inference.py

import torch
from diffusers import StableDiffusionPipeline
import os

def inference(
    model_path: str,
    prompt: str,
    output_image_path: str = "generated_image.png",
    guidance_scale: float = 7.5,
    num_inference_steps: int = 50,
    use_fp16: bool = True,
):
    """
    Generates an image using a fine-tuned Stable Diffusion model.

    Args:
        model_path (str): The path (or repo ID) to the fine-tuned Stable Diffusion model.
        prompt (str): The text prompt used to generate an image.
        output_image_path (str): The path to save the generated image.
        guidance_scale (float): Classifier-Free Guidance scale.
        num_inference_steps (int): Number of inference steps in the diffusion process.
        use_fp16 (bool): Whether to use fp16 (half precision). Recommended if a GPU is available.
    """

    # Load the model (use half precision if GPU is available)
    # If you only have CPU, consider using torch.float32 or omitting torch_dtype
    pipe = StableDiffusionPipeline.from_pretrained(
        model_path,
        subfolder="stable_diffusion-v1-4-wikiart",  
        torch_dtype=torch.float16 if use_fp16 and torch.cuda.is_available() else torch.float32
    )

    # Set the device (use GPU if available)
    device = "cuda" if torch.cuda.is_available() else "cpu"
    pipe.to(device)

    # Generate the image
    with torch.autocast(device) if (use_fp16 and device == "cuda") else torch.no_grad():
        result = pipe(
            prompt=prompt,
            guidance_scale=guidance_scale,
            num_inference_steps=num_inference_steps
        )

    # Save the result
    image = result.images[0]
    image.save(output_image_path)
    print(f"Saved Image: {os.path.abspath(output_image_path)}")


if __name__ == "__main__":
    # Example prompt
    sample_prompt = "A paint of Eiffel tower, in the style of eric fischl."

    # Assuming the fine-tuned model was saved with pipe.save_pretrained("stable-diffusion-wikiart-final")
    finetuned_model_path = "stable-diffusion-wikiart-final"
    
    # Run inference
    inference(
        model_path=finetuned_model_path,
        prompt=sample_prompt,
        output_image_path="wikiart_inference_result.png",
        guidance_scale=7.5,
        num_inference_steps=50,
        use_fp16=True
    )