supervision/tests/utils/test_image.py

514 lines
17 KiB
Python

from __future__ import annotations
import warnings
from unittest.mock import Mock, patch
import numpy as np
import pytest
import requests
from PIL import Image, ImageChops
from supervision import _cv2 as cv2
from supervision.utils.image import (
ImageSink,
_overlay_image,
crop_image,
get_image_resolution_wh,
letterbox_image,
load_image_from_url,
overlay_image,
resize_image,
scale_image,
tint_image,
)
class TestLoadImageFromUrl:
def test_returns_decoded_image(self, tmp_path) -> None:
"""Valid image URL returns an OpenCV image."""
# given
image = np.full((10, 20, 3), 127, dtype=np.uint8)
encoded = cv2.imencode(".jpg", image)[1]
response = Mock()
response.content = encoded.tobytes()
response.raise_for_status.return_value = None
# when
with patch("supervision.utils.file.requests.get", return_value=response) as get:
result = load_image_from_url(
"https://media.roboflow.com/quickstart/dog.jpeg",
cache_dir=tmp_path,
)
# then
get.assert_called_once_with(
"https://media.roboflow.com/quickstart/dog.jpeg",
stream=False,
allow_redirects=True,
timeout=30.0,
)
assert result.shape == image.shape
assert result.dtype == np.uint8
response.close.assert_called_once()
def test_uses_cached_image_on_repeated_calls(self, tmp_path) -> None:
"""Repeated image URL loads use the local cache."""
# given
image = np.full((10, 20, 3), 127, dtype=np.uint8)
encoded = cv2.imencode(".jpg", image)[1]
response = Mock()
response.content = encoded.tobytes()
response.raise_for_status.return_value = None
# when
with patch("supervision.utils.file.requests.get", return_value=response) as get:
first_result = load_image_from_url(
"https://media.roboflow.com/quickstart/dog.jpeg",
cache_dir=tmp_path,
)
second_result = load_image_from_url(
"https://media.roboflow.com/quickstart/dog.jpeg",
cache_dir=tmp_path,
)
# then
get.assert_called_once()
assert first_result.shape == image.shape
assert second_result.shape == image.shape
def test_downloads_each_time_when_cache_is_disabled(self, tmp_path) -> None:
"""Disabled cache skips cache reads and writes."""
# given
image = np.full((10, 20, 3), 127, dtype=np.uint8)
encoded = cv2.imencode(".jpg", image)[1]
first_response = Mock()
first_response.content = encoded.tobytes()
first_response.raise_for_status.return_value = None
second_response = Mock()
second_response.content = encoded.tobytes()
second_response.raise_for_status.return_value = None
# when
with patch(
"supervision.utils.file.requests.get",
side_effect=[first_response, second_response],
) as get:
first_result = load_image_from_url(
"https://media.roboflow.com/quickstart/dog.jpeg",
cache_dir=tmp_path,
use_cache=False,
)
second_result = load_image_from_url(
"https://media.roboflow.com/quickstart/dog.jpeg",
cache_dir=tmp_path,
use_cache=False,
)
# then
assert get.call_count == 2
assert first_result.shape == image.shape
assert second_result.shape == image.shape
assert list(tmp_path.iterdir()) == []
def test_force_reload_refreshes_cached_image(self, tmp_path) -> None:
"""Force reload bypasses the cached image and refreshes it."""
# given
first_image = np.zeros((10, 20, 3), dtype=np.uint8)
second_image = np.full((12, 22, 3), 127, dtype=np.uint8)
first_response = Mock()
first_response.content = cv2.imencode(".jpg", first_image)[1].tobytes()
first_response.raise_for_status.return_value = None
second_response = Mock()
second_response.content = cv2.imencode(".jpg", second_image)[1].tobytes()
second_response.raise_for_status.return_value = None
# when
with patch(
"supervision.utils.file.requests.get",
side_effect=[first_response, second_response],
) as get:
cached_result = load_image_from_url(
"https://media.roboflow.com/quickstart/dog.jpeg",
cache_dir=tmp_path,
)
refreshed_result = load_image_from_url(
"https://media.roboflow.com/quickstart/dog.jpeg",
cache_dir=tmp_path,
force_reload=True,
)
# then
assert get.call_count == 2
assert cached_result.shape == first_image.shape
assert refreshed_result.shape == second_image.shape
def test_redownloads_when_cached_image_is_invalid(self, tmp_path) -> None:
"""Invalid cached image bytes are discarded and downloaded again."""
# given
image = np.full((10, 20, 3), 127, dtype=np.uint8)
first_response = Mock()
first_response.content = cv2.imencode(".jpg", image)[1].tobytes()
first_response.raise_for_status.return_value = None
second_response = Mock()
second_response.content = cv2.imencode(".jpg", image)[1].tobytes()
second_response.raise_for_status.return_value = None
# when
with patch(
"supervision.utils.file.requests.get",
side_effect=[first_response, second_response],
) as get:
load_image_from_url(
"https://media.roboflow.com/quickstart/dog.jpeg",
cache_dir=tmp_path,
)
for cache_file in tmp_path.iterdir():
cache_file.write_bytes(b"not an image")
result = load_image_from_url(
"https://media.roboflow.com/quickstart/dog.jpeg",
cache_dir=tmp_path,
)
# then
assert get.call_count == 2
assert result.shape == image.shape
def test_raises_when_bytes_are_not_image(self, tmp_path) -> None:
"""Invalid image bytes raise ValueError."""
# given
response = Mock()
response.content = b"not an image"
response.raise_for_status.return_value = None
# when / then
with (
patch("supervision.utils.file.requests.get", return_value=response),
pytest.raises(ValueError, match="could not be decoded into image"),
):
load_image_from_url(
"https://media.roboflow.com/quickstart/dog.jpeg",
cache_dir=tmp_path,
)
response.close.assert_called_once()
def test_raises_for_request_error(self, tmp_path) -> None:
"""Request failures are propagated."""
# given
request_error = requests.RequestException("boom")
# when / then
with (
patch("supervision.utils.file.requests.get", side_effect=request_error),
pytest.raises(requests.RequestException, match="boom"),
):
load_image_from_url(
"https://media.roboflow.com/quickstart/dog.jpeg",
cache_dir=tmp_path,
)
def test_rejects_non_http_url(self) -> None:
"""Non-HTTP URLs are rejected before making a request."""
# given
with patch("supervision.utils.file.requests.get") as get:
# when / then
with pytest.raises(ValueError, match="HTTP"):
load_image_from_url("file:///tmp/image.jpg")
get.assert_not_called()
def test_resize_image_for_opencv_image() -> None:
# given
image = np.zeros((480, 640, 3), dtype=np.uint8)
expected_result = np.zeros((768, 1024, 3), dtype=np.uint8)
# when
result = resize_image(
image=image,
resolution_wh=(1024, 1024),
keep_aspect_ratio=True,
)
# then
assert np.allclose(result, expected_result), (
"Expected output shape to be (w, h): (1024, 768)"
)
def test_resize_image_for_pillow_image() -> None:
# given
image = Image.new(mode="RGB", size=(640, 480), color=(0, 0, 0))
expected_result = Image.new(mode="RGB", size=(1024, 768), color=(0, 0, 0))
# when
result = resize_image(
image=image,
resolution_wh=(1024, 1024),
keep_aspect_ratio=True,
)
# then
assert result.size == (1024, 768), "Expected output shape to be (w, h): (1024, 768)"
difference = ImageChops.difference(result, expected_result)
assert difference.getbbox() is None, (
"Expected no difference in resized image content as the image is all zeros"
)
def test_letterbox_image_for_opencv_image() -> None:
# given
image = np.zeros((480, 640, 3), dtype=np.uint8)
expected_result = np.concatenate(
[
np.ones((128, 1024, 3), dtype=np.uint8) * 255,
np.zeros((768, 1024, 3), dtype=np.uint8),
np.ones((128, 1024, 3), dtype=np.uint8) * 255,
],
axis=0,
)
# when
result = letterbox_image(
image=image, resolution_wh=(1024, 1024), color=(255, 255, 255)
)
# then
assert np.allclose(result, expected_result), (
"Expected output shape to be (w, h): "
"(1024, 1024) with padding added top and bottom"
)
def test_letterbox_image_for_grayscale_opencv_image() -> None:
image = np.zeros((4, 6), dtype=np.uint8)
expected_result = np.concatenate(
[
np.ones((2, 10), dtype=np.uint8) * 255,
np.zeros((6, 10), dtype=np.uint8),
np.ones((2, 10), dtype=np.uint8) * 255,
],
axis=0,
)
result = letterbox_image(image=image, resolution_wh=(10, 10), color=(255, 255, 255))
assert result.shape == (10, 10)
assert np.array_equal(result, expected_result)
def test_letterbox_image_for_rgba_opencv_image() -> None:
"""RGBA input: padded alpha=0, interior alpha preserved, input array not mutated."""
# given
image = np.zeros((4, 6, 4), dtype=np.uint8)
image[:, :, 3] = 128
image_before = image.copy()
# when
result = letterbox_image(image=image, resolution_wh=(10, 10), color=(0, 0, 0))
# then
assert result.shape == (10, 10, 4)
assert np.all(result[:2, :, 3] == 0), "padded top rows must have alpha=0"
assert np.all(result[8:, :, 3] == 0), "padded bottom rows must have alpha=0"
assert np.all(result[2:8, :, 3] == 128), "interior rows must preserve alpha"
assert np.array_equal(image, image_before), "input must not be mutated"
def test_letterbox_image_for_pillow_image() -> None:
# given
image = Image.new(mode="RGB", size=(640, 480), color=(0, 0, 0))
expected_result = Image.fromarray(
np.concatenate(
[
np.ones((128, 1024, 3), dtype=np.uint8) * 255,
np.zeros((768, 1024, 3), dtype=np.uint8),
np.ones((128, 1024, 3), dtype=np.uint8) * 255,
],
axis=0,
)
)
# when
result = letterbox_image(
image=image, resolution_wh=(1024, 1024), color=(255, 255, 255)
)
# then
assert result.size == (
1024,
1024,
), "Expected output shape to be (w, h): (1024, 1024)"
difference = ImageChops.difference(result, expected_result)
assert difference.getbbox() is None, (
"Expected padding to be added top and bottom with padding added top and bottom"
)
def test_overlay_image_blends_rgba_with_float32_rounding() -> None:
"""RGBA overlay uses current float32 blend semantics."""
# given
image = np.full((1, 1, 3), 22, dtype=np.uint8)
overlay = np.array([[[39, 39, 39, 60]]], dtype=np.uint8)
expected = np.full((1, 1, 3), 26, dtype=np.uint8)
# when
result = overlay_image(image=image, overlay=overlay, anchor=(0, 0))
# then
np.testing.assert_array_equal(result, expected)
def test_overlay_image_public_wrapper_delegates_to_internal() -> None:
"""Public `overlay_image` still produces the internal `_overlay_image` result."""
# given
image = np.full((1, 1, 3), 22, dtype=np.uint8)
overlay = np.array([[[39, 39, 39, 60]]], dtype=np.uint8)
expected = _overlay_image(image=image.copy(), overlay=overlay, anchor=(0, 0))
# when
with warnings.catch_warnings():
warnings.simplefilter("ignore", FutureWarning)
result = overlay_image(image=image.copy(), overlay=overlay, anchor=(0, 0))
# then
np.testing.assert_array_equal(result, expected)
def test_overlay_image_emits_future_warning() -> None:
"""Public overlay_image must still emit FutureWarning after internal refactor."""
# given
image = np.zeros((2, 2, 3), dtype=np.uint8)
overlay = np.full((1, 1, 3), 255, dtype=np.uint8)
# pyDeprecate tracks per-function warned_calls (default num_warns=1) so the
# warning fires only once per process. Reset to make this test order-independent.
overlay_image._state.warned_calls = 0
# when
with warnings.catch_warnings(record=True) as caught:
warnings.simplefilter("always")
overlay_image(image=image, overlay=overlay, anchor=(0, 0))
# then
assert any(issubclass(w.category, FutureWarning) for w in caught)
def test_overlay_image_crops_rgba_overlay_at_scene_boundary() -> None:
"""RGBA overlay is cropped when anchored outside scene bounds."""
# given
image = np.zeros((3, 3, 3), dtype=np.uint8)
overlay = np.array(
[
[[1, 11, 21, 255], [2, 12, 22, 255], [3, 13, 23, 255]],
[[4, 14, 24, 255], [5, 15, 25, 255], [6, 16, 26, 255]],
[[7, 17, 27, 255], [8, 18, 28, 255], [9, 19, 29, 255]],
],
dtype=np.uint8,
)
expected = np.zeros((3, 3, 3), dtype=np.uint8)
expected[:2, :2] = overlay[1:, 1:, :3]
# when
result = overlay_image(image=image, overlay=overlay, anchor=(-1, -1))
# then
np.testing.assert_array_equal(result, expected)
@pytest.mark.parametrize(
("image", "xyxy", "expected_size"),
[
# NumPy RGB
(
np.zeros((4, 6, 3), dtype=np.uint8),
(2, 1, 5, 3),
(3, 2), # width = 5-2, height = 3-1
),
# NumPy grayscale
(
np.zeros((5, 5), dtype=np.uint8),
(1, 1, 4, 4),
(3, 3),
),
# Pillow RGB
(
Image.new("RGB", (6, 4), color=0),
(2, 1, 5, 3),
(3, 2),
),
# Pillow grayscale
(
Image.new("L", (5, 5), color=0),
(1, 1, 4, 4),
(3, 3),
),
],
)
def test_crop_image(image, xyxy, expected_size) -> None:
cropped = crop_image(image=image, xyxy=xyxy)
if isinstance(image, np.ndarray):
assert isinstance(cropped, np.ndarray)
assert cropped.shape[1] == expected_size[0] # width
assert cropped.shape[0] == expected_size[1] # height
else:
assert isinstance(cropped, Image.Image)
assert cropped.size == expected_size
def test_crop_image_clips_out_of_bounds_coordinates() -> None:
"""Out-of-bounds crops must clip consistently for NumPy and Pillow inputs."""
image_np = np.arange(16, dtype=np.uint8).reshape(4, 4)
image_pil = Image.fromarray(image_np)
xyxy = (-2, -1, 3, 3)
expected = image_np[0:3, 0:3]
np.testing.assert_array_equal(crop_image(image=image_np, xyxy=xyxy), expected)
np.testing.assert_array_equal(
np.asarray(crop_image(image=image_pil, xyxy=xyxy)), expected
)
@pytest.mark.parametrize(
("image", "expected"),
[
# NumPy RGB
(np.zeros((4, 6, 3), dtype=np.uint8), (6, 4)),
# NumPy grayscale
(np.zeros((10, 20), dtype=np.uint8), (20, 10)),
# Pillow RGB
(Image.new("RGB", (6, 4), color=0), (6, 4)),
# Pillow grayscale
(Image.new("L", (20, 10), color=0), (20, 10)),
],
)
def test_get_image_resolution_wh(image, expected) -> None:
resolution = get_image_resolution_wh(image)
assert resolution == expected
def test_image_sink_raises_when_cv2_write_fails(monkeypatch, tmp_path) -> None:
"""ImageSink.save_image raises and keeps count stable when OpenCV write fails."""
monkeypatch.setattr(cv2, "imwrite", lambda *_: False)
with ImageSink(str(tmp_path)) as sink:
with pytest.raises(OSError, match="Failed to save image"):
sink.save_image(np.zeros((2, 2, 3), dtype=np.uint8))
assert sink.image_count == 0
@pytest.mark.parametrize(
("func", "kwargs"),
[
pytest.param(scale_image, {"scale_factor": 1.0}, id="scale_image"),
pytest.param(resize_image, {"resolution_wh": (10, 10)}, id="resize_image"),
pytest.param(
letterbox_image, {"resolution_wh": (10, 10)}, id="letterbox_image"
),
pytest.param(tint_image, {}, id="tint_image"),
],
)
def test_image_utils_wrong_type_raises(func, kwargs):
"""Wrong image type raises TypeError via decorator."""
with pytest.raises(TypeError, match="Unsupported image type"):
func(image="not_an_image", **kwargs)