Re: [ft-devel] [ttfautohint] stem width handling is now selectable

[vern adams]

Did a little testing using OpenSans Reg & Bold under Win7 (cleartype & 
greyscale) and WinXP (cleartype & greyscale) but, to be honest, i didn't see 
any difference :) except under Win7 there the `--strong-stem-width=g gave a 
tiny (i think) better rendering.

In theory, what difference should there be under which render settings? 

-v

On 1 Jul 2012, at 12:49, Werner LEMBERG wrote:

> 
> From the documentation:
> 
> ### Stem Width and Stem Positioning
> 
> `--strong-stem-width=`*string*, `-w`\ *string*
> 
> :   ttfautohint offers two different routines to handle stem widths
>    and stem positions: 'smooth' and 'strong'.  The former uses
>    discrete values which slightly increase the stem contrast with
>    almost no distortion of the outlines, while the latter snaps both
>    stem widths and stem positions to integer pixel values as much as
>    possible, yielding a crisper appearance at the cost of much more
>    distortion.
> 
>    These two routines are mapped onto three possible rendering
>    targets:
> 
>    - grayscale rendering, with or without optimization for subpixel
>      positioning (e.g. Mac OS\ X)
> 
>    - 'GDI ClearType' rendering: the rasterizer version, as returned
>      by the GETINFO bytecode instruction, is in the range 36\ <=
>      version <\ 38 and ClearType is enabled (e.g. Windows XP)
> 
>    - 'DirectWrite ClearType' rendering: the rasterizer version, as
>      returned by the GETINFO bytecode instruction, is >=\ 38,
>      ClearType is enabled, and subpixel positioning is enabled also
>      (e.g.  Windows\ 7)
> 
>    GDI ClearType uses a mode similar to B/W rendering along the
>    vertical axis, while DW ClearType applies grayscale rendering.
>    Additionally, only DW ClearType provides subpixel positioning
>    along the x\ axis.
> 
>    The command line option expects *string* to contain up to three
>    letters with possible values '`g`' for grayscale, '`G`' for GDI
>    ClearType, and '`D`' for DW ClearType.  If a letter is found in
>    *string*, the strong stem width routine is used for the
>    corresponding rendering target.  The default value is '`G`' which
>    means that strong stem width handling is activated for GDI
>    ClearType only.  To use smooth stem width handling for all three
>    rendering targets, use the empty string as an argument, usually
>    connoted with '`""`'.
> 
>    In the GUI, the option is split into three sets of radio buttons
>    to select the stem width routine for a given rendering target.
> 
> 
>  Please test and enjoy!
> 
> 
>     Werner