Fix proxy camera crop breaking after a small frame (#183798)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

homeassistant/components/proxy/camera.py

@@ -160,18 +160,25 @@ def _crop_image(image, opts):
     quality = opts.quality or DEFAULT_QUALITY
     (old_width, old_height) = img.size
     old_size = len(image)
-    if opts.top is None:
-        opts.top = 0
-    if opts.left is None:
-        opts.left = 0
-    if opts.max_width is None or opts.max_width > old_width - opts.left:
-        opts.max_width = old_width - opts.left
-    if opts.max_height is None or opts.max_height > old_height - opts.top:
-        opts.max_height = old_height - opts.top
+    top = opts.top or 0
+    left = opts.left or 0
+    width = old_width - left
+    if opts.max_width is not None:
+        width = min(opts.max_width, width)
+    height = old_height - top
+    if opts.max_height is not None:
+        height = min(opts.max_height, height)
+    if width <= 0 or height <= 0:
+        _LOGGER.debug(
+            "Image (%dx%d) is too small to crop at (%d, %d)",
+            old_width,
+            old_height,
+            left,
+            top,
+        )
+        return image
 
-    img = img.crop(
-        (opts.left, opts.top, opts.left + opts.max_width, opts.top + opts.max_height)
-    )
+    img = img.crop((left, top, left + width, top + height))
     imgbuf = io.BytesIO()
     img.save(imgbuf, "JPEG", optimize=True, quality=quality)
     newimage = imgbuf.getvalue()
@@ -181,8 +188,8 @@ def _crop_image(image, opts):
         old_width,
         old_height,
         old_size,
-        opts.max_width,
-        opts.max_height,
+        width,
+        height,
         len(newimage),
     )
     return newimage

tests/components/proxy/__init__.py

@@ -0,0 +1 @@
+"""Tests for the Camera Proxy integration."""

tests/components/proxy/test_camera.py

@@ -0,0 +1,84 @@
+"""Tests for the Camera Proxy camera platform."""
+
+from collections.abc import AsyncGenerator
+import io
+from unittest.mock import AsyncMock, patch
+
+from PIL import Image as PilImage
+import pytest
+
+from homeassistant.components.camera import Image, async_get_image
+from homeassistant.components.proxy.camera import ProxyCamera
+from homeassistant.core import HomeAssistant
+from homeassistant.setup import async_setup_component
+
+from tests.typing import ClientSessionGenerator
+
+CROP_CONFIG = {
+    "platform": "proxy",
+    "entity_id": "camera.source",
+    "name": "Cropped",
+    "mode": "crop",
+    "max_image_width": 400,
+    "max_image_height": 225,
+    "max_stream_width": 400,
+    "max_stream_height": 225,
+    "image_left": 550,
+    "image_top": 90,
+}
+
+
+def _jpeg(width: int, height: int) -> Image:
+    buffer = io.BytesIO()
+    PilImage.new("RGB", (width, height)).save(buffer, "JPEG")
+    return Image("image/jpeg", buffer.getvalue())
+
+
+def _size(content: bytes) -> tuple[int, int]:
+    return PilImage.open(io.BytesIO(content)).size
+
+
+@pytest.fixture
+async def setup_proxy(hass: HomeAssistant) -> AsyncGenerator[None]:
+    """Set up a cropping proxy camera with no delay between stream frames."""
+    with patch.object(ProxyCamera, "_attr_frame_interval", 0):
+        assert await async_setup_component(hass, "camera", {"camera": CROP_CONFIG})
+        await hass.async_block_till_done()
+        yield
+
+
+@pytest.mark.usefixtures("setup_proxy")
+async def test_crop_image_after_small_frame(hass: HomeAssistant) -> None:
+    """Test a frame smaller than the crop area does not break later crops."""
+    small = _jpeg(320, 180)
+    with patch(
+        "homeassistant.components.proxy.camera.async_get_image",
+        AsyncMock(side_effect=[small, _jpeg(1536, 576)]),
+    ):
+        first = await async_get_image(hass, "camera.cropped")
+        second = await async_get_image(hass, "camera.cropped")
+
+    assert first.content == small.content
+    assert _size(second.content) == (400, 225)
+
+
+@pytest.mark.usefixtures("setup_proxy")
+async def test_crop_stream_after_small_frame(
+    hass: HomeAssistant, hass_client: ClientSessionGenerator
+) -> None:
+    """Test a small frame does not break the cropped MJPEG stream."""
+    client = await hass_client()
+    with patch(
+        "homeassistant.components.proxy.camera.async_get_image",
+        AsyncMock(side_effect=[_jpeg(320, 180), _jpeg(1536, 576), None]),
+    ):
+        response = await client.get("/api/camera_proxy_stream/camera.cropped")
+        body = await response.read()
+
+    assert response.status == 200
+    frames = [
+        part.split(b"\r\n\r\n", 1)[1].rstrip(b"\r\n")
+        for part in body.split(b"--frameboundary\r\n")
+        if b"\r\n\r\n" in part
+    ]
+    assert _size(frames[-1]) == (400, 225)