Added basic theming engine.

This theming engine uses a bytestring (but supports anything indexable,
as long as the index results are a byte long),
stored as `wasp.system._theme`.
It has a default value, which should not change anything about the way this looks currently.

The theme can be set via `wasp.system.set_theme`,
but this should *ONLY* be used in `main.py`.
`wasp.system.set_theme` will return True if it was successful,
or False if the theme is of an old format.
Using an old format theme will *not* crash the watch,
but will use the default theme instead.

To theme this, one has to use tools/themer.py (use flag -h for complete explanation)
to generate a bytestring that's added in main.py (see diff).

The bytestring is then loaded into 'wasp.system._theme'.
Theme values can be looked up by apps by using `wasp.system.theme("theme-key")`.
Theme keys appear in the function body of `wasp.system.theme()`.

I've took the liberty of converting existing apps to use this method,
and it seems to work well.

A test theme is provided in `tools/test_theme.py`

Signed-off-by: kozova1 <mug66kk@gmail.com>

2 files changed, 96 insertions, 0 deletions

diff --git a/tools/test_theme.py b/tools/test_theme.py
new file mode 100644
index 0000000..dc2b990
--- /dev/null
+++ b/tools/test_theme.py
@@ -0,0 +1,15 @@
+from themer import DefaultTheme
+
+class Theme(DefaultTheme):
+    # These colors were chosen specifically because they're hard to miss.
+    # Using this theme on an actual device is not advised
+    # The default theme was generated by removing all the lines below and adding `pass` instead.
+    BLE_COLOR = 0xfb80
+    SCROLL_INDICATOR_COLOR = 0xf800
+    BATTERY_CHARGING_COLOR = 0x07ff
+    SMALL_CLOCK_COLOR = 0x599f
+    NOTIFICATION_COLOR = 0x8fe0
+    ACCENT_MID = 0xf800
+    ACCENT_LO = 0x001f
+    ACCENT_HI = 0x07e0
+    SLIDER_DEFAULT_COLOR = 0x7777
diff --git a/tools/themer.py b/tools/themer.py
new file mode 100755
index 0000000..819c35c
--- /dev/null
+++ b/tools/themer.py
@@ -0,0 +1,81 @@
+#!/usr/bin/env python3
+"""Compiles themes for wasp-os"""
+
+from argparse import ArgumentParser, RawTextHelpFormatter
+from importlib import import_module
+from typing import Tuple
+
+class DefaultTheme():
+    """This represents the default theme.
+
+    Import this file and extend the Theme class, only changing the variables.
+    Export the resulting class as 'Theme'.
+    serialize() should NEVER be overriden!
+    """
+    BLE_COLOR = 0x7bef
+    SCROLL_INDICATOR_COLOR = 0x7bef
+    BATTERY_CHARGING_COLOR = 0x7bef
+    SMALL_CLOCK_COLOR = 0xe73c
+    NOTIFICATION_COLOR = 0x7bef
+    ACCENT_MID = 0xb5b6
+    ACCENT_LO = 0xbdb6
+    ACCENT_HI = 0xffff
+    SLIDER_DEFAULT_COLOR = 0x39ff
+
+    def serialize(self) -> bytes:
+        """Serializes the theme for use in wasp-os"""
+        def split_bytes(x: int) -> Tuple[int, int]:
+            return (x & 0xFF, (x >> 8) & 0xFF)
+        theme_bytes = bytes([
+            *split_bytes(self.BLE_COLOR),
+            *split_bytes(self.SCROLL_INDICATOR_COLOR),
+            *split_bytes(self.BATTERY_CHARGING_COLOR),
+            *split_bytes(self.SMALL_CLOCK_COLOR),
+            *split_bytes(self.NOTIFICATION_COLOR),
+            *split_bytes(self.ACCENT_MID),
+            *split_bytes(self.ACCENT_LO),
+            *split_bytes(self.ACCENT_HI),
+            *split_bytes(self.SLIDER_DEFAULT_COLOR),
+        ])
+        return theme_bytes
+
+
+if __name__ == '__main__':
+    parser = ArgumentParser(
+        description='''Compiles themes into a format understood by wasp-os.
+                       The resulting string should be put in main.py like this:
+
+                           theme_string = THEME_STRING_GOES_HERE
+
+                       for the theme to take effect.
+                    ''',
+        epilog=''' To create a theme,
+               import this file and extend the DefaultTheme class, only changing the variables.
+               Export the resulting class as 'Theme'.
+               Example:
+               --------
+               theme.py:
+                   from themer import DefaultTheme
+
+                   class Theme(DefaultTheme):
+                       BLE_ICON_COLOR = 0x041F
+
+               shell:
+                   $ ./themer.py theme # NOTE: do not include .py at end of file!
+                   > b'\xef{\xef{\xef{<\xe7\xef{\xb6\xb5\xb6\xbd\xff\xff\xff9'
+
+               main.py:
+                   ...
+                   wasp.system.set_theme(b'\xef{\xef{\xef{<\xe7\xef{\xb6\xb5\xb6\xbd\xff\xff\xff9')
+                   ...
+               ''',
+        formatter_class=RawTextHelpFormatter
+    )
+
+    parser.add_argument('input_file', type=str, nargs=1)
+    args = parser.parse_args()
+
+    theme = DefaultTheme()
+    theme = import_module(args.input_file[0]).Theme()
+    print(theme.serialize())
+