如何拍摄图像并从中心裁剪出3x2比例的图像? [英] How can I take an image and get a 3x2 ratio image cropped from the center?

问题描述

有没有简单的方法可以做到这一点? 在Python中，我创建了一个脚本，用于从图像中获取方盒" ...基于中心.

Is there an easy way to do this? In Python, I created a script to get a "square box" from an image...based on the center.

但是，那杀死了我的一些脑细胞.是否有一种简单的方法可以根据中心为3x2(3宽度，2高度)执行此操作?

However, that killed some of my brain cells. Is there an easy way to do this for a 3x2 (3 width, 2 height), based on the center?

这是我的方框"脚本，但我不想为3x2修改它.

This is my "square box" script, but I don't feel like modifying it for the 3x2.

def letterbox(f,thumb_w=None,thumb_h=None):
    try:
        im = Image.open(StringIO(f))
        imagex = int(im.size[0])
        imagey = int(im.size[1])
        thumb_size = (thumb_w,thumb_h) #what if it is too small!?? fix it.
        if imagex > imagey:
            setlen = imagey
            left = (imagex - setlen)/2
            top = 0
            height = setlen
            width = setlen
        if imagey > imagex:
            setlen = imagex
            left = 0
            top = (imagey - setlen)/2
            heigth = setlen
            width = setlen
        if imagex == imagey:
            left = 0
            top = 0
            height = imagey
            width = imagex
        box = (left,top,left+width,top+height)
        im = im.crop(box)
        #im.thumbnail(thumb_size,Image.ANTIALIAS)
        new_file = StringIO()
        im.save(new_file,'JPEG')
        new_file.seek(0)
    except Exception, e:
        pass
    return new_file

在线上有可以满足我需要的脚本吗?

Is there a script online that can do what I need?

推荐答案

使用定义为imagex/imagey的宽高比，因此您将3/2用于3:2，将16/9用于16:9等./p>

Use an aspect ratio which is defined as imagex/imagey, so you use 3/2 for 3:2, 16/9 for 16:9 etc.

def letterbox(f,aspect_ratio=1):
    try:
        im = Image.open(StringIO(f))
        imagex = int(im.size[0])
        imagey = int(im.size[1])
        width = min(imagex, imagey*aspect_ratio)
        height = min(imagex/aspect_ratio, imagey)
        left =(imagex - width)/2
        top = (imagey - height)/2
        box = (left,top,left+width,top+height)
        im = im.crop(box)
        new_file = StringIO()
        im.save(new_file,'JPEG')
        new_file.seek(0)
    except Exception, e:
        pass
    return new_file

您可能希望在某个时候检查舍入错误，但否则会这样做.

You might want to check for roundoff errors at some point, but otherwise this does it.

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