Question

I am having some trouble with saving a PDF page as UIImage…the pdf is loaded from the internet and it has one page(original PDF has been splitted in sever)…but the converted image sometimes is cropped…sometimes it is small and leave white space when it is putted on UIImageview…

here is the code

-(UIImage *)imageFromPdf:(NSString *) pdfUrl{

NSURL *pdfUrlStr=[NSURL URLWithString:pdfUrl];

CFURLRef docURLRef=(CFURLRef)pdfUrlStr;


UIGraphicsBeginImageContext(CGSizeMake(768, 1024)); //840, 960
NSLog(@"save begin");

CGContextRef context = UIGraphicsGetCurrentContext();

//CFURLRef pdfURL = CFBundleCopyResourceURL(CFBundleGetMainBundle(), CFSTR("/file.pdf"), NULL, NULL);

CGPDFDocumentRef pdf = CGPDFDocumentCreateWithURL(docURLRef);

NSLog(@"save complete");

CGContextTranslateCTM(context, 0.0, 900);//320

CGContextScaleCTM(context, 1.0, -1.0);

CGPDFPageRef page = CGPDFDocumentGetPage(pdf, 1);

CGContextSaveGState(context);


CGAffineTransform pdfTransform = CGPDFPageGetDrawingTransform(page, kCGPDFCropBox, CGRectMake(0, 0, 768, 1024), 0, true);

CGContextConcatCTM(context, pdfTransform);

CGContextDrawPDFPage(context, page);

CGContextRestoreGState(context);

UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();  
UIGraphicsEndImageContext();

return resultingImage;

}

btw I have prepared my UIImageview by coding like this

self.PDFImageVIew.contentMode  = UIViewContentModeScaleAspectFit;
self.PDFImageVIew.clipsToBounds = YES;

I just want this image perfectly fitted on UIImageview and may be its reducing the quality of image…can you have suggesion how can I keep the quality also? please help and give me some suggestion

thanks

Answer 1

CGContextTranslateCTM(context, 0.0, 900);//320

• Here generally last parameter of translate operation should be the height of context or height of rectangle for which you creating image. So, i think it should be 1024(You have taken height of image context is 1024 so here i am assuming that status bar is not present). This may eliminate the issue of cropping. Some more things that i have noted on your code you should have to save the state of graphics before any operation on context. You have are saving it but after few operations.
• Above code will try to make it height fit so if height of actual page is bigger than your context height then it will be scaled down. so you can obviously see white space around page.
• One more thing if your original pdf page have white space in it then there is no way to eliminate it as far as i know.