[Tcl-bugs] [ tktoolkit-Bugs-2961564 ] No italic TkDefaultFont in Tk Cocoa

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Bugs item #2961564, was opened at 2010-03-01 14:36
Message generated for change (Comment added) made by tom_goddard
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Category: 45. Aqua Fonts
Group: development: 8.6b1.1
Status: Closed
Resolution: Wont Fix
Priority: 5
Private: No
Submitted By: Tom Goddard (tom_goddard)
Assigned to: Daniel A. Steffen (das)
Summary: No italic TkDefaultFont in Tk Cocoa

Initial Comment:
Making a label with font TkDefaultFont and italic slant displays a non-italic font with Tk Cocoa 8.6, Jan 8, 2010 source code.  With Tk 8.5.8 Aqua (Carbon) an italic font is shown.  The default Tk Cocoa font should have an italic version.

Here's a Wish script demonstrating the problem:

label .l -text "in italics?" -font "TkDefaultFont 13 italic"
puts [font actual {TkDefaultFont 13 italic}]
pack .l

On Tk Cocoa 8.6 this shows a non-italic label and prints the following actual font being used:

-family {Lucida Grande} -size 13 -weight normal -slant roman -underline 0 -overstrike 0

On Tk Aqua (Carbon) 8.5.8 the displayed label is italic and the script prints the actual font as:

-family Geneva -size 13 -weight normal -slant italic -underline 0 -overstrike 0

Both tests were run on Mac OS 10.6.2.



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Comment By: Tom Goddard (tom_goddard)
Date: 2010-03-03 23:46

Message:
It is trouble having a default font without an italic slant available.  It
leaves a couple unsavory choices for the Tk app developer (me) of either
trying to find a similar italic font to use with the default roman font (no
way to do that programmatically) or choose another font that supports both
roman and italic slants.  For the developer of cross-platform apps this
kind of weird platform-specific limitation is troublesome.  We develop for
WIndows, Linux and Mac.  The best fix I can think of is to use Arial font
as the Tk default on the Mac.  It is a very similar looking font to Lucida
Grande and cannot be uninstalled because it is used by the OS and has
roman, bold, italic and italic bold variants.

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Comment By: Daniel A. Steffen (das)
Date: 2010-03-03 22:51

Message:
TkAqua Carbon uses QuickDraw font handling which can draw "fake" italic for
fonts that don't have an italic variant, TkAqua Cocoa uses CoreText which
does not provide this hack.

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Comment By: Tom Goddard (tom_goddard)
Date: 2010-03-03 10:19

Message:
Good point.  The bug still exists with the suggested fix to the Tcl
script:

font create ifont {*}[font configure TkDefaultFont] -slant italic
label .l -text "in italics?" -font ifont
puts [font actual ifont]
pack .l

This script with wish8.6 displays a non-italic font for the label reported
as

-family {Lucida Grande} -size 13 -weight normal -slant roman -underline 0
-overstrike 0

while with Tk 8.5.8 Aqua (Carbon) an italic font is shown and reported as

-family {Lucida Grande} -size 13 -weight normal -slant italic -underline 0
-overstrike 0

This latter correct result is mysterious because the Font Book application
on the Mac OS 10.6
system this was tested on reports no italic Lucida Grande font (only
regular and bold), and info
on the web also says there is no such thing as an italic Lucida Grande. 
So it seems that Tk 8.5.8
reports the actual font to be a non-existent font, yet still displays
correctly.




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Comment By: Pat Thoyts (patthoyts)
Date: 2010-03-03 05:36

Message:
{TkDefaultFont 13 italic} is an invalid font description. On the font
manual page in the "FONT DESCRIPTION" section there are 5 acceptable forms
given. The first is that a named font may be provided. The third form is
{family ?size? ?style? ?style...?}. In this case you are presenting a named
font name as a font family name. The system will try and find some
acceptable font as it cant find a match. When I try the above example on
Windows for instance, [font actual TkDefaultFont] gives a "SegoeUI" font
but [font actual {TkDefaultFont 14 italic}] yields an Arial family font
which is the default Tk family match when it can't find anything else
appropriate.
To make an italic version of the TkDefaultFont you should do:
font create TkDefaultItalicFont {*}[font configure TkDefaultFont] -slant
italic


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