Re: Meaning of NSFont italicAngle?
Re: Meaning of NSFont italicAngle?
- Subject: Re: Meaning of NSFont italicAngle?
- From: Thomas Lachand-Robert <email@hidden>
- Date: Thu, 4 Nov 2004 19:47:14 +0100
Le 4 nov. 04, à 18:28, Henry McGilton a écrit :
On Wednesday, November 3, 2004, at 02:15 PM, Thomas Lachand-Robert
wrote:
Hi all,
I would like to know the true meaning of italicAngle for a NSFont.
The doc says:
- (float)italicAngle
Returns the receiver’s italic angle, the amount that the font is
slanted in degrees clockwise from the vertical, as read from its AFM
file.
What 'doc' are you reading? My documentation of NSFont says:
Returns the receiver's italic angle, the amount that the font
is slanted in degrees counterclockwise from the vertical,
as read from its AFM file.
Note 'counterclockwise'. Given that context, a clockwise slant
should
be interpreted as a negative number. In general, Adobe PostScript (and
by extension, font metrics) use positive values to mean
counterclockwise
rotations.
I return you the question. (Maybe you got the doc for Tiger?) I just
copied and paste from Apple's developer doc. I get the same on the web
site:
http://developer.apple.com/documentation/Cocoa/Reference/
ApplicationKit/ObjC_classic/Classes/NSFont.html#//apple_ref/doc/uid/
20000382/italicAngle
Anyway I don't mind much the sign, since I know how the fonts are
slanted in my case. I am looking for the amount.
And 1.5 degree is a very small angle, so it's probably not that
(but in radians, it's too much!). Could it be the tangent of the
angle?
I checked the AFM file for Times-Italic. The AFM file says that the
Italic angle is -15.5. I used TextEdit to display some Times-Italic
text at large size, and, using my trusty Protractors application,
measured
the angle as being approximately 15 degrees clockwise from the
vertical.
I also checked the AFM file for Helvetica-Oblique. The AFM file says
that the
Italic angle is -12.0. I used TextEdit to display some
Helvetica-Oblique
text at large size, and, using my trusty Protractors application,
measured
the angle as being approximately 12 degrees clockwise from the
vertical.
I also checked for Optima-Oblique (which for some obscure reason Cocoa
wants
to be called Optima-Italic). The AFM file says Italic angle is -11.0
(this
is an old AFM file). The system reports the angle as -1.2.
Very unlikely that the number is the tangent. The tangent of -15.5
degrees
is about -0.278.
There does seem to be some kind of anomaly, though. It's as if the
system is
off by a factor of ten in every case.
Could somebody at Apple comment on this anomaly?
Yes I agree with you: it's probably a factor 10 or something. Anyway
you proved that it is NOT the value in the AFM file, so the doc is
definitely wrong.
Thanks for your comments and experiments,
Thomas Lachand-Robert
********************** email@hidden
<< Et le chemin est long du projet à la chose. >> Molière, Tartuffe.
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