apps: chrono: Implement a simple analogue watch face

Signed-off-by: Daniel Thompson <daniel@redfelineninja.org.uk>

1 files changed, 102 insertions, 0 deletions

diff --git a/wasp/apps/chrono.py b/wasp/apps/chrono.py
new file mode 100644
index 0000000..63a8e23
--- /dev/null
+++ b/wasp/apps/chrono.py
@@ -0,0 +1,102 @@
+# SPDX-License-Identifier: LGPL-3.0-or-later
+# Copyright (C) 2020 Daniel Thompson
+
+"""Analogue clock
+~~~~~~~~~~~~~~~~~
+
+Shows the time as a traditional watch face together with a battery meter.
+
+.. figure:: res/ChronoApp.png
+    :width: 179
+
+    Screenshot of the analogue clock application
+"""
+
+import wasp
+
+class ChronoApp():
+    """Simple analogue clock application.
+    """
+    NAME = 'Chrono'
+
+    def foreground(self):
+        """Activate the application.
+
+        Configure the status bar, redraw the display and request a periodic
+        tick callback every second.
+        """
+        wasp.system.bar.clock = False
+        self._draw(True)
+        wasp.system.request_tick(1000)
+
+    def sleep(self):
+        """Prepare to enter the low power mode.
+
+        :returns: True, which tells the system manager not to automatically
+                  switch to the default application before sleeping.
+        """
+        return True
+
+    def wake(self):
+        """Return from low power mode.
+
+        Time will have changes whilst we have been asleep so we must
+        udpate the display (but there is no need for a full redraw because
+        the display RAM is preserved during a sleep.
+        """
+        self._draw()
+
+    def tick(self, ticks):
+        """Periodic callback to update the display."""
+        self._draw()
+
+    def _draw(self, redraw=False):
+        """Draw or lazily update the display.
+
+        The updates are as lazy by default and avoid spending time redrawing
+        if the time on display has not changed. However if redraw is set to
+        True then a full redraw is be performed.
+        """
+        draw = wasp.watch.drawable
+        hi =  wasp.system.theme('accent-hi')
+        mid = wasp.system.theme('accent-mid')
+        lo =  wasp.system.theme('accent-lo')
+
+        if redraw:
+            now = wasp.watch.rtc.get_localtime()
+
+            # Clear the display and draw that static parts of the watch face
+            draw.fill()
+
+            # Redraw the status bar
+            wasp.system.bar.draw()
+
+            # Draw the dividers
+            draw.set_color(mid)
+            for theta in range(12):
+                draw.polar(120, 120, theta * 360 // 12, 111, 119, 2)
+
+            self._hh = 0
+            self._mm = 0
+        else:
+            now = wasp.system.bar.update()
+            if not now or self._mm == now[4]:
+                # Skip the update
+                return
+
+        # Undraw old time
+        hh = (30 * (self._hh % 12)) + (self._mm / 2)
+        mm = 6 * self._mm
+        draw.polar(120, 120, hh, 5, 80, 5, 0)
+        draw.polar(120, 120, mm, 5, 110, 3, 0)
+
+        # Record the minute that is currently being displayed
+        self._hh = now[3]
+        self._mm = now[4]
+
+        # Draw the new time
+        hh = (30 * (self._hh % 12)) + (self._mm / 2)
+        mm = 6 * self._mm
+        draw.polar(120, 120, hh, 5, 80, 5, hi)
+        draw.polar(120, 120, hh, 5, 60, 3, lo)
+        draw.polar(120, 120, mm, 5, 110, 3, hi)