PDF：如何优化文件大小和转换为PNG（嵌入字体问题）

问题描述

我有一个嵌入字体的PDF，似乎无法使用。现在，我正在使用GhostScript并尝试做两件事：

I have a PDF with embedded fonts that I can't seem to work with. Right now, I'm using GhostScript and trying to do 2 things:

• 最小化PDF的文件大小：

• Minimize filesize of PDF:

gswin32c -dSAFER -dBATCH -dNOPAUSE -dQUIET -sDEVICE = pdfwrite -sOutputFile = output.pdf input.pdf

gswin32c -dSAFER -dBATCH -dNOPAUSE -dQUIET -sDEVICE=pdfwrite -sOutputFile=output.pdf input.pdf

将PDF转换为PNG（超级样本，用于创建其他缩略图）：

Convert PDF to PNG (super sample, to be used for creating other thumbnails):

gswin32c -dSAFER -dBATCH -dNOPAUSE -dQUIET -dFirstPage = 1 -dLastPage = 1 - r288 -sDEVICE = png16m -sOutputFile = output.pdf input.pdf

gswin32c -dSAFER -dBATCH -dNOPAUSE -dQUIET -dFirstPage=1 -dLastPage=1 -r288 -sDEVICE=png16m -sOutputFile=output.pdf input.pdf

以上在处理扫描文档时效果很好。但是当我针对带有嵌入字体的PDF（PDF是由应用程序即时生成）运行它时，它会失败。这是我得到的错误：

The above works well when working on scanned documents. But when I run them against PDFs with embedded fonts (the PDF is generated on the fly by an application), it fails. Here's the error I get:

GPL Ghostscript 8.71: Warning: 'loca' length 274 is greater than numGlyphs 136 i
n the font UUGHDE+ArialMT.
GPL Ghostscript 8.71: Warning: 'loca' length 274 is greater than numGlyphs 136 i
n the font UUGHDE+ArialMT.
GPL Ghostscript 8.71: Warning: 'loca' length 188 is greater than numGlyphs 93 in
 the font UUGHDE+Arial-BoldMT.
GPL Ghostscript 8.71: Warning: 'loca' length 188 is greater than numGlyphs 93 in
 the font UUGHDE+Arial-BoldMT.

除了GhostScript，我还可以访问PDFTK和ImageMagick（可能会被GraphicsMagick取代）。我也对其他解决方案持开放态度。

Aside from GhostScript, I also have access to PDFTK and ImageMagick (which might be replaced with GraphicsMagick). I'm also open to other solutions.

开发在WAMP上。部署到LAMP。

Development is on WAMP. Deployment is to LAMP.

建议？

推荐答案

使用的字体你的PDF内部似乎是OpenType字体。创建这些PDF的软件似乎已经对字体进行了子集化。在通过该软件进行字体嵌入和子集化（即时生成PDF - 它是否也是Ghostscript？！？）时，似乎出现了一个问题，使其不符合规范100％。

The fonts used inside your PDFs seem to be OpenType fonts. The software that created these PDFs seems to have subsetted the fonts. During font embedding and subsetting by this software (which "generates the PDFs on the fly" -- was it also Ghostscript?!?), there seems to have occurred a problem that made it to not comply 100% with the specification.

'loca'表是OpenType字体描述的一部分。它们代表所有字形位置的索引。

'loca' tables are part of OpenType Font descriptions. They represent an index to all glyph locations.

现在使用Ghostscript处理这些不完全'kosher'的PDF。 Ghostscript发出警告，但没有错误。

Now you process these not completely 'kosher' PDFs with Ghostscript. Ghostscript gives out warnings, but no errors.

GS错误通常意味着：我将中止进一步处理。我无法解决问题或修复这个损坏的文件。如果我已经编写了输出文件，它们将毫无用处。

GS errors usually mean: "I'll abort further processing. I can't work around a problem or repair this corrupt file. Should I have written output files already, they will be useless."

GS警告通常意味着：我遇到过但是我会继续处理输入并解决它。我已经编写了一个有效的输出文件。但你最好检查它，特别是它的保真度！

GS warnings usually mean: "I've encountered a problem. But I'll continue to process the input and work around it. I've written a valid output file. But you better check it, especially its fidelity!"

您看到的警告（不错误！）意味着：

The warnings (not errors!) you see mean this:

1. 其中一个有问题的子集化字体根据表格声明字形数为188。


2. 但实际上，实际的字体描述只包含93个字形的定义。

这篇关于PDF：如何优化文件大小和转换为PNG（嵌入字体问题）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！