[Freetype] freetype behaviour below zero

[n++k]

Hello,

calling FT_Outline_Render, using freetype as a rasterizer, i am 
encountering one behaviour i would qualify as a bug if it wasn't
too obvious to have been missed by others. but i can't explain it
either:

given the following outline: 
({ x, y } is a vector)

conic from: { 0.f, -1.f} to: { 1.f,  0.f} control_point: { 1.f, -1.f}
conic from: { 1.f,  0.f} to: { 0.f,  1.f} control_point: { 1.f,  1.f}
conic from: { 0.f,  1.f} to: {-1.f,  0.f} control_point: {-1.f,  1.f}
conic from: {-1.f,  0.f} to: { 0.f, -1.f} control_point: {-1.f, -1.f}

c4  1  c1
 4  .   2
c3  3  c2

I get the result found at http://knos.free.fr/o.gif which displays 
a correct outline above 0 but seems to use a coarse resolution 
below zero. 

Is it expected and is there a way to fix this behaviour other
than always translating outlines so that they always lay above
zero? (which complicates scaling/rotating and such)

Thanks.