/Users/awniemel/Notepad-SVN/svn/trunk/CatNiP/CatNiP/UIDocumentPDF.m

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#import "UIDocumentPDF.h"

@implementation UIDocumentPDF

@synthesize CGPDFDocument = document;
@synthesize box;

static const int MAX_PAGE_WIDTH = 2 * 768;

+ (UIDocumentPDF *)documentWithCGPDFDocument:(CGPDFDocumentRef)CGPDFDocument
{
    return [[[UIDocumentPDF alloc] initWithCGPDFDocument:CGPDFDocument] autorelease];
}

- (id)init
{
    box = kCGPDFMediaBox;
    return self;
}

- (id)initWithCGPDFDocument:(CGPDFDocumentRef)CGPDFDocument
{
    self = [self init];
    if(CGPDFDocument != NULL) {
        document      = CGPDFDocumentRetain(CGPDFDocument);
        numberOfPages = CGPDFDocumentGetNumberOfPages(CGPDFDocument);
        
        // Loop through the pages and calculate the document dimensions: the
        // maximum of the width of the pages and the sum of their heights.
        for(int i = 1; i <= numberOfPages; ++i) {
            CGSize pageSize = [self getSizeOfPage:i];
            size.width   = pageSize.width > size.width ? pageSize.width : size.width;
            size.height += pageSize.height;
        }
        
        return self;
    }
    return nil;
}

- (id)initWithContentsOfFile:(NSString *)path
{
        if(path != nil) {
        NSURL* url = [[NSURL alloc] initFileURLWithPath:path];
        CGPDFDocumentRef pdf = CGPDFDocumentCreateWithURL((CFURLRef)url);
        
        self = [self initWithCGPDFDocument:pdf];
        
        CGPDFDocumentRelease(pdf);
        [url release];
        
        return self;
    }
    return nil;
}

- (id)initWithData:(NSData *)data
{
    // No need to check for data validity¸ CGDataProviderCreateWithCFData
    // returns nil properly on failure.
    
    CGDataProviderRef provider = CGDataProviderCreateWithCFData((CFDataRef)data);
    CGPDFDocumentRef pdf = CGPDFDocumentCreateWithProvider(provider);
    
    self = [self initWithCGPDFDocument:pdf];
    
    CGPDFDocumentRelease(pdf);
    CGDataProviderRelease(provider);
    
    return self;
}

- (UIImage *)getImageOfPage:(int)pageNumber
{
    // PDF internal page coordinates place the origo in the bottom left corner
    // of the page, so the drawing needs to be flipped vertically; hence the
    // curious negative signs in the CGRectMake and CGContextScaleCTM calls.
    
#if DEBUG
    NSLog(@"Started loading page %d",pageNumber);
#endif
    
    CGPDFPageRef page = CGPDFDocumentGetPage(document, pageNumber);
    
    CGSize pageSize = [self getSizeOfPage:pageNumber];
    CGRect pageRect = CGRectMake(0, 0, pageSize.width, -pageSize.height);
    
    UIGraphicsBeginImageContext(pageSize);
    CGContextRef context = UIGraphicsGetCurrentContext();
    
    CGAffineTransform transform = CGPDFPageGetDrawingTransform(page, box, pageRect, 0, YES);
    CGContextScaleCTM(context, 1.0, -1.0);
    CGContextConcatCTM(context, transform);
    
    CGContextDrawPDFPage(context, page);
    
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
#if DEBUG
    NSLog(@"Page %d loaded to memory",pageNumber);
#endif
    
    return image;
}

- (CGSize)getSizeOfPage:(int)pageNumber
{
    CGPDFPageRef page = CGPDFDocumentGetPage(document, pageNumber);
    CGRect boxRect    = CGPDFPageGetBoxRect(page, box);
    int rotationAngle = CGPDFPageGetRotationAngle(page);
    
    CGSize pageSize;
    
    // Fix size if page is portrait-oriented
    if(rotationAngle % 180 == 0)
        pageSize = CGSizeMake(boxRect.size.width, boxRect.size.height);
    else
        pageSize = CGSizeMake(boxRect.size.height, boxRect.size.width);
    
    // Downscale size to conserve processor cycles in case the page is drawn
    if(pageSize.width > MAX_PAGE_WIDTH) {
        CGFloat ratio = MAX_PAGE_WIDTH / pageSize.width;
        pageSize.width  *= ratio;
        pageSize.height *= ratio;
    }
    
    return pageSize;
}

- (void)dealloc
{
    CGPDFDocumentRelease(document);
    [super dealloc];
}

@end