NSAttributedString end of first line indent - ios

Question

I want to have the first line in an NSAttributedString for a UITextView indented from the right side on the first line.
So the firstLineHeadIndent in NSParagraphStyle will indent the first line from the left. I want to do the same thing but from the right in my UITextView.
Here's a screenshot of how I want the text to wrap.

Answer 1

The Setting Text Margins article from the Text System User Interface Layer Programming Guide has this figure:
As you can see, there's no built-in mechanism to have a first line tail indent.
However, NSTextContainer has a property exclusionPaths which represents parts of its rectangular area from which text should be excluded. So, you could add a path for the upper-right corner to prevent text from going there.
UIBezierPath* path = /* compute path for upper-right portion that you want to exclude */;
NSMutableArray* paths = [textView.textContainer.exclusionPaths mutableCopy];
[paths addObject:path];
textView.textContainer.exclusionPaths = paths;

Answer 2

I'd suggest to create 2 different NSParagraphStyle: one specific for the first line and the second one for the rest of the text.
//Creating first Line Paragraph Style
NSMutableParagraphStyle *firstLineStyle = [[NSMutableParagraphStyle alloc] init];
[firstLineStyle setFirstLineHeadIndent:10];
[firstLineStyle setTailIndent:200]; //Note that according to the doc, it's in point, and go from the origin text (left for most case) to the end, it's more a length that a "margin" (from right) that's why I put a "high value"
//Read there: https://developer.apple.com/library/ios/documentation/Cocoa/Reference/ApplicationKit/Classes/NSMutableParagraphStyle_Class/index.html#//apple_ref/occ/instp/NSMutableParagraphStyle/tailIndent
//Creating Rest of Text Paragraph Style
NSMutableParagraphStyle *restOfTextStyle = [[NSMutableParagraphStyle alloc] init];
[restOfTextStyle setAlignement:NSTextAlignmentJustified];
//Other settings if needed
//Creating the NSAttributedString
NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:originalString];
[attributedString addAttribute:NSParagraphStyleAttributeName value:firstLineStyle range:rangeOfFirstLine];
[attributedString addAttribute:NSParagraphStyleAttributeName
value:restOfTextStyle
range:NSMakeRange(rangeOfFirstLine.location+rangeOfFirstLine.length,
[originalString length]-(rangeOfFirstLine.location+rangeOfFirstLine.length))];
//Setting the NSAttributedString to your UITextView
[yourTextView setAttributedText:attributedString];