app.py

import gradio as gr
import torch
from transformers import ViTForImageClassification, AutoImageProcessor
from PIL import Image, ImageDraw, ImageFont
import random
import os

# Load model and processor from Hugging Face
model_name = "akridge/noaa-esd-coral-bleaching-vit-classifier-v1"
model = ViTForImageClassification.from_pretrained(model_name)
processor = AutoImageProcessor.from_pretrained(model_name, use_fast=True)

# Ensure id2label keys are integers and labels are uppercase
id2label = {int(k): v.upper() for k, v in model.config.id2label.items()}

# Label colors (RGBA)
LABEL_COLORS = {
    "CORAL": ((0, 0, 255, 80), (0, 0, 200)),        # Fill: Blue transparent, Border: Dark blue
    "CORAL_BL": ((255, 255, 255, 150), (150, 150, 150))  # Fill: White transparent, Border: Gray
}

def predict_and_overlay(image, rows=2, cols=5, patch_size=224):
    device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
    model.to(device).eval()

    # Load image
    image = image.convert('RGB')
    width, height = image.size
    scale_factor = max(width, height) / 800
    font_size = max(12, int(scale_factor * 8))
    border_width = max(3, int(scale_factor * 3))

    # Create overlay
    overlay = Image.new('RGBA', image.size, (255, 255, 255, 0))
    overlay_draw = ImageDraw.Draw(overlay)

    # Generate sampled points
    cell_width, cell_height = width / cols, height / rows
    sampled_points = [
        (random.randint(int(col * cell_width), int((col + 1) * cell_width - 1)),
         random.randint(int(row * cell_height), int((row + 1) * cell_height - 1)))
        for row in range(rows) for col in range(cols)
    ]

    predictions = []

    # Load font
    try:
        font = ImageFont.truetype("arial.ttf", size=font_size)
    except IOError:
        font = ImageFont.load_default()

    # Predict and draw patches
    for x, y in sampled_points:
        left, upper = max(0, x - patch_size // 2), max(0, y - patch_size // 2)
        right, lower = min(width, left + patch_size), min(height, upper + patch_size)

        # Predict label
        patch = image.crop((left, upper, right, lower))
        inputs = processor(images=patch, return_tensors="pt").to(device)
        with torch.no_grad():
            pred_id = model(**inputs).logits.argmax(-1).item()
            pred_label = id2label.get(pred_id, "UNKNOWN")
            predictions.append(pred_label)

        # Fill and border colors
        fill_color, border_color = LABEL_COLORS.get(pred_label, ((200, 200, 200, 100), (100, 100, 100)))

        # Draw filled rectangle and label
        overlay_draw.rectangle([(left, upper), (right, lower)], fill=fill_color, outline=border_color, width=border_width)

        label_text = pred_label
        bbox = overlay_draw.textbbox((0, 0), label_text, font=font)
        text_width, text_height = bbox[2] - bbox[0], bbox[3] - bbox[1]
        text_bg_coords = [(left, upper - text_height - 6), (left + text_width + 6, upper)]

        overlay_draw.rectangle(text_bg_coords, fill=(0, 0, 0, 200))
        overlay_draw.text((left + 3, upper - text_height - 4), label_text, fill="white", font=font)

    # Merge overlay with original
    final_image = Image.alpha_composite(image.convert('RGBA'), overlay).convert('RGB')

    return final_image, predictions

# Function to load example images
def load_example_image(example_image):
    return Image.open(example_image)

# List example images
example_images = [os.path.join("example_images", img) for img in os.listdir("coral_images")]

# Gradio interface
def gradio_interface(image, rows=2, cols=5):
    final_image, predictions = predict_and_overlay(image, rows, cols)
    return final_image, ", ".join(predictions)

iface = gr.Interface(
    fn=gradio_interface,
    inputs=[
        gr.inputs.Image(type="pil", label="Upload Coral Image", optional=True),
        gr.inputs.Dropdown(choices=example_images, label="Or Select an Example Image"),
        gr.inputs.Slider(1, 10, value=2, step=1, label="Rows of Sample Points"),
        gr.inputs.Slider(1, 10, value=5, step=1, label="Columns of Sample Points"),
    ],
    outputs=[
        gr.outputs.Image(type="pil", label="Image with Predictions"),
        gr.outputs.Textbox(label="Predictions")
    ],
    title="NOAA ESD Coral Bleaching ViT Classifier",
    description="Upload an image or select an example to sample points/patches and predict coral bleaching using the ViT classifier model hosted on Hugging Face."
)

iface.launch()