Question

I’m trying to draw a custom string with color, font, size and alignment.

I got everything working with an NSMutableAttributedString before, but it looks like Text Aligment only works with Paragraph alignement which only works with non mutable version of NSString.

So, I had to change my previous code to this :

    //Note : _name variables are provided by my GUI for text, size and font name.

    //Create the String ColorRef
    CGColorSpaceRef rgb = CGColorSpaceCreateDeviceRGB();
    const CGFloat myColor[] = {_color.r/255.0, _color.g/255.0, _color.b/255.0, 1.0f};
    CGColorRef colorRef = CGColorCreate(rgb, myColor);

    //Setup paragraph Alignment Ref
    CTTextAlignment theAlignment = kCTCenterTextAlignment;
    CFIndex theNumberOfSettings = 1;
    CTParagraphStyleSetting theSettings[1] = {{ kCTParagraphStyleSpecifierAlignment, sizeof(CTTextAlignment), &theAlignment }};
    CTParagraphStyleRef theParagraphRef = CTParagraphStyleCreate(theSettings, theNumberOfSettings);

    //Prep Font
    NSDictionary *fontAttributes = [NSDictionary dictionaryWithObjectsAndKeys: _fontName, (NSString *)kCTFontFamilyNameAttribute,
                                    [NSNumber numberWithFloat:_fontSize], (NSString *)kCTFontSizeAttribute,
                                    nil];
    CTFontRef font = [self newFontWithAttributes:fontAttributes];

    //Prepare String Attributes
    NSDictionary *attributes = [NSDictionary dictionaryWithObjectsAndKeys: (id)font, (NSString *)kCTFontAttributeName,
                                                [NSNumber numberWithFloat:_fontSize], (NSString *)kCTFontSizeAttribute,
                                                                 (id)theParagraphRef, (NSString*)kCTParagraphStyleAttributeName, 
                                                                            colorRef, (NSString *)kCTForegroundColorAttributeName, nil];

    //Create the Attributed String
    NSAttributedString *myString = [[NSAttributedString alloc] initWithString:_textString
                                                                   attributes: attributes];

But the Text Aligment still doesn’t work. Everything else is fine but text remains aligned on the Left.

Why ?

EDIT :
Each of my strings are created inside a class that is a subclass of CATextLayer. Each of those TextLayers are then added to a CALayer as sublayers. On updates I apply trasformation matrix on the sublayers and use setNeedsDisplay. This is how I display the text on screen. Maybe There’s a reason here why the CTParagraphStyleRef set is not working ?

Answer 1

I have no clues why the ParagraphStyle that I’ve set is not working, But I’ve found a solution that’s working for me, so I’m posting it in case someone encounter similar problems :

• My class is subclassing CATextLayer, which I think would’ve been important to mention in my question (my bad, I’ll edit it).
• Inside my CATextLayer class, I create the string using the code
  shown in my question.
• Then I use the self.alignmentMode = kCAAlignmentCenter; to align
  the text the way I want.
• Each string is then added to a CALAyer for display

I’ve also found this very good guide on AttributedStrings that helped me improving my code and finding this solution.