utils/plot.py

import re
from PIL import Image, ImageDraw

def get_boxed_image(image, sub_text, alpha=0.3):
    '''
    image: Image.Image.
    sub_text: String like "(x1, y1), (x2, y2), (x3, y3), (x4, y4)", or it's illegal.
    alpha: The transparency of the box.
    '''
    
    bbox_list = [(int(x), int(y)) for x, y in re.findall(r'\((\d+),(\d+)\)', sub_text)]
    
    if len(bbox_list) % 2 != 0:
        print(f"The coordinate string {sub_text} is illegal, as we extract {len(bbox_list)} coordinates from it!")
        return None
    
    image = Image.open(image)
    width, height = image.size
    image = image.convert("RGBA")
    overlay = Image.new("RGBA", image.size, (255, 0, 0, 0))  
    
    draw = ImageDraw.Draw(overlay)
    red_color = (255, 0, 0, int(255 * alpha))
    border_width = max(1, int(min(image.size) * 0.005))  
    
    for i in range(0, len(bbox_list), 2):
        x1, y1 = bbox_list[i]
        x2, y2 = bbox_list[i + 1]
        
        x1, y1, x2, y2 = int(x1/999 * width), int(y1/999 * height), int(x2/999 * width), int(y2/999 * height)

        x1 = max(0, min(x1, width))
        y1 = max(0, min(y1, height))
        x2 = max(0, min(x2, width))
        y2 = max(0, min(y2, height))
        
        if x2 <= x1 or y2 <= y1:
            print(f"The uniformed coordinates ({x1}, {y1}), ({x2}, {y2}) are illegal, as the positions of them are wrong!")
            return None
        
        for i in range(border_width):
            draw.rectangle(
                [x1 - i, y1 - i, x2 + i, y2 + i],
                outline=red_color
            )
    
    return Image.alpha_composite(image, overlay).convert("RGB") 

id = 1673
image = f'public_eval/bbox_step_300/MathVerse_MINI/20250418/images/{id}.png'
text = '''<think>This table presents information about a point A in relation to a reference point O, including its true bearing and compass direction.\n\nStep 1. Identify the column 'True Bearing'(190,269),(388,935), which contains the true bearing of point A from point O.\nStep 2. Locate the value in the column 'True Bearing': 32°.\nStep 3. Conclude that the true bearing of A from O is 32°.</think>\n<answer>32°</answer>'''

box_image = get_boxed_image(image=image, sub_text=text)
if box_image:
    box_image.show()
    box_image.save(image.replace('.png', '_bbox.png'))