Merge pull request #156 from janvolck/main

[hackapet/Adafruit_Blinka_Displayio.git] / displayio / __init__.py

diff --git a/displayio/__init__.py b/displayio/__init__.py
index c0d35a3f033f274df9b5bf22ebdee16b745aca2e..e42d24a60d48c00019de9cd474d0a8f458497f96 100644 (file)
--- a/displayio/__init__.py
+++ b/displayio/__init__.py
@@ -17,12 +17,9 @@ displayio for Blinka
 
 """
 import threading
+import time
 from typing import Union
 
-import fourwire
-from busdisplay import BusDisplay
-from busdisplay._displaybus import _DisplayBus
-from epaperdisplay import EPaperDisplay
 from ._bitmap import Bitmap
 from ._colorspace import Colorspace
 from ._colorconverter import ColorConverter
@@ -32,10 +29,6 @@ from ._palette import Palette
 from ._tilegrid import TileGrid
 from ._constants import CIRCUITPY_DISPLAY_LIMIT
 
-# 8.x Backwards compatibility, remove at 10.x or
-# when compatibility is removed from core displayio
-Display = BusDisplay
-FourWire = fourwire.FourWire
 
 __version__ = "0.0.0+auto.0"
 __repo__ = "https://github.com/adafruit/Adafruit_Blinka_displayio.git"
@@ -45,12 +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.
@@ -67,14 +64,16 @@ def release_displays() -> None:
     display_buses.clear()
 
 
-def allocate_display(new_display: Union[BusDisplay, 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(
@@ -83,7 +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
@@ -94,6 +96,7 @@ def _start_background():
 
 def _stop_background():
     if background_thread.is_alive():
+        background_thread_stop_event.set()
         # Stop the thread
         background_thread.join()