X-Git-Url: https://git.ayoreis.com/hackapet/Adafruit_Blinka_Displayio.git/blobdiff_plain/cfee25c8ae316776ce54589eae64409ea41bc42b..HEAD:/displayio/__init__.py

diff --git a/displayio/__init__.py b/displayio/__init__.py
index 55bb1d5..e42d24a 100644
--- a/displayio/__init__.py
+++ b/displayio/__init__.py
@@ -17,22 +17,19 @@ displayio for Blinka
 
 """
 import threading
+import time
 from typing import Union
-from ._fourwire import FourWire
-from ._i2cdisplay import I2CDisplay
+
 from ._bitmap import Bitmap
 from ._colorspace import Colorspace
 from ._colorconverter import ColorConverter
-from ._display import Display
-from ._epaperdisplay import EPaperDisplay
 from ._group import Group
 from ._ondiskbitmap import OnDiskBitmap
 from ._palette import Palette
-from ._shape import Shape
 from ._tilegrid import TileGrid
-from ._displaybus import _DisplayBus
 from ._constants import CIRCUITPY_DISPLAY_LIMIT
 
+
 __version__ = "0.0.0+auto.0"
 __repo__ = "https://github.com/adafruit/Adafruit_Blinka_displayio.git"
 
@@ -41,12 +38,16 @@ displays = []
 display_buses = []
 
 
-def _background():
+def _background(stop_event):
     """Main thread function to loop through all displays and update them"""
-    while True:
+    while not stop_event.is_set():
         for display in displays:
             display._background()  # pylint: disable=protected-access
 
+        # relax system when _background does nothing
+        # and we are in a while True loop consuming lots of CPU
+        time.sleep(0.0)
+
 
 def release_displays() -> None:
     """Releases any actively used displays so their busses and pins can be used again.
@@ -63,14 +64,16 @@ def release_displays() -> None:
     display_buses.clear()
 
 
-def allocate_display(new_display: Union[Display, EPaperDisplay]) -> None:
+def allocate_display(
+    new_display: Union["busdisplay.BusDisplay", "epaperdisplay.EPaperDisplay"]
+) -> None:
     """Add a display to the displays pool and return the new display"""
     if len(displays) >= CIRCUITPY_DISPLAY_LIMIT:
         raise RuntimeError("Too many displays")
     displays.append(new_display)
 
 
-def allocate_display_bus(new_display_bus: _DisplayBus) -> None:
+def allocate_display_bus(new_display_bus: "busdisplay._displaybus._DisplayBus") -> None:
     """Add a display bus to the display_buses pool and return the new display bus"""
     if len(display_buses) >= CIRCUITPY_DISPLAY_LIMIT:
         raise RuntimeError(
@@ -79,7 +82,10 @@ def allocate_display_bus(new_display_bus: _DisplayBus) -> None:
     display_buses.append(new_display_bus)
 
 
-background_thread = threading.Thread(target=_background, daemon=True)
+background_thread_stop_event = threading.Event()
+background_thread = threading.Thread(
+    target=_background, args=(background_thread_stop_event,), daemon=True
+)
 
 
 # Start the background thread
@@ -90,6 +96,7 @@ def _start_background():
 
 def _stop_background():
     if background_thread.is_alive():
+        background_thread_stop_event.set()
         # Stop the thread
         background_thread.join()