Question

I am facing some problem in iPhone application development for “Reading PDF”.
I have tried following code. I know I have used wrong methods for parsing – parsing methods are just used for searching purpose. But I want to convert entire pdf text in to a string. Say for example Apple’s MobileHIG.pdf – I have used in this code.

@implementation NetPDFViewController

size_t totalPages;  // a variable to store total pages

// a method to get the pdf ref
CGPDFDocumentRef MyGetPDFDocumentRef (const char *filename) {
    CFStringRef path;
    CFURLRef url;
    CGPDFDocumentRef document;
    path = CFStringCreateWithCString (NULL, filename,kCFStringEncodingUTF8);
    url = CFURLCreateWithFileSystemPath (NULL, path, kCFURLPOSIXPathStyle, 0);
    CFRelease (path);
    document = CGPDFDocumentCreateWithURL (url);// 2
    CFRelease(url);
    int count = CGPDFDocumentGetNumberOfPages (document);// 3
    if (count == 0) {
        printf("`%s' needs at least one page!", filename);
        return NULL;
    }
    return document;
}

// table methods to parse pdf
static void op_MP (CGPDFScannerRef s, void *info) {
    const char *name;
    if (!CGPDFScannerPopName(s, &name))
        return;
    printf("MP /%s\n", name);   
}

static void op_DP (CGPDFScannerRef s, void *info) {
    const char *name;
    if (!CGPDFScannerPopName(s, &name))
        return;
    printf("DP /%s\n", name);   
}

static void op_BMC (CGPDFScannerRef s, void *info) {
    const char *name;
    if (!CGPDFScannerPopName(s, &name))
        return;
    printf("BMC /%s\n", name);  
}

static void op_BDC (CGPDFScannerRef s, void *info) {
    const char *name;
    if (!CGPDFScannerPopName(s, &name))
        return;
    printf("BDC /%s\n", name);  
}

static void op_EMC (CGPDFScannerRef s, void *info) {
    const char *name;
    if (!CGPDFScannerPopName(s, &name))
        return;
    printf("EMC /%s\n", name);  
}

// a method to display pdf page.

void MyDisplayPDFPage (CGContextRef myContext,size_t pageNumber,const char *filename) {
    CGPDFDocumentRef document;
    CGPDFPageRef page;
    document = MyGetPDFDocumentRef (filename);// 1
    totalPages=CGPDFDocumentGetNumberOfPages(document);
    page = CGPDFDocumentGetPage (document, pageNumber);// 2

    CGPDFDictionaryRef d;

    d = CGPDFPageGetDictionary(page);

// ----- edit   problem here - CGPDFDictionary is completely unknown 
// ----- as we don't know keys & values of it.
    CGPDFScannerRef myScanner; 
    CGPDFOperatorTableRef myTable;
    myTable = CGPDFOperatorTableCreate();
    CGPDFOperatorTableSetCallback (myTable, "MP", &op_MP);
    CGPDFOperatorTableSetCallback (myTable, "DP", &op_DP);
    CGPDFOperatorTableSetCallback (myTable, "BMC", &op_BMC);
    CGPDFOperatorTableSetCallback (myTable, "BDC", &op_BDC);
    CGPDFOperatorTableSetCallback (myTable, "EMC", &op_EMC);

    CGPDFContentStreamRef myContentStream = CGPDFContentStreamCreateWithPage (page);// 3
    myScanner = CGPDFScannerCreate (myContentStream, myTable, NULL);// 4

    CGPDFScannerScan (myScanner);// 5

//  CGPDFDictionaryRef d;

    CGPDFStringRef str; // represents a sequence of bytes

    d = CGPDFPageGetDictionary(page);

    if (CGPDFDictionaryGetString(d, "Thumb", &str)){
        CFStringRef s;
        s = CGPDFStringCopyTextString(str);
        if (s != NULL) {
            //need something in here in case it cant find anything
            NSLog(@"%@ testing it", s);
        }
        CFRelease(s);       
//      CFDataRef data = CGPDFStreamCopyData (stream, CGPDFDataFormatRaw);
    }

// -----------------------------------  

    CGContextDrawPDFPage (myContext, page);// 3
    CGContextTranslateCTM(myContext, 0, 20);
    CGContextScaleCTM(myContext, 1.0, -1.0);
    CGPDFDocumentRelease (document);// 4
}

- (void)viewDidLoad {
    [super viewDidLoad];


// -------------------------------------------------------- 
// code for simple direct image from pdf docs.
    UIGraphicsBeginImageContext(CGSizeMake(320, 460));
    initialPage=28;
    MyDisplayPDFPage(UIGraphicsGetCurrentContext(), initialPage, [[[NSBundle mainBundle] pathForResource:@"MobileHIG" ofType:@"pdf"] UTF8String]);
    imgV.image=UIGraphicsGetImageFromCurrentImageContext();
    imgV.image=[imgV.image rotate:UIImageOrientationDownMirrored];  
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    UITouch *touch = [touches anyObject];
    CGPoint LasttouchPoint =  [touch locationInView:self.view];
    int LasttouchX = LasttouchPoint.x;
    startpoint=LasttouchX;
}


- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{

}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
    UITouch *touch = [touches anyObject];
    CGPoint LasttouchPoint =  [touch locationInView:self.view];
    int LasttouchX = LasttouchPoint.x;
    endpoint=LasttouchX;
    if(startpoint>(endpoint+75)){
        initialPage++;
        [self loadPage:initialPage nextOne:YES];
    } else if((startpoint+75)<endpoint){
        initialPage--;
        [self loadPage:initialPage nextOne:NO];
    }
}


-(void)loadPage:(NSUInteger)page nextOne:(BOOL)yesOrNo{
    if(page<=totalPages && page>0){
        UIGraphicsBeginImageContext(CGSizeMake(720, 720));  
        MyDisplayPDFPage(UIGraphicsGetCurrentContext(), page, [[[NSBundle mainBundle] pathForResource:@"MobileHIG" ofType:@"pdf"] UTF8String]);

        CATransition *transition = [CATransition animation];
        transition.duration = 0.75;
        transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
        transition.type=kCATransitionPush;
        if(yesOrNo){
            transition.subtype=kCATransitionFromRight;
        } else {
            transition.subtype=kCATransitionFromLeft;
        }

        transition.delegate = self;
        [imgV.layer addAnimation:transition forKey:nil];
        imgV.image=UIGraphicsGetImageFromCurrentImageContext();
        imgV.image=[imgV.image rotate:UIImageOrientationDownMirrored];
    }
}

But I didn’t get success to read even a single line from the pdf document.
What is still missing?

Answer 1

i have a library that can do this exact thing linked over here : https://bitbucket.org/zachron/pdfiphone/overview