feat: render relevant parts of the screen only

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## Version 0.7.0
+
+- feat: render relevant parts of the screen only
+- feat: keep a copy of the raw data transferred to the display in `config._display.raw_data`
+
 ## Version 0.6.1
 
 - chore: GitHub workflow to publish pushes on `main` branch to PyPI

headless_kivy_pi/__init__.py

@@ -32,7 +32,6 @@
 from kivy.uix.widget import Widget
 
 from headless_kivy_pi import config
-from headless_kivy_pi.constants import IS_TEST_ENVIRONMENT
 from headless_kivy_pi.display import transfer_to_display
 from headless_kivy_pi.logger import logger
 
@@ -61,7 +60,7 @@ class HeadlessWidget(Widget):
 
     def __init__(self: HeadlessWidget, **kwargs: dict[str, object]) -> None:
         """Initialize a `HeadlessWidget`."""
-        if not IS_TEST_ENVIRONMENT:
+        if not config.is_test_environment():
             config.check_initialized()
 
         self.should_ignore_hash = False
@@ -260,6 +259,7 @@ def render_on_display(self: HeadlessWidget, *_: object) -> None:
         thread = Thread(
             target=transfer_to_display,
             args=(
+                (self.x, self.y, self.width, self.height),
                 data,
                 data_hash,
                 last_thread,

headless_kivy_pi/config.py

@@ -8,6 +8,7 @@
 from typing import TYPE_CHECKING, NoReturn, NotRequired, TypedDict
 
 import kivy
+import numpy as np
 from kivy.config import Config
 
 from headless_kivy_pi.constants import (
@@ -20,7 +21,6 @@
     HEIGHT,
     IS_DEBUG_MODE,
     IS_RPI,
-    IS_TEST_ENVIRONMENT,
     MAX_FPS,
     MIN_FPS,
     SYNCHRONOUS_CLOCK,
@@ -80,7 +80,7 @@ class SetupHeadlessConfig(TypedDict):
 
 
 _config: SetupHeadlessConfig | None = None
-_display: DisplaySPI | None = None
+_display: DisplaySPI = None
 
 
 def report_uninitialized() -> NoReturn:
@@ -134,16 +134,19 @@ def setup_headless_kivy(config: SetupHeadlessConfig) -> None:
 {BITS_PER_BYTE}))"""
         raise ValueError(msg)
 
-    if IS_TEST_ENVIRONMENT:
+    if is_test_environment():
         Config.set('graphics', 'window_state', 'hidden')
         from kivy.core.window import Window
-    elif IS_RPI:
+
+    from kivy.metrics import dp
+
+    if IS_RPI:
         Config.set('graphics', 'window_state', 'hidden')
-        spi = board.SPI()
         # Configuration for CS and DC pins (these are PiTFT defaults):
         cs_pin = digitalio.DigitalInOut(board.CE0)
         dc_pin = digitalio.DigitalInOut(board.D25)
         reset_pin = digitalio.DigitalInOut(board.D24)
+        spi = board.SPI()
         _display = display_class(
             spi,
             height=height(),
@@ -171,11 +174,17 @@ def setup_headless_kivy(config: SetupHeadlessConfig) -> None:
         from screeninfo import get_monitors
 
         monitor = get_monitors()[0]
+        _display = Fake()
 
         Window._win.set_always_on_top(True)  # noqa: SLF001
         Window._set_top(200)  # noqa: SLF001
         Window._set_left(monitor.width - Window._size[0])  # noqa: SLF001
 
+    _display.raw_data = np.zeros(
+        (int(dp(width())), int(dp(height())), 3),
+        dtype=np.uint8,
+    )
+
 
 def check_initialized() -> None:
     """Check if the module has been initialized."""
@@ -223,6 +232,14 @@ def is_debug_mode() -> bool:
     report_uninitialized()
 
 
+@cache
+def is_test_environment() -> bool:
+    """Return `True` if the application is running in test environment."""
+    import os
+
+    return 'PYTEST_CURRENT_TEST' in os.environ
+
+
 @cache
 def double_buffering() -> bool:
     """Generate the next frame while sending the last frame to the display."""

headless_kivy_pi/constants.py

@@ -12,9 +12,6 @@
 
 # Configure the headless mode for the Kivy application and initialize the display
 
-IS_TEST_ENVIRONMENT = (
-    strtobool(os.environ.get('HEADLESS_KIVY_PI_TEST_ENVIRONMENT', 'False')) == 1
-)
 MIN_FPS = int(os.environ.get('HEADLESS_KIVY_PI_MIN_FPS', '1'))
 MAX_FPS = int(os.environ.get('HEADLESS_KIVY_PI_MAX_FPS', '32'))
 WIDTH = int(os.environ.get('HEADLESS_KIVY_PI_WIDTH', '240'))

headless_kivy_pi/display.py

@@ -15,6 +15,7 @@
 
 
 def transfer_to_display(
+    rectangle: tuple[int, int, int, int],
     data: NDArray[np.uint16],
     data_hash: int,
     last_render_thread: Thread,
@@ -23,11 +24,7 @@ def transfer_to_display(
     logger.debug(f'Rendering frame with hash "{data_hash}"')
 
     # Flip the image vertically
-    data = data.reshape(
-        config.width(),
-        config.height(),
-        -1,
-    )[::-1, :, :3].astype(np.uint16)
+    data = data.reshape(rectangle[2], rectangle[3], -1)[::-1, :, :3].astype(np.uint8)
 
     color = (
         ((data[:, :, 0] & 0xF8) << 8)
@@ -45,10 +42,7 @@ def transfer_to_display(
     # Only render when running on a Raspberry Pi
     display = config._display  # noqa: SLF001
     if display:
-        display._block(  # noqa: SLF001
-            0,
-            0,
-            config.width() - 1,
-            config.height() - 1,
-            data_bytes,
-        )
+        display.raw_data[rectangle[0] : rectangle[0] + rectangle[2]][
+            rectangle[1] : rectangle[1] + rectangle[3]
+        ] = data
+        display._block(*rectangle, data_bytes)  # noqa: SLF001

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "headless-kivy-pi"
-version = "0.6.1"
+version = "0.7.0"
 description = "Headless renderer for Kivy framework on Raspberry Pi"
 authors = ["Sassan Haradji <[email protected]>"]
 license = "Apache-2.0"