Modular backend - Seamless (#6651)

## Summary

Seamless code from #6577.

## Related Issues / Discussions

#6606 

https://invokeai.notion.site/Modular-Stable-Diffusion-Backend-Design-Document-e8952daab5d5472faecdc4a72d377b0d

## QA Instructions

Run with and without set `USE_MODULAR_DENOISE` environment.

## Merge Plan

Nope.
If you think that there should be some kind of tests - feel free to add.

## Checklist

- [x] _The PR has a short but descriptive title, suitable for a
changelog_
- [ ] _Tests added / updated (if applicable)_
- [ ] _Documentation added / updated (if applicable)_

invokeai/app/invocations/denoise_latents.py

@@ -39,7 +39,7 @@
 from invokeai.backend.lora import LoRAModelRaw
 from invokeai.backend.model_manager import BaseModelType
 from invokeai.backend.model_patcher import ModelPatcher
-from invokeai.backend.stable_diffusion import PipelineIntermediateState, set_seamless
+from invokeai.backend.stable_diffusion import PipelineIntermediateState
 from invokeai.backend.stable_diffusion.denoise_context import DenoiseContext, DenoiseInputs
 from invokeai.backend.stable_diffusion.diffusers_pipeline import (
     ControlNetData,
@@ -62,6 +62,7 @@
 from invokeai.backend.stable_diffusion.extensions.freeu import FreeUExt
 from invokeai.backend.stable_diffusion.extensions.preview import PreviewExt
 from invokeai.backend.stable_diffusion.extensions.rescale_cfg import RescaleCFGExt
+from invokeai.backend.stable_diffusion.extensions.seamless import SeamlessExt
 from invokeai.backend.stable_diffusion.extensions_manager import ExtensionsManager
 from invokeai.backend.stable_diffusion.schedulers import SCHEDULER_MAP
 from invokeai.backend.stable_diffusion.schedulers.schedulers import SCHEDULER_NAME_VALUES
@@ -833,6 +834,10 @@ def step_callback(state: PipelineIntermediateState) -> None:
         if self.unet.freeu_config:
             ext_manager.add_extension(FreeUExt(self.unet.freeu_config))
 
+        ### seamless
+        if self.unet.seamless_axes:
+            ext_manager.add_extension(SeamlessExt(self.unet.seamless_axes))
+
         # context for loading additional models
         with ExitStack() as exit_stack:
             # later should be smth like:
@@ -915,7 +920,7 @@ def _lora_loader() -> Iterator[Tuple[LoRAModelRaw, float]]:
             ExitStack() as exit_stack,
             unet_info.model_on_device() as (model_state_dict, unet),
             ModelPatcher.apply_freeu(unet, self.unet.freeu_config),
-            set_seamless(unet, self.unet.seamless_axes),  # FIXME
+            SeamlessExt.static_patch_model(unet, self.unet.seamless_axes),  # FIXME
             # Apply the LoRA after unet has been moved to its target device for faster patching.
             ModelPatcher.apply_lora_unet(
                 unet,

invokeai/app/invocations/latents_to_image.py

@@ -24,7 +24,7 @@
 from invokeai.app.invocations.model import VAEField
 from invokeai.app.invocations.primitives import ImageOutput
 from invokeai.app.services.shared.invocation_context import InvocationContext
-from invokeai.backend.stable_diffusion import set_seamless
+from invokeai.backend.stable_diffusion.extensions.seamless import SeamlessExt
 from invokeai.backend.stable_diffusion.vae_tiling import patch_vae_tiling_params
 from invokeai.backend.util.devices import TorchDevice
 
@@ -59,7 +59,7 @@ def invoke(self, context: InvocationContext) -> ImageOutput:
 
         vae_info = context.models.load(self.vae.vae)
         assert isinstance(vae_info.model, (AutoencoderKL, AutoencoderTiny))
-        with set_seamless(vae_info.model, self.vae.seamless_axes), vae_info as vae:
+        with SeamlessExt.static_patch_model(vae_info.model, self.vae.seamless_axes), vae_info as vae:
             assert isinstance(vae, (AutoencoderKL, AutoencoderTiny))
             latents = latents.to(vae.device)
             if self.fp32:

invokeai/backend/stable_diffusion/__init__.py

@@ -7,11 +7,9 @@
     StableDiffusionGeneratorPipeline,
 )
 from invokeai.backend.stable_diffusion.diffusion import InvokeAIDiffuserComponent  # noqa: F401
-from invokeai.backend.stable_diffusion.seamless import set_seamless  # noqa: F401
 
 __all__ = [
     "PipelineIntermediateState",
     "StableDiffusionGeneratorPipeline",
     "InvokeAIDiffuserComponent",
-    "set_seamless",
 ]

invokeai/backend/stable_diffusion/extensions/seamless.py

@@ -0,0 +1,71 @@
+from __future__ import annotations
+
+from contextlib import contextmanager
+from typing import Callable, Dict, List, Optional, Tuple
+
+import torch
+import torch.nn as nn
+from diffusers import UNet2DConditionModel
+from diffusers.models.lora import LoRACompatibleConv
+
+from invokeai.backend.stable_diffusion.extensions.base import ExtensionBase
+
+
+class SeamlessExt(ExtensionBase):
+    def __init__(
+        self,
+        seamless_axes: List[str],
+    ):
+        super().__init__()
+        self._seamless_axes = seamless_axes
+
+    @contextmanager
+    def patch_unet(self, unet: UNet2DConditionModel, cached_weights: Optional[Dict[str, torch.Tensor]] = None):
+        with self.static_patch_model(
+            model=unet,
+            seamless_axes=self._seamless_axes,
+        ):
+            yield
+
+    @staticmethod
+    @contextmanager
+    def static_patch_model(
+        model: torch.nn.Module,
+        seamless_axes: List[str],
+    ):
+        if not seamless_axes:
+            yield
+            return
+
+        x_mode = "circular" if "x" in seamless_axes else "constant"
+        y_mode = "circular" if "y" in seamless_axes else "constant"
+
+        # override conv_forward
+        # https://github.com/huggingface/diffusers/issues/556#issuecomment-1993287019
+        def _conv_forward_asymmetric(
+            self, input: torch.Tensor, weight: torch.Tensor, bias: Optional[torch.Tensor] = None
+        ):
+            self.paddingX = (self._reversed_padding_repeated_twice[0], self._reversed_padding_repeated_twice[1], 0, 0)
+            self.paddingY = (0, 0, self._reversed_padding_repeated_twice[2], self._reversed_padding_repeated_twice[3])
+            working = torch.nn.functional.pad(input, self.paddingX, mode=x_mode)
+            working = torch.nn.functional.pad(working, self.paddingY, mode=y_mode)
+            return torch.nn.functional.conv2d(
+                working, weight, bias, self.stride, torch.nn.modules.utils._pair(0), self.dilation, self.groups
+            )
+
+        original_layers: List[Tuple[nn.Conv2d, Callable]] = []
+        try:
+            for layer in model.modules():
+                if not isinstance(layer, torch.nn.Conv2d):
+                    continue
+
+                if isinstance(layer, LoRACompatibleConv) and layer.lora_layer is None:
+                    layer.lora_layer = lambda *x: 0
+                original_layers.append((layer, layer._conv_forward))
+                layer._conv_forward = _conv_forward_asymmetric.__get__(layer, torch.nn.Conv2d)
+
+            yield
+
+        finally:
+            for layer, orig_conv_forward in original_layers:
+                layer._conv_forward = orig_conv_forward