ausboss-ComfyUI-AusBoss/js/docs/AUSBOSS_NODES_Compare.md

Image Compare A/B

Shows two images on one panel so differences pop out instead of hiding in a side-by-side. The first frame of each batch is previewed; image_a and image_b pass through their outputs unchanged, so the node can sit in the middle of a graph without breaking anything downstream.

Inputs

• image_a: The baseline batch. Its first frame is preview A, and the whole batch is what the image_a output carries.
• image_b: The comparison batch. Its first frame is preview B, and the whole batch is what the image_b output carries.
• filename (optional): a name for the files that Erase saves, such as the source picture's file name. Leave it unwired to type the name on the node.

Panel

Run the workflow once to load the previews. The switch under the picture picks what the panel does, and its marker slides to your choice:

• Slide (default): the panel shows the result. Move the pointer across it to compare: A appears on the left of the line and B on the right. Move the pointer away and the result is back. Every new run shows its result too.
• A / B: show that picture and hold it, whatever the pointer does.
• Erase: mix the two pictures by hand. One picture is on top; paint on it and it rubs away, so the other one shows through. Then save the mix. See Erase below.

A picture with see-through parts shows them over a checkerboard, as an editor does.

The labels ride with the split line: A just left of it and B just right of it, on the picture each one names. With one picture showing, its label sits alone at the top centre. The chosen mode and locked side are stored with the node, including support for modes from older workflows. The resolution sits under the picture, beside the switch; differing sizes are labeled individually.

Several pictures

Give the node a list of pictures, such as a folder of images, and it shows arrows under the picture (‹ 2 / 5 ›). Click them to step through the pairs: A and B change together. Erase saves the pair you are looking at.

A batch still shows its first frame only.

Erase

Use it when you want part of one picture and part of the other: the edit is good but it changed the hands, so you paint the old hands back. Or you only want the new sky.

It also brings back a clear background. When the picture underneath has see-through parts, such as a cut-out the model filled in behind, rub the top one away there and they come back clear. The saved PNG and PSD keep them.

Pick Erase on the switch. A row of tools opens above the picture:

• Erase | Restore: what the brush does. Erase rubs the top picture away. Restore paints it back. Holding Ctrl, or using the right mouse button, does the other one for as long as you hold it.
• Size is the brush's width, in pixels of the picture.
• Soft is the brush's edge: 0 is a hard edge, 100 fades all the way from the middle.
• Drag left and right on Size or Soft, on the word, the number or the unit, to change the value. Click the number to type one.
• On top: A | B is the picture you start from. Pick the other and it goes on top instead. Your paint stays where it is.
• ALIGN lines B up with A. Edit models often draw the picture a few pixels to the side or a little zoomed in, so the edges of your paint show a step. Click it and B is moved back over A; Save and Copy use the lined-up B. Click it again to go back to B as it came. It fixes a shift and a zoom, not a picture that bent or changed shape. Where B was moved off its edge, A fills the gap.
• UNDO takes back the last stroke, or a Clear. CLEAR takes all the paint off.

The brush shows around the pointer in teal: a ring at its full size, and its shape inside, solid in the middle and fading where the edge is soft. It turns coral while it paints back.

Set the brush without leaving the picture, with the same keys as in Photoshop:

• E erases and B paints back, as with Photoshop's eraser and brush.
• [ and ] make it smaller and larger.
• Shift + [ and Shift + ] make the edge softer and harder.
• Hold Alt and the right mouse button, then drag: left and right for the size, up and down for the edge (up is softer). The brush stays where you pressed and changes as you drag, with its size and softness written under it; the dashed ring is where its solid middle ends. One drag can do both: go across for the size, then turn up or down for the edge. On a Mac, hold Control and Option and drag.

These keys only work while the pointer is on the picture. ComfyUI's own shortcuts are left alone.

A second row opens under the switch, for saving:

• Name: what the files are called. compare is used when it is empty. Letters, digits, spaces, dots, dashes and underscores are kept; a folder cannot be part of the name. With the filename input wired, the name comes from there and the field only shows it.
• PSD off | on: on makes Save write two more files (see below).
• Copy puts the mix on the clipboard at full size, to paste into an editor or a chat. Nothing is saved. Browsers only allow this when ComfyUI is opened as localhost or over https; from another computer on a plain address, use Save.
• Save, at the right end, writes the mix to ComfyUI's output folder as a PNG, such as compare_00001.png. Nothing is run again, and every save takes the next number, so nothing is written over.

With PSD on, Save also writes:

• compare_00001.psd: both pictures as layers, with your paint as a layer mask on the top one. Open it in Photoshop, GIMP or another editor that reads PSD files, and keep working on the mask there.
• compare_00001_mask.png: the mask alone. White is where the picture underneath shows.

After a save, the line under the picture says Saved with a link for each file. Click one to download it, which helps when ComfyUI runs on another computer.

Your paint is kept with the workflow. A new run keeps it while the picture keeps its size, so you can change a seed and look again; press CLEAR to start over. Pictures of another size start clean.

Which picture is the result

B, the "after" picture. If your graph makes A out of B's picture (B is the picture you loaded and A is the edited one), the result is A. To keep one picture up whatever happens, use the A or B button.

Outputs

• image_a: The image_a batch, untouched.
• image_b: The image_b batch, untouched: the picture you compared against, often the edited one. Wire it on when the picture you want to keep is B.

Previews are written to ComfyUI's temp folder and vanish with it. Nothing is saved to the output folder until you press SAVE in Erase, and no network requests are made.

Technical details

• While sliding, the outer 6% on either side snaps to a full image.
• The result is found from the links: when the node that feeds image_b is somewhere upstream of the node that feeds image_a, A was made from B and A is the result. When both pictures come out of one subgraph, the same check is made inside it. In every other case it is B: two unrelated pictures, both pictures out of one plain node, or a link the node cannot follow (a Set and Get pair, for example).
• Settings → AusBoss → Image Compare → Rest on the result switches this off. The panel then stays on the picture nearest to where the pointer left, and a new run does not change it.
• Erase works on the first picture of each batch, at its full size. The mix is always A's size: a B of another size is resized to fit A.
• See-through parts are kept in a preview only when a picture has some, so solid pictures save exactly as before. The mix lays the top picture over the other as an editor does. In the PSD each layer keeps its own see-through parts, and the flat picture carries the mix's, its colours stored over white the way Photoshop stores them. Align measures the two pictures laid over gray and moves B's see-through parts with it.
• What is kept is the strokes, not a painted picture. The panel draws them for you, and Save draws them again on the server at full size, so the saved edge is as sharp as the picture however small the node is. Copy draws them at full size in the browser.
• Erase never changes the node's size. On a narrow node its rows wrap onto a second line and the picture gets shorter instead.
• The brush is a solid middle with a blurred edge. At Soft 100 the middle is half the brush wide and the blur is an eighth of the size.
• Save mixes the two pictures of the node's last run, which ComfyUI keeps in its temp folder. After a restart of ComfyUI they are gone: run the workflow once more, then save. The browser sends the strokes, a key for that run and the name: it never names a file to read, and the name is checked again on the server.
• A wired name is tidied: its folder and extension are dropped, and anything a file name cannot hold becomes an underscore (sets/a/photo 12.jpg saves photo 12_00001.png).
• The saved files carry no workflow. A mix is made by hand, so there is nothing a workflow could make again.
• The PSD is 8-bit RGB and not compressed: about 12 bytes for each pixel, so 50 MB for a 2048 x 2048 picture. It carries no colour profile, like the PNG.
• Limits: 400 strokes in one mix. The node says so when it is full.