Edit PDF in iphone application

Question

Now I am creating an application that works like \'iAnnotate PDF\' Till now I have completed reading and displaying pdf pages in UIView. Even I am sucessful i

Answer 1

You can create/edit pdf's easily using CoreGraphics. Just create a rect defining the size, then create the context, push the context, call CFPDFContextBeginPage and start drawing like you would normally do...Here's an example:

    CGRect mediaBox = CGRectMake(0, 0, 550, 800);
    NSString *url = [path stringByExpandingTildeInPath];
    CGContextRef ctx = CGPDFContextCreateWithURL((CFURLRef)[NSURL fileURLWithPath:url], &mediaBox, NULL);
    UIGraphicsPushContext(ctx);


//Page1 
    CGPDFContextBeginPage(ctx, NULL);
    CGContextScaleCTM(ctx, 1, -1);
    CGContextTranslateCTM(ctx, 0, -mediaBox.size.height);
    //name and value are NSStrings
    [name drawInRect:rectName withFont:fontName];
    [value drawInRect:rectValue withFont:fontValue];
    [[UIImage imageNamed:@"logo.png"] drawInRect:CGRectMake(8, 15, 91, 99)];
    CGPDFContextEndPage(ctx);

    UIGraphicsPopContext();
    CFRelease(ctx);

UPDATE You can copy the pages you require and then do the drawing over them like this:

CGPDFDocumentRef  originalDoc = NULL;
CGContextRef pdfContext = NULL;
CGRect docRect = CGRectZero;


NSURL *originalURL = [[NSBundle mainBundle] URLForResource:@"test" withExtension:@"pdf"];
NSString *newPath = @"/Users/***/Desktop/new.pdf";
CFURLRef newURL = CFURLCreateWithFileSystemPath (NULL, 
                                                 (CFStringRef)newPath,
                                                 kCFURLPOSIXPathStyle,
                                                 false);

//Original doc and it's dimesnions
originalDoc = CGPDFDocumentCreateWithURL((CFURLRef)originalURL);
CGPDFPageRef firstPage = CGPDFDocumentGetPage(originalDoc, 1);
if (firstPage == NULL) {
    NSLog(@"This document has no pages..Exiting.");
}
docRect = CGPDFPageGetBoxRect(firstPage, kCGPDFCropBox);
NSLog(@"%@", NSStringFromRect(docRect));


//New doc context
if (newURL != NULL) {
    pdfContext = CGPDFContextCreateWithURL(newURL, &docRect, NULL);

    if (pdfContext == NULL) {
        NSLog(@"Error creating context");
    }

    CFRelease(newURL);
} else {
    NSLog(@"Error creating url");
}

And then copy each page individually. In this particular example, I am adding "Bates" (numbering) to the pages.

//Copy original to new, and write bates
size_t count = CGPDFDocumentGetNumberOfPages(originalDoc);

for (size_t pageNumber = 1; pageNumber <= count; pageNumber++) {



    CGPDFPageRef originalPage = CGPDFDocumentGetPage(originalDoc, pageNumber);

    CGContextBeginPage (pdfContext,nil);

    CGContextSetRGBFillColor(pdfContext, 0, 0, 255, 0.1);
    CGContextSetRGBStrokeColor(pdfContext, 0, 0, 255, 0.5);

    // Draw a circle (filled)
    CGContextFillEllipseInRect(pdfContext, CGRectMake(0, 0, 25, 25));

    CGContextSaveGState(pdfContext);

    //flip context due to different origins
    CGContextTranslateCTM(pdfContext, 0.0, (docRect.size.height - (docRect.size.height * 0.80))/2);
    CGContextScaleCTM(pdfContext, 1.0, 0.8);

    //copy content of template page on the corresponding page in new file
    CGContextDrawPDFPage(pdfContext, originalPage);

    CGContextRestoreGState(pdfContext);

    //flip context back
    //CGContextTranslateCTM(pdfContext, 0.0, -(docRect.size.height - (docRect.size.height * 0.80))/2);
    //CGContextScaleCTM(pdfContext, 1.0, 1.25);

    CGContextSetRGBFillColor(pdfContext, 0, 0, 255, 0.1);
    CGContextSetRGBStrokeColor(pdfContext, 0, 0, 255, 0.5);

    // Draw a circle (filled)
    CGContextFillEllipseInRect(pdfContext, CGRectMake(0, 0, 25, 25));

    NSString *bate = [self generateStringForCount:(int)pageNumber-1];

    int fontSize = 15;
    CGContextSelectFont(pdfContext, "Helvetica", fontSize, kCGEncodingMacRoman);
    CGContextSetTextDrawingMode(pdfContext, kCGTextFill);
    CGContextSetTextPosition(pdfContext, 0.0f, round(fontSize / 4.0f));
    CGContextShowText(pdfContext, [bate UTF8String], strlen([bate UTF8String]));


    CGContextEndPage(pdfContext);

}

CFRelease(pdfContext);