app.py

import gradio as gr
import torch
from diffusers import DiffusionPipeline, StableDiffusionPipeline, StableDiffusionXLPipeline, EulerDiscreteScheduler, UNet2DConditionModel, StableDiffusion3Pipeline
from transformers import BlipProcessor, BlipForConditionalGeneration
from pathlib import Path
from safetensors.torch import load_file
from huggingface_hub import hf_hub_download
from PIL import Image
import matplotlib.pyplot as plt
from matplotlib.colors import hex2color
import stone
import os
import spaces

# Define model initialization functions
def load_model(model_name, token=None):
    if model_name == "stabilityai/sdxl-turbo":
        pipeline = DiffusionPipeline.from_pretrained(
            model_name, 
            torch_dtype=torch.float16, 
            variant="fp16"
        ).to("cuda")
    elif model_name == "runwayml/stable-diffusion-v1-5":
        pipeline = StableDiffusionPipeline.from_pretrained(
            model_name, 
            torch_dtype=torch.float16
        ).to("cuda")
    elif model_name == "ByteDance/SDXL-Lightning":
        base = "stabilityai/stable-diffusion-xl-base-1.0"
        ckpt = "sdxl_lightning_4step_unet.safetensors"
        unet = UNet2DConditionModel.from_config(base, subfolder="unet").to("cuda", torch.float16)
        unet.load_state_dict(load_file(hf_hub_download(model_name, ckpt), device="cuda"))
        pipeline = StableDiffusionXLPipeline.from_pretrained(
            base, 
            unet=unet, 
            torch_dtype=torch.float16, 
            variant="fp16"
        ).to("cuda")
        pipeline.scheduler = EulerDiscreteScheduler.from_config(pipeline.scheduler.config, timestep_spacing="trailing")
    elif model_name == "segmind/SSD-1B":
        pipeline = StableDiffusionXLPipeline.from_pretrained(
            model_name, 
            torch_dtype=torch.float16, 
            use_safetensors=True, 
            variant="fp16"
        ).to("cuda")
    elif model_name == "stabilityai/stable-diffusion-3-medium-diffusers":
        if token is None:
            raise ValueError("Hugging Face token is required to access this model")
        pipeline = StableDiffusion3Pipeline.from_pretrained(
            model_name, 
            torch_dtype=torch.float16,
            use_auth_token=token
        ).to("cuda")
    else:
        raise ValueError("Unknown model name")
    return pipeline

# Initialize the default model
default_model = "stabilityai/sdxl-turbo"
pipeline_text2image = load_model(default_model)

@spaces.GPU
def getimgen(prompt, model_name):
    global pipeline_text2image
    pipeline_text2image = load_model(model_name)
    if model_name == "stabilityai/sdxl-turbo":
        return pipeline_text2image(prompt=prompt, guidance_scale=0.0, num_inference_steps=2).images[0]
    elif model_name == "runwayml/stable-diffusion-v1-5":
        return pipeline_text2image(prompt).images[0]
    elif model_name == "ByteDance/SDXL-Lightning":
        return pipeline_text2image(prompt, num_inference_steps=4, guidance_scale=0).images[0]
    elif model_name == "segmind/SSD-1B":
        neg_prompt = "ugly, blurry, poor quality"
        return pipeline_text2image(prompt=prompt, negative_prompt=neg_prompt).images[0]
    elif model_name == "stabilityai/stable-diffusion-3-medium-diffusers":
        return pipeline_text2image(prompt=prompt, negative_prompt="", num_inference_steps=28, guidance_scale=7.0).images[0]

blip_processor = BlipProcessor.from_pretrained("Salesforce/blip-image-captioning-large")
blip_model = BlipForConditionalGeneration.from_pretrained("Salesforce/blip-image-captioning-large", torch_dtype=torch.float16).to("cuda")

@spaces.GPU
def blip_caption_image(image, prefix):
    inputs = blip_processor(image, prefix, return_tensors="pt").to("cuda", torch.float16)
    out = blip_model.generate(**inputs)
    return blip_processor.decode(out[0], skip_special_tokens=True)

def genderfromcaption(caption):
    cc = caption.split()
    if "man" in cc or "boy" in cc:
        return "Man"
    elif "woman" in cc or "girl" in cc:
        return "Woman"
    return "Unsure"

def genderplot(genlist):    
    order = ["Man", "Woman", "Unsure"]
    words = sorted(genlist, key=lambda x: order.index(x))
    colors = {"Man": "lightgreen", "Woman": "darkgreen", "Unsure": "lightgrey"}
    word_colors = [colors[word] for word in words]
    fig, axes = plt.subplots(2, 5, figsize=(5,5))
    plt.subplots_adjust(hspace=0.1, wspace=0.1)
    for i, ax in enumerate(axes.flat):
        ax.set_axis_off()
        ax.add_patch(plt.Rectangle((0, 0), 1, 1, color=word_colors[i]))
    return fig

def skintoneplot(hex_codes):
    hex_codes = [code for code in hex_codes if code is not None]
    rgb_values = [hex2color(hex_code) for hex_code in hex_codes]
    luminance_values = [0.299 * r + 0.587 * g + 0.114 * b for r, g, b in rgb_values]
    sorted_hex_codes = [code for _, code in sorted(zip(luminance_values, hex_codes), reverse=True)]
    fig, axes = plt.subplots(2, 5, figsize=(5,5))
    plt.subplots_adjust(hspace=0.1, wspace=0.1)
    for i, ax in enumerate(axes.flat):
        ax.set_axis_off()
        if i < len(sorted_hex_codes):
            ax.add_patch(plt.Rectangle((0, 0), 1, 1, color=sorted_hex_codes[i]))
    return fig

@spaces.GPU
def generate_images_plots(prompt, model_name, token=None):
    global pipeline_text2image
    pipeline_text2image = load_model(model_name, token)
    foldername = "temp"
    Path(foldername).mkdir(parents=True, exist_ok=True)
    images = [getimgen(prompt, model_name) for _ in range(10)]
    genders = []
    skintones = []
    for image, i in zip(images, range(10)):
        prompt_prefix = "photo of a "
        caption = blip_caption_image(image, prefix=prompt_prefix)
        image.save(f"{foldername}/image_{i}.png")
        try:
            skintoneres = stone.process(f"{foldername}/image_{i}.png", return_report_image=False)
            tone = skintoneres['faces'][0]['dominant_colors'][0]['color']
            skintones.append(tone)
        except:
            skintones.append(None)
        genders.append(genderfromcaption(caption))
    return images, skintoneplot(skintones), genderplot(genders)

with gr.Blocks(title="Skin Tone and Gender bias in Text to Image Models") as demo:
    gr.Markdown("# Skin Tone and Gender bias in Text to Image Models")
    model_dropdown = gr.Dropdown(
        label="Choose a model", 
        choices=[
            "stabilityai/sdxl-turbo", 
            "runwayml/stable-diffusion-v1-5", 
            "ByteDance/SDXL-Lightning", 
            "segmind/SSD-1B",
            "stabilityai/stable-diffusion-3-medium-diffusers"
        ], 
        value=default_model
    )
    prompt = gr.Textbox(label="Enter the Prompt")
    gallery = gr.Gallery(
        label="Generated images", 
        show_label=False, 
        elem_id="gallery", 
        columns=[5], 
        rows=[2], 
        object_fit="contain", 
        height="auto"
    )
    gr.LoginButton() 
    token = gr.OAuthToken()
    gr.Markdown('### You need to log in to your Hugging Face account to run Stable Diffusion 3')
    btn = gr.Button("Generate images", scale=0)
    with gr.Row(equal_height=True):
        skinplot = gr.Plot(label="Skin Tone")
        genplot = gr.Plot(label="Gender")
    btn.click(generate_images_plots, inputs=[prompt, model_dropdown, token], outputs=[gallery, skinplot, genplot])

demo.launch(debug=True)