使用 Ghostscript 9.01 裁剪 PDF [英] Cropping a PDF using Ghostscript 9.01

问题描述

我不是程序员，但想学习如何使用 Ghostscript 裁剪 PDF.

I am not a programmer, but would like to learn how to crop a PDF using Ghostscript.

我已经在我的机器上安装了 Ghostscript 9.01.

I have installed Ghostscript 9.01 in my machine.

请指导我逐步(从调用 Ghostscript 开始)使用特定坐标裁剪 PDF.

Please guide me step by step process (starting from invoking Ghostscript) to crop a PDF with the specific coordinates.

我什至是 Ghostscript 的新手.

I am even new to Ghostscript.

推荐答案

首先，请注意 PDF 的度量单位与 PostScript 相同:称为 point [pt].

First, take note that the measurement unit for PDF is the same as for PostScript: it's called a point [pt].

72 points == 1 inch == 25.4 millimeters

假设您的页面大小为 A4.那么媒体维度是:

Assuming you have a page size of A4. Then the media dimensions are:

595 points width  == 210 millimeters
842 points height == 297 millimeters

假设你想剪掉:

   left edge: 24 points == 1/3 inch ~=  8.5 millimeters
  right edge: 36 points == 1/2 inch ~= 12.7 millimeters
    top edge: 48 points == 2/3 inch ~= 17.0 millimeters
 bottom edge: 72 points ==   1 inch ~= 25.4 millimeters

那么你的 Ghostscript 命令行是这样的(在 Windows 上):

Then your Ghostscript commandline is this (on Windows):

gswin32c.exe                     ^
  -o cropped.pdf                 ^
  -sDEVICE=pdfwrite              ^
  -c "[/CropBox [24 72 559 794]" ^
  -c " /PAGES pdfmark"           ^
  -f uncropped-input.pdf

或者在 Linux 上:

Or on Linux:

gs                               
  -o cropped.pdf                 
  -sDEVICE=pdfwrite              
  -c "[/CropBox [24 72 559 794]" 
  -c " /PAGES pdfmark"           
  -f uncropped-input.pdf

但是，这可能不适用于所有类型的 PDF^[1].在这些情况下，您也应该尝试以下命令:

However, this may not work reliably for all types of PDFs ^[1]. In those cases you should alternatively try these commands:

gswin32c.exe                 ^
  -o cropped.pdf             ^
  -sDEVICE=pdfwrite          ^
  -dDEVICEWIDTHPOINTS=595    ^
  -dDEVICEHEIGHTPOINTS=842   ^
  -dFIXEDMEDIA               ^
  -c "24 72 translate"       ^
  -c " 0 0 535 722 rectclip" ^
  -f uncropped-input.pdf

或

gs                           
  -o cropped.pdf             
  -sDEVICE=pdfwrite          
  -dDEVICEWIDTHPOINTS=595    
  -dDEVICEHEIGHTPOINTS=842   
  -dFIXEDMEDIA               
  -c "24 72 translate"       
  -c " 0 0 535 722 rectclip" 
  -f uncropped-input.pdf

<小时>

[^] : _{更具体地说:它不适用于带有自己的 /CropBox 的 PDF已经定义为特定值.一个肮脏的黑客是在运行之前使用文本编辑器更改所有需要 /cROPBoX(或类似的大小写更改)的页面的字符串 /CropBox上面的 GS 命令.大小写更改有效地解除"了cropbox 设置(不更改任何使现有xref 表无效的PDF 对象偏移量)，因此PDF 渲染器不再考虑它.}

---

[^] : _{To be more specific: it will not work for PDFs which come along with their own /CropBox already defined to specific values. A dirty hack around that is to change the string /CropBox for all pages where it is desired to /cROPBoX (or similar case-changing) with a text editor prior to running the above GS command. The case-change effectively "disarms" the cropbox setting (without changing any PDF object offsets invalidating the existing xref table) so it is no longer considered by PDF renderers.}

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