RE: Shadows and Borders

[Adam Meyerowitz]

> The outline of a glyph is a series of on- and off-curve points.  By
> drawing straight and curved lines through them, you can outline the
> character.  IIRC, someone on the list was working on code to do just
> that.

I would be very interested in seeing what they have done.  Is there anyway
to get the freetype library to only generate the outline of the character 
instead
of a filled character bitmap?  Unfortunately compositing this outline with 
the filled
character bitmap would lead to the border taking up some of the original 
character
space.  The border should be additional pixels and not take up pixels from the
character body (well in my application at least!)

> > Basically I use a second buffer and for each pixel do a
> > shadow or border.
> > For a border I move up and to the left border pixels and then
> > draw a filled
> > rectangle
> > border*2+1 wide and high.  Then I combine both buffers (the
> > glyph and the
> > border
> > buffer) to make a single bordered character buffer.  For a shadow I
> > basically do what
> > you mentioned for each pixel and then combine the two buffers.
> >
> > This might be the only way, but I thought there might be some
> > other more
> > interesting
> > ways.
>
> Well, stroking the outline would probably look better, particularly if
> you're working with antialiased characters.

Yes that is true.  In my method there is no way of carrying the antialiasing
into the border (this could carry into the shadow though!).  I'd have to see
stroked outlines in action to really understand what you were referring to.


> As for shadowing-- if you're anti-aliasing, I'd actually draw the
> character twice rather than doing a pixel-by-pixel operation.  FreeType
> will give you a grayscale bitmap of the character.  Just composite that
> grayscale bitmap into your target canvas (which could be another bitmap
> or the screen or whatever...) twice, in different positions.  I'd guess
> it would look better than the method you described.

Actually the method I described looks very nice but is comparable to what
you describe.  The problem arises when you want a shadow that is wider
then the regular character.  My method achieves this very easily while yours
might not.


> Alternatively, you could render two copies of the glyph -- one of which
> would be used for the shadow and could be transformed differently (for
> example, stretched to make the shadow appear to disappear into the
> distance).
>
> There are lots of methods for shadowing and outlining; it really depends
> on exactly what you're trying to accomplish.
>
> --Matthew

I would like to generate excellent looking characters that are presentable 
on NTSC
video screens (very bandwidth limited).  Antialiasing is a must.  I would 
like to be able
to do texture mapped fonts (pretty easy in 2d space), with various shadows 
and borders
with varying opacity, etc.

Thanks
Adam