Re: [Devel] Freetype 2.1.2 & rotated text

[Detlef Würkner]

address@hidden (Jan Slupski) wrote:

> After I have switched to 2.1.2 (from 2.1.0) all rendered texts
> that was rotated of 45 degrees, are rotated now of -45 degrees
> (or 315 degrees).
> 
> Is it a bug or a planned future?

Its a problem... The latest fix of FT_Vector_Transform() swapped
xy and yx of the input matrix. Now the rotation has changed direction,
and the shearing has changed the axis. We'll have to check all calls
to FT_Vector|Outline|Glyph_Transform()...?

The documentation (docs/tutorial/step2.html) describes the new behaviour
(xy = 0 for horizontal shear)
----8<----
// transform glyph2 (horizontal shear)
    //
    matrix.xx = 0x10000;
    matrix.xy = 0;
    matrix.yx = 0.12 * 0x10000;
    matrix.yy = 0x10000;

    FT_Glyph_Transform( glyph2, &matrix, 0 );
----8<----

while the source code (src/base/ftsynth.c) uses the old behaviour
(yx = 0 for horizontal shear)
----8<----
    /* For italic, simply apply a shear transform, with an angle */
    /* of about 12 degrees.                                      */

    transform.xx = 0x10000L;
    transform.yx = 0x00000L;

    transform.xy = 0x06000L;
    transform.yy = 0x10000L;

    FT_Outline_Transform( outline, &transform );
----8<----

Just looked into the source code of ttf.library which uses
old FreeType 1.3.1 and found it uses yx = 0 for horizontal shear
(old behaviour).

Ciao, Detlef
-- 
_ // address@hidden
\X/  Detlef Wuerkner, Langgoens/Germany