# Copyright 2025 Black Forest Labs and The HuggingFace Team. All rights reserved. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. import inspect import math from typing import Any, Callable import numpy as np import PIL import torch from transformers import Qwen2TokenizerFast, Qwen3ForCausalLM from ...image_processor import PipelineImageInput from ...loaders import Flux2LoraLoaderMixin from ...models import AutoencoderKLFlux2, Flux2Transformer2DModel from ...schedulers import FlowMatchEulerDiscreteScheduler from ...utils import is_torch_xla_available, logging, replace_example_docstring from ...utils.torch_utils import randn_tensor from ..pipeline_utils import DiffusionPipeline from .image_processor import Flux2ImageProcessor from .pipeline_output import Flux2PipelineOutput if is_torch_xla_available(): import torch_xla.core.xla_model as xm XLA_AVAILABLE = True else: XLA_AVAILABLE = False logger = logging.get_logger(__name__) # pylint: disable=invalid-name EXAMPLE_DOC_STRING = """ Examples: # Inpainting with text only ```py >>> import torch >>> from diffusers import Flux2KleinInpaintPipeline >>> from diffusers.utils import load_image >>> pipe = Flux2KleinInpaintPipeline.from_pretrained( ... "black-forest-labs/FLUX.2-klein-base-9B", torch_dtype=torch.bfloat16 ... ) >>> pipe.to("cuda") >>> prompt = "Face of a yellow cat, high resolution, sitting on a park bench" >>> img_url = "https://raw.githubusercontent.com/CompVis/latent-diffusion/main/data/inpainting_examples/overture-creations-5sI6fQgYIuo.png" >>> mask_url = "https://raw.githubusercontent.com/CompVis/latent-diffusion/main/data/inpainting_examples/overture-creations-5sI6fQgYIuo_mask.png" >>> source = load_image(img_url) >>> mask = load_image(mask_url) >>> image = pipe(prompt=prompt, image=source, mask_image=mask).images[0] >>> image.save("flux2klein_inpainting.png") ``` # Inpainting with image reference conditioning ```py >>> import torch >>> from diffusers import Flux2KleinInpaintPipeline >>> from diffusers.utils import load_image >>> pipe = Flux2KleinInpaintPipeline.from_pretrained( ... "black-forest-labs/FLUX.2-klein-base-9B", torch_dtype=torch.bfloat16 ... ) >>> pipe.to("cuda") >>> prompt = "Replace this ball" >>> img_url = "https://huggingface.co/datasets/diffusers/docs-images/resolve/main/klein_inpaint/the-ball-stadion-football-the-pitch-39362.jpeg" >>> mask_url = "https://huggingface.co/datasets/diffusers/docs-images/resolve/main/klein_inpaint/ball_mask.png" >>> image_reference_url = ( ... "https://huggingface.co/datasets/diffusers/docs-images/resolve/main/klein_inpaint/ball.jpg" ... ) >>> source = load_image(img_url) >>> mask = load_image(mask_url) >>> image_reference = load_image(image_reference_url) >>> mask = pipe.mask_processor.blur(mask, blur_factor=12) >>> image = pipe( ... prompt=prompt, image=source, mask_image=mask, image_reference=image_reference, strength=1.0 ... ).images[0] >>> image.save("flux2klein_inpainting_ref.png") ``` """ # Copied from diffusers.pipelines.flux2.pipeline_flux2.compute_empirical_mu def compute_empirical_mu(image_seq_len: int, num_steps: int) -> float: a1, b1 = 8.73809524e-05, 1.89833333 a2, b2 = 0.00016927, 0.45666666 if image_seq_len > 4300: mu = a2 * image_seq_len + b2 return float(mu) m_200 = a2 * image_seq_len + b2 m_10 = a1 * image_seq_len + b1 a = (m_200 - m_10) / 190.0 b = m_200 - 200.0 * a mu = a * num_steps + b return float(mu) # Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion.retrieve_timesteps def retrieve_timesteps( scheduler, num_inference_steps: int | None = None, device: str | torch.device | None = None, timesteps: list[int] | None = None, sigmas: list[float] | None = None, **kwargs, ): r""" Calls the scheduler's `set_timesteps` method and retrieves timesteps from the scheduler after the call. Handles custom timesteps. Any kwargs will be supplied to `scheduler.set_timesteps`. Args: scheduler (`SchedulerMixin`): The scheduler to get timesteps from. num_inference_steps (`int`): The number of diffusion steps used when generating samples with a pre-trained model. If used, `timesteps` must be `None`. device (`str` or `torch.device`, *optional*): The device to which the timesteps should be moved to. If `None`, the timesteps are not moved. timesteps (`list[int]`, *optional*): Custom timesteps used to override the timestep spacing strategy of the scheduler. If `timesteps` is passed, `num_inference_steps` and `sigmas` must be `None`. sigmas (`list[float]`, *optional*): Custom sigmas used to override the timestep spacing strategy of the scheduler. If `sigmas` is passed, `num_inference_steps` and `timesteps` must be `None`. Returns: `tuple[torch.Tensor, int]`: A tuple where the first element is the timestep schedule from the scheduler and the second element is the number of inference steps. """ if timesteps is not None and sigmas is not None: raise ValueError("Only one of `timesteps` or `sigmas` can be passed. Please choose one to set custom values") if timesteps is not None: accepts_timesteps = "timesteps" in set(inspect.signature(scheduler.set_timesteps).parameters.keys()) if not accepts_timesteps: raise ValueError( f"The current scheduler class {scheduler.__class__}'s `set_timesteps` does not support custom" f" timestep schedules. Please check whether you are using the correct scheduler." ) scheduler.set_timesteps(timesteps=timesteps, device=device, **kwargs) timesteps = scheduler.timesteps num_inference_steps = len(timesteps) elif sigmas is not None: accept_sigmas = "sigmas" in set(inspect.signature(scheduler.set_timesteps).parameters.keys()) if not accept_sigmas: raise ValueError( f"The current scheduler class {scheduler.__class__}'s `set_timesteps` does not support custom" f" sigmas schedules. Please check whether you are using the correct scheduler." ) scheduler.set_timesteps(sigmas=sigmas, device=device, **kwargs) timesteps = scheduler.timesteps num_inference_steps = len(timesteps) else: scheduler.set_timesteps(num_inference_steps, device=device, **kwargs) timesteps = scheduler.timesteps return timesteps, num_inference_steps # Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion_img2img.retrieve_latents def retrieve_latents( encoder_output: torch.Tensor, generator: torch.Generator | None = None, sample_mode: str = "sample" ): if hasattr(encoder_output, "latent_dist") and sample_mode == "sample": return encoder_output.latent_dist.sample(generator) elif hasattr(encoder_output, "latent_dist") and sample_mode == "argmax": return encoder_output.latent_dist.mode() elif hasattr(encoder_output, "latents"): return encoder_output.latents else: raise AttributeError("Could not access latents of provided encoder_output") class Flux2KleinInpaintPipeline(DiffusionPipeline, Flux2LoraLoaderMixin): r""" Flux2 Klein pipeline for image inpainting with optional reference image conditioning. Reference: [https://bfl.ai/blog/flux2-klein-towards-interactive-visual-intelligence](https://bfl.ai/blog/flux2-klein-towards-interactive-visual-intelligence) Args: transformer ([`Flux2Transformer2DModel`]): Conditional Transformer (MMDiT) architecture to denoise the encoded image latents. scheduler ([`FlowMatchEulerDiscreteScheduler`]): A scheduler to be used in combination with `transformer` to denoise the encoded image latents. vae ([`AutoencoderKLFlux2`]): Variational Auto-Encoder (VAE) Model to encode and decode images to and from latent representations. text_encoder ([`Qwen3ForCausalLM`]): [Qwen3ForCausalLM](https://huggingface.co/docs/transformers/en/model_doc/qwen3#transformers.Qwen3ForCausalLM) tokenizer (`Qwen2TokenizerFast`): Tokenizer of class [Qwen2TokenizerFast](https://huggingface.co/docs/transformers/en/model_doc/qwen2#transformers.Qwen2TokenizerFast). """ model_cpu_offload_seq = "text_encoder->transformer->vae" _callback_tensor_inputs = ["latents", "prompt_embeds"] def __init__( self, scheduler: FlowMatchEulerDiscreteScheduler, vae: AutoencoderKLFlux2, text_encoder: Qwen3ForCausalLM, tokenizer: Qwen2TokenizerFast, transformer: Flux2Transformer2DModel, is_distilled: bool = False, ): super().__init__() self.register_modules( vae=vae, text_encoder=text_encoder, tokenizer=tokenizer, scheduler=scheduler, transformer=transformer, ) self.register_to_config(is_distilled=is_distilled) self.vae_scale_factor = 2 ** (len(self.vae.config.block_out_channels) - 1) if getattr(self, "vae", None) else 8 # Flux latents are turned into 2x2 patches and packed. This means the latent width and height has to be divisible # by the patch size. So the vae scale factor is multiplied by the patch size to account for this self.latent_channels = self.vae.config.latent_channels if getattr(self, "vae", None) else 32 self.image_processor = Flux2ImageProcessor( vae_scale_factor=self.vae_scale_factor * 2, vae_latent_channels=self.latent_channels ) self.mask_processor = Flux2ImageProcessor( vae_scale_factor=self.vae_scale_factor * 2, vae_latent_channels=self.latent_channels, do_normalize=False, do_binarize=True, do_convert_rgb=False, do_convert_grayscale=True, ) self.tokenizer_max_length = 512 self.default_sample_size = 128 @staticmethod # Copied from diffusers.pipelines.flux2.pipeline_flux2_klein.Flux2KleinPipeline._get_qwen3_prompt_embeds def _get_qwen3_prompt_embeds( text_encoder: Qwen3ForCausalLM, tokenizer: Qwen2TokenizerFast, prompt: str | list[str], dtype: torch.dtype | None = None, device: torch.device | None = None, max_sequence_length: int = 512, hidden_states_layers: list[int] = (9, 18, 27), ): dtype = text_encoder.dtype if dtype is None else dtype device = text_encoder.device if device is None else device prompt = [prompt] if isinstance(prompt, str) else prompt all_input_ids = [] all_attention_masks = [] for single_prompt in prompt: messages = [{"role": "user", "content": single_prompt}] text = tokenizer.apply_chat_template( messages, tokenize=False, add_generation_prompt=True, enable_thinking=False, ) inputs = tokenizer( text, return_tensors="pt", padding="max_length", truncation=True, max_length=max_sequence_length, ) all_input_ids.append(inputs["input_ids"]) all_attention_masks.append(inputs["attention_mask"]) input_ids = torch.cat(all_input_ids, dim=0).to(device) attention_mask = torch.cat(all_attention_masks, dim=0).to(device) # Forward pass through the model output = text_encoder( input_ids=input_ids, attention_mask=attention_mask, output_hidden_states=True, use_cache=False, ) # Only use outputs from intermediate layers and stack them out = torch.stack([output.hidden_states[k] for k in hidden_states_layers], dim=1) out = out.to(dtype=dtype, device=device) batch_size, num_channels, seq_len, hidden_dim = out.shape prompt_embeds = out.permute(0, 2, 1, 3).reshape(batch_size, seq_len, num_channels * hidden_dim) return prompt_embeds @staticmethod # Copied from diffusers.pipelines.flux2.pipeline_flux2.Flux2Pipeline._prepare_text_ids def _prepare_text_ids( x: torch.Tensor, # (B, L, D) or (L, D) t_coord: torch.Tensor | None = None, ): B, L, _ = x.shape out_ids = [] for i in range(B): t = torch.arange(1) if t_coord is None else t_coord[i] h = torch.arange(1) w = torch.arange(1) l = torch.arange(L) coords = torch.cartesian_prod(t, h, w, l) out_ids.append(coords) return torch.stack(out_ids) @staticmethod # Copied from diffusers.pipelines.flux2.pipeline_flux2.Flux2Pipeline._prepare_latent_ids def _prepare_latent_ids( latents: torch.Tensor, # (B, C, H, W) ): r""" Generates 4D position coordinates (T, H, W, L) for latent tensors. Args: latents (torch.Tensor): Latent tensor of shape (B, C, H, W) Returns: torch.Tensor: Position IDs tensor of shape (B, H*W, 4) All batches share the same coordinate structure: T=0, H=[0..H-1], W=[0..W-1], L=0 """ batch_size, _, height, width = latents.shape t = torch.arange(1) # [0] - time dimension h = torch.arange(height) w = torch.arange(width) l = torch.arange(1) # [0] - layer dimension # Create position IDs: (H*W, 4) latent_ids = torch.cartesian_prod(t, h, w, l) # Expand to batch: (B, H*W, 4) latent_ids = latent_ids.unsqueeze(0).expand(batch_size, -1, -1) return latent_ids @staticmethod def _prepare_image_ids( image_latents: list[torch.Tensor], # list of (B_i, C, H, W) before packing batch_size: int, scale: int = 10, ): r""" Generates 4D time-space coordinates (T, H, W, L) for a sequence of image latents. This function creates a unique coordinate for every pixel/patch across all input latent with different dimensions. Args: image_latents (list[torch.Tensor]): A list of image latent feature tensors, typically of shape (C, H, W). scale (int, optional): A factor used to define the time separation (T-coordinate) between latents. T-coordinate for the i-th latent is: 'scale + scale * i'. Defaults to 10. Returns: torch.Tensor: The combined coordinate tensor. Shape: (1, N_total, 4) Where N_total is the sum of (H * W) for all input latents. Coordinate Components (Dimension 4): - T (Time): The unique index indicating which latent image the coordinate belongs to. - H (Height): The row index within that latent image. - W (Width): The column index within that latent image. - L (Seq. Length): A sequence length dimension, which is always fixed at 0 (size 1) """ if not isinstance(image_latents, list): raise ValueError(f"Expected `image_latents` to be a list, got {type(image_latents)}.") all_image_latent_ids = [] t_offset = scale for x in image_latents: b_i, _, height, width = x.shape # Create IDs for a single image at this t_offset t = torch.tensor([t_offset]).view(-1) x_ids = torch.cartesian_prod(t, torch.arange(height), torch.arange(width), torch.arange(1)) if b_i == 1 or b_i == batch_size: x_ids = x_ids.unsqueeze(0).expand(batch_size, -1, -1) all_image_latent_ids.append(x_ids) t_offset += scale else: # multiple images per sample in the batch item_ids = [x_ids] for _ in range(1, b_i): t_offset += scale t = torch.tensor([t_offset]).view(-1) item_ids.append( torch.cartesian_prod(t, torch.arange(height), torch.arange(width), torch.arange(1)) ) x_ids = torch.cat(item_ids, dim=0) # (b_i * h * w, 4) x_ids = x_ids.unsqueeze(0).expand(batch_size, -1, -1) all_image_latent_ids.append(x_ids) t_offset += scale image_latent_ids = torch.cat(all_image_latent_ids, dim=1) return image_latent_ids @staticmethod # Copied from diffusers.pipelines.flux2.pipeline_flux2.Flux2Pipeline._patchify_latents def _patchify_latents(latents): batch_size, num_channels_latents, height, width = latents.shape latents = latents.view(batch_size, num_channels_latents, height // 2, 2, width // 2, 2) latents = latents.permute(0, 1, 3, 5, 2, 4) latents = latents.reshape(batch_size, num_channels_latents * 4, height // 2, width // 2) return latents @staticmethod # Copied from diffusers.pipelines.flux2.pipeline_flux2.Flux2Pipeline._unpatchify_latents def _unpatchify_latents(latents): batch_size, num_channels_latents, height, width = latents.shape latents = latents.reshape(batch_size, num_channels_latents // (2 * 2), 2, 2, height, width) latents = latents.permute(0, 1, 4, 2, 5, 3) latents = latents.reshape(batch_size, num_channels_latents // (2 * 2), height * 2, width * 2) return latents @staticmethod # Copied from diffusers.pipelines.flux2.pipeline_flux2.Flux2Pipeline._pack_latents def _pack_latents(latents): """ pack latents: (batch_size, num_channels, height, width) -> (batch_size, height * width, num_channels) """ batch_size, num_channels, height, width = latents.shape latents = latents.reshape(batch_size, num_channels, height * width).permute(0, 2, 1) return latents @staticmethod # Copied from diffusers.pipelines.flux2.pipeline_flux2.Flux2Pipeline._unpack_latents_with_ids def _unpack_latents_with_ids(x: torch.Tensor, x_ids: torch.Tensor) -> list[torch.Tensor]: """ using position ids to scatter tokens into place """ x_list = [] for data, pos in zip(x, x_ids): _, ch = data.shape # noqa: F841 h_ids = pos[:, 1].to(torch.int64) w_ids = pos[:, 2].to(torch.int64) h = torch.max(h_ids) + 1 w = torch.max(w_ids) + 1 flat_ids = h_ids * w + w_ids out = torch.zeros((h * w, ch), device=data.device, dtype=data.dtype) out.scatter_(0, flat_ids.unsqueeze(1).expand(-1, ch), data) # reshape from (H * W, C) to (H, W, C) and permute to (C, H, W) out = out.view(h, w, ch).permute(2, 0, 1) x_list.append(out) return torch.stack(x_list, dim=0) @staticmethod def _get_raw_image_size(image: PipelineImageInput) -> tuple[int, int]: """Helper to get (height, width) without rounding/scaling.""" if isinstance(image, list): image = image[0] if isinstance(image, PIL.Image.Image): return image.height, image.width elif isinstance(image, torch.Tensor): return image.shape[-2], image.shape[-1] elif isinstance(image, np.ndarray): if image.ndim >= 3: return image.shape[-3], image.shape[-2] return image.shape[-2], image.shape[-1] if hasattr(image, "shape"): return image.shape[-2], image.shape[-1] raise ValueError(f"Unsupported image type: {type(image)}") # Copied from diffusers.pipelines.flux2.pipeline_flux2_klein.Flux2KleinPipeline.encode_prompt def encode_prompt( self, prompt: str | list[str], device: torch.device | None = None, num_images_per_prompt: int = 1, prompt_embeds: torch.Tensor | None = None, max_sequence_length: int = 512, text_encoder_out_layers: tuple[int] = (9, 18, 27), ): device = device or self._execution_device if prompt is None: prompt = "" prompt = [prompt] if isinstance(prompt, str) else prompt if prompt_embeds is None: prompt_embeds = self._get_qwen3_prompt_embeds( text_encoder=self.text_encoder, tokenizer=self.tokenizer, prompt=prompt, device=device, max_sequence_length=max_sequence_length, hidden_states_layers=text_encoder_out_layers, ) batch_size, seq_len, _ = prompt_embeds.shape prompt_embeds = prompt_embeds.repeat(1, num_images_per_prompt, 1) prompt_embeds = prompt_embeds.view(batch_size * num_images_per_prompt, seq_len, -1) text_ids = self._prepare_text_ids(prompt_embeds) text_ids = text_ids.to(device) return prompt_embeds, text_ids # Copied from diffusers.pipelines.flux2.pipeline_flux2.Flux2Pipeline._encode_vae_image def _encode_vae_image(self, image: torch.Tensor, generator: torch.Generator): if image.ndim != 4: raise ValueError(f"Expected image dims 4, got {image.ndim}.") image_latents = retrieve_latents(self.vae.encode(image), generator=generator, sample_mode="argmax") image_latents = self._patchify_latents(image_latents) latents_bn_mean = self.vae.bn.running_mean.view(1, -1, 1, 1).to(image_latents.device, image_latents.dtype) latents_bn_std = torch.sqrt(self.vae.bn.running_var.view(1, -1, 1, 1) + self.vae.config.batch_norm_eps).to( image_latents.device, image_latents.dtype ) image_latents = (image_latents - latents_bn_mean) / latents_bn_std return image_latents def prepare_latents( self, image, timestep, batch_size, num_latents_channels, height, width, dtype, device, generator: torch.Generator | list[torch.Generator] | None = None, latents: torch.Tensor | None = None, ): 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." ) # VAE applies 8x compression on images but we must also account for packing which requires # latent height and width to be divisible by 2. height = 2 * (int(height) // (self.vae_scale_factor * 2)) width = 2 * (int(width) // (self.vae_scale_factor * 2)) shape = (batch_size, num_latents_channels * 4, height // 2, width // 2) # Create a dummy tensor for _prepare_latent_ids dummy_latents = torch.zeros(shape, device=device, dtype=dtype) latent_image_ids = self._prepare_latent_ids(dummy_latents) latent_image_ids = latent_image_ids.to(device) image = image.to(device=device, dtype=dtype) if image.shape[1] != self.latent_channels * 4: image_latents = self._encode_vae_image(image=image, generator=generator) else: image_latents = image latents_bn_mean = self.vae.bn.running_mean.view(1, -1, 1, 1).to(image_latents.device, image_latents.dtype) latents_bn_std = torch.sqrt(self.vae.bn.running_var.view(1, -1, 1, 1) + self.vae.config.batch_norm_eps).to( image_latents.device, image_latents.dtype ) image_latents = (image_latents - latents_bn_mean) / latents_bn_std if batch_size > image_latents.shape[0] and batch_size % image_latents.shape[0] == 0: # expand init_latents for batch_size additional_image_per_prompt = batch_size // image_latents.shape[0] image_latents = torch.cat([image_latents] * additional_image_per_prompt, dim=0) elif batch_size > image_latents.shape[0] and batch_size % image_latents.shape[0] != 0: raise ValueError( f"Cannot duplicate `image` of batch size {image_latents.shape[0]} to {batch_size} text prompts." ) if latents is None: noise = randn_tensor(shape, generator=generator, device=device, dtype=dtype) latents = self.scheduler.scale_noise(image_latents, timestep, noise) else: noise = latents.to(device) latents = noise noise = self._pack_latents(noise) packed_image_latents = self._pack_latents(image_latents) latents = self._pack_latents(latents) return latents, noise, packed_image_latents, image_latents, latent_image_ids def prepare_image_latents( self, images: list[torch.Tensor], batch_size, generator: torch.Generator, device, dtype, ): image_latents = [] for image in images: image = image.to(device=device, dtype=dtype) if image.shape[1] != self.latent_channels * 4: image_latent = self._encode_vae_image(image=image, generator=generator) else: image_latent = image image_latents.append(image_latent) image_latent_ids = self._prepare_image_ids(image_latents, batch_size) # Pack each latent and combine batch properly final_latents = [] for latent in image_latents: packed = self._pack_latents(latent) # (B_i, seq_len, 128) b_i = packed.shape[0] if b_i == 1 and batch_size > 1: packed = packed.repeat(batch_size, 1, 1) elif b_i == batch_size: pass else: # Concatenate all reference tokens along sequence dimension for each sample seq_len = packed.shape[1] packed = packed.reshape(1, b_i * seq_len, -1) if batch_size > 1: packed = packed.repeat(batch_size, 1, 1) final_latents.append(packed) image_latents = torch.cat(final_latents, dim=1) # (batch_size, total_seq_len, 128) image_latent_ids = image_latent_ids.to(device) return image_latents, image_latent_ids def prepare_mask_latents( self, mask, batch_size, num_images_per_prompt, height, width, dtype, device, ): # Interpolate the mask directly to the final packed spatial size. target_h = int(height) // (self.vae_scale_factor * 2) target_w = int(width) // (self.vae_scale_factor * 2) mask = torch.nn.functional.interpolate(mask, size=(target_h, target_w), mode="bilinear") mask = mask.to(device=device, dtype=dtype) batch_size = batch_size * num_images_per_prompt # duplicate mask for each generation per prompt, using mps friendly method if mask.shape[0] < batch_size: if not batch_size % mask.shape[0] == 0: raise ValueError( "The passed mask and the required batch size don't match. Masks are supposed to be duplicated to" f" a total batch size of {batch_size}, but {mask.shape[0]} masks were passed. Make sure the number" " of masks that you pass is divisible by the total requested batch size." ) mask = mask.repeat(batch_size // mask.shape[0], 1, 1, 1) # Pack to (B, seq_len, 1), will broadcast against (B, seq_len, C) latents mask = self._pack_latents(mask) return mask # Copied from diffusers.pipelines.stable_diffusion_3.pipeline_stable_diffusion_3_img2img.StableDiffusion3Img2ImgPipeline.get_timesteps def get_timesteps(self, num_inference_steps, strength, device): # get the original timestep using init_timestep init_timestep = min(num_inference_steps * strength, num_inference_steps) t_start = int(max(num_inference_steps - init_timestep, 0)) timesteps = self.scheduler.timesteps[t_start * self.scheduler.order :] if hasattr(self.scheduler, "set_begin_index"): self.scheduler.set_begin_index(t_start * self.scheduler.order) return timesteps, num_inference_steps - t_start def check_inputs( self, prompt, image, mask_image, image_reference, strength, height, width, output_type, prompt_embeds=None, callback_on_step_end_tensor_inputs=None, padding_mask_crop=None, guidance_scale=None, ): if image is None: raise ValueError("`image` has to be provided for inpainting.") if mask_image is None: raise ValueError("`mask_image` has to be provided for inpainting.") if strength < 0 or strength > 1: raise ValueError(f"The value of strength should in [0.0, 1.0] but is {strength}") if ( height is not None and height % (self.vae_scale_factor * 2) != 0 or width is not None and width % (self.vae_scale_factor * 2) != 0 ): logger.warning( f"`height` and `width` have to be divisible by {self.vae_scale_factor * 2} but are {height} and {width}. Dimensions will be resized accordingly" ) if callback_on_step_end_tensor_inputs is not None and not all( k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs ): raise ValueError( f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}" ) 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 padding_mask_crop is not None: if not isinstance(image, PIL.Image.Image): raise ValueError( f"The image should be a PIL image when inpainting mask crop, but is of type {type(image)}." ) if not isinstance(mask_image, PIL.Image.Image): raise ValueError( f"The mask image should be a PIL image when inpainting mask crop, but is of type" f" {type(mask_image)}." ) if output_type != "pil": raise ValueError(f"The output type should be PIL when inpainting mask crop, but is {output_type}.") else: if image is not None: if not isinstance(image, (PIL.Image.Image, torch.Tensor, np.ndarray, list)): raise ValueError( f"`image` has to be of type `PIL.Image.Image`, `torch.Tensor`, `np.ndarray`, or `list`" f" but is {type(image)}." ) if mask_image is not None: if not isinstance(mask_image, (PIL.Image.Image, torch.Tensor, np.ndarray, list)): raise ValueError( f"`mask_image` has to be of type `PIL.Image.Image`, `torch.Tensor`, `np.ndarray`, or `list`" f" but is {type(mask_image)}." ) if image_reference is not None: if not isinstance(image_reference, (PIL.Image.Image, torch.Tensor, np.ndarray, list)): raise ValueError( f"`image_reference` has to be of type `PIL.Image.Image`, `torch.Tensor`, `np.ndarray`, or `list`" f" but is {type(image_reference)}." ) if guidance_scale > 1.0 and self.config.is_distilled: logger.warning(f"Guidance scale {guidance_scale} is ignored for step-wise distilled models.") @property def guidance_scale(self): return self._guidance_scale @property def do_classifier_free_guidance(self): return self._guidance_scale > 1 and not self.config.is_distilled @property def attention_kwargs(self): return self._attention_kwargs @property def num_timesteps(self): return self._num_timesteps @property def current_timestep(self): return self._current_timestep @property def interrupt(self): return self._interrupt @torch.no_grad() @replace_example_docstring(EXAMPLE_DOC_STRING) def __call__( self, prompt: str | list[str] | None = None, image: PipelineImageInput | None = None, image_reference: PipelineImageInput | None = None, mask_image: PipelineImageInput | None = None, height: int | None = None, width: int | None = None, padding_mask_crop: int | None = None, strength: float = 0.8, num_inference_steps: int = 50, sigmas: list[float] | None = None, guidance_scale: float = 8.0, num_images_per_prompt: int = 1, generator: torch.Generator | list[torch.Generator] | None = None, latents: torch.Tensor | None = None, prompt_embeds: torch.Tensor | None = None, negative_prompt_embeds: torch.Tensor | None = None, output_type: str = "pil", return_dict: bool = True, attention_kwargs: dict[str, Any] | None = None, callback_on_step_end: Callable[[int, int, dict], None] | None = None, callback_on_step_end_tensor_inputs: list[str] = ["latents"], max_sequence_length: int = 512, text_encoder_out_layers: tuple[int, ...] = (9, 18, 27), ): r""" Function invoked when calling the pipeline for inpainting. 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`, `PIL.Image.Image`, `np.ndarray`, `List[torch.Tensor]`, `List[PIL.Image.Image]`, or `List[np.ndarray]`): `Image`, numpy array or tensor representing an image batch to be used as the starting point. For both numpy array and pytorch tensor, the expected value range is between `[0, 1]`. If it's a tensor or a list of tensors, the expected shape should be `(B, C, H, W)` or `(C, H, W)`. If it is a numpy array or a list of arrays, the expected shape should be `(B, H, W, C)` or `(H, W, C)`. It can also accept image latents directly, in which case encoding is skipped. Latents must be in patchified form of shape `(B, latent_channels * 4, H // 2, W // 2)`, where each 2×2 spatial patch has been folded into the channel dimension. image_reference (`torch.Tensor`, `PIL.Image.Image`, `np.ndarray`, `List[torch.Tensor]`, `List[PIL.Image.Image]`, or `List[np.ndarray]`, *optional*): `Image`, numpy array or tensor representing an image batch to be used as the reference for the masked area. This allows conditioning the inpainted region on a specific reference image. For both numpy array and pytorch tensor, the expected value range is between `[0, 1]`. If it's a tensor or a list of tensors, the expected shape should be `(B, C, H, W)` or `(C, H, W)`. If it is a numpy array or a list of arrays, the expected shape should be `(B, H, W, C)` or `(H, W, C)`. It can also accept image latents directly, in which case encoding is skipped. Latents must be in patchified form of shape `(B, latent_channels * 4, H // 2, W // 2)`, where each 2×2 spatial patch has been folded into the channel dimension. mask_image (`torch.Tensor`, `PIL.Image.Image`, `np.ndarray`, `List[torch.Tensor]`, `List[PIL.Image.Image]`, or `List[np.ndarray]`): `Image`, numpy array or tensor representing an image batch to mask `image`. White pixels in the mask are repainted while black pixels are preserved. If `mask_image` is a PIL image, it is converted to a single channel (luminance) before use. If it's a numpy array or pytorch tensor, it should contain one color channel (L) instead of 3, so the expected shape for pytorch tensor would be `(B, 1, H, W)`, `(B, H, W)`, `(1, H, W)`, `(H, W)`. And for numpy array would be for `(B, H, W, 1)`, `(B, H, W)`, `(H, W, 1)`, or `(H, W)`. height (`int`, *optional*, defaults to self.default_sample_size * self.vae_scale_factor): The height in pixels of the generated image. This is set to 1024 by default for the best results. width (`int`, *optional*, defaults to self.default_sample_size * self.vae_scale_factor): The width in pixels of the generated image. This is set to 1024 by default for the best results. padding_mask_crop (`int`, *optional*, defaults to `None`): The size of margin in the crop to be applied to the image and masking. If `None`, no crop is applied to image and mask_image. If `padding_mask_crop` is not `None`, it will first find a rectangular region with the same aspect ration of the image and contains all masked area, and then expand that area based on `padding_mask_crop`. The image and mask_image will then be cropped based on the expanded area before resizing to the original image size for inpainting. This is useful when the masked area is small while the image is large and contain information irrelevant for inpainting, such as background. strength (`float`, *optional*, defaults to 0.8): Indicates extent to transform the reference `image`. Must be between 0 and 1. `image` is used as a starting point and more noise is added the higher the `strength`. The number of denoising steps depends on the amount of noise initially added. When `strength` is 1, added noise is maximum and the denoising process runs for the full number of iterations specified in `num_inference_steps`. A value of 1 essentially ignores `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. sigmas (`List[float]`, *optional*): Custom sigmas to use for the denoising process with schedulers which support a `sigmas` argument in their `set_timesteps` method. If not defined, the default behavior when `num_inference_steps` is passed will be used. guidance_scale (`float`, *optional*, defaults to 8.0): Guidance scale as defined in [Classifier-Free Diffusion Guidance](https://huggingface.co/papers/2207.12598). `guidance_scale` is defined as `w` of equation 2. of [Imagen Paper](https://huggingface.co/papers/2205.11487). 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. For step-wise distilled models, `guidance_scale` is ignored. num_images_per_prompt (`int`, *optional*, defaults to 1): The number of images to generate per prompt. 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.Tensor`, *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 be generated by sampling using the supplied random `generator`. prompt_embeds (`torch.Tensor`, *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.Tensor`, *optional*): Pre-generated negative text embeddings. Note that "" is used as the negative prompt in this pipeline. If not provided, will be generated from "". 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.flux2.Flux2PipelineOutput`] instead of a plain tuple. attention_kwargs (`dict`, *optional*): A kwargs dictionary that if specified is passed along to the `AttentionProcessor` as defined under `self.processor` in [diffusers.models.attention_processor](https://github.com/huggingface/diffusers/blob/main/src/diffusers/models/attention_processor.py). callback_on_step_end (`Callable`, *optional*): A function that calls at the end of each denoising steps during the inference. The function is called with the following arguments: `callback_on_step_end(self: DiffusionPipeline, step: int, timestep: int, callback_kwargs: Dict)`. `callback_kwargs` will include a list of all tensors as specified by `callback_on_step_end_tensor_inputs`. callback_on_step_end_tensor_inputs (`List`, *optional*): The list of tensor inputs for the `callback_on_step_end` function. The tensors specified in the list will be passed as `callback_kwargs` argument. You will only be able to include variables listed in the `._callback_tensor_inputs` attribute of your pipeline class. max_sequence_length (`int` defaults to 512): Maximum sequence length to use with the `prompt`. text_encoder_out_layers (`Tuple[int]`): Layer indices to use in the `text_encoder` to derive the final prompt embeddings. Examples: Returns: [`~pipelines.flux2.Flux2PipelineOutput`] or `tuple`: [`~pipelines.flux2.Flux2PipelineOutput`] if `return_dict` is True, otherwise a `tuple`. When returning a tuple, the first element is a list with the generated images. """ height = height or self.default_sample_size * self.vae_scale_factor width = width or self.default_sample_size * self.vae_scale_factor # 1. Check inputs. Raise error if not correct self.check_inputs( prompt=prompt, image=image, mask_image=mask_image, image_reference=image_reference, strength=strength, height=height, width=width, output_type=output_type, prompt_embeds=prompt_embeds, callback_on_step_end_tensor_inputs=callback_on_step_end_tensor_inputs, padding_mask_crop=padding_mask_crop, guidance_scale=guidance_scale, ) self._guidance_scale = guidance_scale self._attention_kwargs = attention_kwargs self._current_timestep = None self._interrupt = False # 2. Preprocess image multiple_of = self.vae_scale_factor * 2 if isinstance(image, torch.Tensor) and image.ndim == 4 and image.size(1) == self.latent_channels * 4: init_image = image original_image = image crops_coords = None resize_mode = "default" height = image.shape[2] * self.vae_scale_factor * 2 width = image.shape[3] * self.vae_scale_factor * 2 elif image is not None: if isinstance(image, list) and isinstance(image[0], torch.Tensor) and image[0].ndim == 4: image = torch.cat(image, dim=0) img = image[0] if isinstance(image, list) else image raw_h, raw_w = self._get_raw_image_size(img) if raw_h * raw_w > 1024 * 1024: scale = math.sqrt(1024 * 1024 / (raw_h * raw_w)) image = self.image_processor.resize(image, int(raw_h * scale), int(raw_w * scale)) img = image[0] if isinstance(image, list) else image raw_h, raw_w = self._get_raw_image_size(img) image_width = (raw_w // multiple_of) * multiple_of image_height = (raw_h // multiple_of) * multiple_of # Use the resolution of the input image width = image_width height = image_height # 2.1 Preprocess mask if padding_mask_crop is not None: crops_coords = self.mask_processor.get_crop_region(mask_image, width, height, pad=padding_mask_crop) resize_mode = "fill" else: crops_coords = None resize_mode = "default" original_image = image init_image = self.image_processor.preprocess( image, image_height, image_width, crops_coords=crops_coords, resize_mode=resize_mode ) # 2.2 Preprocess reference image processed_image_reference = None if image_reference is not None and not ( isinstance(image_reference, torch.Tensor) and image_reference.size(1) == self.latent_channels * 4 ): if ( isinstance(image_reference, list) and isinstance(image_reference[0], torch.Tensor) and image_reference[0].ndim == 4 ): image_reference = torch.cat(image_reference, dim=0) img_reference = image_reference[0] if isinstance(image_reference, list) else image_reference raw_ref_h, raw_ref_w = self._get_raw_image_size(img_reference) if raw_ref_h * raw_ref_w > 1024 * 1024: scale = math.sqrt(1024 * 1024 / (raw_ref_h * raw_ref_w)) image_reference = self.image_processor.resize( image_reference, int(raw_ref_h * scale), int(raw_ref_w * scale) ) img_reference = image_reference[0] if isinstance(image_reference, list) else image_reference raw_ref_h, raw_ref_w = self._get_raw_image_size(img_reference) image_reference_width = (raw_ref_w // multiple_of) * multiple_of image_reference_height = (raw_ref_h // multiple_of) * multiple_of processed_image_reference = self.image_processor.preprocess( image_reference, image_reference_height, image_reference_width, resize_mode="crop", ) else: if image_reference is not None: bn_mean = self.vae.bn.running_mean.view(1, -1, 1, 1).to(image_reference.device, image_reference.dtype) bn_std = torch.sqrt(self.vae.bn.running_var.view(1, -1, 1, 1) + self.vae.config.batch_norm_eps).to( image_reference.device, image_reference.dtype ) processed_image_reference = (image_reference - bn_mean) / bn_std # 3. 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 # 4. Prepare text embeddings prompt_embeds, text_ids = self.encode_prompt( prompt=prompt, prompt_embeds=prompt_embeds, device=device, num_images_per_prompt=num_images_per_prompt, max_sequence_length=max_sequence_length, text_encoder_out_layers=text_encoder_out_layers, ) if self.do_classifier_free_guidance: negative_prompt = "" if prompt is not None and isinstance(prompt, list): negative_prompt = [negative_prompt] * len(prompt) negative_prompt_embeds, negative_text_ids = self.encode_prompt( prompt=negative_prompt, prompt_embeds=negative_prompt_embeds, device=device, num_images_per_prompt=num_images_per_prompt, max_sequence_length=max_sequence_length, text_encoder_out_layers=text_encoder_out_layers, ) # 5. Prepare timesteps sigmas = np.linspace(1.0, 1 / num_inference_steps, num_inference_steps) if sigmas is None else sigmas if hasattr(self.scheduler.config, "use_flow_sigmas") and self.scheduler.config.use_flow_sigmas: sigmas = None image_seq_len = (int(height) // self.vae_scale_factor // 2) * (int(width) // self.vae_scale_factor // 2) mu = compute_empirical_mu(image_seq_len=image_seq_len, num_steps=num_inference_steps) timesteps, num_inference_steps = retrieve_timesteps( self.scheduler, num_inference_steps, device, sigmas=sigmas, mu=mu, ) timesteps, num_inference_steps = self.get_timesteps(num_inference_steps, strength, device) if num_inference_steps < 1: raise ValueError( f"After adjusting the num_inference_steps by strength parameter: {strength}, the number of pipeline " f"steps is {num_inference_steps} which is < 1 and not appropriate for this pipeline." ) latent_timestep = timesteps[:1].repeat(batch_size * num_images_per_prompt) # 6. Prepare latent variables num_channels_latents = self.transformer.config.in_channels // 4 latents, noise, image_latents, image_latents_encoded, latent_image_ids = self.prepare_latents( init_image, latent_timestep, batch_size * num_images_per_prompt, num_channels_latents, height, width, prompt_embeds.dtype, device, generator, latents, ) ref_images = [image_latents_encoded] if processed_image_reference is not None: ref_images.append(processed_image_reference) condition_image_latents, condition_image_ids = self.prepare_image_latents( ref_images, batch_size * num_images_per_prompt, generator, device, prompt_embeds.dtype, ) mask_condition = self.mask_processor.preprocess( mask_image, height=height, width=width, resize_mode=resize_mode, crops_coords=crops_coords ) mask = self.prepare_mask_latents( mask_condition, batch_size, num_images_per_prompt, height, width, prompt_embeds.dtype, device, ) num_warmup_steps = max(len(timesteps) - num_inference_steps * self.scheduler.order, 0) self._num_timesteps = len(timesteps) # Combine base latent position IDs with condition image position IDs. combined_image_ids = torch.cat([latent_image_ids, condition_image_ids], dim=1) # 7. Denoising loop with self.progress_bar(total=num_inference_steps) as progress_bar: for i, t in enumerate(timesteps): if self.interrupt: continue self._current_timestep = t # broadcast to batch dimension in a way that's compatible with ONNX/Core ML timestep = t.expand(latents.shape[0]).to(latents.dtype) latent_model_input = torch.cat([latents, condition_image_latents], dim=1) img_ids = combined_image_ids latent_model_input = latent_model_input.to(self.transformer.dtype) with self.transformer.cache_context("cond"): noise_pred = self.transformer( hidden_states=latent_model_input, # (B, image_seq_len, C) timestep=timestep / 1000, guidance=None, encoder_hidden_states=prompt_embeds, txt_ids=text_ids, # B, text_seq_len, 4 img_ids=img_ids, # B, image_seq_len, 4 joint_attention_kwargs=self.attention_kwargs, return_dict=False, )[0] noise_pred = noise_pred[:, : latents.size(1)] if self.do_classifier_free_guidance: with self.transformer.cache_context("uncond"): neg_noise_pred = self.transformer( hidden_states=latent_model_input, timestep=timestep / 1000, guidance=None, encoder_hidden_states=negative_prompt_embeds, txt_ids=negative_text_ids, img_ids=img_ids, joint_attention_kwargs=self.attention_kwargs, return_dict=False, )[0] neg_noise_pred = neg_noise_pred[:, : latents.size(1)] noise_pred = neg_noise_pred + guidance_scale * (noise_pred - neg_noise_pred) # compute the previous noisy sample x_t -> x_t-1 latents_dtype = latents.dtype latents = self.scheduler.step(noise_pred, t, latents, return_dict=False)[0] init_latents_proper = image_latents init_mask = mask if i < len(timesteps) - 1: noise_timestep = timesteps[i + 1] init_latents_proper = self.scheduler.scale_noise( init_latents_proper, torch.tensor([noise_timestep]), noise ) latents = (1 - init_mask) * init_latents_proper + init_mask * latents if latents.dtype != latents_dtype: if torch.backends.mps.is_available(): # some platforms (eg. apple mps) misbehave due to a pytorch bug: https://github.com/pytorch/pytorch/pull/99272 latents = latents.to(latents_dtype) if callback_on_step_end is not None: callback_kwargs = {} for k in callback_on_step_end_tensor_inputs: callback_kwargs[k] = locals()[k] callback_outputs = callback_on_step_end(self, i, t, callback_kwargs) latents = callback_outputs.pop("latents", latents) prompt_embeds = callback_outputs.pop("prompt_embeds", prompt_embeds) # 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 XLA_AVAILABLE: xm.mark_step() self._current_timestep = None # 8. Post-processing latents = self._unpack_latents_with_ids(latents, latent_image_ids) latents_bn_mean = self.vae.bn.running_mean.view(1, -1, 1, 1).to(latents.device, latents.dtype) latents_bn_std = torch.sqrt(self.vae.bn.running_var.view(1, -1, 1, 1) + self.vae.config.batch_norm_eps).to( latents.device, latents.dtype ) latents = latents * latents_bn_std + latents_bn_mean latents = self._unpatchify_latents(latents) if output_type == "latent": image = latents else: image = self.vae.decode(latents, return_dict=False)[0] image = self.image_processor.postprocess(image, output_type=output_type) if padding_mask_crop is not None: image = [ self.image_processor.apply_overlay(mask_image, original_image, i, crops_coords) for i in image ] # Offload all models self.maybe_free_model_hooks() if not return_dict: return (image,) return Flux2PipelineOutput(images=image)