[Freetype] Transforming glyph : use of API

[SOULLARD Clement]

Hi,

I want to transform some glyph but I'm not sure that I do a correct use
of the APIs for doing that. I may write a tutorial on this if someone
explain it to me... This would probably be a good Part III in the
tutorial...

So, to perform this I use the method :
- FT_Load_Glyph (face, nglyph, FT_LOAD_DEFAULT);
- FT_Get_Glyph( face->glyph,  &glyph );
- FT_Glyph_Transform(glyph,&trans,&vect);
At that point no error is raised at that point...
Then calling :
- FT_Glyph_To_Bitmap( &glyph, FT_RENDER_MODE_NORMAL, 0, 1 ); return me
an error code -1...
Why ? Is this a bad use of the api ?

For details I give you the code I use hereafter. The transformation I
perform is
[2  0]
[1  1]
and the vector is [0,0]
Thanks for your help.
---------------------------------------
/**
Transform the glyph
**/
FT_Glyph
FTFont::transformGlyph(int nglyph,double x00,double x01,double
x10,double x11){
FT_Matrix trans;
trans.xx=x00;trans.xy=x01;trans.yx=x10;trans.yy=x11;
FT_Vector vect;vect.x=0;error=0;
vect.y=0;
FT_Glyph  glyph;
FT_Load_Glyph (face, nglyph, FT_LOAD_DEFAULT);
FT_Get_Glyph( face->glyph,  &glyph );
error=FT_Glyph_Transform(glyph,&trans,&vect);
if(error){
Tracer::printErr("FTFont::transformGlyph erreur dans
error=FT_Glyph_Transform"+QString::number(error));
}
return glyph;
}
------------------------------------------------------------------------- 
-----

/**
Compute the bitmap of a glyph
\param glyph a glyph
**/

uchar*
FTFont::getUmap (FT_Glyph glyph){
FT_BitmapGlyph  glyph_bitmap;

// convert to a bitmap (default render mode + destroy old)
  if ( glyph->format != FT_GLYPH_FORMAT_BITMAP )
  {
    error = FT_Glyph_To_Bitmap( &glyph, FT_RENDER_MODE_NORMAL, 0, 1 );

}
if(error){
Tracer::printErr("FTFont::getUmap Error dans FT_Glyph_To_Bitmap
error="+QString::number(error)+",glyph="+QString::number((long)glyph,16)) 
;
}
  // access bitmap content by typecasting
  glyph_bitmap = (FT_BitmapGlyph)glyph;
FT_Bitmap bitmap=glyph_bitmap->bitmap;
  // discard glyph image (bitmap or not)
return face->glyph->bitmap.buffer;
}



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