Added SevenSegmentDisplay

- From gpiozero/gpiozero#488

src/hardware/indicators.py

@@ -25,7 +25,7 @@
 
 # See: https://gpiozero.readthedocs.io/en/stable/
 # See: https://gpiozero.readthedocs.io/en/stable/api_output.html#led
-from gpiozero import LED, PWMLED
+from gpiozero import LED, PWMLED, LEDBoard, OutputDeviceError, LEDCollection
 from pprint import pprint
 import time
 
@@ -109,6 +109,172 @@ def __init__(self, gpio_pin=GPIO_MESSAGE):
         super().__init__(gpio_pin)
 
 
+
+
+class SevenSegmentDisplay(LEDBoard):
+    """
+    Extends :class:`LEDBoard` for a 7 segment LED display
+
+    7 segment displays have either 7 or 8 pins, 7 pins for the digit display
+    and an optional 8th pin for a decimal point. 7 segment displays
+    typically have either a common anode or common cathode pin, when
+    using a common anode display 'active_high' should be set to False.
+    Instances of this class can be used to display characters or control
+    individual leds on the display. For example::
+
+        from gpiozero import SevenSegmentDisplay
+
+        seven = SevenSegmentDisplay(1,2,3,4,5,6,7,8,active_high=False)
+        seven.display("7")
+
+    :param int \*pins:
+        Specify the GPIO pins that the 7 segment display is attached to.
+        Pins should be in the LED segment order A,B,C,D,E,F,G,decimal_point
+        (the decimal_point is optional).
+
+    :param bool pwm:
+        If ``True``, construct :class:`PWMLED` instances for each pin. If
+        ``False`` (the default), construct regular :class:`LED` instances. This
+        parameter can only be specified as a keyword parameter.
+
+    :param bool active_high:
+        If ``True`` (the default), the :meth:`on` method will set all the
+        associated pins to HIGH. If ``False``, the :meth:`on` method will set
+        all pins to LOW (the :meth:`off` method always does the opposite). This
+        parameter can only be specified as a keyword parameter.
+
+    :param bool initial_value:
+        If ``False`` (the default), all LEDs will be off initially. If
+        ``None``, each device will be left in whatever state the pin is found
+        in when configured for output (warning: this can be on). If ``True``,
+        the device will be switched on initially. This parameter can only be
+        specified as a keyword parameter.
+
+    From https://www.stuffaboutcode.com/2016/10/raspberry-pi-7-segment-display-gpiozero.html
+    See: https://github.com/gpiozero/gpiozero/pull/488
+    """
+    def __init__(self, *pins, **kwargs):
+        # 7 segment displays must have 7 or 8 pins
+        if len(pins) < 7 or len(pins) > 8:
+            raise ValueError('SevenSegmentDisplay must have 7 or 8 pins')
+        # Don't allow 7 segments to contain collections
+        for pin in pins:
+            assert not isinstance(pin, LEDCollection)
+        pwm = kwargs.pop('pwm', False)
+        active_high = kwargs.pop('active_high', True)
+        initial_value = kwargs.pop('initial_value', False)
+        if kwargs:
+            raise TypeError('unexpected keyword argument: %s' % kwargs.popitem()[0])
+
+        self._layouts = {
+            '1': (False, True, True, False, False, False, False),
+            '2': (True, True, False, True, True, False, True),
+            '3': (True, True, True, True, False, False, True),
+            '4': (False, True, True, False, False, True, True),
+            '5': (True, False, True, True, False, True, True),
+            '6': (True, False, True, True, True, True, True),
+            '7': (True, True, True, False, False, False, False),
+            '8': (True, True, True, True, True, True, True),
+            '9': (True, True, True, True, False, True, True),
+            '0': (True, True, True, True, True, True, False),
+            'A': (True, True, True, False, True, True, True),
+            'B': (False, False, True, True, True, True, True),
+            'C': (True, False, False, True, True, True, False),
+            'D': (False, True, True, True, True, False, True),
+            'E': (True, False, False, True, True, True, True),
+            'F': (True, False, False, False, True, True, True),
+            'G': (True, False, True, True, True, True, False),
+            'H': (False, True, True, False, True, True, True),
+            'I': (False, False, False, False, True, True, False),
+            'J': (False, True, True, True, True, False, False),
+            'K': (True, False, True, False, True, True, True),
+            'L': (False, False, False, True, True, True, False),
+            'M': (True, False, True, False, True, False, False),
+            'N': (True, True, True, False, True, True, False),
+            'O': (True, True, True, True, True, True, False),
+            'P': (True, True, False, False, True, True, True),
+            'Q': (True, True, False, True, False, True, True),
+            'R': (True, True, False, False, True, True, False),
+            'S': (True, False, True, True, False, True, True),
+            'T': (False, False, False, True, True, True, True),
+            'U': (False, False, True, True, True, False, False),
+            'V': (False, True, True, True, True, True, False),
+            'W': (False, True, False, True, False, True, False),
+            'X': (False, True, True, False, True, True, True),
+            'Y': (False, True, True, True, False, True, True),
+            'Z': (True, True, False, True, True, False, True),
+            '-': (False, False, False, False, False, False, True),
+            ' ': (False, False, False, False, False, False, False),
+            '=': (False, False, False, True, False, False, True)
+        }
+
+        super(SevenSegmentDisplay, self).__init__(*pins, pwm=pwm, active_high=active_high, initial_value=initial_value)
+
+    def display(self, char):
+        """
+        Display a character on the 7 segment display
+
+        :param string char:
+            A single character to be displayed
+        """
+        char = str(char).upper()
+        if len(char) > 1:
+            raise ValueError('only a single character can be displayed')
+        if char not in self._layouts:
+            raise ValueError('there is no layout for character - %s' % char)
+        layout = self._layouts[char]
+        for led in range(7):
+            self[led].value = layout[led]
+
+    def display_hex(self, hexnumber):
+        """
+        Display a hex number (0-F) on the 7 segment display
+
+        :param int hexnumber:
+            The number to be displayed in hex
+        """
+        self.display(hex(hexnumber)[2:])
+
+    @property
+    def decimal_point(self):
+        """
+        Represents the status of the decimal point led
+        """
+        # does the 7seg display have a decimal point (i.e pin 8)
+        if len(self) > 7:
+            return self[7].value
+        else:
+            raise OutputDeviceError('there is no 8th pin for the decimal point')
+
+    @decimal_point.setter
+    def decimal_point(self, value):
+        """
+        Sets the status of the decimal point led
+        """
+        if len(self) > 7:
+            self[7].value = value
+        else:
+            raise OutputDeviceError('there is no 8th pin for the decimal point')
+
+    def set_char_layout(self, char, layout):
+        """
+        Create or update a custom character layout, which can be used with the
+        `display` method.
+
+        :param string char:
+            A single character to be displayed
+
+        :param tuple layout:
+            A 7 bool tuple of LED values in the segment order A, B, C, D, E, F, G
+        """
+        char = str(char).upper()
+        if len(char) != 1:
+            raise ValueError('only a single character can be used in a layout')
+        if len(layout) != 7:
+            raise ValueError('a character layout must have 7 segments')
+        self._layouts[char] = layout
+
+
 def test():
     """ Unit Tests """
     import os