[ft] Clipping Of Empty Glyphs (space)

[Mickey Gabel]

Hi all,

I am writing a text rendering library based on FreeType 2.3.5. and 
encountered some problems.

One of the problems I encountered was translation of "empty" glyphs like 
the space character ' '.

        // assume chacater is loaded and copied to glyph[i]
        FT_Glyph_Transform( glyph[i], NULL, &pen_pos[i] );  
        FT_Glyph_Get_CBox( glyph[i], FT_GLYPH_BBOX_PIXELS, &bbox );
        FT_Glyph_To_Bitmap( glyph[i], FT_RENDER_MODE_NORMAL, NULL, 1 );
        DrawBitmap( (FT_BitmapGlyph)glyph[i], clip_region, ... );

I also do some clipping in DrawBitmap(). Everything works just fine so 
far, including clipping, mostly.

My goal is to determine if a glyph is inside the clip region, or 
outside, or partially clipped. It works fine for most glyphs.
However for empty glyphs like ' ' it seems that the CBox (bbox) is all 
zeros, and the bitmap->left and bitmap->top are also some unrelated 
value that ignores the transform I set. For ' ' I was sort of expecting 
a bbox with height 0 but with a real width and position.

Even if these characters don't need to be drawn anyway, I need to 
determine if they are inside the clip_region.
How do I do that?


Thanks,
        Mickey