Python PIL图片怎么按比例裁剪

这篇文章主要介绍"Python PIL图片怎么按比例裁剪"，在日常操作中，相信很多人在Python PIL图片怎么按比例裁剪问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答"Python PIL图片怎么按比例裁剪"的疑惑有所帮助！接下来，请跟着小编一起来学习吧！

PIL图片如何按比例裁剪

问题描述

如图片比例为 1:1 裁剪为 4:3

1.jpg

解决方案

from PIL import Imagedef image_clip(filename, savename, width_scale, height_scale):    """图像裁剪    :param filename: 原图路径    :param savename: 保存图片路径    :param width_scale: 宽的比例    :param height_scale: 高的比例    """    image = Image.open(filename)    (width, height), (_width, _height) = image.size, image.size    _height = width / width_scale * height_scale    if _height > height:        _height = height        _width = width_scale * height / height_scale    image.crop((0, 0, _width, _height)).save(savename)  # 左上角    # image.crop((0, height - _height, _width, height)).save(savename)  # 左下角    # image.crop((width - _width, 0, width, _height)).save(savename)  # 右上角    # image.crop((width - _width, height - _height, width, height)).save(savename)  # 右下角if __name__ == '__main__':    filename = '1.jpg'    savename = 'result.jpg'    image_clip(filename, savename, width_scale=4, height_scale=3)    # image_clip(filename, savename, width_scale=3, height_scale=4)

效果

PIL调整图片大小

使用 PIL 在图片比例不变的情况下修改图片大小。

介绍

Image.resize

def resize(self, size, resample=BICUBIC, box=None, reducing_gap=None):    """    Returns a resized copy of this image.    返回此图像的大小调整后的副本。    :param size: The requested size in pixels, as a 2-tuple:       (width, height).     param size: 请求的大小(以像素为单位)，是一个二元数组：(width, height)    :param resample: An optional resampling filter.  This can be       one of :py:attr:`PIL.Image.NEAREST`, :py:attr:`PIL.Image.BOX`,       :py:attr:`PIL.Image.BILINEAR`, :py:attr:`PIL.Image.HAMMING`,       :py:attr:`PIL.Image.BICUBIC` or :py:attr:`PIL.Image.LANCZOS`.       Default filter is :py:attr:`PIL.Image.BICUBIC`.       If the image has mode "1" or "P", it is       always set to :py:attr:`PIL.Image.NEAREST`.       See: :ref:`concept-filters`.     param resample: 一个可选的重采样过滤器。    :param box: An optional 4-tuple of floats providing       the source image region to be scaled.       The values must be within (0, 0, width, height) rectangle.       If omitted or None, the entire source is used.     param box: 可选的4元浮点数，提供要缩放的源映像区域。    :param reducing_gap: Apply optimization by resizing the image       in two steps. First, reducing the image by integer times       using :py:meth:`~PIL.Image.Image.reduce`.       Second, resizing using regular resampling. The last step       changes size no less than by ``reducing_gap`` times.       ``reducing_gap`` may be None (no first step is performed)       or should be greater than 1.0. The bigger ``reducing_gap``,       the closer the result to the fair resampling.       The smaller ``reducing_gap``, the faster resizing.       With ``reducing_gap`` greater or equal to 3.0, the result is       indistinguishable from fair resampling in most cases.       The default value is None (no optimization).     param reducing_gap: 通过两个步骤调整图像大小来应用优化。    :returns: An :py:class:`~PIL.Image.Image` object.     returns: 返回一个 PIL.Image.Image 对象    """

看代码吧

from PIL import Image  image = Image.open('图片路径') # 调整图片大小，并保持比例不变# 给定一个基本宽度base_width = 50 # 基本宽度与原图宽度的比例w_percent = base_width / float(image.size[0]) # 计算比例不变的条件下新图的长度h_size = int(float(image.size[1]) * float(w_percent)) # 重新设置大小# 默认情况下，PIL使用Image.NEAREST过滤器进行大小调整，从而获得良好的性能，但质量很差。image = image.resize((base_width, h_size), Image.ANTIALIAS)

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