ios – 如何使用Annots创建PDF？

2023年5月9日 210次阅读

我试图在具有注释的代码中生成PDF,例如小部件和链接.我可以生成PDF并修改文档信息和页面的MediaBox,但我无法弄清楚如何添加到Annotations.我尝试将其添加到页面字典中,但由于某种原因,PDF不接受它.

有谁知道如何为新创建的PDF添加注释？下面是我要生成PDF的代码和我试图添加到它的测试Annotation字典：

-(void) createPDFFile: (CGPDFPageRef) pageRef{

CGContextRef pdfContext;

CFStringRef path;

CFURLRef url;


CFMutableDictionaryRef myDictionary = NULL;

 NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
 NSString *documentsDirectory = [paths objectAtIndex:0]; // Get documents folder
 const char *filepath = [[documentsDirectory stringByAppendingString:@"/fileTest.pdf"] UTF8String];

path = CFStringCreateWithCString (NULL, filepath, kCFStringEncodingUTF8);

url = CFURLCreateWithFileSystemPath (NULL, path,  kCFURLPOSIXPathStyle, 0);

CFRelease (path);

myDictionary = CFDictionaryCreateMutable(NULL, 0,

                                         &kCFTypeDictionaryKeyCallBacks,

                                         &kCFTypeDictionaryValueCallBacks); 

CFDictionarySetValue(myDictionary, kCGPDFContextTitle, CFSTR("My PDF File"));

CFDictionarySetValue(myDictionary, kCGPDFContextCreator, CFSTR("My Name"));

CGRect pageRect = self.bounds;
pdfContext = CGPDFContextCreateWithURL (url, &pageRect, myDictionary); // 5

CFRelease(myDictionary);

CFRelease(url);

CGRect mediaBox;
mediaBox = CGRectMake (0, 0, pageRect.size.width, 100);
CFStringRef myKeys[1];

CFTypeRef myValues[1];

myKeys[0] = CFSTR("MediaBox");

myValues[0] = (CFTypeRef) CFDataCreate(NULL,(const UInt8 *)&mediaBox, sizeof (CGRect));

CFDictionaryRef pageDictionary = CFDictionaryCreate(NULL, (const void **) myKeys,
                                                    (const void **) myValues, 1,
                                                    &kCFTypeDictionaryKeyCallBacks,
                                                    & kCFTypeDictionaryValueCallBacks);
CFMutableDictionaryRef pageDictionaryMutable = CFDictionaryCreateMutableCopy(NULL, 0, pageDictionary);

CFMutableDictionaryRef  metaDataDictionary = CFDictionaryCreateMutable(NULL, 0, &kCFTypeDictionaryKeyCallBacks,&kCFTypeDictionaryValueCallBacks); 

CFDictionarySetValue(metaDataDictionary, CFSTR("DA"), CFSTR("/Helvetica 10 Tf 0 g"));
CFDictionarySetValue(metaDataDictionary, CFSTR("F"), CFSTR("4"));
CFDictionarySetValue(metaDataDictionary, CFSTR("FT"), CFSTR("Tx"));
CFDictionarySetValue(metaDataDictionary, CFSTR("Subtype"), CFSTR("Widget"));
CFDictionarySetValue(metaDataDictionary, CFSTR("T"), CFSTR("undefined"));
CFDictionarySetValue(metaDataDictionary, CFSTR("Type"), CFSTR("Annot"));
CFDictionarySetValue(metaDataDictionary, CFSTR("V"), CFSTR(""));
CFMutableArrayRef array = CFArrayCreateMutable(kCFAllocatorDefault,0, &kCFTypeArrayCallBacks);
CFArrayInsertValueAtIndex(array, 0, metaDataDictionary);

CFDictionarySetValue(pageDictionaryMutable, CFSTR("Annots"), array);


CGPDFContextBeginPage (pdfContext, pageDictionaryMutable);


CGPDFContextEndPage (pdfContext);

CGContextRelease (pdfContext);

CFRelease(pageDictionary);}

打印出CFMutableDictionary pageDictionaryMutable表示应该将Annots字典添加到PDF以及MediaBox：

(gdb) po pageDictionaryMutable
{
    Annots =     (
                {
            DA = "/Helvetica 10 Tf 0 g";
            F = 4;
            FT = Tx;
            Subtype = Widget;
            T = undefined;
            Type = Annot;
            V = "";
        }
    );
    MediaBox = <00000000 00000000 00008044 0000c842>;
}

Media Box需要,但Annots没有.请帮助任何人！

最佳答案 看看PoDoFo Library：
http://podofo.sourceforge.net

PoDoFo根据GPL和LGPL获得部分许可.

有了它,您可以修改pdf文件并为其添加注释.它可以移植到iOS.查看文档,它是否可以处理您想要的内容并查看其工作原理.

如果您有兴趣,也可以查看this sample project on GitHub.我将库集成到iOS项目中,您可以使用iPad添加FreeText和Square Annotations.

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