[Freeciv-Dev] Re: Betr: Re: (PR#7123) Metaissue for FS

["Vasco Alexandre da Silva Costa" <vasc@xxxxxxxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=7123 >

On Fri, 2 Jan 2004, Raimar Falke wrote:

>
> <URL: http://rt.freeciv.org/Ticket/Display.html?id=7123 >
>
> On Fri, Jan 02, 2004 at 05:58:11AM -0800, Raimar Falke wrote:
> > > Regarding overlays of text over complex drawn backgrounds: always add an
> > > outline around the text. The outline should always be black unless the
> > > text is black or very dark, in that case the outline should be white.
> > >
> > > The reason should be obvious:
> > > http://webreference.com/graphics/column20/art/psout.gif
> >
> > Also added to my todo-list.
>
> A difficult topic. The poor-man version (I call this the
> halo-method) looks like this:
>
>       for (d = 0; d < 8; d++) {
>       struct ct_point p2 = p;
>
>       p2.x += DIR_DX[d];
>       p2.y += DIR_DY[d];
>       be_draw_bitmap(target, 0, black, &p2,
>                        string->data->glyphs[i].bitmap);
>       }
>       be_draw_bitmap(target, 0, string->foreground, &p,
>                    string->data->glyphs[i].bitmap);
>
> You first draw 8 different versions of the bitmap in black and then
> the final one in the real color.
>
> I was under the impression that there must be a more elegant
> method. freetype since around version 2.1.3 includes FT_Stroker. This
> module is supposed to draw the stroke (another word for the outline we
> want) based on the vector outlines (this "outline" is a different one)
> of the font. The only usage of this modul is the titler plugin of the
> cinelerra project. However in my own experiments with freetype 2.1.4
> this ftstroker modul was buggy (it misses the outlines of the right
> side).

We used a simpler trick on the Amiga when doing computer art. The trick is
to draw the black text first, with the same center, but a slightly larger
font size, say, +2 pts. Then you draw the regular text on top. This
requires only two steps.

> ImageMagick also has a stroke feature. The implementation is very
> similar to the ftstroker (decompose the outline of the glyph into
> Bezier curves and lines and draw these onto a bitmap) but is working.
>
> A comparison of the methods is available at
> http://freeciv.org/~rfalke/fs3_pics/outline.png. The first is drawed
> by gui-fs with the halo method. The remaining items are drawn by
> ImageMagick into the screenshot with various strokewidths. A
> strokewidth of 1.5 is comparable to the halo-method. See
> http://freeciv.org/~rfalke/fs3_pics/outline_contrast.png for an easy
> comparison.
>
> Even with the MUCH more complex methods used by ftstroker and
> ImageMagick the results are comparable to the halo-method. The halo
> method however only supports integral stroke widths.

---
Vasco Alexandre da Silva Costa @ Instituto Superior Tecnico, Lisboa