test_image.py

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
from pathlib import Path

import numpy as np
import pytest
from PIL import Image, ImageChops

from vllm.multimodal.image import ImageMediaIO, convert_image_mode

pytestmark = pytest.mark.cpu_test

ASSETS_DIR = Path(__file__).parent / "assets"
assert ASSETS_DIR.exists()


def test_rgb_to_rgb():
    # Start with an RGB image.
    original_image = Image.open(ASSETS_DIR / "image1.png").convert("RGB")
    converted_image = convert_image_mode(original_image, "RGB")

    # RGB to RGB should be a no-op.
    diff = ImageChops.difference(original_image, converted_image)
    assert diff.getbbox() is None


def test_rgba_to_rgb():
    original_image = Image.open(ASSETS_DIR / "rgba.png")
    original_image_numpy = np.array(original_image)

    converted_image = convert_image_mode(original_image, "RGB")
    converted_image_numpy = np.array(converted_image)

    for i in range(original_image_numpy.shape[0]):
        for j in range(original_image_numpy.shape[1]):
            # Verify that all transparent pixels are converted to white.
            if original_image_numpy[i][j][3] == 0:
                assert converted_image_numpy[i][j][0] == 255
                assert converted_image_numpy[i][j][1] == 255
                assert converted_image_numpy[i][j][2] == 255


def test_rgba_to_rgb_custom_background(tmp_path):
    """Test RGBA to RGB conversion with custom background colors."""
    # Create a simple RGBA image with transparent and opaque pixels
    rgba_image = Image.new("RGBA", (10, 10), (255, 0, 0, 255))  # Red with full opacity

    # Make top-left quadrant transparent
    for i in range(5):
        for j in range(5):
            rgba_image.putpixel((i, j), (0, 0, 0, 0))  # Fully transparent

    # Save the test image to tmp_path
    test_image_path = tmp_path / "test_rgba.png"
    rgba_image.save(test_image_path)

    # Test 1: Default white background (backward compatibility)
    image_io_default = ImageMediaIO()
    converted_default = image_io_default.load_file(test_image_path)
    default_numpy = np.array(converted_default)

    # Check transparent pixels are white
    assert default_numpy[0][0][0] == 255  # R
    assert default_numpy[0][0][1] == 255  # G
    assert default_numpy[0][0][2] == 255  # B
    # Check opaque pixels remain red
    assert default_numpy[5][5][0] == 255  # R
    assert default_numpy[5][5][1] == 0  # G
    assert default_numpy[5][5][2] == 0  # B

    # Test 2: Custom black background via kwargs
    image_io_black = ImageMediaIO(rgba_background_color=(0, 0, 0))
    converted_black = image_io_black.load_file(test_image_path)
    black_numpy = np.array(converted_black)

    # Check transparent pixels are black
    assert black_numpy[0][0][0] == 0  # R
    assert black_numpy[0][0][1] == 0  # G
    assert black_numpy[0][0][2] == 0  # B
    # Check opaque pixels remain red
    assert black_numpy[5][5][0] == 255  # R
    assert black_numpy[5][5][1] == 0  # G
    assert black_numpy[5][5][2] == 0  # B

    # Test 3: Custom blue background via kwargs (as list)
    image_io_blue = ImageMediaIO(rgba_background_color=[0, 0, 255])
    converted_blue = image_io_blue.load_file(test_image_path)
    blue_numpy = np.array(converted_blue)

    # Check transparent pixels are blue
    assert blue_numpy[0][0][0] == 0  # R
    assert blue_numpy[0][0][1] == 0  # G
    assert blue_numpy[0][0][2] == 255  # B

    # Test 4: Test with load_bytes method
    with open(test_image_path, "rb") as f:
        image_data = f.read()

    image_io_green = ImageMediaIO(rgba_background_color=(0, 255, 0))
    converted_green = image_io_green.load_bytes(image_data)
    green_numpy = np.array(converted_green)

    # Check transparent pixels are green
    assert green_numpy[0][0][0] == 0  # R
    assert green_numpy[0][0][1] == 255  # G
    assert green_numpy[0][0][2] == 0  # B


def test_rgba_background_color_validation():
    """Test that invalid rgba_background_color values are properly rejected."""

    # Test invalid types
    with pytest.raises(
        ValueError, match="rgba_background_color must be a list or tuple"
    ):
        ImageMediaIO(rgba_background_color="255,255,255")

    with pytest.raises(
        ValueError, match="rgba_background_color must be a list or tuple"
    ):
        ImageMediaIO(rgba_background_color=255)

    # Test wrong number of elements
    with pytest.raises(
        ValueError, match="rgba_background_color must be a list or tuple"
    ):
        ImageMediaIO(rgba_background_color=(255, 255))

    with pytest.raises(
        ValueError, match="rgba_background_color must be a list or tuple"
    ):
        ImageMediaIO(rgba_background_color=(255, 255, 255, 255))

    # Test non-integer values
    with pytest.raises(
        ValueError, match="rgba_background_color must be a list or tuple"
    ):
        ImageMediaIO(rgba_background_color=(255.0, 255.0, 255.0))

    with pytest.raises(
        ValueError, match="rgba_background_color must be a list or tuple"
    ):
        ImageMediaIO(rgba_background_color=(255, "255", 255))

    # Test out of range values
    with pytest.raises(
        ValueError, match="rgba_background_color must be a list or tuple"
    ):
        ImageMediaIO(rgba_background_color=(256, 255, 255))

    with pytest.raises(
        ValueError, match="rgba_background_color must be a list or tuple"
    ):
        ImageMediaIO(rgba_background_color=(255, -1, 255))

    # Test that valid values work
    ImageMediaIO(rgba_background_color=(0, 0, 0))  # Should not raise
    ImageMediaIO(rgba_background_color=[255, 255, 255])  # Should not raise
    ImageMediaIO(rgba_background_color=(128, 128, 128))  # Should not raise