text-generation-webui/modules/image_models.py

# modules/image_models.py
import time
import torch

import modules.shared as shared
from modules.logging_colors import logger
from modules.utils import resolve_model_path
from modules.torch_utils import get_device


def load_image_model(model_name, dtype='bfloat16', attn_backend='sdpa', cpu_offload=False, compile_model=False):
    """
    Load a diffusers image generation model.

    Args:
        model_name: Name of the model directory
        dtype: 'bfloat16' or 'float16'
        attn_backend: 'sdpa', 'flash_attention_2', or 'flash_attention_3'
        cpu_offload: Enable CPU offloading for low VRAM
        compile_model: Compile the model for faster inference (slow first run)
    """
    from diffusers import ZImagePipeline

    logger.info(f"Loading image model \"{model_name}\"")
    t0 = time.time()

    dtype_map = {"bfloat16": torch.bfloat16, "float16": torch.float16}
    target_dtype = dtype_map.get(dtype, torch.bfloat16)

    model_path = resolve_model_path(model_name, image_model=True)

    try:
        pipe = ZImagePipeline.from_pretrained(
            str(model_path),
            torch_dtype=target_dtype,
            low_cpu_mem_usage=False,
        )

        if not cpu_offload:
            pipe.to(get_device())

        # Set attention backend
        if attn_backend == 'flash_attention_2':
            pipe.transformer.set_attention_backend("flash")
        elif attn_backend == 'flash_attention_3':
            pipe.transformer.set_attention_backend("_flash_3")
        # sdpa is the default, no action needed

        if compile_model:
            logger.info("Compiling model (first run will be slow)...")
            pipe.transformer.compile()

        if cpu_offload:
            pipe.enable_model_cpu_offload()

        shared.image_model = pipe
        shared.image_model_name = model_name

        logger.info(f"Loaded image model \"{model_name}\" in {(time.time()-t0):.2f} seconds.")
        return pipe

    except Exception as e:
        logger.error(f"Failed to load image model: {str(e)}")
        return None


def unload_image_model():
    """Unload the current image model and free VRAM."""
    if shared.image_model is None:
        return

    del shared.image_model
    shared.image_model = None
    shared.image_model_name = 'None'

    # Clear CUDA cache
    if torch.cuda.is_available():

        torch.cuda.empty_cache()

    logger.info("Image model unloaded.")