filters.py

import cv2
import numpy as np
from registry import registry


@registry.register("Original")
def original(image):
    """
    ## Original Image - no filter applied.
    
    **Args:**
    * `image` (numpy.ndarray): Input image
    
    **Returns:**
    * `numpy.ndarray`: Original image
    """
    return image


@registry.register("Dot Effect", defaults={
    "dot_size": 10,
    "dot_spacing": 2,
    "invert": False,
}, min_vals={
    "dot_size": 1,
    "dot_spacing": 1,
}, max_vals={
    "dot_size": 20,
    "dot_spacing": 10,
}, step_vals={
    "dot_size": 1,
    "dot_spacing": 1,
})
def dot_effect(image, dot_size: int = 10, dot_spacing: int = 2, invert: bool = False):
    """
    ## Convert image to artistic dot pattern effect.
    
    **Args:**
    * `image` (numpy.ndarray): Input image (BGR or grayscale)
    * `dot_size` (int): Size of each dot
    * `dot_spacing` (int): Spacing between dots
    * `invert` (bool): Invert dot colors
    
    **Returns:**
    * `numpy.ndarray`: Dotted image
    """
    if len(image.shape) == 3:
        gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
    else:
        gray = image

    gray = cv2.adaptiveThreshold(
        gray, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C,
        cv2.THRESH_BINARY, 25, 5
    )

    height, width = gray.shape
    canvas = np.zeros_like(gray) if not invert else np.full_like(gray, 255)

    y_dots = range(0, height, dot_size + dot_spacing)
    x_dots = range(0, width, dot_size + dot_spacing)

    dot_color = 255 if not invert else 0
    for y in y_dots:
        for x in x_dots:
            region = gray[y:min(y+dot_size, height), x:min(x+dot_size, width)]
            if region.size > 0:
                brightness = np.mean(region)
                relative_brightness = brightness / 255.0
                if invert:
                    relative_brightness = 1 - relative_brightness
                radius = int((dot_size/2) * relative_brightness)
                if radius > 0:
                    cv2.circle(canvas, (x + dot_size//2, y + dot_size//2),
                             radius, (dot_color), -1)

    return canvas


@registry.register("Pixelize", defaults={
    "pixel_size": 10,
}, min_vals={
    "pixel_size": 1,
}, max_vals={
    "pixel_size": 50,
}, step_vals={
    "pixel_size": 1,
})
def pixelize(image, pixel_size: int = 10):
    """
    ## Create pixelated effect (8-bit retro style).
    
    **Args:**
    * `image` (numpy.ndarray): Input image
    * `pixel_size` (int): Size of each pixel block
    
    **Returns:**
    * `numpy.ndarray`: Pixelized image
    """
    height, width = image.shape[:2]
    small_height = height // pixel_size
    small_width = width // pixel_size
    small_image = cv2.resize(image, (small_width, small_height), interpolation=cv2.INTER_LINEAR)
    pixelized_image = cv2.resize(small_image, (width, height), interpolation=cv2.INTER_NEAREST)
    return pixelized_image


@registry.register("Sketch Effect")
def sketch_effect(image):
    """
    ## Convert image to pencil sketch.
    
    **Args:**
    * `image` (numpy.ndarray): Input image
    
    **Returns:**
    * `numpy.ndarray`: Sketch effect image
    """
    if len(image.shape) == 3:
        gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
    else:
        gray = image

    inverted_gray = cv2.bitwise_not(gray)
    blurred = cv2.GaussianBlur(inverted_gray, (21, 21), 0)
    sketch = cv2.divide(gray, 255 - blurred, scale=256)
    return sketch


@registry.register("Warm", defaults={
    "intensity": 30,
}, min_vals={
    "intensity": 0,
}, max_vals={
    "intensity": 100,
}, step_vals={
    "intensity": 1,
})
def warm_filter(image, intensity: int = 30):
    """
    ## Add warm tones to image (sunset, autumn style).
    
    **Args:**
    * `image` (numpy.ndarray): Input image (BGR)
    * `intensity` (int): Effect intensity (0-100)
    
    **Returns:**
    * `numpy.ndarray`: Warm-toned image
    """
    intensity_scale = intensity / 100.0
    b, g, r = cv2.split(image.astype(np.float32))
    r = np.clip(r * (1 + 0.5 * intensity_scale), 0, 255)
    g = np.clip(g * (1 + 0.1 * intensity_scale), 0, 255)
    b = np.clip(b * (1 - 0.1 * intensity_scale), 0, 255)
    return cv2.merge([b, g, r]).astype(np.uint8)


@registry.register("Cool", defaults={
    "intensity": 30,
}, min_vals={
    "intensity": 0,
}, max_vals={
    "intensity": 100,
}, step_vals={
    "intensity": 1,
})
def cool_filter(image, intensity: int = 30):
    """
    ## Add cool tones to image (ice, ocean style).
    
    **Args:**
    * `image` (numpy.ndarray): Input image (BGR)
    * `intensity` (int): Effect intensity (0-100)
    
    **Returns:**
    * `numpy.ndarray`: Cool-toned image
    """
    intensity_scale = intensity / 100.0
    b, g, r = cv2.split(image.astype(np.float32))
    b = np.clip(b * (1 + 0.5 * intensity_scale), 0, 255)
    g = np.clip(g * (1 + 0.1 * intensity_scale), 0, 255)
    r = np.clip(r * (1 - 0.1 * intensity_scale), 0, 255)
    return cv2.merge([b, g, r]).astype(np.uint8)


@registry.register("Saturation", defaults={
    "factor": 50,
}, min_vals={
    "factor": 0,
}, max_vals={
    "factor": 100,
}, step_vals={
    "factor": 1,
})
def adjust_saturation(image, factor: int = 50):
    """
    ## Adjust color saturation of image.
    
    **Args:**
    * `image` (numpy.ndarray): Input image (BGR)
    * `factor` (int): Saturation factor (0-100, 50 is normal)
    
    **Returns:**
    * `numpy.ndarray`: Saturation-adjusted image
    """
    factor = (factor / 50.0)
    hsv = cv2.cvtColor(image, cv2.COLOR_BGR2HSV).astype(np.float32)
    hsv[:, :, 1] = np.clip(hsv[:, :, 1] * factor, 0, 255)
    return cv2.cvtColor(hsv.astype(np.uint8), cv2.COLOR_HSV2BGR)


@registry.register("Vintage", defaults={
    "intensity": 50,
}, min_vals={
    "intensity": 0,
}, max_vals={
    "intensity": 100,
}, step_vals={
    "intensity": 1,
})
def vintage_filter(image, intensity: int = 50):
    """
    ## Create vintage/retro photo effect (70s style).
    
    **Args:**
    * `image` (numpy.ndarray): Input image (BGR)
    * `intensity` (int): Vintage effect intensity (0-100)
    
    **Returns:**
    * `numpy.ndarray`: Vintage-styled image
    """
    intensity_scale = intensity / 100.0
    b, g, r = cv2.split(image.astype(np.float32))
    r = np.clip(r * (1 + 0.3 * intensity_scale), 0, 255)
    g = np.clip(g * (1 - 0.1 * intensity_scale), 0, 255)
    b = np.clip(b * (1 - 0.2 * intensity_scale), 0, 255)
    result = cv2.merge([b, g, r]).astype(np.uint8)
    if intensity > 0:
        blur_amount = int(3 * intensity_scale) * 2 + 1
        result = cv2.GaussianBlur(result, (blur_amount, blur_amount), 0)
    return result


@registry.register("Vignette", defaults={
    "intensity": 50,
}, min_vals={
    "intensity": 0,
}, max_vals={
    "intensity": 100,
}, step_vals={
    "intensity": 1,
})
def vignette_effect(image, intensity: int = 50):
    """
    ## Add darkening effect to image corners (vignette).
    
    **Args:**
    * `image` (numpy.ndarray): Input image (BGR)
    * `intensity` (int): Vignette intensity (0-100)
    
    **Returns:**
    * `numpy.ndarray`: Vignetted image
    """
    height, width = image.shape[:2]
    X_resultant = np.abs(np.linspace(-1, 1, width)[None, :])
    Y_resultant = np.abs(np.linspace(-1, 1, height)[:, None])
    mask = np.sqrt(X_resultant**2 + Y_resultant**2)
    mask = 1 - np.clip(mask, 0, 1)
    mask = (mask - mask.min()) / (mask.max() - mask.min())
    mask = mask ** (1 + intensity/50)
    mask = mask[:, :, None]
    result = image.astype(np.float32) * mask
    return np.clip(result, 0, 255).astype(np.uint8)


@registry.register("HDR Effect", defaults={
    "strength": 50,
}, min_vals={
    "strength": 0,
}, max_vals={
    "strength": 100,
}, step_vals={
    "strength": 1,
})
def hdr_effect(image, strength: int = 50):
    """
    ## Enhance image details with HDR effect.
    
    **Args:**
    * `image` (numpy.ndarray): Input image (BGR)
    * `strength` (int): HDR strength (0-100)
    
    **Returns:**
    * `numpy.ndarray`: HDR-enhanced image
    """
    strength_scale = strength / 100.0
    lab = cv2.cvtColor(image, cv2.COLOR_BGR2LAB).astype(np.float32)
    l, a, b = cv2.split(lab)
    clahe = cv2.createCLAHE(clipLimit=3.0 * strength_scale, tileGridSize=(8, 8))
    l = clahe.apply(l.astype(np.uint8)).astype(np.float32)
    if strength > 0:
        blur = cv2.GaussianBlur(l, (0, 0), 3)
        detail = cv2.addWeighted(l, 1 + strength_scale, blur, -strength_scale, 0)
        l = cv2.addWeighted(l, 1 - strength_scale/2, detail, strength_scale/2, 0)
    enhanced_lab = cv2.merge([l, a, b])
    result = cv2.cvtColor(enhanced_lab.astype(np.uint8), cv2.COLOR_LAB2BGR)
    return result


@registry.register("Gaussian Blur", defaults={
    "kernel_size": 5,
}, min_vals={
    "kernel_size": 1,
}, max_vals={
    "kernel_size": 31,
}, step_vals={
    "kernel_size": 2,
})
def gaussian_blur(image, kernel_size: int = 5):
    """
    ## Blur image with Gaussian filter.
    
    **Args:**
    * `image` (numpy.ndarray): Input image
    * `kernel_size` (int): Kernel size (must be odd number)
    
    **Returns:**
    * `numpy.ndarray`: Blurred image
    """
    if kernel_size % 2 == 0:
        kernel_size += 1
    return cv2.GaussianBlur(image, (kernel_size, kernel_size), 0)


@registry.register("Sharpen", defaults={
    "amount": 50,
}, min_vals={
    "amount": 0,
}, max_vals={
    "amount": 100,
}, step_vals={
    "amount": 1,
})
def sharpen(image, amount: int = 50):
    """
    ## Sharpen image details.
    
    **Args:**
    * `image` (numpy.ndarray): Input image
    * `amount` (int): Sharpening intensity (0-100)
    
    **Returns:**
    * `numpy.ndarray`: Sharpened image
    """
    amount = amount / 100.0
    kernel = np.array([[-1, -1, -1], [-1, 9, -1], [-1, -1, -1]])
    sharpened = cv2.filter2D(image, -1, kernel)
    return cv2.addWeighted(image, 1 - amount, sharpened, amount, 0)


@registry.register("Emboss", defaults={
    "strength": 50,
    "direction": 0,
}, min_vals={
    "strength": 0,
    "direction": 0,
}, max_vals={
    "strength": 100,
    "direction": 7,
}, step_vals={
    "strength": 1,
    "direction": 1,
})
def emboss(image, strength: int = 50, direction: int = 0):
    """
    ## Create 3D embossed effect.
    
    **Args:**
    * `image` (numpy.ndarray): Input image
    * `strength` (int): Emboss strength (0-100)
    * `direction` (int): Light direction (0-7)
    
    **Returns:**
    * `numpy.ndarray`: Embossed image
    """
    strength = strength / 100.0 * 2.0
    kernels = [
        np.array([[-1, -1, 0], [-1, 1, 1], [0, 1, 1]]),
        np.array([[-1, 0, 1], [-1, 1, 1], [-1, 0, 1]]),
        np.array([[0, 1, 1], [-1, 1, 1], [-1, -1, 0]]),
        np.array([[1, 1, 1], [0, 1, 0], [-1, -1, -1]]),
        np.array([[1, 1, 0], [1, 1, -1], [0, -1, -1]]),
        np.array([[1, 0, -1], [1, 1, -1], [1, 0, -1]]),
        np.array([[0, -1, -1], [1, 1, -1], [1, 1, 0]]),
        np.array([[-1, -1, -1], [0, 1, 0], [1, 1, 1]])
    ]
    kernel = kernels[direction % 8]
    gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
    embossed = cv2.filter2D(gray, -1, kernel * strength)
    embossed = cv2.normalize(embossed, None, 0, 255, cv2.NORM_MINMAX)
    return cv2.cvtColor(embossed.astype(np.uint8), cv2.COLOR_GRAY2BGR)


@registry.register("Oil Painting", defaults={
    "size": 5,
    "dynRatio": 1,
}, min_vals={
    "size": 1,
    "dynRatio": 1,
}, max_vals={
    "size": 15,
    "dynRatio": 7,
}, step_vals={
    "size": 2,
    "dynRatio": 1,
})
def oil_painting(image, size: int = 5, dynRatio: int = 1):
    """
    ## Create oil painting effect.
    
    **Args:**
    * `image` (numpy.ndarray): Input image
    * `size` (int): Processing area size
    * `dynRatio` (int): Dynamic ratio affecting color intensity
    
    **Returns:**
    * `numpy.ndarray`: Oil painting styled image
    """
    return cv2.xphoto.oilPainting(image, size, dynRatio)


@registry.register("Black and White")
def black_and_white(image):
    """
    ## Convert to classic black and white.
    
    **Args:**
    * `image` (numpy.ndarray): Input image
    
    **Returns:**
    * `numpy.ndarray`: Grayscale image
    """
    return cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)


@registry.register("Sepia")
def sepia(image):
    """
    ## Create sepia tone classic brown effect.
    
    **Args:**
    * `image` (numpy.ndarray): Input image
    
    **Returns:**
    * `numpy.ndarray`: Sepia-toned image
    """
    rgb = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
    sepia_matrix = np.array([
        [0.393, 0.769, 0.189],
        [0.349, 0.686, 0.168],
        [0.272, 0.534, 0.131]
    ])
    sepia_image = np.dot(rgb, sepia_matrix.T)
    sepia_image = np.clip(sepia_image, 0, 255)
    return cv2.cvtColor(sepia_image.astype(np.uint8), cv2.COLOR_RGB2BGR)


@registry.register("Negative")
def negative(image):
    """
    ## Invert colors for negative film effect.
    
    **Args:**
    * `image` (numpy.ndarray): Input image
    
    **Returns:**
    * `numpy.ndarray`: Negative image
    """
    return cv2.bitwise_not(image)


@registry.register("Watercolor")
def watercolor(image):
    """
    ## Create watercolor painting effect.
    
    **Args:**
    * `image` (numpy.ndarray): Input image
    
    **Returns:**
    * `numpy.ndarray`: Watercolor styled image
    """
    return cv2.xphoto.oilPainting(image, 7, 1)


@registry.register("Posterization")
def posterize(image):
    """
    ## Reduce colors for artistic poster effect.
    
    **Args:**
    * `image` (numpy.ndarray): Input image
    
    **Returns:**
    * `numpy.ndarray`: Posterized image
    """
    hsv = cv2.cvtColor(image, cv2.COLOR_BGR2HSV)
    hsv[:, :, 1] = cv2.equalizeHist(hsv[:, :, 1])
    hsv[:, :, 2] = cv2.equalizeHist(hsv[:, :, 2])
    return cv2.cvtColor(hsv, cv2.COLOR_HSV2BGR)


@registry.register("Cross Process")
def cross_process(image):
    """
    ## Film cross-processing effect.
    
    **Args:**
    * `image` (numpy.ndarray): Input image
    
    **Returns:**
    * `numpy.ndarray`: Cross-processed image
    """
    b, g, r = cv2.split(image.astype(np.float32))
    b = np.clip(b * 1.2, 0, 255)
    g = np.clip(g * 0.8, 0, 255)
    r = np.clip(r * 1.4, 0, 255)
    return cv2.merge([b, g, r]).astype(np.uint8)