ios- pdf generation in uiscrollview - objective-c

Question

in my ios app i am listing out some data in scroll view. When a button is clicked the datas in the page are been generated in pdf file format. Following is the bit of code.
- (void)createPDFfromUIView:(UIView*)aView saveToDocumentsWithFileName:(NSString*)aFilename{
// Creates a mutable data object for updating with binary data, like a byte array
NSMutableData *pdfData = [NSMutableData data];
// Points the pdf converter to the mutable data object and to the UIView to be converted
UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, nil);
UIGraphicsBeginPDFPage();
CGContextRef pdfContext = UIGraphicsGetCurrentContext();
// draws rect to the view and thus this is captured by UIGraphicsBeginPDFContextToData
[aView.layer renderInContext:pdfContext];
// remove PDF rendering context
UIGraphicsEndPDFContext();
// Retrieves the document directories from the iOS device
NSArray* documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);
NSString* documentDirectory = [documentDirectories objectAtIndex:0];
NSString* documentDirectoryFilename = [documentDirectory stringByAppendingPathComponent:aFilename];
// instructs the mutable data object to write its context to a file on disk
[pdfData writeToFile:documentDirectoryFilename atomically:YES];
NSLog(#"documentDirectoryFileName: %#",documentDirectoryFilename);
}
From the above code, i am able to generate a pdf file, but i am facing the following issue.
If i have more than 50 data, in my app i am able to see only the first 10 data and to see the others i need to scroll them. In this case when the pdf file gets generated it is taking only the data of first 10 and not the others. How to get the other data too

Answer 1

renderInContext: will only render what you currently see - UIScrollView is smart and will only have the views in the hierarchy that you need right now. You need a for-loop to manually scroll and redraw. This might be tricky to get right, maybe call [aView layoutSubviews] manually after scrolling to force the scrollView to rearrange the subviews instantly.

Answer 2

as steipete said, you can use loop to renderIncontext
- You need to calculate num of loop
numOfLoop = webview.ScrollView.ContentSize.Height/weview.frame.size.height
use loop to renderInContext
for(int i = 0; i < numOfLopp; i ++)
1.UIGraphicsBeginPDFPage()
get current context
renderIncontext
This way run correct in my app but I am getting with BIG issue when the numOfLoop lager
- you will get slow to renderInContext
- Memory will be increase -> Close app
In this way, How can I remove/release context when I am in once loop ?
Other way, you can use https://github.com/iclems/iOS-htmltopdf/blob/master/NDHTMLtoPDF.h
to generate to PDF

Answer 3

#steipete, #all Hi i tried the below code it generate multipage PDF, but the visible area in view is repeated for all the pages. please add any further ideas to improve the result.
-(void)createPDFfromUIView:(UIWebView*)aView saveToDocumentsWithFileName:(NSString*)aFilename
{
NSString *oldFilePath= [[NSBundle mainBundle] pathForResource:#"ABC" ofType:#"pdf"];
NSMutableData *pdfData = [NSMutableData data];
UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, nil);
CFURLRef url = CFURLCreateWithFileSystemPath (NULL, (CFStringRef)oldFilePath, kCFURLPOSIXPathStyle, 0);
CGPDFDocumentRef templateDocument = CGPDFDocumentCreateWithURL(url);
CFRelease(url); size_t count = CGPDFDocumentGetNumberOfPages(templateDocument);
for (size_t pageNumber = 1; pageNumber <= count; pageNumber++)
{
UIGraphicsBeginPDFPage();
CGContextRef pdfContext = UIGraphicsGetCurrentContext();
[aView.layer renderInContext:pdfContext];
}
CGPDFDocumentRelease(templateDocument);
// remove PDF rendering context UIGraphicsEndPDFContext();
// Retrieves the document directories from the iOS device
NSArray* documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
NSString* documentDirectory = [documentDirectories objectAtIndex:0];
NSString* documentDirectoryFilename = [documentDirectory stringByAppendingPathComponent:aFilename];
[pdfData writeToFile:documentDirectoryFilename atomically:YES];
NSLog(#"documentDirectoryFileName: %#",documentDirectoryFilename);
}

Answer 4

Check ScrollViewToPDF example
It uses same scrollview's layer renderInContext but here PDF is created according to your requirement such as one page PDF or multiple page PDF
Note : It captures all visible as well as invisible part of scrollView