如何使用iPhone SDK生成PDF文档的缩略图? [英] How to generate a thumbnails form a PDF document with iPhone SDK?
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问题描述
我已阅读使用Quartz的Apple PDF文档:
http://developer.apple.com/library/ios/#documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/dq_pdf_scan/dq_pdf_scan.html# // apple_ref / doc / uid / TP30001066-CH220-TPXREF101
I have read the Apple PDF documentation with Quartz: http://developer.apple.com/library/ios/#documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/dq_pdf_scan/dq_pdf_scan.html#//apple_ref/doc/uid/TP30001066-CH220-TPXREF101
但我不知道如何从PDF文档生成thubmnails ...
but i do not know how to generate the thubmnails from a PDF document...
任何想法/示例代码?
推荐答案
这是我的示例代码。
NSURL* pdfFileUrl = [NSURL fileURLWithPath:finalPath];
CGPDFDocumentRef pdf = CGPDFDocumentCreateWithURL((CFURLRef)pdfFileUrl);
CGPDFPageRef page;
CGRect aRect = CGRectMake(0, 0, 70, 100); // thumbnail size
UIGraphicsBeginImageContext(aRect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
UIImage* thumbnailImage;
NSUInteger totalNum = CGPDFDocumentGetNumberOfPages(pdf);
for(int i = 0; i < totalNum; i++ ) {
CGContextSaveGState(context);
CGContextTranslateCTM(context, 0.0, aRect.size.height);
CGContextScaleCTM(context, 1.0, -1.0);
CGContextSetGrayFillColor(context, 1.0, 1.0);
CGContextFillRect(context, aRect);
// Grab the first PDF page
page = CGPDFDocumentGetPage(pdf, i + 1);
CGAffineTransform pdfTransform = CGPDFPageGetDrawingTransform(page, kCGPDFMediaBox, aRect, 0, true);
// And apply the transform.
CGContextConcatCTM(context, pdfTransform);
CGContextDrawPDFPage(context, page);
// Create the new UIImage from the context
thumbnailImage = UIGraphicsGetImageFromCurrentImageContext();
//Use thumbnailImage (e.g. drawing, saving it to a file, etc)
CGContextRestoreGState(context);
}
UIGraphicsEndImageContext();
CGPDFDocumentRelease(pdf);
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