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.

我已经在计算机上安装了Ghostscript 9.01.

I have installed Ghostscript 9.01 in my machine.

请逐步指导我(从调用Ghostscript开始)以裁剪具有特定坐标的PDF.

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

我什至不熟悉Ghostscript.

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

假设页面大小为A4.然后，媒体尺寸为:

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

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

假设您要裁剪:

   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

然后您的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

或在Linux上:

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] .在这种情况下，您还可以尝试以下命令:

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

---

[^] :_{更具体地说:它不适用于已将其/CropBox定义为特定值的PDF.解决此问题的肮脏办法是，在运行上述GS命令之前，使用文本编辑器将所有需要的页面的字符串/CropBox更改为/cROPBoX(或类似的大小写更改).大小写更改可以有效地撤消" cropbox设置(无需更改任何使现有xref表无效的PDF对象偏移量)，因此PDF渲染器不再考虑该设置.}

---

[^] : _{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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