apps: fibonacci_clock: Add a Fibonacci clock application

Signed-off-by: Johannes Wache <jbwa@posteo.de>
[daniel@redfelineninja.org.uk: Tidy up the "git soup", dropped the manifest
changes and integrated the description from the original PR into the
docstring for the app]
Signed-off-by: Daniel Thompson <daniel@redfelineninja.org.uk>

wasp/apps/fibonacci_clock.py

@@ -0,0 +1,105 @@
+# SPDX-License-Identifier: LGPL-3.0-or-later
+# Copyright (C) 2020 Johannes Wache
+"""Fibonacci clock
+
+The Fibonacci sequence is a sequence of numbers created by the Italian
+mathematician Fibonacci in the 13th century. This is a sequence starting with
+1 and 1, where each subsequent number is the sum of the previous two. For the
+clock I used the first 5 terms: 1, 1, 2, 3 and 5.
+
+The screen of the clock is made up of five squares whose side lengths match
+the first five Fibonacci numbers: 1, 1, 2, 3 and 5. The hours are displayed
+using red and the minutes using green. When a square is used to display both
+the hours and minutes it turns blue. White squares are ignored.
+
+To tell time on the Fibonacci clock you need to do some calculations. To read
+the hour, simply add up the corresponding values of the red and blue squares.
+To read the minutes, do the same with the green and blue squares. The minutes
+are displayed in 5 minute increments (0 to 12) so you have to multiply your
+result by 5 to get the actual number.
+"""
+
+import wasp
+import icons
+
+MONTH = 'JanFebMarAprMayJunJulAugSepOctNovDec'
+
+class FibonacciClockApp():
+    """Displays the time as a Fibonacci Clock
+    """
+    NAME = 'Fibo'
+    ICON = icons.app
+
+    def __init__(self):
+        self.meter = wasp.widgets.BatteryMeter()
+        self.fields = b'\x05\x03\x02\x01\x01'
+        self.color_codes = [0xffff,0xf800,0x07e0,0x001f] # White, red, green and blue
+
+    def foreground(self):
+        """Activate the application."""
+        self.on_screen = ( -1, -1, -1, -1, -1, -1 )
+        self.draw()
+        wasp.system.request_tick(1000)
+
+    def sleep(self):
+        return True
+
+    def wake(self):
+        self.update()
+
+    def tick(self, ticks):
+        self.update()
+
+    def draw(self):
+        """Redraw the display from scratch."""
+        draw = wasp.watch.drawable
+
+        draw.fill()
+        self.on_screen = ( -1, -1, -1, -1, -1, -1 )
+        self.update()
+        self.meter.draw()
+
+    def update(self):
+        """Update the display (if needed).
+
+        The updates are a lazy as possible and rely on an prior call to
+        draw() to ensure the screen is suitably prepared.
+        """
+        now = wasp.watch.rtc.get_localtime()
+        if now[3] == self.on_screen[3] and now[4] == self.on_screen[4]:
+            if now[5] != self.on_screen[5]:
+                self.meter.update()
+                self.on_screen = now
+            return False
+        draw = wasp.watch.drawable
+
+        #calculate colors of fields:
+        field_colors = bytearray(5)
+        hr = now[3]
+        mn = now[4] // 5 # Clock can only display every 5 minutes
+        if (hr >= 12):
+            hr -= 12
+        for i in range(5):
+            if ((hr - self.fields[i]) >= 0):
+                hr -= self.fields[i]
+                field_colors[i] += 1
+
+            if ((mn - self.fields[i]) >= 0):
+                mn -= self.fields[i]
+                field_colors[i] += 2
+
+        draw.fill(x=71,y=51,w=23,h=23,bg=self.color_codes[field_colors[4]]) # 1 field
+        draw.fill(x=71,y=76,w=23,h=23,bg=self.color_codes[field_colors[3]]) # 1 field
+        draw.fill(x=21,y=51,w=48,h=48,bg=self.color_codes[field_colors[2]]) # 2 field
+        draw.fill(x=21,y=101,w=73,h=73,bg=self.color_codes[field_colors[1]]) # 3 field
+        draw.fill(x=96,y=51,w=123,h=123,bg=self.color_codes[field_colors[0]]) # 5 field
+
+        self.on_screen = now
+
+        month = now[1] - 1
+        month = MONTH[month*3:(month+1)*3]
+        draw.string('{}. {} {}'.format(now[2], month, now[0]),
+                0, 185, width=240)
+
+        self.meter.update()
+        return True