图像库从JPEG转换为 [英] Image Library convert from JPEG to

问题描述

我正在尝试将带有200 dpi的JPEG文件转换为PDF文件，但是，当我将文件另存为PDF时，我认为它将dpi更改为72，从而使图像更大。我最初尝试将JPEG图像缩放到较小的尺寸时遇到了类似的问题，并且能够通过在保存图像时指定dpi来解决这个问题。

I'm attempting to convert a JPEG file with, 200 dpi, to a PDF file, however, when I save the file as a PDF I think it's changing the dpi to 72, and thus making the image larger. I had a similar problem when initially trying to scale my JPEG image to a smaller size, and was able to solve that by specifying the dpi when I save the image.

im = Image.open("Image.jpg")

dpi=im.info['dpi']

if im.size == (2592, 1728):
    out = im.resize((1188,792), Image.ANTIALIAS)
elif im.size == (1728,2592):
    out = im.resize((792,1188), Image.ANTIALIAS)

out.save(project, dpi=dpi)

现在，当我尝试将此JPEG格式保存为PDF时，指定dpi似乎没有任何区别，我得到的图像比我原来的图像看起来更像dpi较低。使用PIL从JPEG转换为PDF时，有没有办法保持一致的分辨率？或者有更好的方法让我这样做吗？

Now when I try to save this JPEG as a PDF, specifying the dpi doesn't seem to make any difference, and I get an image that is larger than my original that looks like it has a lower dpi. Is there a way to mantain a consistent resolution when converting from JPEG to PDF using PIL? Or is there a better way for me to go about doing this?

这就是我将文件目录从JPEG转换为PDF的原因：

This is what I have for converting a directory of files from JPEG to PDF:

for infile in listing:

    outfile = destpath + os.path.splitext(infile)[0] + ".pdf"
    current = path + infile

    if infile != outfile:
        im = Image.open(current)
        dpi=im.info['dpi']

        im.save(outfile, "PDF", Quality = 100)

推荐答案

在 PIL 1.1.7 的CHANGES文件中，可以读取：

In the CHANGES file of PIL 1.1.7 sources one can read:

• 为PDF文件添加了分辨率保存选项。

• Added resolution save option for PDF files.

Andreas Kostyrka写道：我' ve包括一个修补的PdfImagePlugin.py

，基于1.1.6，包含在Ubuntu中，支持分辨率

保存选项。不是很好，但它使PDF保存更有用，因为
允许不完全是72dpi的PDF。

Andreas Kostyrka writes: I've included a patched PdfImagePlugin.py
based on 1.1.6 as included in Ubuntu, that supports a "resolution"
save option. Not great, but it makes the PDF saving more useful by
allowing PDFs that are not exactly 72dpi.

所以你应该可以这样做：

So you should be able to do:

im.save(outfile, "PDF", resolution=100.0)

（似乎在我的Ubuntu盒子上工作正常）。

(seems to work fine on my Ubuntu box).

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