Re: ATSUI support on Carbon Emacs

[YAMAMOTO Mitsuharu]

>>>>> On Wed, 12 Oct 2005 10:24:49 +0100, David Reitter <address@hidden> said:

> No, not in terms of letter spacing. I've fallen victim to an optical
> illusion.  It's the line-spacing that makes text appear more loose
> in other apps. Take a look at these screenshots. The enlarged image
> shows Emacs on the left, and TextEdit on the right.

> Also, note that the first line is glued to the tool-bar, which
> doesn't look good at all.

Hmm, I've no idea.  Two ways to calculate the line height are shown in

  
http://developer.apple.com/documentation/Carbon/Conceptual/ATSUI_Concepts/atsui_chap4/chapter_4_section_12.html

and Carbon Emacs applies the second one to the space character for
getting font ascent and descent(+leading).  I also tried some
alternatives such as the first one, the maximum value among all ASCII
characters, a metric function in ATS, and several adjustment of
parameters in ATSUI.  But all of them give essentially the same
results.  Moreover, QuickDraw Text + `SwapQDTextFlags
(kQDUseCGTextRendering | kQDUseCGTextMetrics)' also shows the same
result.  So I think it is the inherent metric for Helvetica.

Maybe Cocoa does something special?  Do you know how other Carbon
applications that use ATSUI look?

                                     YAMAMOTO Mitsuharu
                                address@hidden