122 lines
5.1 KiB
Python
122 lines
5.1 KiB
Python
# pip install pillow
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from PIL import Image
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import os
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import shutil
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SUPPORTED_OUTPUT_FORMATS = ("jpg", "jpeg", "png", "webp")
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def get_file_kb(file_path: str) -> float:
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return os.path.getsize(file_path) / 1024
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def _save_image(img: Image.Image, output_path: str, output_format: str, quality: int):
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if output_format == "png":
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img.save(output_path, format="PNG", optimize=True, compress_level=9)
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elif output_format == "webp":
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img.save(output_path, format="WEBP", quality=quality, method=6)
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else:
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img.save(output_path, format="JPEG", quality=quality, optimize=True)
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def compress_to_format_loop(input_path, output_path, min_size_kb, max_size_kb,
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init_quality, quality_step, min_quality,
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max_width, max_height, output_format):
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try:
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# None 表示保持输入图片格式。
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if output_format is None:
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output_format = os.path.splitext(input_path)[1].lower().lstrip(".")
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output_format = output_format.lower().lstrip(".")
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if output_format not in SUPPORTED_OUTPUT_FORMATS:
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raise ValueError(f"不支持的输出格式: {output_format}")
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ori_size = get_file_kb(input_path)
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print(f"\n原图: {os.path.basename(input_path)} | 大小: {ori_size:.2f} KB")
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# INIT_QUALITY=None：不压缩、不缩放；目标格式不同则只做格式转换。
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# 小于阈值：同样不压缩、不缩放；目标格式不同则只做格式转换。
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if init_quality is None or ori_size < min_size_kb:
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if os.path.splitext(input_path)[1].lower().lstrip(".") == output_format:
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shutil.copy2(input_path, output_path)
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print(f"✅ 小于{min_size_kb}KB，无需压缩，直接复制")
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else:
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img = Image.open(input_path)
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img = _prepare_image(img, output_format)
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_save_image(img, output_path, output_format, init_quality)
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reason = "INIT_QUALITY=None" if init_quality is None else f"小于{min_size_kb}KB"
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print(f"✅ {reason}，不压缩，仅转换为 {output_format}")
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return
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img = Image.open(input_path)
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img = _prepare_image(img, output_format)
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if max_width and max_height:
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img.thumbnail((max_width, max_height))
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# PNG 没有 quality 参数，直接用最高无损压缩保存。
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if output_format == "png":
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_save_image(img, output_path, output_format, init_quality)
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print(f"✅ PNG 已保存 | 输出大小: {get_file_kb(output_path):.2f} KB")
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return
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quality = init_quality
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while True:
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_save_image(img, output_path, output_format, quality)
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out_size = get_file_kb(output_path)
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if out_size <= max_size_kb or quality <= min_quality:
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print(f"✅ 最终画质 {quality} | 输出大小: {out_size:.2f} KB")
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break
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quality = max(min_quality, quality - quality_step)
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print(f"⚠️ {out_size:.2f}KB > {max_size_kb}KB，降低画质至 {quality} 重新压缩")
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except Exception as e:
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print(f"❌ 处理失败 {input_path}：{str(e)}")
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def _prepare_image(img, output_format):
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has_alpha = "A" in img.getbands() or (img.mode == "P" and "transparency" in img.info)
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if output_format in ("jpg", "jpeg"):
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if has_alpha:
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rgba = img.convert("RGBA")
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result = Image.new("RGB", rgba.size, (255, 255, 255))
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result.paste(rgba, mask=rgba.getchannel("A"))
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return result
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return img.convert("RGB")
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return img.convert("RGBA" if has_alpha else "RGB")
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def batch_compress_folder(input_dir, output_dir, min_kb, max_kb, init_q,
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q_step, min_q, max_w, max_h, output_format):
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os.makedirs(output_dir, exist_ok=True)
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support_ext = (".png", ".jpg", ".jpeg", ".webp", ".bmp")
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for filename in os.listdir(input_dir):
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file_path = os.path.join(input_dir, filename)
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if os.path.isdir(file_path) or not filename.lower().endswith(support_ext):
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continue
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name_no_ext = os.path.splitext(filename)[0]
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suffix = output_format or os.path.splitext(filename)[1].lstrip(".")
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out_file = os.path.join(output_dir, f"{name_no_ext}.{suffix}")
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compress_to_format_loop(file_path, out_file, min_kb, max_kb, init_q,
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q_step, min_q, max_w, max_h, output_format)
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if __name__ == "__main__":
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# 输入输出文件夹
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INPUT_FOLDER = "./input"
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OUTPUT_FOLDER = "./output"
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# 首次压缩质量，不压缩填 None
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INIT_QUALITY = 75
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# 过小不压缩，过大重复压缩
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MIN_SIZE_KB = 100
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MAX_SIZE_KB = 500
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# 重复压缩质量递减及最小值
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QUALITY_STEP = 8
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MIN_QUALITY = 20
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# 更换格式，不转换格式填 None
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OUTPUT_FORMAT = "webp"
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# 尺寸压缩，不缩放填 None
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LIMIT_W = 2560
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LIMIT_H = 1440
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batch_compress_folder(INPUT_FOLDER, OUTPUT_FOLDER, MIN_SIZE_KB, MAX_SIZE_KB,
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INIT_QUALITY, QUALITY_STEP, MIN_QUALITY, LIMIT_W,
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LIMIT_H, OUTPUT_FORMAT)
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