app.py

import gradio as gr
from PIL import Image
import tempfile
import os

def convert_image(input_image: Image.Image, output_format: str, quality: int | float):
    """画像を指定した形式に変換する関数"""
    if input_image is None:
        return None, None
    
    img = input_image
    
    # PNGの場合はRGBA、それ以外はRGBに変換
    if output_format.lower() == 'png':
        if img.mode != 'RGBA' and 'A' not in img.mode:
            img = img.convert('RGBA')
    elif img.mode == 'RGBA':
        img = img.convert('RGB')
    
    # 保存
    
    args = {}
    
    fmt = output_format.lower()
    quality = int(quality)
    
    if "webp" in fmt:
        lossless = "lossless" in fmt
        fmt = "WEBP"
        args["quality"] = quality
        if lossless:
            args["lossless"] = True
    elif "jpeg" in fmt:
        fmt = "JPEG"
        args["quality"] = quality
    
    # 一時ファイルを作成
    with tempfile.NamedTemporaryFile(delete=False, suffix=f'.{fmt.lower()}') as temp_file:
        temp_filename = temp_file.name
    
    img.save(temp_filename, format=fmt, **args)
    
    html = f'<img src="{temp_filename}" />'
    
    return html, temp_filename

# Gradioインターフェースの作成
with gr.Blocks(title="画像形式変換ツール") as demo:
    gr.Markdown("## お嬢様の画像形式変換ツール")
    gr.Markdown("画像をアップロードして、変換したい形式を選んでくださいませ。")
    
    with gr.Row():
        with gr.Column():
            convert_btn = gr.Button("変換する")
            output_format = gr.Dropdown(
                choices=["png", "webp (lossless)", "jpeg", "webp (lossy)"],
                value="webp (lossless)", 
                label="変換後の形式"
            )
            quality = gr.Slider(0, 100, step=1, value=100, label="品質 (JPEG および WebP のみ)")
            input_image = gr.Image(type="pil", label="入力画像", format="png")
        
        with gr.Column():
            download_btn = gr.Button("ダウンロード")
            download_file = gr.File(label="変換ファイル")
            output_image = gr.HTML("")
    
    convert_btn.click(
        fn=convert_image, 
        inputs=[input_image, output_format, quality], 
        outputs=[output_image, download_file]
    )

# 実行
if __name__ == "__main__":
    demo.launch()