asagi4-comfyui-prompt-control/doc/regional_prompts.md

Regional prompting

This section documents the masking functionality of PCTextEncode

See also Attention Couple

Remember that when using the lazy nodes, prompt scheduling applies to masks as well, so you can change or enable/disable regional prompts at any point during sampling.

Behaviour

For each prompt separated by AND, you can specify either latent masks or an area.

• When masked, ComfyUI generates the model output using the full latent as the input, and then applies the mask to the output before adding it to your latent for the next step.
• When an area is specified, ComfyUI generates a separate model output using the part of the latent specified by the area and then composites it into the full latent afterwards.
• You can have both an AREA and a MASK specified, in which case the mask is applied to the latent specified by the AREA.

For example, consider a 1024 by 1024 (width x height) generation:

• cat MASK(0 0.5, 0 1) AND dog MASK(0.5 1, 0 1) generates two outputs at 1024x1024 for "dog" and "cat", then masks half of them off and adds the results together. The following step still see both the dog and the cat from the previous step, so they may blend slightly.

• cat AREA(0 0.5, 0 1) AND dog AREA(0.5 1, 0 1) generates two completely separate outputs at 512x1024 and then composites them together into the 1024x1024 latent. Because the areas do not overlap, the generation for cat will not see the output of dog and vice versa in subsequent steps as long as the area restriction is in effect.

MASK, IMASK and AREA

You can use MASK(x1 x2, y1 y2, weight, op) to specify a region mask for a prompt. The values are specified as a percentage with a float between 0 and 1, or as absolute pixel values (these can't be mixed). 1 will be interpreted as a percentage instead of a pixel value.

Multiple MASK or IMASK calls will be composited together using ComfyUI's MaskComposite node, using op as the operation parameter (defaulting to multiply).

Similarly, you can use AREA(x1 x2, y1 y2, weight) to specify an area for the prompt (see ComfyUI's area composition examples). The area is calculated by ComfyUI relative to your latent size.

Custom masks: IMASK and PCAddMaskToCLIP

You can attach custom masks to a CLIP with the PC: Attach Mask nodes and then refer to those masks in the prompt using IMASK(index, weight, op). Indexing starts from zero, so 0 is the first attached mask etc. PCSCheduleAddMasks ignores empty inputs, so if you only add a mask to the mask4 input, it will still have index 0.

Applying the nodes multiple times appends masks rather than overriding existing ones, so if you need more than 4, you can just use it more than once.

Behaviour of multiple masks

If multiple MASKs are specified, they are combined together with ComfyUI's MaskComposite node, with op specifying the operation to use (default multiply). In this case, the combined mask weight can be set with MASKW(weight) (defaults to 1.0).

Masks assume a size of (512, 512), unless overridden with PC: Configure PCTextEncode and pixel values will be relative to that. ComfyUI will scale the mask to match the image resolution. You can change it manually by using MASK_SIZE(width, height) anywhere in the prompt,

These are handled per AND-ed prompt, so in prompt1 AND MASK(...) prompt2, the mask will only affect prompt2.

The default values are MASK(0 1, 0 1, 1) and you can omit unnecessary ones, that is, MASK(0 0.5, 0.3) is MASK(0 0.5, 0.3 1, 1)

Note that because the default values are percentages, MASK(0 256, 64 512) is valid, but MASK(0 200) will raise an error.

Masking does not affect LoRA scheduling unless you set unet weights to 0 for a LoRA.

FEATHER: Mask operations

When you use MASK or IMASK, you can also call FEATHER(left top right bottom) to apply feathering using ComfyUI's FeatherMask node. The values are in pixels and default to 0.

If multiple masks are used, FEATHER is applied before compositing in the order they appear in the prompt, and any leftovers are applied to the combined mask. If you want to skip feathering a mask while compositing, just use FEATHER() with no arguments.

For example:

MASK(1) MASK(2) MASK(3) FEATHER(1) FEATHER() FEATHER(3) weirdmask FEATHER(4)

gives you a mask that is a combination of 1, 2 and 3, where 1 and 3 are feathered before compositing and then FEATHER(4) is applied to the composite.

The order of the FEATHER and MASK calls doesn't matter; you can have FEATHER before MASK or even interleave them.