Re: How to know the geometry of a string on the screen ?

[Bertrand Gmail]

Le 29/10/2017 à 11:30, David Chisnall a écrit :
> On 27 Oct 2017, at 20:34, Bertrand Gmail <bertrand.dekoninck@gmail.com> wrote:
> > Le 27/10/2017 à 20:36, Josh Freeman a écrit :
> > > I think you meant to use 'string', not '[NSString string]' - the latter returns 
> > > an empty string.
> > >
> > > stringSize=[[NSString string] sizeWithAttributes:attributes];
> > >   ->
> > > stringSize=[string sizeWithAttributes:attributes];
> > I introduced  [NSString string] because of this warning at compile time :
> >
> > GSPanel.m:75:23: warning: 'NSMutableAttributedString' may not respond to
> >       'sizeWithAttributes:'
> >    stringSize=[string sizeWithAttributes:attributes];
> >
> > And the executable doesn't work.
> But now you are asking what the length of an empty string is, when a set of 
> attributes are applied.  You want to be asking what the length of @“GNUstep” 
> is.  You do not need to construct an NSAttributedString to call a method on 
> NSString.
Thanks for your answer. So I can't just use a method of NSString on an 
NSattributedString.

I just wanted to put a centered label as a subview of a window (a simple 
UI element indeed), using a boldSystemFont attribute. So I needed to 
calculate the size of the attributed string. And I don't need line wrapping.
Josh's "[string size]" advice seems to be the way to go.

Moreover, I could put "string.size" instead of "[string size]". But I 
wonder if it ist an Objc-2 feature and  if it will compile with gcc and 
it's libobjc.

I use somewhere else in my code :

 "screenFrame = [[NSScreen mainScreen] frame];
  screenSize = screenFrame.size;"

Is it also Objc-2 only ?
I ask because I wanted to be Objc-1 only and I tried "[screenFrame 
size]" instead but it doesn't work : I've got this message from the 
compiler :

 "error: bad receiver type 'NSRect' (aka 'struct _NSRect')
  screenSize = [screenFrame size];"

That's not a big deal because I already I had another more complicated 
code for this borrowed from the internet. It's my will to understand 
what's going wrong there.

Cheers,
Bertrand