Python 实现 AI 图像生成：调用 Stable Diffusion API 完整教程

从零开始学习使用 Python 调用 Stable Diffusion API 生成图像，涵盖本地部署、API 调用、ControlNet、图生图等进阶技巧。

1. 技术架构

Python 客户端

Stable Diffusion API

本地部署
SD WebUI / ComfyUI

云端 API
Replicate / Stability AI

Stable Diffusion 模型

文生图
txt2img

图生图
img2img

局部重绘
inpainting

超分辨率
upscale

输出图像

后处理管道

存储
本地/OSS

2. 图像生成方式对比

50%25%15%10%各生成方式使用占比统计文生图 (txt2img)图生图 (img2img)局部重绘 (inpainting)超分辨率 (upscale)

3. 环境准备

3.1 本地部署 Stable Diffusion WebUI

# 克隆 Stable Diffusion WebUIgit clone https://github.com/AUTOMATIC1111/stable-diffusion-webui.git cd stable-diffusion-webui # 启动（开启 API 模式） ./webui.sh --api--listen# Windows 用户 webui.bat --api--listen

3.2 安装依赖

pip install requests Pillow io base64 

4. 核心代码实现

4.1 SD API 客户端封装

# sd_client.pyimport requests import base64 import io import json import time from pathlib import Path from PIL import Image from dataclasses import dataclass, field from typing import Optional @dataclassclassGenerationConfig:"""图像生成配置""" prompt:str="" negative_prompt:str="low quality, blurry, deformed" width:int=512 height:int=512 steps:int=30 cfg_scale:float=7.0 sampler_name:str="DPM++ 2M Karras" seed:int=-1# -1 表示随机 batch_size:int=1 n_iter:int=1# 迭代次数 model: Optional[str]=NoneclassStableDiffusionClient:"""Stable Diffusion API 客户端"""def__init__(self, base_url:str="http://127.0.0.1:7860"): self.base_url = base_url self.api_url =f"{base_url}/sdapi/v1"def_save_base64_image(self, b64_str:str, output_path:str)->str:"""将 base64 图片保存到文件""" img_data = base64.b64decode(b64_str) img = Image.open(io.BytesIO(img_data)) img.save(output_path)return output_path # ---- 文生图 ----deftxt2img(self, config: GenerationConfig, output_dir:str="./output")->list[str]:"""文生图：从文本描述生成图像""" payload ={"prompt": config.prompt,"negative_prompt": config.negative_prompt,"width": config.width,"height": config.height,"steps": config.steps,"cfg_scale": config.cfg_scale,"sampler_name": config.sampler_name,"seed": config.seed,"batch_size": config.batch_size,"n_iter": config.n_iter,}if config.model: self._switch_model(config.model) response = requests.post(f"{self.api_url}/txt2img", json=payload) response.raise_for_status() data = response.json() Path(output_dir).mkdir(exist_ok=True) saved_paths =[]for i, img_b64 inenumerate(data["images"]): path =f"{output_dir}/txt2img_{int(time.time())}_{i}.png" self._save_base64_image(img_b64, path) saved_paths.append(path)print(f"已保存: {path}")return saved_paths # ---- 图生图 ----defimg2img(self, init_image_path:str, prompt:str, denoising_strength:float=0.75, config: GenerationConfig =None, output_dir:str="./output")->list[str]:"""图生图：基于参考图 + 提示词生成新图""" config = config or GenerationConfig()# 读取初始图片并转 base64withopen(init_image_path,"rb")as f: init_images =[base64.b64encode(f.read()).decode()] payload ={"init_images": init_images,"prompt": prompt,"negative_prompt": config.negative_prompt,"width": config.width,"height": config.height,"steps": config.steps,"cfg_scale": config.cfg_scale,"sampler_name": config.sampler_name,"denoising_strength": denoising_strength,"seed": config.seed,} response = requests.post(f"{self.api_url}/img2img", json=payload) response.raise_for_status() data = response.json() Path(output_dir).mkdir(exist_ok=True) saved_paths =[]for i, img_b64 inenumerate(data["images"]): path =f"{output_dir}/img2img_{int(time.time())}_{i}.png" self._save_base64_image(img_b64, path) saved_paths.append(path)print(f"已保存: {path}")return saved_paths # ---- 局部重绘 ----definpaint(self, init_image_path:str, mask_image_path:str, prompt:str, denoising_strength:float=0.85, output_dir:str="./output")->list[str]:"""局部重绘：只修改 mask 区域"""withopen(init_image_path,"rb")as f: init_images =[base64.b64encode(f.read()).decode()]withopen(mask_image_path,"rb")as f: mask = base64.b64encode(f.read()).decode() payload ={"init_images": init_images,"mask": mask,"prompt": prompt,"negative_prompt":"low quality, blurry","denoising_strength": denoising_strength,"inpainting_fill":1,# 0=fill, 1=original, 2=latent noise"inpaint_full_res":True,"steps":30,"cfg_scale":7.0,"sampler_name":"DPM++ 2M Karras","width":512,"height":512,} response = requests.post(f"{self.api_url}/img2img", json=payload) response.raise_for_status() data = response.json() Path(output_dir).mkdir(exist_ok=True) saved_paths =[]for i, img_b64 inenumerate(data["images"]): path =f"{output_dir}/inpaint_{int(time.time())}_{i}.png" self._save_base64_image(img_b64, path) saved_paths.append(path)return saved_paths # ---- 超分辨率 ----defupscale(self, image_path:str, scale:int=2, output_dir:str="./output")->str:"""使用 ESRGAN 进行超分辨率放大"""withopen(image_path,"rb")as f: img_b64 = base64.b64encode(f.read()).decode() payload ={"image": img_b64,"upscaler_1":"R-ESRGAN 4x+","upscaling_resize": scale,} response = requests.post(f"{self.api_url}/extra-single-image", json=payload) response.raise_for_status() data = response.json() Path(output_dir).mkdir(exist_ok=True) path =f"{output_dir}/upscaled_{int(time.time())}.png" self._save_base64_image(data["image"], path)print(f"超分辨率完成: {path}")return path # ---- 模型管理 ----def_switch_model(self, model_name:str):"""切换模型""" response = requests.post(f"{self.api_url}/options", json={"sd_model_checkpoint": model_name},) response.raise_for_status() time.sleep(3)# 等待模型加载deflist_models(self)->list[str]:"""列出可用模型""" response = requests.get(f"{self.api_url}/sd-models")return[m["title"]for m in response.json()]deflist_samplers(self)->list[str]:"""列出可用采样器""" response = requests.get(f"{self.api_url}/samplers")return[s["name"]for s in response.json()]

4.2 批量生成示例

# batch_generate.pyfrom sd_client import StableDiffusionClient, GenerationConfig defbatch_generate_portraits():"""批量生成人物肖像""" sd = StableDiffusionClient()# 查看可用模型和采样器print("可用模型:", sd.list_models()[:5])print("可用采样器:", sd.list_samplers())# 风格列表 styles =["cyberpunk neon city","watercolor painting","oil painting renaissance","anime style","photorealistic 8k",] base_prompt =("portrait of a young woman, detailed face, beautiful eyes, ""dramatic lighting, masterpiece, best quality")for style in styles: config = GenerationConfig( prompt=f"{base_prompt}, {style}", negative_prompt="lowres, bad anatomy, bad hands, text, error", width=512, height=768, steps=30, cfg_scale=7.5,) paths = sd.txt2img(config, output_dir=f"./output/{style.replace(' ','_')}")print(f"风格 [{style}] -> {paths}")if __name__ =="__main__": batch_generate_portraits()

4.3 调用 Stability AI 云端 API

# stability_cloud.pyimport requests import base64 from pathlib import Path from PIL import Image from io import BytesIO classStabilityAIClient:"""Stability AI 官方云端 API"""def__init__(self, api_key:str): self.api_key = api_key self.base_url ="https://api.stability.ai/v2beta"defgenerate(self, prompt:str, aspect_ratio:str="1:1", style:str="photographic", output_path:str="output.png")->str:"""调用 Stable Diffusion 3 生成图像""" response = requests.post(f"{self.base_url}/stable-image/generate/sd3", headers={"Authorization":f"Bearer {self.api_key}","Accept":"image/*",}, files={"none":""}, data={"prompt": prompt,"aspect_ratio": aspect_ratio,"style_preset": style,"output_format":"png",},)if response.status_code !=200:raise Exception(f"API 错误: {response.status_code} - {response.text}")withopen(output_path,"wb")as f: f.write(response.content)print(f"已生成: {output_path}")return output_path # 使用示例if __name__ =="__main__": client = StabilityAIClient(api_key="sk-your-api-key") client.generate( prompt="A majestic dragon flying over a neon-lit cyberpunk city at night, ""highly detailed, cinematic lighting, 8k", aspect_ratio="16:9", style="cinematic", output_path="dragon_city.png",)

4.4 图像后处理管道

# postprocess.pyfrom PIL import Image, ImageEnhance, ImageFilter from pathlib import Path classImagePostProcessor:"""图像后处理：调整色彩、锐化、添加水印"""@staticmethoddefenhance(image_path:str, brightness:float=1.1, contrast:float=1.15, sharpness:float=1.3, output_path:str=None)->str:"""综合增强""" img = Image.open(image_path) img = ImageEnhance.Brightness(img).enhance(brightness) img = ImageEnhance.Contrast(img).enhance(contrast) img = ImageEnhance.Sharpness(img).enhance(sharpness) output_path = output_path or image_path.replace(".","_enhanced.") img.save(output_path, quality=95)return output_path @staticmethoddefadd_watermark(image_path:str, text:str="AI Generated", output_path:str=None)->str:"""添加水印"""from PIL import ImageDraw, ImageFont img = Image.open(image_path).convert("RGBA") overlay = Image.new("RGBA", img.size,(0,0,0,0)) draw = ImageDraw.Draw(overlay)# 半透明白色文字 draw.text((img.width -200, img.height -40), text, fill=(255,255,255,128),) img = Image.alpha_composite(img, overlay).convert("RGB") output_path = output_path or image_path.replace(".","_wm.") img.save(output_path, quality=95)return output_path @staticmethoddefcreate_grid(image_paths:list[str], cols:int=3, output_path:str="grid.png")->str:"""将多张图片拼成网格""" images =[Image.open(p)for p in image_paths] w, h = images[0].size rows =(len(images)+ cols -1)// cols grid = Image.new("RGB",(w * cols, h * rows),"white")for i, img inenumerate(images): row, col =divmod(i, cols) grid.paste(img,(col * w, row * h)) grid.save(output_path, quality=95)print(f"网格图已保存: {output_path}")return output_path 

5. Prompt 工程技巧

Prompt 结构

主体描述

风格关键词

质量修饰词

负面提示词

高质量 Prompt 模板

PROMPT_TEMPLATES ={"人物肖像":("{subject}, {style}, detailed face, expressive eyes, ""dramatic lighting, masterpiece, best quality, ultra detailed"),"风景":("{scene}, {mood}, volumetric lighting, god rays, ""landscape photography, 8k uhd, cinematic composition"),"产品设计":("{product}, minimalist design, studio lighting, ""white background, product photography, professional, 4k"),"动漫":("{character}, anime style, vibrant colors, ""detailed illustration, cel shading, masterpiece"),} NEGATIVE_PROMPTS ={"通用":"lowres, bad anatomy, bad hands, text, error, missing fingers, ""extra digit, cropped, worst quality, low quality, blurry","写实":"illustration, painting, drawing, art, sketch, anime, cartoon, ""CG, render, 3D, watermark, text, font, signature","动漫":"photo, realistic, 3d, western, ugly, duplicate, morbid, ""deformed, bad anatomy, blurry",}

6. 关键参数影响

35%20%15%15%10%5%不同参数对生成质量的影响权重Prompt 质量采样步数 (steps)CFG Scale采样器选择模型选择分辨率

7. 完整使用流程

# complete_demo.pyfrom sd_client import StableDiffusionClient, GenerationConfig from stability_cloud import StabilityAIClient from postprocess import ImagePostProcessor defmain():# ===== 方式一：本地 SD WebUI ===== sd = StableDiffusionClient("http://127.0.0.1:7860")# 文生图 config = GenerationConfig( prompt="A serene Japanese garden with cherry blossoms, ""koi pond, stone bridge, golden hour, cinematic, 8k", negative_prompt="lowres, blurry, text, watermark", width=768, height=512, steps=30, cfg_scale=7.5,) paths = sd.txt2img(config)print(f"生成完成: {paths}")# 图生图if paths: new_paths = sd.img2img( init_image_path=paths[0], prompt="same scene but in autumn, orange and red leaves, snow", denoising_strength=0.6,)print(f"图生图完成: {new_paths}")# 超分辨率if paths: upscaled = sd.upscale(paths[0], scale=2)print(f"超分辨率完成: {upscaled}")# 后处理 pp = ImagePostProcessor()if paths: enhanced = pp.enhance(paths[0]) watermarked = pp.add_watermark(enhanced, text="AI Art")print(f"后处理完成: {watermarked}")# ===== 方式二：云端 API =====# cloud = StabilityAIClient("sk-xxx")# cloud.generate("A futuristic cityscape at sunset", "16:9", "cinematic")if __name__ =="__main__": main()

8. 总结

本文覆盖了 Stable Diffusion 图像生成的完整链路：

1. 本地部署 SD WebUI 并开启 API 模式
2. 封装 Python 客户端 支持文生图、图生图、局部重绘、超分辨率
3. 云端 API 作为无 GPU 环境的替代方案
4. Prompt 工程 模板化的提示词编写技巧
5. 后处理管道 增强色彩、添加水印、拼图网格

生成速度参考：RTX 4090 生成 512x512 约 3-5 秒，512x768 约 5-8 秒。云端 API 约 10-20 秒。