Paste hyperlink to PDF using Core Graphics on iOS

Question

I'm trying to do a fairly simple thing: write the URL inside the PDF file, which can actually be clicked by the user.

I know for sure that with libharu this can be done. What I'm looking for is to do the same using Core Graphics, since all the code that I already have in my application already uses these methods.

== edit ==

I think I found something: UIGraphicsSetPDFContextURLForRect , but I can't get it to work.

I am using something like:

 NSURL *url = [NSURL URLWithString:@"http://www.google.com"]; UIGraphicsSetPDFContextURLForRect( url, CGRectMake(0, 0, 100, 100)); 

Not directly clickable.

Answer 1

Well, I managed to find out why it does not work.

The context of the main graphic is “reversed” in the sense of the presence in the lower left corner of the page, and UIKit has the origin in the upper left corner.

This is the method I came up with:

 - (void) drawTextLink:(NSString *) text inFrame:(CGRect) frameRect { CGContextRef context = UIGraphicsGetCurrentContext(); CGAffineTransform ctm = CGContextGetCTM(context); // Translate the origin to the bottom left. // Notice that 842 is the size of the PDF page. CGAffineTransformTranslate(ctm, 0.0, 842); // Flip the handedness of the coordinate system back to right handed. CGAffineTransformScale(ctm, 1.0, -1.0); // Convert the update rectangle to the new coordiante system. CGRect xformRect = CGRectApplyAffineTransform(frameRect, ctm); NSURL *url = [NSURL URLWithString:text]; UIGraphicsSetPDFContextURLForRect( url, xformRect ); CGContextSaveGState(context); NSDictionary *attributesDict; NSMutableAttributedString *attString; NSNumber *underline = [NSNumber numberWithInt:NSUnderlineStyleSingle]; attributesDict = @{NSUnderlineStyleAttributeName : underline, NSForegroundColorAttributeName : [UIColor blueColor]}; attString = [[NSMutableAttributedString alloc] initWithString:url.absoluteString attributes:attributesDict]; [attString drawInRect:frameRect]; CGContextRestoreGState(context); } 

What this method does:

• to get the current context and apply the transformation to the provided rectangle, to get the rectangle that will work when marking the window when UIGraphicsSetPDFContextURLForRect it as clickable
• to mark the new rectangle ( xformRect ) as clickable using the above method
• to preserve the current context so that everything that was done later (color, size, attributes, etc.) does not remain constant in the current context.
• to draw text in the provided rectangle (now using the UIKit coordinate system)
• to restore the GState context