iPhone - How to draw text in the middle of a rect

Question

Is there a method to draw text in the middle of a rectangle. I can find various alignments, but nothing I have tried can vertically centre the text in a rect.

Is there a simple method to do this, or is there some way to centre a rectangle and then draw in that?

I'm drawing direct to the CGContext, trying to use NSString::drawWithRect or something similar, as I dont really want to have to add a Label just to render some basic text.

Answer 1

Ok, assuming I understand your question :) , you want to draw an UILabel centered inside a CGRect/UIView?

There are more than a couple of ways to achieve this, a couple of things you could do are:

UILabel *aLabel = [[UILabel alloc] initWithFrame:CGRectMake(0,0,0,0)];

[aLabel setText:"This is some sample text"];
[aLabel sizeToFit];
/*If it's a CGRect*/
[aLabel setCenter:CGPointMake(CGRectGetMidX(someCGRect),CGRectGetMidY(someCGRect))];

/*If the rect it's an UIView (or something that inherits from that)*/
[aLabel setCenter:[aView center]];

/* add aLabel to UIView as a subView etc. */

Hope this is what you are looking for.

Answer 2

Well, the font property "pointSize" corresponds directly to the height in pixels of a string drawn in that font, so your formula would be something like this:

- (void) drawString: (NSString*) s withFont: (UIFont*) font inRect: (CGRect) contextRect {

    CGFloat fontHeight = font.pointSize;
    CGFloat yOffset = (contextRect.size.height - fontHeight) / 2.0;

    CGRect textRect = CGRectMake(0, yOffset, contextRect.size.width, fontHeight);

    [s drawInRect: textRect withFont: font lineBreakMode: UILineBreakModeClip 
             alignment: UITextAlignmentCenter];
}

UITextAlignmentCenter handles the horizontal centering, so we use the full width of the contextRect. The lineBreakMode can be whatever you like.