buttons):
+                if button.contains(point[0:2]):
+                    # if button contains point, set state to True
+                    button_states[button_index] = True
+                    break
+        # selected state == button state
+        for button_index, button in enumerate(buttons):
+            button.selected = button_states[button_index]
+    else:
+        # if no touch points, then no buttons are selected
+        for button in buttons:
+            button.selected = False
+
+    time.sleep(0.1)