import inspect
from typing import Any, Callable, Dict, List, Optional, Tuple, Union
import numpy as np
import PIL.Image
import torch
from diffusers import (AutoencoderKL, ControlNetModel, DiffusionPipeline,
UNet2DConditionModel)
from diffusers.loaders import LoraLoaderMixin
from diffusers.pipelines.stable_diffusion import (
StableDiffusionPipelineOutput, StableDiffusionSafetyChecker)
from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion_controlnet import \
MultiControlNetModel
from diffusers.schedulers import KarrasDiffusionSchedulers
from diffusers.utils import (PIL_INTERPOLATION, is_accelerate_available,
is_accelerate_version, randn_tensor,
replace_example_docstring)
from transformers import CLIPImageProcessor, CLIPTextModel, CLIPTokenizer
EXAMPLE_DOC_STRING = """
Examples:
```py
>>> import numpy as np
>>> import torch
>>> from PIL import Image
>>> from diffusers import ControlNetModel, UniPCMultistepScheduler
>>> from diffusers.utils import load_image
>>> input_image = load_image("https://hf.co/datasets/huggingface/documentation-images/resolve/main/diffusers/input_image_vermeer.png")
>>> controlnet = ControlNetModel.from_pretrained("lllyasviel/sd-controlnet-canny", torch_dtype=torch.float16)
>>> pipe_controlnet = StableDiffusionControlNetImg2ImgPipeline.from_pretrained(
"runwayml/stable-diffusion-v1-5",
controlnet=controlnet,
safety_checker=None,
torch_dtype=torch.float16
)
>>> pipe_controlnet.scheduler = UniPCMultistepScheduler.from_config(pipe_controlnet.scheduler.config)
>>> pipe_controlnet.enable_xformers_memory_efficient_attention()
>>> pipe_controlnet.enable_model_cpu_offload()
# using image with edges for our canny controlnet
>>> control_image = load_image(
"https://hf.co/datasets/huggingface/documentation-images/resolve/main/diffusers/vermeer_canny_edged.png")
>>> result_img = pipe_controlnet(controlnet_conditioning_image=control_image,
image=input_image,
prompt="an android robot, cyberpank, digitl art masterpiece",
num_inference_steps=20).images[0]
>>> result_img.show()
```
"""
def prepare_image(image):
if isinstance(image, torch.Tensor):
# Batch single image
if image.ndim == 3:
image = image.unsqueeze(0)
image = image.to(dtype=torch.float32)
else:
# preprocess image
if isinstance(image, (PIL.Image.Image, np.ndarray)):
image = [image]
if isinstance(image, list) and isinstance(image[0], PIL.Image.Image):
image = [np.array(i.convert("RGB"))[None, :] for i in image]
image = np.concatenate(image, axis=0)
elif isinstance(image, list) and isinstance(image[0], np.ndarray):
image = np.concatenate([i[None, :] for i in image], axis=0)
image = image.transpose(0, 3, 1, 2)
image = torch.from_numpy(image).to(dtype=torch.float32) / 127.5 - 1.0
return image
def prepare_controlnet_conditioning_image(
controlnet_conditioning_image,
width,
height,
batch_size,
num_images_per_prompt,
device,
dtype,
do_classifier_free_guidance,
):
if not isinstance(controlnet_conditioning_image, torch.Tensor):
if isinstance(controlnet_conditioning_image, PIL.Image.Image):
controlnet_conditioning_image = [controlnet_conditioning_image]
if isinstance(controlnet_conditioning_image[0], PIL.Image.Image):
controlnet_conditioning_image = [
np.array(
i.resize((width, height), resample=PIL_INTERPOLATION["lanczos"])
)[None, :]
for i in controlnet_conditioning_image
]
controlnet_conditioning_image = np.concatenate(
controlnet_conditioning_image, axis=0
)
controlnet_conditioning_image = (
np.array(controlnet_conditioning_image).astype(np.float32) / 255.0
)
controlnet_conditioning_image = controlnet_conditioning_image.transpose(
0, 3, 1, 2
)
controlnet_conditioning_image = torch.from_numpy(
controlnet_conditioning_image
)
elif isinstance(controlnet_conditioning_image[0], torch.Tensor):
controlnet_conditioning_image = torch.cat(
controlnet_conditioning_image, dim=0
)
image_batch_size = controlnet_conditioning_image.shape[0]
if image_batch_size == 1:
repeat_by = batch_size
else:
# image batch size is the same as prompt batch size
repeat_by = num_images_per_prompt
controlnet_conditioning_image = controlnet_conditioning_image.repeat_interleave(
repeat_by, dim=0
)
controlnet_conditioning_image = controlnet_conditioning_image.to(
device=device, dtype=dtype
)
if do_classifier_free_guidance:
controlnet_conditioning_image = torch.cat([controlnet_conditioning_image] * 2)
return controlnet_conditioning_image
class StableDiffusionControlNetImg2ImgPipeline(DiffusionPipeline, LoraLoaderMixin):
"""
Inspired by: https://github.com/haofanwang/ControlNet-for-Diffusers/
"""
_optional_components = ["safety_checker", "feature_extractor"]
def __init__(
self,
vae: AutoencoderKL,
text_encoder: CLIPTextModel,
tokenizer: CLIPTokenizer,
unet: UNet2DConditionModel,
controlnet: Union[
ControlNetModel,
List[ControlNetModel],
Tuple[ControlNetModel],
MultiControlNetModel,
],
scheduler: KarrasDiffusionSchedulers,
safety_checker: StableDiffusionSafetyChecker,
feature_extractor: CLIPImageProcessor,
requires_safety_checker: bool = True,
):
super().__init__()
if safety_checker is None and requires_safety_checker:
print(
f"You have disabled the safety checker for {self.__class__} by passing `safety_checker=None`. Ensure"
" that you abide to the conditions of the Stable Diffusion license and do not expose unfiltered"
" results in services or applications open to the public. Both the diffusers team and Hugging Face"
" strongly recommend to keep the safety filter enabled in all public facing circumstances, disabling"
" it only for use-cases that involve analyzing network behavior or auditing its results. For more"
" information, please have a look at https://github.com/huggingface/diffusers/pull/254 ."
)
if safety_checker is not None and feature_extractor is None:
raise ValueError(
"Make sure to define a feature extractor when loading {self.__class__} if you want to use the safety"
" checker. If you do not want to use the safety checker, you can pass `'safety_checker=None'` instead."
)
if isinstance(controlnet, (list, tuple)):
controlnet = MultiControlNetModel(controlnet)
self.register_modules(
vae=vae,
text_encoder=text_encoder,
tokenizer=tokenizer,
unet=unet,
controlnet=controlnet,
scheduler=scheduler,
safety_checker=safety_checker,
feature_extractor=feature_extractor,
)
self.vae_scale_factor = 2 ** (len(self.vae.config.block_out_channels) - 1)
self.register_to_config(requires_safety_checker=requires_safety_checker)
def enable_vae_slicing(self):
r"""
Enable sliced VAE decoding.
When this option is enabled, the VAE will split the input tensor in slices to compute decoding in several
steps. This is useful to save some memory and allow larger batch sizes.
"""
self.vae.enable_slicing()
def disable_vae_slicing(self):
r"""
Disable sliced VAE decoding. If `enable_vae_slicing` was previously invoked, this method will go back to
computing decoding in one step.
"""
self.vae.disable_slicing()
def enable_sequential_cpu_offload(self, gpu_id=0):
r"""
Offloads all models to CPU using accelerate, significantly reducing memory usage. When called, unet,
text_encoder, vae, controlnet, and safety checker have their state dicts saved to CPU and then are moved to a
`torch.device('meta') and loaded to GPU only when their specific submodule has its `forward` method called.
Note that offloading happens on a submodule basis. Memory savings are higher than with
`enable_model_cpu_offload`, but performance is lower.
"""
if is_accelerate_available():
from accelerate import cpu_offload
else:
raise ImportError("Please install accelerate via `pip install accelerate`")
device = torch.device(f"cuda:{gpu_id}")
for cpu_offloaded_model in [
self.unet,
self.text_encoder,
self.vae,
self.controlnet,
]:
cpu_offload(cpu_offloaded_model, device)
if self.safety_checker is not None:
cpu_offload(
self.safety_checker, execution_device=device, offload_buffers=True
)
def enable_model_cpu_offload(self, gpu_id=0):
r"""
Offloads all models to CPU using accelerate, reducing memory usage with a low impact on performance. Compared
to `enable_sequential_cpu_offload`, this method moves one whole model at a time to the GPU when its `forward`
method is called, and the model remains in GPU until the next model runs. Memory savings are lower than with
`enable_sequential_cpu_offload`, but performance is much better due to the iterative execution of the `unet`.
"""
if is_accelerate_available() and is_accelerate_version(">=", "0.17.0.dev0"):
from accelerate import cpu_offload_with_hook
else:
raise ImportError(
"`enable_model_cpu_offload` requires `accelerate v0.17.0` or higher."
)
device = torch.device(f"cuda:{gpu_id}")
hook = None
for cpu_offloaded_model in [self.text_encoder, self.unet, self.vae]:
_, hook = cpu_offload_with_hook(
cpu_offloaded_model, device, prev_module_hook=hook
)
if self.safety_checker is not None:
# the safety checker can offload the vae again
_, hook = cpu_offload_with_hook(
self.safety_checker, device, prev_module_hook=hook
)
# control net hook has be manually offloaded as it alternates with unet
cpu_offload_with_hook(self.controlnet, device)
# We'll offload the last model manually.
self.final_offload_hook = hook
@property
def _execution_device(self):
r"""
Returns the device on which the pipeline's models will be executed. After calling
`pipeline.enable_sequential_cpu_offload()` the execution device can only be inferred from Accelerate's module
hooks.
"""
if not hasattr(self.unet, "_hf_hook"):
return self.device
for module in self.unet.modules():
if (
hasattr(module, "_hf_hook")
and hasattr(module._hf_hook, "execution_device")
and module._hf_hook.execution_device is not None
):
return torch.device(module._hf_hook.execution_device)
return self.device
def _encode_prompt(
self,
prompt,
device,
num_images_per_prompt,
do_classifier_free_guidance,
negative_prompt=None,
prompt_embeds: Optional[torch.FloatTensor] = None,
negative_prompt_embeds: Optional[torch.FloatTensor] = None,
):
r"""
Encodes the prompt into text encoder hidden states.
Args:
prompt (`str` or `List[str]`, *optional*):
prompt to be encoded
device: (`torch.device`):
torch device
num_images_per_prompt (`int`):
number of images that should be generated per prompt
do_classifier_free_guidance (`bool`):
whether to use classifier free guidance or not
negative_prompt (`str` or `List[str]`, *optional*):
The prompt or prompts not to guide the image generation. If not defined, one has to pass
`negative_prompt_embeds` instead. Ignored when not using guidance (i.e., ignored if `guidance_scale` is less than `1`).
prompt_embeds (`torch.FloatTensor`, *optional*):
Pre-generated text embeddings. Can be used to easily tweak text inputs, *e.g.* prompt weighting. If not
provided, text embeddings will be generated from `prompt` input argument.
negative_prompt_embeds (`torch.FloatTensor`, *optional*):
Pre-generated negative text embeddings. Can be used to easily tweak text inputs, *e.g.* prompt
weighting. If not provided, negative_prompt_embeds will be generated from `negative_prompt` input
argument.
"""
if prompt is not None and isinstance(prompt, str):
batch_size = 1
elif prompt is not None and isinstance(prompt, list):
batch_size = len(prompt)
else:
batch_size = prompt_embeds.shape[0]
if prompt_embeds is None:
text_inputs = self.tokenizer(
prompt,
padding="max_length",
max_length=self.tokenizer.model_max_length,
truncation=True,
return_tensors="pt",
)
text_input_ids = text_inputs.input_ids
untruncated_ids = self.tokenizer(
prompt, padding="longest", return_tensors="pt"
).input_ids
if untruncated_ids.shape[-1] >= text_input_ids.shape[
-1
] and not torch.equal(text_input_ids, untruncated_ids):
removed_text = self.tokenizer.batch_decode(
untruncated_ids[:, self.tokenizer.model_max_length - 1 : -1]
)
print(
"The following part of your input was truncated because CLIP can only handle sequences up to"
f" {self.tokenizer.model_max_length} tokens: {removed_text}"
)
if (
hasattr(self.text_encoder.config, "use_attention_mask")
and self.text_encoder.config.use_attention_mask
):
attention_mask = text_inputs.attention_mask.to(device)
else:
attention_mask = None
prompt_embeds = self.text_encoder(
text_input_ids.to(device),
attention_mask=attention_mask,
)
prompt_embeds = prompt_embeds[0]
prompt_embeds = prompt_embeds.to(dtype=self.text_encoder.dtype, device=device)
bs_embed, seq_len, _ = prompt_embeds.shape
# duplicate text embeddings for each generation per prompt, using mps friendly method
prompt_embeds = prompt_embeds.repeat(1, num_images_per_prompt, 1)
prompt_embeds = prompt_embeds.view(
bs_embed * num_images_per_prompt, seq_len, -1
)
# get unconditional embeddings for classifier free guidance
if do_classifier_free_guidance and negative_prompt_embeds is None:
uncond_tokens: List[str]
if negative_prompt is None:
uncond_tokens = [""] * batch_size
elif type(prompt) is not type(negative_prompt):
raise TypeError(
f"`negative_prompt` should be the same type to `prompt`, but got {type(negative_prompt)} !="
f" {type(prompt)}."
)
elif isinstance(negative_prompt, str):
uncond_tokens = [negative_prompt]
elif batch_size != len(negative_prompt):
raise ValueError(
f"`negative_prompt`: {negative_prompt} has batch size {len(negative_prompt)}, but `prompt`:"
f" {prompt} has batch size {batch_size}. Please make sure that passed `negative_prompt` matches"
" the batch size of `prompt`."
)
else:
uncond_tokens = negative_prompt
max_length = prompt_embeds.shape[1]
uncond_input = self.tokenizer(
uncond_tokens,
padding="max_length",
max_length=max_length,
truncation=True,
return_tensors="pt",
)
if (
hasattr(self.text_encoder.config, "use_attention_mask")
and self.text_encoder.config.use_attention_mask
):
attention_mask = uncond_input.attention_mask.to(device)
else:
attention_mask = None
negative_prompt_embeds = self.text_encoder(
uncond_input.input_ids.to(device),
attention_mask=attention_mask,
)
negative_prompt_embeds = negative_prompt_embeds[0]
if do_classifier_free_guidance:
# duplicate unconditional embeddings for each generation per prompt, using mps friendly method
seq_len = negative_prompt_embeds.shape[1]
negative_prompt_embeds = negative_prompt_embeds.to(
dtype=self.text_encoder.dtype, device=device
)
negative_prompt_embeds = negative_prompt_embeds.repeat(
1, num_images_per_prompt, 1
)
negative_prompt_embeds = negative_prompt_embeds.view(
batch_size * num_images_per_prompt, seq_len, -1
)
# For classifier free guidance, we need to do two forward passes.
# Here we concatenate the unconditional and text embeddings into a single batch
# to avoid doing two forward passes
prompt_embeds = torch.cat([negative_prompt_embeds, prompt_embeds])
return prompt_embeds
def run_safety_checker(self, image, device, dtype):
if self.safety_checker is not None:
safety_checker_input = self.feature_extractor(
self.numpy_to_pil(image), return_tensors="pt"
).to(device)
image, has_nsfw_concept = self.safety_checker(
images=image, clip_input=safety_checker_input.pixel_values.to(dtype)
)
else:
has_nsfw_concept = None
return image, has_nsfw_concept
def decode_latents(self, latents):
latents = 1 / self.vae.config.scaling_factor * latents
image = self.vae.decode(latents).sample
image = (image / 2 + 0.5).clamp(0, 1)
# we always cast to float32 as this does not cause significant overhead and is compatible with bfloat16
image = image.cpu().permute(0, 2, 3, 1).float().numpy()
return image
def prepare_extra_step_kwargs(self, generator, eta):
# prepare extra kwargs for the scheduler step, since not all schedulers have the same signature
# eta (η) is only used with the DDIMScheduler, it will be ignored for other schedulers.
# eta corresponds to η in DDIM paper: https://arxiv.org/abs/2010.02502
# and should be between [0, 1]
accepts_eta = "eta" in set(
inspect.signature(self.scheduler.step).parameters.keys()
)
extra_step_kwargs = {}
if accepts_eta:
extra_step_kwargs["eta"] = eta
# check if the scheduler accepts generator
accepts_generator = "generator" in set(
inspect.signature(self.scheduler.step).parameters.keys()
)
if accepts_generator:
extra_step_kwargs["generator"] = generator
return extra_step_kwargs
def check_controlnet_conditioning_image(self, image, prompt, prompt_embeds):
image_is_pil = isinstance(image, PIL.Image.Image)
image_is_tensor = isinstance(image, torch.Tensor)
image_is_pil_list = isinstance(image, list) and isinstance(
image[0], PIL.Image.Image
)
image_is_tensor_list = isinstance(image, list) and isinstance(
image[0], torch.Tensor
)
if (
not image_is_pil
and not image_is_tensor
and not image_is_pil_list
and not image_is_tensor_list
):
raise TypeError(
"image must be passed and be one of PIL image, torch tensor, list of PIL images, or list of torch tensors"
)
if image_is_pil:
image_batch_size = 1
elif image_is_tensor:
image_batch_size = image.shape[0]
elif image_is_pil_list:
image_batch_size = len(image)
elif image_is_tensor_list:
image_batch_size = len(image)
else:
raise ValueError("controlnet condition image is not valid")
if prompt is not None and isinstance(prompt, str):
prompt_batch_size = 1
elif prompt is not None and isinstance(prompt, list):
prompt_batch_size = len(prompt)
elif prompt_embeds is not None:
prompt_batch_size = prompt_embeds.shape[0]
else:
raise ValueError("prompt or prompt_embeds are not valid")
if image_batch_size != 1 and image_batch_size != prompt_batch_size:
raise ValueError(
f"If image batch size is not 1, image batch size must be same as prompt batch size. image batch size: {image_batch_size}, prompt batch size: {prompt_batch_size}"
)
def check_inputs(
self,
prompt,
image,
controlnet_conditioning_image,
height,
width,
callback_steps,
negative_prompt=None,
prompt_embeds=None,
negative_prompt_embeds=None,
strength=None,
controlnet_guidance_start=None,
controlnet_guidance_end=None,
controlnet_conditioning_scale=None,
):
if height % 8 != 0 or width % 8 != 0:
raise ValueError(
f"`height` and `width` have to be divisible by 8 but are {height} and {width}."
)
if (callback_steps is None) or (
callback_steps is not None
and (not isinstance(callback_steps, int) or callback_steps <= 0)
):
raise ValueError(
f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
f" {type(callback_steps)}."
)
if prompt is not None and prompt_embeds is not None:
raise ValueError(
f"Cannot forward both `prompt`: {prompt} and `prompt_embeds`: {prompt_embeds}. Please make sure to"
" only forward one of the two."
)
elif prompt is None and prompt_embeds is None:
raise ValueError(
"Provide either `prompt` or `prompt_embeds`. Cannot leave both `prompt` and `prompt_embeds` undefined."
)
elif prompt is not None and (
not isinstance(prompt, str) and not isinstance(prompt, list)
):
raise ValueError(
f"`prompt` has to be of type `str` or `list` but is {type(prompt)}"
)
if negative_prompt is not None and negative_prompt_embeds is not None:
raise ValueError(
f"Cannot forward both `negative_prompt`: {negative_prompt} and `negative_prompt_embeds`:"
f" {negative_prompt_embeds}. Please make sure to only forward one of the two."
)
if prompt_embeds is not None and negative_prompt_embeds is not None:
if prompt_embeds.shape != negative_prompt_embeds.shape:
raise ValueError(
"`prompt_embeds` and `negative_prompt_embeds` must have the same shape when passed directly, but"
f" got: `prompt_embeds` {prompt_embeds.shape} != `negative_prompt_embeds`"
f" {negative_prompt_embeds.shape}."
)
# check controlnet condition image
if isinstance(self.controlnet, ControlNetModel):
self.check_controlnet_conditioning_image(
controlnet_conditioning_image, prompt, prompt_embeds
)
elif isinstance(self.controlnet, MultiControlNetModel):
if not isinstance(controlnet_conditioning_image, list):
raise TypeError("For multiple controlnets: `image` must be type `list`")
if len(controlnet_conditioning_image) != len(self.controlnet.nets):
raise ValueError(
"For multiple controlnets: `image` must have the same length as the number of controlnets."
)
for image_ in controlnet_conditioning_image:
self.check_controlnet_conditioning_image(image_, prompt, prompt_embeds)
else:
assert False
# Check `controlnet_conditioning_scale`
if isinstance(self.controlnet, ControlNetModel):
if not isinstance(controlnet_conditioning_scale, float):
raise TypeError(
"For single controlnet: `controlnet_conditioning_scale` must be type `float`."
)
elif isinstance(self.controlnet, MultiControlNetModel):
if isinstance(controlnet_conditioning_scale, list) and len(
controlnet_conditioning_scale
) != len(self.controlnet.nets):
raise ValueError(
"For multiple controlnets: When `controlnet_conditioning_scale` is specified as `list`, it must have"
" the same length as the number of controlnets"
)
else:
assert False
if isinstance(image, torch.Tensor):
if image.ndim != 3 and image.ndim != 4:
raise ValueError("`image` must have 3 or 4 dimensions")
if image.ndim == 3:
image_batch_size = 1
image_channels, image_height, image_width = image.shape
elif image.ndim == 4:
(
image_batch_size,
image_channels,
image_height,
image_width,
) = image.shape
else:
assert False
if image_channels != 3:
raise ValueError("`image` must have 3 channels")
if image.min() < -1 or image.max() > 1:
raise ValueError("`image` should be in range [-1, 1]")
if self.vae.config.latent_channels != self.unet.config.in_channels:
raise ValueError(
f"The config of `pipeline.unet` expects {self.unet.config.in_channels} but received"
f" latent channels: {self.vae.config.latent_channels},"
f" Please verify the config of `pipeline.unet` and the `pipeline.vae`"
)
if strength < 0 or strength > 1:
raise ValueError(
f"The value of `strength` should in [0.0, 1.0] but is {strength}"
)
if controlnet_guidance_start < 0 or controlnet_guidance_start > 1:
raise ValueError(
f"The value of `controlnet_guidance_start` should in [0.0, 1.0] but is {controlnet_guidance_start}"
)
if controlnet_guidance_end < 0 or controlnet_guidance_end > 1:
raise ValueError(
f"The value of `controlnet_guidance_end` should in [0.0, 1.0] but is {controlnet_guidance_end}"
)
if controlnet_guidance_start > controlnet_guidance_end:
raise ValueError(
"The value of `controlnet_guidance_start` should be less than `controlnet_guidance_end`, but got"
f" `controlnet_guidance_start` {controlnet_guidance_start} >= `controlnet_guidance_end` {controlnet_guidance_end}"
)
def get_timesteps(self, num_inference_steps, strength, device):
# get the original timestep using init_timestep
init_timestep = min(int(num_inference_steps * strength), num_inference_steps)
t_start = max(num_inference_steps - init_timestep, 0)
timesteps = self.scheduler.timesteps[t_start:]
return timesteps, num_inference_steps - t_start
def prepare_latents(
self,
image,
timestep,
batch_size,
num_images_per_prompt,
dtype,
device,
generator=None,
):
if not isinstance(image, (torch.Tensor, PIL.Image.Image, list)):
raise ValueError(
f"`image` has to be of type `torch.Tensor`, `PIL.Image.Image` or list but is {type(image)}"
)
image = image.to(device=device, dtype=dtype)
batch_size = batch_size * num_images_per_prompt
if isinstance(generator, list) and len(generator) != batch_size:
raise ValueError(
f"You have passed a list of generators of length {len(generator)}, but requested an effective batch"
f" size of {batch_size}. Make sure the batch size matches the length of the generators."
)
if isinstance(generator, list):
init_latents = [
self.vae.encode(image[i : i + 1]).latent_dist.sample(generator[i])
for i in range(batch_size)
]
init_latents = torch.cat(init_latents, dim=0)
else:
init_latents = self.vae.encode(image).latent_dist.sample(generator)
init_latents = self.vae.config.scaling_factor * init_latents
if (
batch_size > init_latents.shape[0]
and batch_size % init_latents.shape[0] == 0
):
raise ValueError(
f"Cannot duplicate `image` of batch size {init_latents.shape[0]} to {batch_size} text prompts."
)
else:
init_latents = torch.cat([init_latents], dim=0)
shape = init_latents.shape
noise = randn_tensor(shape, generator=generator, device=device, dtype=dtype)
# get latents
init_latents = self.scheduler.add_noise(init_latents, noise, timestep)
latents = init_latents
return latents
def _default_height_width(self, height, width, image):
if isinstance(image, list):
image = image[0]
if height is None:
if isinstance(image, PIL.Image.Image):
height = image.height
elif isinstance(image, torch.Tensor):
height = image.shape[3]
height = (height // 8) * 8 # round down to nearest multiple of 8
if width is None:
if isinstance(image, PIL.Image.Image):
width = image.width
elif isinstance(image, torch.Tensor):
width = image.shape[2]
width = (width // 8) * 8 # round down to nearest multiple of 8
return height, width
@torch.no_grad()
@replace_example_docstring(EXAMPLE_DOC_STRING)
def __call__(
self,
prompt: Union[str, List[str]] = None,
image: Union[torch.Tensor, PIL.Image.Image] = None,
controlnet_conditioning_image: Union[
torch.FloatTensor,
PIL.Image.Image,
List[torch.FloatTensor],
List[PIL.Image.Image],
] = None,
strength: float = 0.8,
height: Optional[int] = None,
width: Optional[int] = None,
num_inference_steps: int = 50,
guidance_scale: float = 7.5,
negative_prompt: Optional[Union[str, List[str]]] = None,
num_images_per_prompt: Optional[int] = 1,
eta: float = 0.0,
generator: Optional[Union[torch.Generator, List[torch.Generator]]] = None,
latents: Optional[torch.FloatTensor] = None,
prompt_embeds: Optional[torch.FloatTensor] = None,
negative_prompt_embeds: Optional[torch.FloatTensor] = None,
output_type: Optional[str] = "pil",
return_dict: bool = True,
callback: Optional[Callable[[int, int, torch.FloatTensor], None]] = None,
callback_steps: int = 1,
cross_attention_kwargs: Optional[Dict[str, Any]] = None,
controlnet_conditioning_scale: Union[float, List[float]] = 1.0,
controlnet_guidance_start: float = 0.0,
controlnet_guidance_end: float = 1.0,
):
r"""
Function invoked when calling the pipeline for generation.
Args:
prompt (`str` or `List[str]`, *optional*):
The prompt or prompts to guide the image generation. If not defined, one has to pass `prompt_embeds`.
instead.
image (`torch.Tensor` or `PIL.Image.Image`):
`Image`, or tensor representing an image batch which will be inpainted, *i.e.* parts of the image will
be masked out with `mask_image` and repainted according to `prompt`.
controlnet_conditioning_image (`torch.FloatTensor`, `PIL.Image.Image`, `List[torch.FloatTensor]` or `List[PIL.Image.Image]`):
The ControlNet input condition. ControlNet uses this input condition to generate guidance to Unet. If
the type is specified as `Torch.FloatTensor`, it is passed to ControlNet as is. PIL.Image.Image` can
also be accepted as an image. The control image is automatically resized to fit the output image.
strength (`float`, *optional*):
Conceptually, indicates how much to transform the reference `image`. Must be between 0 and 1. `image`
will be used as a starting point, adding more noise to it the larger the `strength`. The number of
denoising steps depends on the amount of noise initially added. When `strength` is 1, added noise will
be maximum and the denoising process will run for the full number of iterations specified in
`num_inference_steps`. A value of 1, therefore, essentially ignores `image`.
height (`int`, *optional*, defaults to self.unet.config.sample_size * self.vae_scale_factor):
The height in pixels of the generated image.
width (`int`, *optional*, defaults to self.unet.config.sample_size * self.vae_scale_factor):
The width in pixels of the generated image.
num_inference_steps (`int`, *optional*, defaults to 50):
The number of denoising steps. More denoising steps usually lead to a higher quality image at the
expense of slower inference.
guidance_scale (`float`, *optional*, defaults to 7.5):
Guidance scale as defined in [Classifier-Free Diffusion Guidance](https://arxiv.org/abs/2207.12598).
`guidance_scale` is defined as `w` of equation 2. of [Imagen
Paper](https://arxiv.org/pdf/2205.11487.pdf). Guidance scale is enabled by setting `guidance_scale >
1`. Higher guidance scale encourages to generate images that are closely linked to the text `prompt`,
usually at the expense of lower image quality.
negative_prompt (`str` or `List[str]`, *optional*):
The prompt or prompts not to guide the image generation. If not defined, one has to pass
`negative_prompt_embeds` instead. Ignored when not using guidance (i.e., ignored if `guidance_scale` is less than `1`).
num_images_per_prompt (`int`, *optional*, defaults to 1):
The number of images to generate per prompt.
eta (`float`, *optional*, defaults to 0.0):
Corresponds to parameter eta (η) in the DDIM paper: https://arxiv.org/abs/2010.02502. Only applies to
[`schedulers.DDIMScheduler`], will be ignored for others.
generator (`torch.Generator` or `List[torch.Generator]`, *optional*):
One or a list of [torch generator(s)](https://pytorch.org/docs/stable/generated/torch.Generator.html)
to make generation deterministic.
latents (`torch.FloatTensor`, *optional*):
Pre-generated noisy latents, sampled from a Gaussian distribution, to be used as inputs for image
generation. Can be used to tweak the same generation with different prompts. If not provided, a latents
tensor will ge generated by sampling using the supplied random `generator`.
prompt_embeds (`torch.FloatTensor`, *optional*):
Pre-generated text embeddings. Can be used to easily tweak text inputs, *e.g.* prompt weighting. If not
provided, text embeddings will be generated from `prompt` input argument.
negative_prompt_embeds (`torch.FloatTensor`, *optional*):
Pre-generated negative text embeddings. Can be used to easily tweak text inputs, *e.g.* prompt
weighting. If not provided, negative_prompt_embeds will be generated from `negative_prompt` input
argument.
output_type (`str`, *optional*, defaults to `"pil"`):
The output format of the generate image. Choose between
[PIL](https://pillow.readthedocs.io/en/stable/): `PIL.Image.Image` or `np.array`.
return_dict (`bool`, *optional*, defaults to `True`):
Whether or not to return a [`~pipelines.stable_diffusion.StableDiffusionPipelineOutput`] instead of a
plain tuple.
callback (`Callable`, *optional*):
A function that will be called every `callback_steps` steps during inference. The function will be
called with the following arguments: `callback(step: int, timestep: int, latents: torch.FloatTensor)`.
callback_steps (`int`, *optional*, defaults to 1):
The frequency at which the `callback` function will be called. If not specified, the callback will be
called at every step.
cross_attention_kwargs (`dict`, *optional*):
A kwargs dictionary that if specified is passed along to the `AttentionProcessor` as defined under
`self.processor` in
[diffusers.cross_attention](https://github.com/huggingface/diffusers/blob/main/src/diffusers/models/cross_attention.py).
controlnet_conditioning_scale (`float`, *optional*, defaults to 1.0):
The outputs of the controlnet are multiplied by `controlnet_conditioning_scale` before they are added
to the residual in the original unet.
controlnet_guidance_start ('float', *optional*, defaults to 0.0):
The percentage of total steps the controlnet starts applying. Must be between 0 and 1.
controlnet_guidance_end ('float', *optional*, defaults to 1.0):
The percentage of total steps the controlnet ends applying. Must be between 0 and 1. Must be greater
than `controlnet_guidance_start`.
Examples:
Returns:
[`~pipelines.stable_diffusion.StableDiffusionPipelineOutput`] or `tuple`:
[`~pipelines.stable_diffusion.StableDiffusionPipelineOutput`] if `return_dict` is True, otherwise a `tuple.
When returning a tuple, the first element is a list with the generated images, and the second element is a
list of `bool`s denoting whether the corresponding generated image likely represents "not-safe-for-work"
(nsfw) content, according to the `safety_checker`.
"""
# 0. Default height and width to unet
height, width = self._default_height_width(
height, width, controlnet_conditioning_image
)
# 1. Check inputs. Raise error if not correct
self.check_inputs(
prompt,
image,
controlnet_conditioning_image,
height,
width,
callback_steps,
negative_prompt,
prompt_embeds,
negative_prompt_embeds,
strength,
controlnet_guidance_start,
controlnet_guidance_end,
controlnet_conditioning_scale,
)
# 2. Define call parameters
if prompt is not None and isinstance(prompt, str):
batch_size = 1
elif prompt is not None and isinstance(prompt, list):
batch_size = len(prompt)
else:
batch_size = prompt_embeds.shape[0]
device = self._execution_device
# here `guidance_scale` is defined analog to the guidance weight `w` of equation (2)
# of the Imagen paper: https://arxiv.org/pdf/2205.11487.pdf . `guidance_scale = 1`
# corresponds to doing no classifier free guidance.
do_classifier_free_guidance = guidance_scale > 1.0
if isinstance(self.controlnet, MultiControlNetModel) and isinstance(
controlnet_conditioning_scale, float
):
controlnet_conditioning_scale = [controlnet_conditioning_scale] * len(
self.controlnet.nets
)
# 3. Encode input prompt
prompt_embeds = self._encode_prompt(
prompt,
device,
num_images_per_prompt,
do_classifier_free_guidance,
negative_prompt,
prompt_embeds=prompt_embeds,
negative_prompt_embeds=negative_prompt_embeds,
)
# 4. Prepare image, and controlnet_conditioning_image
image = prepare_image(image)
# condition image(s)
if isinstance(self.controlnet, ControlNetModel):
controlnet_conditioning_image = prepare_controlnet_conditioning_image(
controlnet_conditioning_image=controlnet_conditioning_image,
width=width,
height=height,
batch_size=batch_size * num_images_per_prompt,
num_images_per_prompt=num_images_per_prompt,
device=device,
dtype=self.controlnet.dtype,
do_classifier_free_guidance=do_classifier_free_guidance,
)
elif isinstance(self.controlnet, MultiControlNetModel):
controlnet_conditioning_images = []
for image_ in controlnet_conditioning_image:
image_ = prepare_controlnet_conditioning_image(
controlnet_conditioning_image=image_,
width=width,
height=height,
batch_size=batch_size * num_images_per_prompt,
num_images_per_prompt=num_images_per_prompt,
device=device,
dtype=self.controlnet.dtype,
do_classifier_free_guidance=do_classifier_free_guidance,
)
controlnet_conditioning_images.append(image_)
controlnet_conditioning_image = controlnet_conditioning_images
else:
assert False
# 5. Prepare timesteps
self.scheduler.set_timesteps(num_inference_steps, device=device)
timesteps, num_inference_steps = self.get_timesteps(
num_inference_steps, strength, device
)
latent_timestep = timesteps[:1].repeat(batch_size * num_images_per_prompt)
# 6. Prepare latent variables
latents = self.prepare_latents(
image,
latent_timestep,
batch_size,
num_images_per_prompt,
prompt_embeds.dtype,
device,
generator,
)
# 7. Prepare extra step kwargs. TODO: Logic should ideally just be moved out of the pipeline
extra_step_kwargs = self.prepare_extra_step_kwargs(generator, eta)
# 8. Denoising loop
num_warmup_steps = len(timesteps) - num_inference_steps * self.scheduler.order
with self.progress_bar(total=num_inference_steps) as progress_bar:
for i, t in enumerate(timesteps):
# expand the latents if we are doing classifier free guidance
latent_model_input = (
torch.cat([latents] * 2) if do_classifier_free_guidance else latents
)
latent_model_input = self.scheduler.scale_model_input(
latent_model_input, t
)
# compute the percentage of total steps we are at
current_sampling_percent = i / len(timesteps)
if (
current_sampling_percent < controlnet_guidance_start
or current_sampling_percent > controlnet_guidance_end
):
# do not apply the controlnet
down_block_res_samples = None
mid_block_res_sample = None
else:
# apply the controlnet
down_block_res_samples, mid_block_res_sample = self.controlnet(
latent_model_input,
t,
encoder_hidden_states=prompt_embeds,
controlnet_cond=controlnet_conditioning_image,
conditioning_scale=controlnet_conditioning_scale,
return_dict=False,
)
# predict the noise residual
noise_pred = self.unet(
latent_model_input,
t,
encoder_hidden_states=prompt_embeds,
cross_attention_kwargs=cross_attention_kwargs,
down_block_additional_residuals=down_block_res_samples,
mid_block_additional_residual=mid_block_res_sample,
).sample
# perform guidance
if do_classifier_free_guidance:
noise_pred_uncond, noise_pred_text = noise_pred.chunk(2)
noise_pred = noise_pred_uncond + guidance_scale * (
noise_pred_text - noise_pred_uncond
)
# compute the previous noisy sample x_t -> x_t-1
latents = self.scheduler.step(
noise_pred, t, latents, **extra_step_kwargs
).prev_sample
# call the callback, if provided
if i == len(timesteps) - 1 or (
(i + 1) > num_warmup_steps and (i + 1) % self.scheduler.order == 0
):
progress_bar.update()
if callback is not None and i % callback_steps == 0:
callback(i, t, latents)
# If we do sequential model offloading, let's offload unet and controlnet
# manually for max memory savings
if hasattr(self, "final_offload_hook") and self.final_offload_hook is not None:
self.unet.to("cpu")
self.controlnet.to("cpu")
torch.cuda.empty_cache()
if output_type == "latent":
image = latents
has_nsfw_concept = None
elif output_type == "pil":
# 8. Post-processing
image = self.decode_latents(latents)
# 9. Run safety checker
image, has_nsfw_concept = self.run_safety_checker(
image, device, prompt_embeds.dtype
)
# 10. Convert to PIL
image = self.numpy_to_pil(image)
else:
# 8. Post-processing
image = self.decode_latents(latents)
# 9. Run safety checker
image, has_nsfw_concept = self.run_safety_checker(
image, device, prompt_embeds.dtype
)
# Offload last model to CPU
if hasattr(self, "final_offload_hook") and self.final_offload_hook is not None:
self.final_offload_hook.offload()
if not return_dict:
return (image, has_nsfw_concept)
return StableDiffusionPipelineOutput(
images=image, nsfw_content_detected=has_nsfw_concept
)