Question

I’ve been looking for a solution for this one all day.

I have 4 NSTextFields (actually subclassed for a few custom operations), which all share the same X position.

The problem is, some have different styles (light, regular, bold) and might have different sizes.

What happens is that, even though the X origin is the same, the 1st letter always has a bit of (consistently different) left margins.

Please see pic: https://dl.dropbox.com/u/1977230/Screen%20Shot%202012-12-11%20at%2017.55.58.png

I want to make sure that all lines start exactly at the same point, say 100px from the left.

Any idea how to override that weird padding?

Cheers

Answer 1

The margin you’re talking about I’m pretty sure is the lineFragmentPadding on the NSTextContainer that is used by the NSTextField.

See the NSTextContainer reference:

http://developer.apple.com/library/Mac/#documentation/Cocoa/Reference/ApplicationKit/Classes/NSTextContainer_Class/Reference/Reference.html

And here’s a page from the tutorial on Text Layout:

https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/TextLayout/Concepts/CalcTextLayout.html

It states in that article:

The typesetter makes one final adjustment when it actually fits text
into the rectangle. This adjustment is a small amount fixed by the
NSTextContainer object, called the line fragment padding, which
defines the portion on each end of the line fragment rectangle left
blank. Text is inset within the line fragment rectangle by this amount
(the rectangle itself is unaffected). Padding allows for small-scale
adjustment of the text container’s region at the edges and around any
holes and keeps text from directly abutting any other graphics
displayed near the region. You can change the padding from its default
value with the setLineFragmentPadding: method. Note that line fragment
padding isn’t a suitable means for expressing margins; you should set
the NSTextView object’s position and size for document margins or the
paragraph margin attributes for text margins.

Unfortunately, it looks like NSTextField‘s NSTextContainer and NSLayoutManager are private and inaccessible, but it appears they are accessible in an NSTextView:

https://developer.apple.com/library/mac/#documentation/Cocoa/Reference/ApplicationKit/Classes/NSTextView_Class/Reference/Reference.html#//apple_ref/occ/cl/NSTextView

So that may be the class you need to subclass if you want to have minute control over this kind of functionality.