向 pdf 添加签名图像而不向 iOS 中的用户显示 pdf 数据

Question

我想在现有的 pdf 上添加签名。我通过以下方式做到了这一点：

1) 在 UIView 上加载现有的 pdf，比如 mainView。

2) 在 mainView 上添加签名图片。

3) 调用以下函数

-(NSMutableData *)getPDFDatafromUIView
{
DebugLog(@"");
// Creates a mutable data object for updating with binary data, like a byte array
NSMutableData *pdfData = [NSMutableData data];

// Points the pdf converter to the mutable data object and to the UIView to be converted
UIGraphicsBeginPDFContextToData(pdfData, mainView.bounds, nil);
UIGraphicsBeginPDFPage();
CGContextRef pdfContext = UIGraphicsGetCurrentContext();

// draws rect to the view and thus this is captured by UIGraphicsBeginPDFContextToData
mainView.layer renderInContext:pdfContext];

// remove PDF rendering context
UIGraphicsEndPDFContext();

return pdfData;
} 

4) 这个函数会阻塞你的 UI 一段时间，所以在新线程上调用它

   [NSThread detachNewThreadSelector:@selector(launchExportViewForExportDrawing) toTarget:self withObject:nil];

使用上述方法，我得到一个带有签名的 pdf 数据，其中也包含旧的 pdf 数据。

但是对于上述方法，我必须在 UIView 中显示 pdf。如果我想在不加载 UIView、不向用户显示 pdf 的情况下执行上述操作，我该怎么做？

我可以通过创建新的 pdf 页面在 pdf 上添加图像。如何在现有 pdf 上添加图像？

Answer 1

我已经通过创建新的 PDF 并在其上绘制 pdf 数据和签名来解决。请参考以下代码：

// For adding the Siganture we need to wite the content on new PDF
-(void) addSignature:(UIImage *) imgSignature onPDFData:(NSData *)pdfData {

NSMutableData* outputPDFData = [[NSMutableData alloc] init];
CGDataConsumerRef dataConsumer = CGDataConsumerCreateWithCFData((CFMutableDataRef)outputPDFData);

CFMutableDictionaryRef attrDictionary = NULL;
attrDictionary = CFDictionaryCreateMutable(NULL, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
CFDictionarySetValue(attrDictionary, kCGPDFContextTitle, CFSTR("My Doc"));
CGContextRef pdfContext = CGPDFContextCreate(dataConsumer, NULL, attrDictionary);
CFRelease(dataConsumer);
CFRelease(attrDictionary);
CGRect pageRect;

// Draw the old "pdfData" on pdfContext
CFDataRef myPDFData = (__bridge CFDataRef) pdfData;
CGDataProviderRef provider = CGDataProviderCreateWithCFData(myPDFData);
CGPDFDocumentRef pdf = CGPDFDocumentCreateWithProvider(provider);
CGDataProviderRelease(provider);
CGPDFPageRef page = CGPDFDocumentGetPage(pdf, 1);
pageRect = CGPDFPageGetBoxRect(page, kCGPDFMediaBox);
CGContextBeginPage(pdfContext, &pageRect);
CGContextDrawPDFPage(pdfContext, page);

// Draw the signature on pdfContext
pageRect = CGRectMake(0, 0,imgSignature.size.width , imgSignature.size.height);
CGImageRef pageImage = [imgSignature CGImage];
CGContextDrawImage(pdfContext, pageRect, pageImage);

// release the allocated memory
CGPDFContextEndPage(pdfContext);
CGPDFContextClose(pdfContext);
CGContextRelease(pdfContext);

// write new PDFData in "outPutPDF.pdf" file in document directory
NSString *docsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *pdfFilePath =[NSString stringWithFormat:@"%@/outPutPDF.pdf",docsDirectory];
[outputPDFData writeToFile:pdfFilePath atomically:YES];

}

Answer 2

Rohit Answer 运行良好，但它只适用于单页，所以我只是为所有显示图像的页面添加了一些代码（单页铰页中显示的图像看起来相同）。谢谢@Rohit

NSString *path = [[NSBundle mainBundle] pathForResource:@"PartB" ofType:@"pdf"];
NSURL *docURL = [NSURL fileURLWithPath:path];
NSString *pdfName = [NSString stringWithFormat:@"%@",docURL];
NSLog(@"pdfName: %@", pdfName);
NSData *pdfData = [NSData dataWithContentsOfFile:path];


NSURL *pdfURL = [[NSBundle mainBundle] URLForResource:@"PartB.pdf" withExtension:nil];
CGPDFDocumentRef pdf1 = CGPDFDocumentCreateWithURL((CFURLRef)pdfURL);
long pageCount = CGPDFDocumentGetNumberOfPages(pdf1);
NSLog(@"the page count %ld",pageCount);



NSMutableData* outputPDFData = [[NSMutableData alloc] init];
CGDataConsumerRef dataConsumer = CGDataConsumerCreateWithCFData((CFMutableDataRef)outputPDFData);

CFMutableDictionaryRef attrDictionary = NULL;
attrDictionary = CFDictionaryCreateMutable(NULL, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
CFDictionarySetValue(attrDictionary, kCGPDFContextTitle, CFSTR("My Doc"));
CGContextRef pdfContext = CGPDFContextCreate(dataConsumer, NULL, attrDictionary);
CFRelease(dataConsumer);
CFRelease(attrDictionary);
CGRect pageRect;


// Draw the old "pdfData" on pdfContext
CFDataRef myPDFData = (__bridge CFDataRef) pdfData;
CGDataProviderRef provider = CGDataProviderCreateWithCFData(myPDFData);
CGPDFDocumentRef pdf = CGPDFDocumentCreateWithProvider(provider);
CGDataProviderRelease(provider);

for (int k=1; k<=pageCount; k++) {

    CGPDFPageRef page3 = CGPDFDocumentGetPage(pdf, k);
    pageRect = CGPDFPageGetBoxRect(page3, kCGPDFMediaBox);
    CGContextBeginPage(pdfContext, &pageRect);
    CGContextDrawPDFPage(pdfContext, page3);
    if (k==pageSelect) {
        pageRect = CGRectMake(0, 0,100 , 100);
        CGImageRef pageImage = [mainImage.image CGImage];
        CGContextDrawImage(pdfContext, pageRect, pageImage);
    }
    CGPDFContextEndPage(pdfContext);
}
CGPDFContextClose(pdfContext);
CGContextRelease(pdfContext);

// write new PDFData in "outPutPDF.pdf" file in document directory
NSString *docsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *pdfFilePath =[NSString stringWithFormat:@"%@/outPutPDF.pdf",docsDirectory];
[outputPDFData writeToFile:pdfFilePath atomically:YES];
NSLog(@"save the pdf %@",pdfFilePath);

Answer 3

我不确定我是否完全理解您的问题。据我所知，您有一个 UIView 正在渲染到 PDF 文档上，并且您想要添加签名图像而不是向用户显示。

如果您尝试将“签名图像”添加到您的 pdf，您可以将 UIImageView 添加到您正在渲染到 pdf 的 UIView。

如果您不希望用户同时看到 UIView，您可以将其原点更改为超出范围的位置，例如：

CGRect originalFrame = mainView.frame;
CGRect newFrame = mainView.frame;
newFrame.origin.x = -newFrame.size.width;
newFrame.origin.y = -newFrame.size.height;
mainView.frame = newFrame; 

//do all your PDF stuff here

mainView.frame = originalFrame; 

我希望这会有所帮助。如果不是，请澄清问题:)