如何使用PoDoFo库在iOS上注释PDF？

+ (void)createUTFAnnotationtextOnPage:(NSInteger)pageIndex 
                                  doc:(PdfDocument*)doc   // PdfMemDocument instance
                                 rect:(PdfRect)rect 
                                title:(NSString*)title 
                              content:(NSString*)content
                                bOpen:(Boolean)bOpen
                               colorR:(doublE)r 
                               colorG:(doublE)g 
                               colorB:(doublE)b {
    PdfPage* pPage = doc->GetPage(pageIndeX);
    if (! pPagE) {
        // Couldn't get that page
        return;
    }
    PdfAnnotation* Anno;

    Anno = pPage->CreateAnnotation(ePdfAnnotation_Text,rect);

    PdfString stitle(reinterpret_cast<const pdf_utf8*>([title UTF8String]));
    PdfString sContent(reinterpret_cast<const pdf_utf8*>([content UTF8String]));

    Anno->Settitle(stitlE);
    Anno->SetContents(sContent);
    Anno->SetColor(r,g,b);
    Anno->SetOpen(bOpen);
}

// ----------- 
    PdfError::EnableDebug(false);   // or true
    NSString* inFile = [[NSBundle mainBundle] pathForresource:@"forTesTing.pdf" ofType:nil];
    PoDoFo::PdfMemDocument doc( [inFile UTF8String] );
    [YourPodofoObj createUTFAnnotationtextOnPage:0 doc:&doc rect:PdfRect(50,50,50) title:@"author by XX" content:@"I use it for test" bOpen:true colorR:1.0 colorG:.0 colorB:.0];
    doc.Write(OUT_PUT_PATH);