support for longer prompt and weighting using custom_pipeline

Now we can input prompt without 77 tokens limit and adjust weighting by using custom_pipeline="waifu-research-department/long-prompt-weighting-pipeline".

It requires diffusers>=0.4.0

Check out [waifu-research-department/long-prompt-weighting-pipeline](https://huggingface.co/waifu-research-department/long-prompt-weighting-pipeline) for detial.

README.md

@@ -44,19 +44,20 @@ This model can be used for entertainment purposes and as a generative art assist
 ## Example Code
 
 ```python
+from diffusers import DiffusionPipeline
 import torch
-from torch import autocast
-from diffusers import StableDiffusionPipeline
 
-pipe = StableDiffusionPipeline.from_pretrained(
+pipe = DiffusionPipeline.from_pretrained(
     'hakurei/waifu-diffusion',
-    torch_dtype=torch.float32
-).to('cuda')
-
-prompt = "1girl, aqua eyes, baseball cap, blonde hair, closed mouth, earrings, green background, hat, hoop earrings, jewelry, looking at viewer, shirt, short hair, simple background, solo, upper body, yellow shirt"
-with autocast("cuda"):
-    image = pipe(prompt, guidance_scale=6)["sample"][0]  
-    
+    custom_pipeline="waifu-research-department/long-prompt-weighting-pipeline",
+    revision="fp16",
+    torch_dtype=torch.float16
+)
+pipe=pipe.to("cuda")
+
+prompt = "best quality, masterpiece, 1girl, aqua eyes, baseball cap, blonde hair, closed mouth, earrings, green background, hat, hoop earrings, jewelry, looking at viewer, shirt, short hair, simple background, solo, upper body, yellow shirt"
+neg_prompt = "lowres, bad anatomy, error body, error hair, error arm, error hands, bad hands, error fingers, bad  fingers, missing fingers, error legs, bad legs, multiple legs, missing legs, error lighting, error shadow, error reflection, text, error, extra digit, fewer digits, cropped, worst quality, low quality, normal quality, jpeg artifacts, signature, watermark, username, blurry"
+image = pipe.text2img(prompt, neg_prompt, guidance_scale=6).images[0]
 image.save("test.png")
 ```