[Gnash-dev] Matrix hell

[strk]

Zou, I'm having an hard time with that gnash matrix...

This is the test:

1) Matrix is read from SWF:
        (a=1, b=0, c=0, d=-2, tx=200, ty=200)
        _xscale==100;
        _yscale==200; // expected to be positive on extraction
        _rotation==0;

2) _yscale is set to 100:
        (a=1, b=0, c=0, d=-1, tx=200, ty=200) // 'd' expected to retain sign
        _xscale==100;
        _yscale==100; // expected to be positive 
        _rotation==0;

3) _yscale is set to -100
        (a=1, b=0, c=0, d=1, tx=200, ty=200) // 'd' expected to change sign
        _xscale==100;
        _yscale==-100; // as set by AS
        _rotation==0;

4) _yscale is set to 100 [ HERE GNASH FAILS ]
        (a=1, b=0, c=0, d=-1, tx=200, ty=200) // gnash gives 'd=1'
        _xscale==100;
        _yscale==100;
        _rotation==0;

The test is in misc-ming.all/matrix_test.c starting at line 898 as
of revno 9876.

A similar test is in actionscript.all/MovieClip.as, that one succeeding
due to a dirty hack I implemented in character::set_y_scale, that was:
if the character is the _root character, use set_scale_rotation..

--strk;