WebP Python bindings

安装

pip install webp

在 Windows 系统上，您可能会在安装过程中遇到以下错误:

conans.errors.ConanException: 'settings.compiler' value not defined

这意味着您需要安装一个 C 编译器，并配置 Conan 以便它知道使用哪个编译器。详见 anibali#20 for more details.

依赖

• Python 3.8+

使用

import webp

示例 API

# 保存图像
webp.save_image(img, 'image.webp', quality=80)

# 加载图像
img = webp.load_image('image.webp', 'RGBA')

# 保存动画
webp.save_images(imgs, 'anim.webp', fps=10, lossless=True)

# 加载动画
imgs = webp.load_images('anim.webp', 'RGB', fps=10)

如果您更喜欢使用numpy数组，请使用函数imwrite、imread、mimwrite和mimread。

高级 API

# 将PIL图像编码为内存中的WebP，并添加编码器提示
pic = webp.WebPPicture.from_pil(img)
config = WebPConfig.new(preset=webp.WebPPreset.PHOTO, quality=70)
buf = pic.encode(config).buffer()
# 读取WebP文件并将其解码为BGR numpy数组
with open('image.webp', 'rb') as f:
  webp_data = webp.WebPData.from_buffer(f.read())
  arr = webp_data.decode(color_mode=WebPColorMode.BGR)
# 保存动画
enc = webp.WebPAnimEncoder.new(width, height)
timestamp_ms = 0
for img in imgs:
  pic = webp.WebPPicture.from_pil(img)
  enc.encode_frame(pic, timestamp_ms)
  timestamp_ms += 250
anim_data = enc.assemble(timestamp_ms)
with open('anim.webp', 'wb') as f:
  f.write(anim_data.buffer())
# 加载动画
with open('anim.webp', 'rb') as f:
  webp_data = webp.WebPData.from_buffer(f.read())
  dec = webp.WebPAnimDecoder.new(webp_data)
  for arr, timestamp_ms in dec.frames():
    # `arr` 包含了解码后的帧像素
    # `timestamp_ms` 包含了帧的结束时间
    pass

功能特点

• 图像编码/解码
• 动画编码/解码
• 自动内存管理
• 用于操作PIL.Image对象的简单API

未实现的功能

• 在YUV色彩模式下编码/解码静态图像
• 高级复用/解复用（色彩配置文件等）
• 暴露所有有用的字段

开发者笔记

设置

1. Install mamba and conda-lock. The easiest way to do this is by installing Mambaforge and then running mamba install conda-lock. 安装mamba和conda-lock。最简单的方法是安装Mambaforge，然后运行mamba install conda-lock。
2. 创建并激活Conda环境:

   $ conda-lock install -n webp
   $ mamba activate webp

3. 安装PyPI依赖项:

   $ pdm install -G:all

运行测试

$ pytest tests/

Cutting a new release

1. Ensure that tests are passing and everything is ready for release.
2. Create and push a Git tag:

   $ git tag v0.1.6
   $ git push --tags

3. Download the artifacts from GitHub Actions, which will include the source distribution tarball and binary wheels.
4. Create a new release on GitHub from the tagged commit and upload the packages as attachments to the release.
5. Also upload the packages to PyPI using Twine:

   $ twine upload webp-*.tar.gz webp-*.whl

6. Bump the version number in pyproject.toml and create a commit, signalling the start of development on the next version.

These files should also be added to a GitHub release.

Known issues

• An animation where all frames are identical will "collapse" in on itself, resulting in a single frame. Unfortunately, WebP seems to discard timestamp information in this case, which breaks webp.load_images when the FPS is specified.
• There are currently no 32-bit binaries of libwebp uploaded to Conan Center. If you are running 32-bit Python, libwebp will be built from source.