将txt文件读入R中的数据帧(reading txt file into data frame in R)

 据我所知，没有直接的方法来确定是否可以嵌入字体。 我做了一个快速搜索，除了使用Erik在评论中提到的异常catch方法之外，我认为不可能。 
 
 // 1) have a list of all fonts ArrayList allAvailableFonts;
 // 2) second list of fonts that that can be embedded ArrayList embedableFonts;

//Iterate through every available font in allAvailableFonts

for( .... allAvailableFonts ..... )
{
   boolean isFontEmbeddable = true;
   try
   {
          // try to embed the font
   }
   catch( DocumentException de)
   {
        //this font cannot be embedded
        isEmbeddable = false;
   } 

   if( isEmbeddable )
   {
       // add to list of embeddable fonts
       embedableFonts.add ( font );
   }
}
 
 您可以真正去硬核并执行对Windows Apis的本机调用以获得相同的结果，但我认为这对于一个简单的任务来说太多了。 
 
 做了一些研究，发现Java如何抛出这个异常 
 
 可以在此处找到生成上述异常的代码。 http://kickjava.com/src/com/lowagie/text/pdf/TrueTypeFont.java.htm行号367,368 
 
if (!justNames && embedded && os_2.fsType == 2)
     throw new DocumentException(fileName + style + " cannot be embedded due to licensing restrictions.");
 
 需要注意的有趣部分是条件os_2.fsType == 2 
 
 os_2是WindowsMetrics一个实例，请参见第174行http://kickjava.com/src/com/lowagie/text/pdf/TrueTypeFont.java.htm 
 
 在Google中搜索WindowsMetrics，这就是我所获得的。 
 
 这解释了参数fsType保存了是否可以嵌入字体的信息。 http://www.microsoft.com/typography/otspec/os2ver3.htm#fst 
 
 在itext中使用的java等价的WindowsMetrics http://www.docjar.org/docs/api/com/lowagie/text/pdf/TrueTypeFont.WindowsMetrics.html 

As far as I can tell there is no direct way to identify whether a font can be embedded. I did a quick search and I don't think it is possible other than using the exception catch method as mentioned by Erik in the comments.
 
 // 1) have a list of all fonts ArrayList allAvailableFonts;
 // 2) second list of fonts that that can be embedded ArrayList embedableFonts;

//Iterate through every available font in allAvailableFonts

for( .... allAvailableFonts ..... )
{
   boolean isFontEmbeddable = true;
   try
   {
          // try to embed the font
   }
   catch( DocumentException de)
   {
        //this font cannot be embedded
        isEmbeddable = false;
   } 

   if( isEmbeddable )
   {
       // add to list of embeddable fonts
       embedableFonts.add ( font );
   }
}
 
You can probably go really hardcore and execute native calls to Windows Apis to get the same result, but I think its too much work for a simple task as this.
 
Did some research and found out how this exception is thrown by Java
 
The code which generates the above exception can be found here. http://kickjava.com/src/com/lowagie/text/pdf/TrueTypeFont.java.htm Line number 367,368
 
if (!justNames && embedded && os_2.fsType == 2)
     throw new DocumentException(fileName + style + " cannot be embedded due to licensing restrictions.");
 
The interesting part to note is the condition os_2.fsType == 2
 
os_2 is an instance of WindowsMetrics see line 174 here http://kickjava.com/src/com/lowagie/text/pdf/TrueTypeFont.java.htm
 
A search for WindowsMetrics in Google and this was what I got.
 
This explains that the parameter fsType holds information whether font can be embedded. http://www.microsoft.com/typography/otspec/os2ver3.htm#fst
 
The java equivalent of WindowsMetrics as used in itext http://www.docjar.org/docs/api/com/lowagie/text/pdf/TrueTypeFont.WindowsMetrics.html