iphone alcuni file PDF di rendering come immagine in bianco

Question

Sto cercando di disegnare le pagine di un file PDF usando il codice seguente. Some PDF di rendering in modo corretto, ma altri semplicemente mostrare come immagine completamente nera, o di avere porzioni parziali resi e il nero resto. Nel confronto tra quello che sta succedendo, quelle che mostrano OK sembrano avere sempre avere un testo "normale" in loro insieme ad alcuni elementi grafici (schemi, ecc), mentre quelli che escono nero sono in genere tutti gli elementi grafici (come una pagina di foglio di musica, per esempio). Qualcuno mi può punto nella giusta direzione su questo? Ho costruire questo sul nuovo 3.2 SDK.

Grazie!

// PDF page drawing expects a Lower-Left coordinate system, so we flip the coordinate system
// before we start drawing.
 CGContextTranslateCTM(context, 0.0, self.bounds.size.height);
 CGContextScaleCTM(context, 1.0, -1.0);

 // Grab the first PDF page
CGPDFPageRef page = CGPDFDocumentGetPage(myPDF, pageNo);
// We're about to modify the context CTM to draw the PDF page where we want it, so save     the graphics state in case we want to do more drawing
CGContextSaveGState(context);
// CGPDFPageGetDrawingTransform provides an easy way to get the transform for a PDF page. It will scale down to fit, including any
// base rotations necessary to display the PDF page correctly. 
CGAffineTransform pdfTransform = CGPDFPageGetDrawingTransform(page, kCGPDFCropBox, self.bounds, 0, true);
// And apply the transform.
CGContextConcatCTM(context, pdfTransform);
// Finally, we draw the page and restore the graphics state for further manipulations!
CGContextDrawPDFPage(context, page);
CGContextRestoreGState(context);

Answer 1

CGPDFDocumentRef MyGetPDFDocumentRef (const char * filename) {         percorso CFStringRef;         CFURLRef URL;         documento CGPDFDocumentRef;         path = CFStringCreateWithCString (NULL, nome file, kCFStringEncodingUTF8);         url = CFURLCreateWithFileSystemPath (NULL, percorso, kCFURLPOSIXPathStyle, 0);         CFRelease (percorso);         documento = CGPDFDocumentCreateWithURL (url); // 2         CFRelease (url);         int count = CGPDFDocumentGetNumberOfPages (documento); // 3         Se (count == 0) {             printf ( "`% s'ha bisogno di almeno una pagina!", il nome del file);             ritornare NULL;         }         restituire il documento;     }

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



#import "DashBoard.h"

#import <QuartzCore/QuartzCore.h>

@interface UIImage (WBImage)
// rotate UIImage to any angle
-(UIImage*)rotate:(UIImageOrientation)orient;
@end

@implementation UIImage (WBImage)


static inline CGFloat degreesToRadians(CGFloat degrees)
{
    return M_PI * (degrees / 180.0);
}

static inline CGSize swapWidthAndHeight(CGSize size)
{
    CGFloat  swap = size.width;

    size.width  = size.height;
    size.height = swap;

    return size;
}


-(UIImage*)rotate:(UIImageOrientation)orient
{
    CGRect             bnds = CGRectZero;
    UIImage*           copy = nil;
    CGContextRef       ctxt = nil;
    CGRect             rect = CGRectZero;
    CGAffineTransform  tran = CGAffineTransformIdentity;

    bnds.size = self.size;
    rect.size = self.size;

    switch (orient)
    {
        case UIImageOrientationUp:
            return self;

        case UIImageOrientationUpMirrored:
            tran = CGAffineTransformMakeTranslation(rect.size.width, 0.0);
            tran = CGAffineTransformScale(tran, -1.0, 1.0);
            break;

        case UIImageOrientationDown:
            tran = CGAffineTransformMakeTranslation(rect.size.width,
                                                    rect.size.height);
            tran = CGAffineTransformRotate(tran, degreesToRadians(180.0));
            break;

        case UIImageOrientationDownMirrored:
            tran = CGAffineTransformMakeTranslation(0.0, rect.size.height);
            tran = CGAffineTransformScale(tran, 1.0, -1.0);
            break;

        case UIImageOrientationLeft:
            bnds.size = swapWidthAndHeight(bnds.size);
            tran = CGAffineTransformMakeTranslation(0.0, rect.size.width);
            tran = CGAffineTransformRotate(tran, degreesToRadians(-90.0));
            break;

        case UIImageOrientationLeftMirrored:
            bnds.size = swapWidthAndHeight(bnds.size);
            tran = CGAffineTransformMakeTranslation(rect.size.height,
                                                    rect.size.width);
            tran = CGAffineTransformScale(tran, -1.0, 1.0);
            tran = CGAffineTransformRotate(tran, degreesToRadians(-90.0));
            break;

        case UIImageOrientationRight:
            bnds.size = swapWidthAndHeight(bnds.size);
            tran = CGAffineTransformMakeTranslation(rect.size.height, 0.0);
            tran = CGAffineTransformRotate(tran, degreesToRadians(90.0));
            break;

        case UIImageOrientationRightMirrored:
            bnds.size = swapWidthAndHeight(bnds.size);
            tran = CGAffineTransformMakeScale(-1.0, 1.0);
            tran = CGAffineTransformRotate(tran, degreesToRadians(90.0));
            break;

        default:
            // orientation value supplied is invalid
            assert(false);
            return nil;
    }

    UIGraphicsBeginImageContext(bnds.size);
    ctxt = UIGraphicsGetCurrentContext();

    switch (orient)
    {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            CGContextScaleCTM(ctxt, -1.0, 1.0);
            CGContextTranslateCTM(ctxt, -rect.size.height, 0.0);
            break;

        default:
            CGContextScaleCTM(ctxt, 1.0, -1.0);
            CGContextTranslateCTM(ctxt, 0.0, -rect.size.height);
            break;
    }

    CGContextConcatCTM(ctxt, tran);
    CGContextDrawImage(ctxt, rect, self.CGImage);

    copy = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return copy;
}


@end




@implementation DashBoard

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad];
    filePath=[[NSString alloc] initWithString:[[NSBundle mainBundle] pathForResource:@"roadie" ofType:@"pdf"]];

    // an IBOutlet UIScrollView
    [scrMain setContentSize:CGSizeMake(720, 720)];
    // an IBOutlet UIImageView
    [imgV setFrame:CGRectMake(0, 0, 720, 720)];
    UIGraphicsBeginImageContext(CGSizeMake(720, 720));
    // initial page is an size_t variable
    initialPage=1;
    MyDisplayPDFPage(UIGraphicsGetCurrentContext(), initialPage, [filePath UTF8String],myTable,mainString);
    imgV.image=UIGraphicsGetImageFromCurrentImageContext();
    imgV.image=[imgV.image rotate:UIImageOrientationDownMirrored];
}

Basta copiare e incollare sopra il codice. Si lavorerà per voi.

Answer 2

Il problema era il colore di sfondo - in particolare, il pdf del stavo avendo problemi con non hanno uno sfondo bianco. Compilando la vista con un rettangolo bianco, il mio problema è stato risolto.