data/flux/demo_gr.py

import os
import time
import uuid

import gradio as gr
import numpy as np
import torch
from einops import rearrange
from PIL import ExifTags, Image
from transformers import pipeline

from flux.cli import SamplingOptions
from flux.sampling import denoise, get_noise, get_schedule, prepare, unpack
from flux.util import configs, embed_watermark, load_ae, load_clip, load_flow_model, load_t5

NSFW_THRESHOLD = 0.85


def get_models(name: str, device: torch.device, offload: bool, is_schnell: bool):
    t5 = load_t5(device, max_length=256 if is_schnell else 512)
    clip = load_clip(device)
    model = load_flow_model(name, device="cpu" if offload else device)
    ae = load_ae(name, device="cpu" if offload else device)
    nsfw_classifier = pipeline("image-classification", model="Falconsai/nsfw_image_detection", device=device)
    return model, ae, t5, clip, nsfw_classifier


class FluxGenerator:
    def __init__(self, model_name: str, device: str, offload: bool):
        self.device = torch.device(device)
        self.offload = offload
        self.model_name = model_name
        self.is_schnell = model_name == "flux-schnell"
        self.model, self.ae, self.t5, self.clip, self.nsfw_classifier = get_models(
            model_name,
            device=self.device,
            offload=self.offload,
            is_schnell=self.is_schnell,
        )

    @torch.inference_mode()
    def generate_image(
        self,
        width,
        height,
        num_steps,
        guidance,
        seed,
        prompt,
        init_image=None,
        image2image_strength=0.0,
        add_sampling_metadata=True,
    ):
        seed = int(seed)
        if seed == -1:
            seed = None

        opts = SamplingOptions(
            prompt=prompt,
            width=width,
            height=height,
            num_steps=num_steps,
            guidance=guidance,
            seed=seed,
        )

        if opts.seed is None:
            opts.seed = torch.Generator(device="cpu").seed()
        print(f"Generating '{opts.prompt}' with seed {opts.seed}")
        t0 = time.perf_counter()

        if init_image is not None:
            if isinstance(init_image, np.ndarray):
                init_image = torch.from_numpy(init_image).permute(2, 0, 1).float() / 255.0
                init_image = init_image.unsqueeze(0)
            init_image = init_image.to(self.device)
            init_image = torch.nn.functional.interpolate(init_image, (opts.height, opts.width))
            if self.offload:
                self.ae.encoder.to(self.device)
            init_image = self.ae.encode(init_image.to())
            if self.offload:
                self.ae = self.ae.cpu()
                torch.cuda.empty_cache()

        # prepare input
        x = get_noise(
            1,
            opts.height,
            opts.width,
            device=self.device,
            dtype=torch.bfloat16,
            seed=opts.seed,
        )
        timesteps = get_schedule(
            opts.num_steps,
            x.shape[-1] * x.shape[-2] // 4,
            shift=(not self.is_schnell),
        )
        if init_image is not None:
            t_idx = int((1 - image2image_strength) * num_steps)
            t = timesteps[t_idx]
            timesteps = timesteps[t_idx:]
            x = t * x + (1.0 - t) * init_image.to(x.dtype)

        if self.offload:
            self.t5, self.clip = self.t5.to(self.device), self.clip.to(self.device)
        inp = prepare(t5=self.t5, clip=self.clip, img=x, prompt=opts.prompt)

        # offload TEs to CPU, load model to gpu
        if self.offload:
            self.t5, self.clip = self.t5.cpu(), self.clip.cpu()
            torch.cuda.empty_cache()
            self.model = self.model.to(self.device)

        # denoise initial noise
        x = denoise(self.model, **inp, timesteps=timesteps, guidance=opts.guidance)

        # offload model, load autoencoder to gpu
        if self.offload:
            self.model.cpu()
            torch.cuda.empty_cache()
            self.ae.decoder.to(x.device)

        # decode latents to pixel space
        x = unpack(x.float(), opts.height, opts.width)
        with torch.autocast(device_type=self.device.type, dtype=torch.bfloat16):
            x = self.ae.decode(x)

        if self.offload:
            self.ae.decoder.cpu()
            torch.cuda.empty_cache()

        t1 = time.perf_counter()

        print(f"Done in {t1 - t0:.1f}s.")
        # bring into PIL format
        x = x.clamp(-1, 1)
        x = embed_watermark(x.float())
        x = rearrange(x[0], "c h w -> h w c")

        img = Image.fromarray((127.5 * (x + 1.0)).cpu().byte().numpy())
        nsfw_score = [x["score"] for x in self.nsfw_classifier(img) if x["label"] == "nsfw"][0]

        if nsfw_score < NSFW_THRESHOLD:
            filename = f"output/gradio/{uuid.uuid4()}.jpg"
            os.makedirs(os.path.dirname(filename), exist_ok=True)
            exif_data = Image.Exif()
            if init_image is None:
                exif_data[ExifTags.Base.Software] = "AI generated;txt2img;flux"
            else:
                exif_data[ExifTags.Base.Software] = "AI generated;img2img;flux"
            exif_data[ExifTags.Base.Make] = "Black Forest Labs"
            exif_data[ExifTags.Base.Model] = self.model_name
            if add_sampling_metadata:
                exif_data[ExifTags.Base.ImageDescription] = prompt

            img.save(filename, format="jpeg", exif=exif_data, quality=95, subsampling=0)

            return img, str(opts.seed), filename, None
        else:
            return None, str(opts.seed), None, "Your generated image may contain NSFW content."


def create_demo(
    model_name: str, device: str = "cuda" if torch.cuda.is_available() else "cpu", offload: bool = False
):
    generator = FluxGenerator(model_name, device, offload)
    is_schnell = model_name == "flux-schnell"

    with gr.Blocks() as demo:
        gr.Markdown(f"# Flux Image Generation Demo - Model: {model_name}")

        with gr.Row():
            with gr.Column():
                prompt = gr.Textbox(
                    label="Prompt",
                    value='a photo of a forest with mist swirling around the tree trunks. The word "FLUX" is painted over it in big, red brush strokes with visible texture',
                )
                do_img2img = gr.Checkbox(label="Image to Image", value=False, interactive=not is_schnell)
                init_image = gr.Image(label="Input Image", visible=False)
                image2image_strength = gr.Slider(
                    0.0, 1.0, 0.8, step=0.1, label="Noising strength", visible=False
                )

                with gr.Accordion("Advanced Options", open=False):
                    width = gr.Slider(128, 8192, 1360, step=16, label="Width")
                    height = gr.Slider(128, 8192, 768, step=16, label="Height")
                    num_steps = gr.Slider(1, 50, 4 if is_schnell else 50, step=1, label="Number of steps")
                    guidance = gr.Slider(
                        1.0, 10.0, 3.5, step=0.1, label="Guidance", interactive=not is_schnell
                    )
                    seed = gr.Textbox(-1, label="Seed (-1 for random)")
                    add_sampling_metadata = gr.Checkbox(
                        label="Add sampling parameters to metadata?", value=True
                    )

                generate_btn = gr.Button("Generate")

            with gr.Column():
                output_image = gr.Image(label="Generated Image")
                seed_output = gr.Number(label="Used Seed")
                warning_text = gr.Textbox(label="Warning", visible=False)
                download_btn = gr.File(label="Download full-resolution")

        def update_img2img(do_img2img):
            return {
                init_image: gr.update(visible=do_img2img),
                image2image_strength: gr.update(visible=do_img2img),
            }

        do_img2img.change(update_img2img, do_img2img, [init_image, image2image_strength])

        generate_btn.click(
            fn=generator.generate_image,
            inputs=[
                width,
                height,
                num_steps,
                guidance,
                seed,
                prompt,
                init_image,
                image2image_strength,
                add_sampling_metadata,
            ],
            outputs=[output_image, seed_output, download_btn, warning_text],
        )

    return demo


if __name__ == "__main__":
    import argparse

    parser = argparse.ArgumentParser(description="Flux")
    parser.add_argument(
        "--name", type=str, default="flux-schnell", choices=list(configs.keys()), help="Model name"
    )
    parser.add_argument(
        "--device", type=str, default="cuda" if torch.cuda.is_available() else "cpu", help="Device to use"
    )
    parser.add_argument("--offload", action="store_true", help="Offload model to CPU when not in use")
    parser.add_argument("--share", action="store_true", help="Create a public link to your demo")
    args = parser.parse_args()

    demo = create_demo(args.name, args.device, args.offload)
    demo.launch(share=args.share)