Add brightness control for forum post 10985

Add global brightness control, as requested here: https://forums.pimoroni.com/t/how-many-plasma-lights-can-the-picade-x-hat-drive/10985

Pass brightness from PlasmaMatrix to individual drivers.

Author: Gadgetoid

daemon/usr/bin/plasma

@@ -14,6 +14,7 @@ CONFIG_FILE = "/etc/plasma/plasma.conf"
 PIPE_FILE = "/tmp/plasma"
 PATTERNS = "/etc/plasma/"
 FPS = 30
+BRIGHTNESS = 1.0
 LIGHTS = 10  # Actual number of pixels is 4x this number
 DEBUG = False
 
@@ -115,6 +116,12 @@ def main():
                         log("Framerate set to: {}fps".format(rgb[1]))
                     except ValueError:
                         log("Invalid framerate: {}".format(rgb[1]))
+                elif len(rgb) == 2 and rgb[0] == "brightness":
+                    try:
+                        args.brightness = float(rgb[1])
+                        log("Brightness set to: {}".format(args.brightness))
+                    except ValueError:
+                        log("Invalid brightness {}".format(rgb[1]))
                 else:
                     pattern, pattern_w, pattern_h, pattern_meta = load_pattern(command)
                     alpha = pattern_meta['alpha']
@@ -126,9 +133,9 @@ def main():
                 for x in range(plasma.get_pixel_count()):
                     offset_x = (x * channels) % (pattern_w * channels)
                     r, g, b = row[offset_x:offset_x + 3]
-                    plasma.set_pixel(x, r, g, b)
+                    plasma.set_pixel(x, r, g, b, brightness=args.brightness)
             else:
-                plasma.set_all(r, g, b)
+                plasma.set_all(r, g, b, brightness=args.brightness)
 
             plasma.show()
 
@@ -152,6 +159,8 @@ def get_args():
                       help="run plasma as a daemon")
     parser.add_argument("-f", "--fps", type=int, default=FPS,
                       help="set plasma LED update framerate")
+    parser.add_argument("-b", "--brightness", type=float, default=BRIGHTNESS,
+                      help="set plasma LED brightness")
     parser.add_argument("-c", "--config", type=str, default=CONFIG_FILE,
                       help="path to plasma config file")
     return parser.parse_known_args()[0]

daemon/usr/bin/plasmactl

@@ -37,6 +37,7 @@ if __name__ == "__main__":
     parser.add_argument('--list', action='store_true', help='List available animations')
     parser.add_argument('--colour', nargs=3, type=Color, help='Display an RGB colour (all values 0-255)')
     parser.add_argument('--fps', type=int, help='Set the update framerate')
+    parser.add_argument('--brightness', type=float, help='Set the LED brightness')
     parser.add_argument('--pattern', type=str, help='Display an image-based aniamtion from /etc/plasma', choices=list(valid_patterns()))
 
     args = parser.parse_args()
@@ -62,5 +63,13 @@ if __name__ == "__main__":
             fifo.flush()
         sys.exit(0)
 
+    if args.brightness is not None:
+        brightness = args.brightness
+        print(f"Setting brightness to {brightness}")
+        with open_fifo(FIFO) as fifo:
+            fifo.write(f"brightness {brightness}\n".encode("utf-8"))
+            fifo.flush()
+        sys.exit(0)
+
     parser.print_help()
     sys.exit(1)

library/plasma/matrix.py

@@ -109,7 +109,7 @@ def set_light(self, index, r, g, b, brightness=None):
     def set_all(self, r, g, b, brightness=None):
         """Set the RGB value and optionally brightness of all pixels."""
         for n, d in self._devices.items():
-            d.get('device').set_all(r, g, b, brightness)
+            d.get('device').set_all(r, g, b, brightness=brightness)
 
     def set_sequence(self, sequence):
         """Set all LEDs from a buffer of individual colours."""
@@ -141,7 +141,7 @@ def set_pixel(self, x, r, g, b, brightness=None):
             count = device.get_pixel_count()
 
             if x >= offset and x < offset + count:
-                device.set_pixel(x - offset, r, g, b)
+                device.set_pixel(x - offset, r, g, b, brightness=brightness)
 
     def show(self):
         """Display lights across devices.