如何在 PDF 中输出欧元符号
我正在尝试使用 Core Graphics 将欧元符号输出到 PDF。我有以下代码，它使用 NSMacOSRomanStringEncoding （我必须使用它来使 £ 和 $ 符号正确显示），但欧元符号显示为 ¤
CGRect pageRect = CGRectMake(0, 0, 800, 1150);
CFMutableDataRef pdfData = (CFMutableDataRef) [NSMutableData dataWithCapacity:0];
CGDataConsumerRef dataConsumer = CGDataConsumerCreateWithCFData(pdfData);
CGContextRef pdfContext = CGPDFContextCreate(dataConsumer, &pageRect, nil);
CGContextSelectFont(pdfContext, "Helvetica", 15, kCGEncodingMacRoman);
CGContextSetTextDrawingMode (pdfContext, kCGTextFill);
CGContextSetRGBFillColor (pdfContext, 0, 0, 0, 1);
const char *ctext = [@"€" cStringUsingEncoding:NSMacOSRomanStringEncoding];
CGContextShowTextAtPoint(pdfContext, 10, 10, ctext, strlen(ctext));
I am trying to output a Euro symbol to a PDF using Core Graphics. I have the following code, which uses NSMacOSRomanStringEncoding (I had to use this to get £ and $ symbols to appear correctly), but the Euro symbol comes out as ¤
CGRect pageRect = CGRectMake(0, 0, 800, 1150);
CFMutableDataRef pdfData = (CFMutableDataRef) [NSMutableData dataWithCapacity:0];
CGDataConsumerRef dataConsumer = CGDataConsumerCreateWithCFData(pdfData);
CGContextRef pdfContext = CGPDFContextCreate(dataConsumer, &pageRect, nil);
CGContextSelectFont(pdfContext, "Helvetica", 15, kCGEncodingMacRoman);
CGContextSetTextDrawingMode (pdfContext, kCGTextFill);
CGContextSetRGBFillColor (pdfContext, 0, 0, 0, 1);
const char *ctext = [@"€" cStringUsingEncoding:NSMacOSRomanStringEncoding];
CGContextShowTextAtPoint(pdfContext, 10, 10, ctext, strlen(ctext));
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那是因为
MacRomanEncoding默认情况下不包含欧元符号，请参阅“PDF 参考 1.7”（第 D.1 节拉丁字符集和编码）中的引用：Thats because
MacRomanEncodingdoesn't contain euro symbol by default, see this quote from "PDF reference 1.7" (Section D.1 Latin Character Set and Encodings):您应该能够使用 CGContextShowGlyphsAtPoint 来绘制欧元符号。问题是您需要向该函数传递一个
CGGlyph作为输入，而不是一个 Unicode 字符。此外，从 Unicode 字符到CGGlyphs的映射依赖于字体，而且通常很重要。 （有时它是一个简单的偏移量，您可以根据试验和错误来猜测。）看起来 Core Text 有一个函数
CTFontGetGlyphsForCharacters可以执行转换；不过，我从未在实践中使用过它：http://developer.apple.com/library/mac/#documentation/Carbon/Reference/CTFontRef/Reference/reference.html
另外：如果您使用
CGContextShowGlyphsAtPoint您需要将对CGContextSelectFont的调用替换为CGContextSetFont和CGContextSetFontSize。You should be able to use
CGContextShowGlyphsAtPointto draw the Euro symbol. The catch is that you need to pass that function aCGGlyphas input, rather than a Unicode character. Furthermore, the mapping from Unicode characters toCGGlyphsis font-dependent and often nontrivial. (Sometimes it's a simple offset that you can guess based on trial and error.)It looks like Core Text has a function
CTFontGetGlyphsForCharacterswhich might perform the transformation; I've never used it in practice, though:http://developer.apple.com/library/mac/#documentation/Carbon/Reference/CTFontRef/Reference/reference.html
Also: if you use
CGContextShowGlyphsAtPointyou will need to replace the call toCGContextSelectFontwithCGContextSetFontandCGContextSetFontSizeinstead.