在iOS上合并PDF文件

Question

在iOS中有没有办法合并PDF文件,也​​就是说,将一个页面附加到另一个页面并将其保存到磁盘？

Answer 1

我对Jonathan的代码做了一些重构,以加入任何大小的PDF文件:

+ (NSString *)joinPDF:(NSArray *)listOfPaths {
    // File paths
    NSString *fileName = @"ALL.pdf";
    NSString *pdfPathOutput = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingPathComponent:fileName];

    CFURLRef pdfURLOutput = (  CFURLRef)CFBridgingRetain([NSURL fileURLWithPath:pdfPathOutput]);

    NSInteger numberOfPages = 0;
    // Create the output context
    CGContextRef writeContext = CGPDFContextCreateWithURL(pdfURLOutput, NULL, NULL);

    for (NSString *source in listOfPaths) {
        CFURLRef pdfURL = (  CFURLRef)CFBridgingRetain([[NSURL alloc] initFileURLWithPath:source]);

        //file ref
        CGPDFDocumentRef pdfRef = CGPDFDocumentCreateWithURL((CFURLRef) pdfURL);
        numberOfPages = CGPDFDocumentGetNumberOfPages(pdfRef);

        // Loop variables
        CGPDFPageRef page;
        CGRect mediaBox;

        // Read the first PDF and generate the output pages
        DLog(@"GENERATING PAGES FROM PDF 1 (%@)...", source);
        for (int i=1; i<=numberOfPages; i++) {
            page = CGPDFDocumentGetPage(pdfRef, i);
            mediaBox = CGPDFPageGetBoxRect(page, kCGPDFMediaBox);
            CGContextBeginPage(writeContext, &mediaBox);
            CGContextDrawPDFPage(writeContext, page);
            CGContextEndPage(writeContext);
        }

        CGPDFDocumentRelease(pdfRef);
        CFRelease(pdfURL);
    }
    CFRelease(pdfURLOutput);

    // Finalize the output file
    CGPDFContextClose(writeContext);
    CGContextRelease(writeContext);

    return pdfPathOutput;
}

希望有所帮助

Answer 2

我出来了这个解决方案:

// Documents dir
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];

// File paths
NSString *pdfPath1 = [documentsDirectory stringByAppendingPathComponent:@"1.pdf"];
NSString *pdfPath2 = [documentsDirectory stringByAppendingPathComponent:@"2.pdf"];
NSString *pdfPathOutput = [documentsDirectory stringByAppendingPathComponent:@"out.pdf"];

// File URLs
CFURLRef pdfURL1 = (CFURLRef)[[NSURL alloc] initFileURLWithPath:pdfPath1];
CFURLRef pdfURL2 = (CFURLRef)[[NSURL alloc] initFileURLWithPath:pdfPath2];
CFURLRef pdfURLOutput = (CFURLRef)[[NSURL alloc] initFileURLWithPath:pdfPathOutput];

// File references
CGPDFDocumentRef pdfRef1 = CGPDFDocumentCreateWithURL((CFURLRef) pdfURL1);
CGPDFDocumentRef pdfRef2 = CGPDFDocumentCreateWithURL((CFURLRef) pdfURL2);

// Number of pages
NSInteger numberOfPages1 = CGPDFDocumentGetNumberOfPages(pdfRef1);
NSInteger numberOfPages2 = CGPDFDocumentGetNumberOfPages(pdfRef2);

// Create the output context
CGContextRef writeContext = CGPDFContextCreateWithURL(pdfURLOutput, NULL, NULL);

// Loop variables
CGPDFPageRef page;
CGRect mediaBox;

// Read the first PDF and generate the output pages
NSLog(@"GENERATING PAGES FROM PDF 1 (%i)...", numberOfPages1);
for (int i=1; i<=numberOfPages1; i++) {
    page = CGPDFDocumentGetPage(pdfRef1, i);
    mediaBox = CGPDFPageGetBoxRect(page, kCGPDFMediaBox);
    CGContextBeginPage(writeContext, &mediaBox);
    CGContextDrawPDFPage(writeContext, page);
    CGContextEndPage(writeContext);
}

// Read the second PDF and generate the output pages
NSLog(@"GENERATING PAGES FROM PDF 2 (%i)...", numberOfPages2);
for (int i=1; i<=numberOfPages2; i++) {
    page = CGPDFDocumentGetPage(pdfRef2, i);
    mediaBox = CGPDFPageGetBoxRect(page, kCGPDFMediaBox);
    CGContextBeginPage(writeContext, &mediaBox);
    CGContextDrawPDFPage(writeContext, page);
    CGContextEndPage(writeContext);      
}
NSLog(@"DONE!");

// Finalize the output file
CGPDFContextClose(writeContext);

// Release from memory
CFRelease(pdfURL1);
CFRelease(pdfURL2);
CFRelease(pdfURLOutput);
CGPDFDocumentRelease(pdfRef1);
CGPDFDocumentRelease(pdfRef2);
CGContextRelease(writeContext);

这里最大的问题是内存分配.如您所见,在这种方法中,您必须同时读取要合并的两个PDF文件,同时生成输出.版本只发生在最后.我尝试将一个PDF文件与500页(约15MB)组合在一起,另一个包含100页(约3MB),它生成了一个600页(当然!)的新文件,大小只有~5MB(魔术？).执行花了大约30秒(考虑到iPad 1,并没有那么糟糕)并分配了17MB(哎哟!).该应用程序幸运地没有崩溃,但我认为iOS会喜欢杀死像这样消耗17MB的应用程序.,P

Answer 3

我在 swift 3 中的功能：

// sourcePdfFiles is array of source file full paths, destPdfFile is dest file full path
func mergePdfFiles(sourcePdfFiles:[String], destPdfFile:String) {

    guard UIGraphicsBeginPDFContextToFile(destPdfFile, CGRect.zero, nil) else {
        return
    }
    guard let destContext = UIGraphicsGetCurrentContext() else {
        return
    }

    for index in 0 ..< sourcePdfFiles.count {
        let pdfFile = sourcePdfFiles[index]
        let pdfUrl = NSURL(fileURLWithPath: pdfFile)
        guard let pdfRef = CGPDFDocument(pdfUrl) else {
            continue
        }

        for i in 1 ... pdfRef.numberOfPages {
            if let page = pdfRef.page(at: i) {
                var mediaBox = page.getBoxRect(.mediaBox)
                destContext.beginPage(mediaBox: &mediaBox)
                destContext.drawPDFPage(page)
                destContext.endPage()
            }
        }
    }

    destContext.closePDF()
    UIGraphicsEndPDFContext()
}