Re: [ft] bitmap_left description

[Phil Endecott]

Hi Werner & others,

Werner LEMBERG wrote:
> > The docs for bitmap_left say:
> >
> >     This is the bitmap's left bearing expressed in integer
> >     pixels. Of course, this is only valid if the format is
> >     FT_GLYPH_FORMAT_BITMAP.
> >
> > I'm rendering individual glyphs from a TrueType font using
> > FT_Load_Glyph() followed by FT_Render_Glyph().  Having done that I
> > had been struggling to work out the metrics for the result.  Then I
> > discovered that bitmap_left and bitmap_top seem to tell me exactly
> > what I need to know - but I had been avoiding them because this not
> > a bitmap font and the description quoted above.
>
> Well, after calling FT_Render_Glyph, `face->glyph' *does* hold a
> bitmap, as specified by the `face->glyph->format' field.  Please read
> the documentation of its type, `FT_GlyphSlotRec'.
>
> > Is it OK to use bitmap_left/top after FT_Render_Glyph()?
>
> Yes.

Thanks for confirming that.  I'll shortly write a more general "am
I doing this right?" email, but I do seem to be getting the results
I expected now that I'm using bitmap_left/top.

> > Is this a documentation issue?
>
> Obviously.  Please suggest an improvement.

My "mental disconnect" was between the format of the glyph, which
I imagined to be vector (and only vector) for a glyph from a vector
font, and the presence of a bitmap in the glyph slot after rendering.

So my suggestion would be to say:

     This is the bitmap's left bearing expressed in integer
     pixels. This is only valid if the glyph slot contains
     a bitmap.


Thanks,  Phil.