ComfyUI PixelArt Detector v1.5.2

Generate, downscale, change palletes and restore pixel art images with SDXL.

Save a picture as Webp (+optional JPEG) file in Comfy + Workflow loading.

Update 1.5.2:

Fixed the compatibility with Python <3.10
Fixed a scipy 'signal' error

Update 1.5.1: @tsone added a new dithering node: PixelArtAddDitherPattern

with prepared patterns
with custom patterns from a mask
also added a b&w palette

Update 1.5: Maintenance & Dithering + bugfixes

added dithering
made the node compatible with Pillow < 10 & Pillow > 10
fixed an issue where changing the fontSize in grids did not work
fixed an issue with Pillow library and ImageDraw.textsize not available in Pillow>= 10.0
fixed an issue with text too long in Grids
fixed an issue with the NP.quantize method

Dithering examples:

Update 1.4: Added a check and installation for the opencv (cv2) library used with the nodes. This should fix the reported issues people were having.

Update 1.3: Updated all 4 nodes. Please, pull this and exchange all your PixelArt nodes in your workflow. Mind the settings.

added OpenCV.kmeans algo to reduce colors in an image. Working only when reducing colors.
added "clean up" pixels function which uses Image.quantize to iterate over the image and eliminate colors based on given threshold. Runs after optional reducing of colors step
added different algos to reduce image with Image.quantize method (default one). MEDIANCUT, MAXCOVERAGE etc. MAXCOVERAGE seems to produce cleaner pixel art. FASTOCTREE is fast and bad
updated choices to BOOLEANs and toggles
added the "NP.quantize" method using fast numpy arrays to reduce and exchange palettes
moved out the grid settings from the Palette Converter to the Palette Loader
and many other small additions

Update 1.2: PixelArtDetectorConverter will upscale the image BEFORE the pixelization/quantization process if the input image is smaller than the resize sizes. If bigger, it will downscale after quantization.

Update 1.1: changed the default workflow.json to use the default "Save Image" node. workflow_webp.json will be using the webp node.

[!IMPORTANT] If you have an older version of the nodes, delete the node and add it again. Location of the nodes: "Image/PixelArt". I've added some example workflow in the workflow.json. The example images might have outdated workflows with older node versions embedded inside.

Description:

Pixel Art manipulation code based on: https://github.com/Astropulse/pixeldetector

This adds 4 custom nodes:

PixelArt Detector (+Save) - this node is All in One reduce palette, resize, saving image node
PixelArt Detector (Image->) - this node will downscale and reduce the palette and forward the image to another node
PixelArt Palette Converter - this node will change the palette of your input. There are a couple of embedded palettes. Use the Palette Loader for more
PixelArt Palette Loader - this node comes with a lot of custom palettes which can be an input to the PixelArt Palette Converter "paletteList" input. Optional GRIDS preview of all palettes

The plugin also adds a script to Comfy to drag and drop generated webp|jpeg files into the UI to load the workflows.

The nodes are able to manipulate the pixel art image in ways that it should look pixel perfect (downscales, changes palette, upscales etc.).

[!IMPORTANT] You can disable the embedded resize function in the nodes by setting W & H to 0.

Installation:

To use these nodes, simply open a terminal in ComfyUI/custom_nodes/ and run:

git clone https://github.com/dimtoneff/ComfyUI-PixelArt-Detector

I am using a "Save_as_webp" node to save my output images (check the workflow_webp.json). You can find my customization in the following repo (part of the workflow).

Just execute this command in ComfyUI/custom_nodes/ too.

git clone https://github.com/dimtoneff/ComfyUI-Saveaswebp

Original "Save_as_webp" node repo: https://github.com/Kaharos94/ComfyUI-Saveaswebp.

If you don't want to use "Save_as_webp" nodes, just delete them from my workflow in workflow_webp.json and add the default "Save Image" node to save as PNG (or use the default workflow.json)

Restart ComfyUI afterwards.

Usage

Use LoRa: https://civitai.com/models/120096/pixel-art-xl

Drag the workflow.json file in your ComfyUI

Set the resize inputs to 0 to disable upscaling in the "Save" node.

Reduce palettes or completely exchange palettes on your images.

text2image

Positive prompt: pixelart, {your scene}, pixel-art. low-res, blocky, pixel art style, 8-bit graphics, sharp details, less colors, early computer game art

Negative prompt: sloppy, messy, blurry, noisy, highly detailed, ultra textured, photo, realistic, high-resolution, photo-realistic

image2image

on a pixel drawing converting to a pixel asset for finetuning:

Input:

Output:

Workflow WEBP (drag & drop):

Feel free to experiment! Free web tool for pixel art: https://www.pixilart.com/draw

Other image2image examples: Discussion in the issues

Extra info about the "PixelArt Detector (+Save)" Node:

There is a compression slider and a lossy/lossless option for webp. The compression slider is a bit misleading.

In lossless mode, it only affects the "effort" taken to compress where 100 is the smallest possible size and 1 is the biggest possible size, it's a tradeoff for saving speed.

In lossy mode, that's the other way around, where 100 is the biggest possible size with the least compression and 1 is the smallest possible size with maximum compression.

There is an option to save a JPEG alongside the webp file.

Extra info about the "PixelArt Palette Converter" Node:

palette: a couple of retro palettes used if the paletteList input is not used
pixelize: here we have different algos to reduce colors & replace palettes
- Image.quantize: uses PIL Image functions to reduce colors & replace palettes. You can change the reduce algo with "image_quantize_reduce_method"
- Grid.pixelate: a custom algo to exchange palettes. Slow when grid_pixelate_grid_scan_size is 1
- NP.quantize: a custom algo to exchange paletes. Using fast numpy arrays. Slower than Image.quantize
- OpenCV.kmeans.reduce: using the OpenCV library to reduce colors. Used only when reducing colors before the pallete swap. Palette exchange is done with Image.quantize. It is slow but good when attempts & iterations are higher. You can change the way it picks colors with the option "opencv_kmeans_centers".
grid_pixelate_grid_scan_size option is for the pixelize grid.Pixelate option. Size of 1 is pixel by pixel. Very slow. Increasing the size improves speed but kills quality. Experiment or not use that option.
resize_w & resize_h: it will downscale or upscale the end result to these sizes
reduce_colos_before_palette_swap: it's going to reduce colors with either Image.quantize or OpenCV.kmeans.
reduce_colors_max_colors: the colors count to reduce the image to
apply_pixeldetector_max_colors: use the Astropulse's PixelDetector to grab the max dominant colors.
image_quantize_reduce_method: the method used from Image.quantize pixelize option to reduce colors. MAXCOVERAGE seems good for pixel art. But try the rest too.
opencv_kmeans_centers: a flag how to pick the labels/colors. RANDOM is.. random. Interesting results. Increasing attempts makes it slower but picks the best colors.
- KMEANS_RANDOM_CENTERS: it always starts with a random set of initial samples, and tries to converge from there depending upon TermCriteria. Fast but doesn't guarantee same labels for the exact same image. Needs more "attempts" to find the "best" labels
- KMEANS_PP_CENTERS: it first iterates the whole image to determine the probable centers and then starts to converge. Slow but will yield optimum and consistent results for same input image.
opencv_kmeans_attempts: how many times to attempt finding the best colors to reduce the image to
opencv_criteria_max_iterations: how many iterations per attempt
cleanup_colors: given a threshold, iterate over the image and eliminate less used colors. May be combined with the reduce_colos_before_palette_swap option for optimal clean up. Or optimal break of the image :)
cleanup_pixels_threshold: the threshold for the cleanup function. Good values: 0.01-0.05. If it eliminates too much, lower the value. LOWER VALUE = MORE COLORS
dither: apply dithering for more "retro" look

Extra info about the "PixelArt Palette Converter" and "PixelArt Palette Loader" Nodes:

Included palettes from: https://lospec.com/palette-list

[!IMPORTANT] If you like some palette, download the 1px one and add it to the "ComfyUI-PixelArt-Detector\palettes\1x" directory.

GRIDS

Connect the PixelArt Palette Loader to the PixelArt Palette Converter or use the "grid.json" file and drag&drop into ComfyUI
enable the render_all_palettes_in_grid
use the default "Preview Image" node to preview the grids (preferably)
play with the settings

Grids