电子书pdf文件网站_如何转换PDF文件以便于阅读电子书

电子书pdf文件网站

Many ebook readers natively support PDF documents but, unfortunately, not all PDF documents are easy to read on a small ebook reader screen. Let’s take a look at two simple and free ways to convert PDF files for enjoyable reading.

许多电子书阅读器本机都支持PDF文档，但不幸的是，并非所有PDF文档都易于在小的电子书阅读器屏幕上阅读。 让我们看一下两种简单而免费的方式来转换PDF文件以获得愉悦的阅读效果。

Kindles, Nooks, Sony Pocket Readers, and other popular readers support native PDF rendering. The problem with native rendering, however, is that many PDF documents are formatted to be read on a large screen or printed and read in hard copy. Large margins, multiple columns, and other formatting choices that aren’t such a big deal when the document in printed on 8.5×11 paper or displayed on a 20” monitor render the document almost unreadable when loaded into an e-reader with a 6” screen. Today we’re going to look at two ways you can re-format a PDF file for enjoyable reading on your favorite reader.

Kindle，Nooks，Sony Pocket Reader和其他流行的阅读器均支持本机PDF呈现。 但是，本机渲染的问题在于，许多PDF文档被格式化为在大屏幕上阅读或打印并以硬拷贝阅读。 当文档以8.5×11的纸张打印或以20英寸的显示器显示时，大页边距，多列和其他格式选择不是什么大问题，当将文档加载到带有6的电子阅读器中时，文档几乎不可读”屏幕。 今天，我们将探讨两种重新格式化PDF文件的方式，以便在您喜欢的阅读器上阅读愉快。

你需要什么 (What You’ll Need)

For our tutorial you’ll need the following things:

对于我们的教程，您需要满足以下条件：

• A copy of ebook management software Calibre.

  电子书管理软件Calibre的副本。

• A copy of K2pdfopt.

  K2pdfopt的副本。

• A PDF file to convert.
  要转换的PDF文件。
• An e-reader to try the file out on.
  一个电子阅读器，可以试用该文件。

We suggest keep a clean copy of your PDF test file in a separate directory so if all your conversion attempts go awry you’ll have the original safe and sound.

我们建议您将PDF测试文件的干净副本保存在单独的目录中，这样，如果所有转换尝试都出错了，您将拥有原始的安全和声音。

使用口径转换

(Converting Using Calibre)

Calibre is an awesome and open source ebook management tool. If you’ve read this far and have no intention of even mucking around with any PDF files you should go and download it regardless. It’s a fantastic tool for managing ebooks and ebook readers. What we’re interested in, book management aside, is the conversion tool built into Calibre.

Caliber是一款很棒的开源电子书管理工具。 如果您已经读了那么多书，甚至不想弄乱任何PDF文件，那么无论如何都应该去下载它。 这是管理电子书和电子书阅读器的绝佳工具。 除了书本管理之外，我们感兴趣的是Calibre中内置的转换工具。

If you’re totally new to using Calibre and need help installing it and getting your books into it, check out one of our previous Calibre-based guides to get started. Once you’ve installed it and you’ve loaded up a book you want to convert it’s time to get converting.

如果您对使用Calibre完全陌生，并且需要帮助来安装和使用它，请查看我们以前基于Calibre的指南之一，以开始使用。 安装完书并加载书后，您就可以进行转换了。

For our example we’ll be using a particularly complex textbook (multiple columns, charts, graphic headers for each chapter, etc.) and a Kindle. First let’s look at what the original PDF file looks like on the Kindle screen.

对于我们的示例，我们将使用一本特别复杂的教科书(多章，图表，每章的图形标题等)和Kindle。 首先，让我们看看Kindle屏幕上原始PDF文件的外观。

That’s eye-squintingly small on a large monitor screen and nearly illegible on a Kindle screen. There’s no way we could comfortable read that on a 6” kindle screen without serious eye strain and a headache. Let’s see if we can convert it with Calibre.

在大型显示器屏幕上，该尺寸很小，而在Kindle屏幕上，几乎难以辨认。 在没有严重眼疲劳和头痛的情况下，我们不可能在6英寸的点燃屏幕上轻松地阅读到它。 让我们看看是否可以使用Calibre进行转换。

Open Calibre and right click on the book. Select Convert Books –> Convert individually. Here you’ll find an enormously detailed menu with toggles and settings galore. It’s easy to get overwhelmed and some of the settings are pretty arcane if you’re unfamiliar with printing terms and/or search string expressions. For the first conversion stick with the default settings and convert between PDF and a suitable format for your ebook reader or even PDF to PDF to restructure multi-column PDF files into a more streamlined document.

打开口径，然后在书上单击鼠标右键。 选择转换书籍–>单独转换 。 在这里，您会发现一个非常详细的菜单，其中包含丰富的切换和设置。 很容易不知所措，如果您不熟悉打印术语和/或搜索字符串表达式，则某些设置非常不可思议。 对于第一次转换，请使用默认设置，并在PDF和适合您的电子书阅读器的合适格式之间进行转换，甚至将PDF转换为PDF，以将多列PDF文件重组为更简化的文档。

When it’s done converting you can check the formatting on your computer by double clicking on the converted file in the right hand book information column or you can transfer it to your device. We transferred it to the device to get a real sense of how it looked on the page.

转换完成后，您可以通过在右手簿信息列中双击转换后的文件来检查计算机上的格式，也可以将其传输到设备中。 我们将其转移到设备上以真实了解页面上的外观。

Although we’ve used Calibre to convert hundreds of ebooks over the last few years with very few problems this particular PDF file proved to be a real challenge for it. The multiple columns, odd formatting choices, and other factors really stumped Calibre.

尽管在过去几年中我们使用Calibre转换了数百本电子书，但几乎没有问题，但事实证明，这种特殊的PDF文件确实是一个挑战。 多列，奇数格式选择和其他因素确实困扰着Calibre。

While Calibre normally does a fine job converting PDF files we picked one of the most difficult to convert PDFs we had on hand to demonstrate that things don’t always go as planned. We also picked a really hard to convert PDF so that we could in turn show off the next tool in our tutorial, K2pdfopt. It’s like the nuclear option when the normally reliable Calibre fails to crank out a working conversion.  If you find yourself in a similar boat, your complex PDF document didn’t turn out right, you’ll likely be thrilled with K2pdfopt.

尽管Calibre通常在转换PDF文件方面做得很好，但我们选择了现有的最难转换的PDF之一，以证明事情并非总是按计划进行。 我们还选择了一个很难转换的PDF，这样我们就可以在本教程中炫耀下一个工具K2pdfopt。 当通常可靠的Calibre无法启动有效的转换时，这就像核选项。 如果您发现自己遇到了类似情况，那么复杂的PDF文档并没有得到正确的显示，您可能会对K2pdfopt感到兴奋。

使用K2pdfopt转换优化PDF文件 (Converting Optimizing PDF files using K2pdfopt)

First, we want to give a big thanks to Abhijeet at Guiding Tech; we’d been looking for a tool like this and he tipped us off at just the right time. K2pdfopt is designed to optimize PDF documents for small screen e-readers. Rather than convert the document into raw text and try to reformat it, it instead carefully crops and realigns the pieces as though they were a series of images. The end result is a new PDF file that is really true to the original document and free from odd OCR blunders (as it doesn’t attempt to convert or reflow the text).

首先，我们要感谢Guiding Tech的Abhijeet ； 我们一直在寻找这样的工具，他在适当的时候给了我们提示。 K2pdfopt旨在为小屏幕电子阅读器优化PDF文档。 与其将文档转换为原始文本并尝试对其重新格式化，不如仔细地裁剪并重新排列各个部分，就好像它们是一系列图像一样。 最终结果是一个新的PDF文件，该文件对原始文档真正适用，并且没有奇怪的OCR错误(因为它不尝试转换或重排文本)。

Using K2pdfopt is a snap. Extract the executable into a folder, drag a PDF file onto the EXE and let it work—as seen in the screenshot above. We dropped the same difficult to format textbook PDF into K2pdfopt and crossed our fingers. Given how much Calibre struggled with the document we weren’t sure what to expect. When the conversion completed (you’ll see a copy of your PDF file with the file named annotated like filename_k2opt.pdf in the K2pdfopt folder) we copied it over to our Kindle and were shocked at how well it handled the complex text we threw at it.

使用K2pdfopt很简单。 将可执行文件解压缩到一个文件夹中，将PDF文件拖到EXE上并让其工作-如上面的屏幕截图所示。 我们将同样难以格式化的教科书PDF放到K2pdfopt中，然后用手指交叉。 鉴于Calibre在处理文档方面有多少困难，我们不确定会发生什么。 转换完成后(您会在K2pdfopt文件夹中看到一个名为filename_k2opt.pdf的带注释文件的PDF文件的副本)，我们将其复制到了Kindle上，并对它处理复杂文本的效果感到震惊它。

The text is slightly less crisp than in our PDF to MOBI conversion (see the screen capture in the Calibre section) but it is all there, with proper formatting, and without any screwy OCR errors. Thanks to K2pdfopt we went from having a PDF that was illegible on the Kindle to having a PDF that was as easy to read as a clean photocopy.

文本的清晰度不如我们的PDF到MOBI转换(请参见“口径”部分的屏幕截图)中的内容一样，但都以正确的格式存在，没有任何螺丝错误的OCR错误。 由于有了K2pdfopt，我们从Kindle上难以辨认的PDF变成了像干净的影印本一样易于阅读的PDF。

The only downside we could find in using K2pdfopt was the increase in file size. A 15MB PDF file, when converted with K2pdfopt, ballooned to 93MB. When you consider how few conversions Calibre doesn’t properly handle and how few books we’d need to actually send through the K2pdfopt image-based conversion process, though, it’s not a bad trade off. We can stand to increase the file size on a few PDFs in order to gain access to a portable and easily read copy.

我们使用K2pdfopt时发现的唯一弊端是文件大小的增加。 用K2pdfopt转换时，一个15MB的PDF文件会膨胀为93MB。 不过，当您考虑Caliber无法正确处理多少转换以及我们实际上需要通过基于K2pdfopt基于图像的转换过程发送的书籍数量时，这并不是一个不好的折衷。 我们可以增加一些PDF的文件大小，以便获得可移植且易于阅读的副本。

Update: Shortly after this article went live on the site Marcus wrote in and asked

更新：本文在网站上发布之后不久，Marcus在其中写道并询问

What if you took the K2pdfopt.exe output and ran the resulting PDF through Calibre again to convert it to a MOBI or ePUB? Maybe that would stop Calibre from choking on the multi-column format since it would now be formatted more like a standard book. Could you guys try it out?

如果您获取了K2pdfopt.exe输出，并再次通过Caliber运行生成的PDF以将其转换为MOBI或ePUB，该怎么办？ 也许这将阻止Calibre停止使用多列格式，因为它现在的格式更像是一本标准书。 你们可以尝试一下吗？

What if, Marcus? What if, indeed. We dove in deeper, Inception-style, and performed a test just as you requested. Calibre handled the conversion beautifully and the text cleaned up perfectly. How perfectly? Here’s a snippet of the text seen in the screenshot above (which is properly formatted but a little grainy) after the reconversion process:

如果，马库斯？ 如果的确如此。 我们以更深入的入门风格进行了测试，并按照您的要求进行了测试。 Calibre很好地处理了转换，并且文本完美地清理了。 多么完美？ 这是上面的屏幕快照中经过重新转换后的文本的一部分(格式正确，但有点粗糙)：

And there you have it. For a particularly tricky PDF file you can run it through K2pdfopt.exe, then dump it back into Calibre for a cleanup pass (check out how smooth the font is now in the above sample), and enjoy a totally optimized PDF. Good call, Marcus! The extra step only adds a few minutes to the process and really tidies things up.

那里有。 对于特别棘手的PDF文件，您可以通过K2pdfopt.exe运行它，然后将其转回Caliber以进行清理(检查上面示例中的字体现在有多平滑)，并享受完全优化的PDF。 打个招呼，马库斯！ 额外的步骤仅增加了几分钟的时间，并真正整理了一切。

Have a conversion tip, trick, or tool to share? We’re interested to hear about it so shoot us an email at [email protected] or sound off about it in the comments here.

有转换技巧，窍门或工具可以分享吗？ 我们很想听到有关它的信息，所以请给我们发送电子邮件，电子邮件地址为[email protected]，或在此处的评论中取消它。

翻译自: https://www.howtogeek.com/69481/how-to-convert-pdf-files-for-easy-ebook-reading/

电子书pdf文件网站