PDF Document Creation, Viewing

【PDF Document Creation, Viewing, and Transforming】

　　Quartz provides the data type CGPDFDocumentRef to represent a PDF document. You create a CGPDFDocument object using either the function CGPDFDocumentCreateWithProvider or the function CGPDFDocumentCreateWithURL. After you create a CGPDFDocument object, you can draw it to a graphics context.

　　Following code shows how to create a CGPDFDocument object and obtain the number of pages in the document. by

CGPDFDocumentGetNumberOfPages function. A detailed explanation for each numbered line of code appears following the listing.

CGPDFDocumentRef MyGetPDFDocumentRef (const char *filename)
{
    CFStringRef path;
    CFURLRef url;
    CGPDFDocumentRef document;
    size_t count;
 
    path = CFStringCreateWithCString (NULL, filename,
                         kCFStringEncodingUTF8);
    url = CFURLCreateWithFileSystemPath (NULL, path, // 1
                        kCFURLPOSIXPathStyle, 0);
    CFRelease (path);
    document = CGPDFDocumentCreateWithURL (url);// 2
    CFRelease(url);
    count = CGPDFDocumentGetNumberOfPages (document);// 3
    if (count == 0) {
        printf("`%s' needs at least one page!", filename);
        return NULL;
    }
    return document;
}

　　Drawing a PDF page:

void MyDisplayPDFPage (CGContextRef myContext,
                    size_t pageNumber,
                    const char *filename)
{
    CGPDFDocumentRef document;
    CGPDFPageRef page;
 
    document = MyGetPDFDocumentRef (filename);// 1
    page = CGPDFDocumentGetPage (document, pageNumber);// 2
    CGContextDrawPDFPage (myContext, page);// 3
    CGPDFDocumentRelease (document);// 4
}