Add Composable diffusion to community pipeline examples

[MarkRich]

Part of #876 and bigger story #841

Followed the rough format of #900 and the code here: https://github.com/energy-based-model/Compositional-Visual-Generation-with-Composable-Diffusion-Models-PyTorch/tree/16e630f7fee5483bb986cb828762d6e06c2869c3, here's a script that allows for users to create "composable" prompts delimited by |.

For instance:

import torch as th
import numpy as np
import torchvision.utils as tvu
from diffusers import DiffusionPipeline

has_cuda = th.cuda.is_available()
device = th.device('cpu' if not has_cuda else 'cuda')

pipe = DiffusionPipeline.from_pretrained(
    "CompVis/stable-diffusion-v1-4",
    use_auth_token=True,
    custom_pipeline="composable_stable_diffusion"
).to(device)


def dummy(images, **kwargs):
    return images, False

pipe.safety_checker = dummy

images = []
generator = th.Generator("cuda").manual_seed(0)

seed = 0
prompt = "a forest | a camel"
weights = " 1 | 1"  # Equal weight to each prompt. Cna be negative

images = []
for i in range(4):
    res = pipe(
        prompt,
        guidance_scale=7.5,
        num_inference_steps=50,
        weights=weights,
        generator=generator)
    image = res.images[0]
    images.append(image)

for i, img in enumerate(images):
    img.save(f"./composable_diffusion/image_{i}.png")

yields:

Note for reviewers:
The script above is actually not 100% accurate, if I run it exactly as is I get the following error:

Could not locate the pipeline.py inside composable_stable_diffusion.
Traceback (most recent call last):
  File "/home/mark/.local/lib/python3.8/site-packages/huggingface_hub/utils/_errors.py", line 213, in hf_raise_for_status
    response.raise_for_status()
  File "/usr/local/lib/python3.8/dist-packages/requests/models.py", line 941, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 404 Client Error: Not Found for url: https://raw.githubusercontent.com/huggingface/diffusers/main/examples/community/composable_stable_diffusion.py

The trick is I have to change one line in the script to:

pipe = DiffusionPipeline.from_pretrained(
    "CompVis/stable-diffusion-v1-4",
    use_auth_token=True,
    custom_pipeline="/home/mark/open_source/diffusers/examples/community"
).to(device)

and in diffusers/src/pipeline_utils.py I need to change the following line:

CUSTOM_PIPELINE_FILE_NAME = "pipeline.py"

to

CUSTOM_PIPELINE_FILE_NAME = "composable_stable_diffusion.py"

Given the nature of the error above (i.e. it is searching on github for composable_stable_diffusion.py" I am guessing that I am just missing something about how we're expected to test these changes? 😅 . Open to more testing!

Anyway, based on the initial tests seems like it works

[HuggingFaceDocBuilderDev]

The documentation is not available anymore as the PR was closed or merged.

[patrickvonplaten]

Very cool! Thanks a lot for the PR :-)

[patrickvonplaten]

cc @osanseviero @apolinario FYI