tools/util.py

"""
Modified from: https://github.com/IDEA-Research/Rex-Omni/blob/master/rex_omni/utils.py
"""
from typing import Any, Dict, List, Optional, Tuple

import numpy as np
from PIL import Image, ImageDraw, ImageFont

class ColorGenerator:
    """Generate consistent colors for visualization"""

    def __init__(self, color_type: str = "text"):
        self.color_type = color_type

        if color_type == "same":
            self.color = tuple((np.random.randint(0, 127, size=3) + 128).tolist())
        elif color_type == "text":
            np.random.seed(3396)
            self.num_colors = 300
            self.colors = np.random.randint(0, 127, size=(self.num_colors, 3)) + 128
        else:
            raise ValueError(f"Unknown color type: {color_type}")

    def get_color(self, text: str) -> Tuple[int, int, int]:
        """Get color for given text"""
        if self.color_type == "same":
            return self.color

        if self.color_type == "text":
            text_hash = hash(text)
            index = text_hash % self.num_colors
            color = tuple(self.colors[index])
            return color

        raise ValueError(f"Unknown color type: {self.color_type}")

def Visualize(
    image: Image.Image,
    annotations: Dict[str, List[Dict]],
    font_size: int = 10, 
    draw_width: int = 6,
    show_labels: bool = True,
    custom_colors: Optional[Dict[str, Tuple[int, int, int]]] = None,
    font_path: Optional[str] = None,
) -> Image.Image:
    """
    Visualize predictions on image

    Args:
        image: Input image
        annotations: Target entities (from the JSON file) need to be drawn on the image
        font_size: Font size for labels
        draw_width: Line width for drawing
        show_labels: Whether to show text labels
        custom_colors: Custom colors for categories
        font_path: Path to font file

    Returns:
        Image with visualizations
    """

    # Create a copy of the image
    vis_image = image.copy()
    draw = ImageDraw.Draw(vis_image)

    # Load font
    font = _load_font(font_size, font_path)

    # Color generator
    color_generator = ColorGenerator("same")
    color_generator.color = (255, 0, 0)

    for i, entity in enumerate(annotations):
        # Get color
        color = color_generator.color
        annotation_type = entity.get("entity_type", "region")
        coords = entity.get("bbox", [])

        if annotation_type in ["region", "object", "human"] and len(coords) == 4:
            draw_width = _adjust_draw_width(coords, vis_image.size)
            if "label" in entity.keys():
                _draw_box(draw, coords, color, draw_width, entity["label"], font, show_labels)
            else:
                _draw_box(draw, coords, color, draw_width, "", font, show_labels=False)
        elif annotation_type == "point" and len(coords) == 2:
            draw_width = 1
            _draw_point(
                draw, coords, color, draw_width, entity["label"], font, show_labels
            )

    return vis_image

def _adjust_draw_width(
    coords: List[float], 
    image_size: Tuple[int, int]
) -> int:
    x0, y0, x1, y1 = coords
    image_width, image_height = image_size
    
    box_width = max(1, x1 - x0) 
    box_height = max(1, y1 - y0) 
    box_area = box_width * box_height
    image_total_area = image_width * image_height
    
    if image_total_area == 0:
        return 6
    
    area_ratio = box_area / image_total_area 

    if area_ratio >= 0.05:  
        return 6
    elif area_ratio >= 0.01:
        return 4
    elif area_ratio >= 0.005: 
        return 3
    else:  
        return 2

def _load_font(font_size: int, font_path: Optional[str] = None) -> ImageFont.ImageFont:
    """Load font for drawing"""
    font_paths = [
        "C:/Windows/Fonts/simhei.ttf",
        "C:/Windows/Fonts/arial.ttf",
        "/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf",
        "/System/Library/Fonts/Arial.ttf",
        "/System/Library/Fonts/Helvetica.ttc",
        "arial.ttf",
    ]

    font = None
    for font_path_ in font_paths:
        try:
            font = ImageFont.truetype(font_path_, font_size)
            break
        except:
            continue

    if font is None:
        font = ImageFont.load_default()

    return font

def _draw_box(
    draw: ImageDraw.ImageDraw,
    coords: List[float],
    color: Tuple[int, int, int],
    draw_width: int,
    label: str,
    font: ImageFont.ImageFont,
    show_labels: bool,
):
    """Draw bounding box"""
    x0, y0, x1, y1 = [int(c) for c in coords]

    # Check valid box
    if x0 >= x1 or y0 >= y1:
        return

    # Draw rectangle
    draw.rectangle([x0, y0, x1, y1], outline=color, width=draw_width)

    # Draw label
    if show_labels and label:
        bbox = draw.textbbox((x0, y0), label, font)
        box_h = bbox[3] - bbox[1]

        y0_text = y0 - box_h - (draw_width * 2)
        y1_text = y0 + draw_width

        if y0_text < 0:
            y0_text = 0
            y1_text = y0 + 2 * draw_width + box_h

        draw.rectangle(
            [x0, y0_text, bbox[2] + draw_width * 2, y1_text],
            fill=color,
        )
        draw.text(
            (x0 + draw_width, y0_text),
            label,
            fill="black",
            font=font,
        )


def _draw_point(
    draw: ImageDraw.ImageDraw,
    coords: List[float],
    color: Tuple[int, int, int],
    draw_width: int,
    label: str,
    font: ImageFont.ImageFont,
    show_labels: bool,
):
    """Draw point"""
    x, y = [int(c) for c in coords]

    # Draw point as circle
    radius = min(8, draw_width)
    border_width = 2

    # Draw white border
    draw.ellipse(
        [
            x - radius - border_width,
            y - radius - border_width,
            x + radius + border_width,
            y + radius + border_width,
        ],
        fill="white",
        outline="white",
    )

    # Draw colored center
    draw.ellipse(
        [x - radius, y - radius, x + radius, y + radius],
        fill=color,
        outline=color,
    )

    # Draw label
    if show_labels and label:
        label_x, label_y = x + 5, y - 5
        if label_y < 0:
            label_y = y + 15
        bbox = draw.textbbox((label_x, label_y), label, font)
        box_h = bbox[3] - bbox[1]
        box_w = bbox[2] - bbox[0]

        padding = 4

        """
        We choose not to draw background as the ground occludes key perceptual information in many cases.
        """
        # Draw background
        # draw.rectangle(
        #     [
        #         label_x - padding,
        #         label_y - box_h - padding,
        #         label_x + box_w + padding,
        #         label_y + padding,
        #     ],
        #     fill=color,
        # )

        # Draw text
        draw.text((label_x, label_y - box_h), label, fill="red", font=font)