chore: import upstream snapshot with attribution

invokeai/backend/stable_diffusion/extensions/inpaint_model.py

@@ -0,0 +1,88 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Optional
+
+import torch
+from diffusers import UNet2DConditionModel
+
+from invokeai.backend.stable_diffusion.extension_callback_type import ExtensionCallbackType
+from invokeai.backend.stable_diffusion.extensions.base import ExtensionBase, callback
+
+if TYPE_CHECKING:
+    from invokeai.backend.stable_diffusion.denoise_context import DenoiseContext
+
+
+class InpaintModelExt(ExtensionBase):
+    """An extension for inpainting with inpainting models. See `InpaintExt` for inpainting with non-inpainting
+    models.
+    """
+
+    def __init__(
+        self,
+        mask: Optional[torch.Tensor],
+        masked_latents: Optional[torch.Tensor],
+        is_gradient_mask: bool,
+    ):
+        """Initialize InpaintModelExt.
+        Args:
+            mask (Optional[torch.Tensor]): The inpainting mask. Shape: (1, 1, latent_height, latent_width). Values are
+                expected to be in the range [0, 1]. A value of 1 means that the corresponding 'pixel' should not be
+                inpainted.
+            masked_latents (Optional[torch.Tensor]): Latents of initial image, with masked out by black color inpainted area.
+                If mask provided, then too should be provided. Shape: (1, 1, latent_height, latent_width)
+            is_gradient_mask (bool): If True, mask is interpreted as a gradient mask meaning that the mask values range
+                from 0 to 1. If False, mask is interpreted as binary mask meaning that the mask values are either 0 or
+                1.
+        """
+        super().__init__()
+        if mask is not None and masked_latents is None:
+            raise ValueError("Source image required for inpaint mask when inpaint model used!")
+
+        # Inverse mask, because inpaint models treat mask as: 0 - remain same, 1 - inpaint
+        self._mask = None
+        if mask is not None:
+            self._mask = 1 - mask
+        self._masked_latents = masked_latents
+        self._is_gradient_mask = is_gradient_mask
+
+    @staticmethod
+    def _is_inpaint_model(unet: UNet2DConditionModel):
+        """Checks if the provided UNet belongs to a regular model.
+        The `in_channels` of a UNet vary depending on model type:
+        - normal - 4
+        - depth - 5
+        - inpaint - 9
+        """
+        return unet.conv_in.in_channels == 9
+
+    @callback(ExtensionCallbackType.PRE_DENOISE_LOOP)
+    def init_tensors(self, ctx: DenoiseContext):
+        if not self._is_inpaint_model(ctx.unet):
+            raise ValueError("InpaintModelExt should be used only on inpaint models!")
+
+        if self._mask is None:
+            self._mask = torch.ones_like(ctx.latents[:1, :1])
+        self._mask = self._mask.to(device=ctx.latents.device, dtype=ctx.latents.dtype)
+
+        if self._masked_latents is None:
+            self._masked_latents = torch.zeros_like(ctx.latents[:1])
+        self._masked_latents = self._masked_latents.to(device=ctx.latents.device, dtype=ctx.latents.dtype)
+
+    # Do last so that other extensions works with normal latents
+    @callback(ExtensionCallbackType.PRE_UNET, order=1000)
+    def append_inpaint_layers(self, ctx: DenoiseContext):
+        batch_size = ctx.unet_kwargs.sample.shape[0]
+        b_mask = torch.cat([self._mask] * batch_size)
+        b_masked_latents = torch.cat([self._masked_latents] * batch_size)
+        ctx.unet_kwargs.sample = torch.cat(
+            [ctx.unet_kwargs.sample, b_mask, b_masked_latents],
+            dim=1,
+        )
+
+    # Restore unmasked part as inpaint model can change unmasked part slightly
+    @callback(ExtensionCallbackType.POST_DENOISE_LOOP)
+    def restore_unmasked(self, ctx: DenoiseContext):
+        if self._is_gradient_mask:
+            ctx.latents = torch.where(self._mask > 0, ctx.latents, ctx.inputs.orig_latents)
+        else:
+            ctx.latents = torch.lerp(ctx.inputs.orig_latents, ctx.latents, self._mask)