Re: [Gegl-developer] Proposition : GeglInterpolator

[Øyvind Kolås]

On 10/15/06, Geert Jordaens <[EMAIL PROTECTED]> wrote:

I've added the implementation to bug report : Bug 360888 – Interpolation

snip

usage :

snip

Maybe something along the following lines would be a better API?

/Øyvind K.

void
displacementmap (GeglBuffer *src,
                GeglBuffer *aux,
                GeglBuffer *dst,
                gdouble     scale,
                gint        cx,
                gint        cy)
{
 gint i, j;
 gint dst_pos=0;
 gfloat *buf     = g_malloc0 (4 * 4 * 4);
 gfloat *aux_buf = g_malloc0 (aux->width * aux->height * 4 * 4);
 gfloat *dst_buf = g_malloc0 (dst->width * dst->height * 4 * 4);
 gegl_buffer_get_fmt (aux, aux_buf, babl_format ("RGBA float"));
 gegl_buffer_get_fmt (dst, dst_buf, babl_format ("RaGaBaA float"));

 *GeglSampler *sampler = g_object_new (GEGL_TYPE_SAMPLER_CUBIC,
      "input", src,
      "format", babl_format ("RaGaBaA float"),
      "x", 50,
      "y", 50,
      "width", 200,  /* or a rect could be passed, or a subbuffer of
      "height", 200,    buffer expected to be created before making a
sampler */
      NULL);

 for (i = 0; i < src->height; i++)
   for (j = 0; j < src->width; j++)
     {
       gdouble dx, dy, xc, yc;

       /* Calculate x/y - offset relative to origin */
       dx = (gdouble) j / (src->width-1.0);
       dy = (gdouble) i / (src->height-1.0);
       xc = j + (gint) (displacement (aux, aux_buf, dx, dy, cx) * scale);
       yc = i + (gint) (displacement (aux, aux_buf, dx, dy, cy) * scale);

       /* returns a freshly sampled pixel in dst */
       gegl_sampler_get (sampler, xc, yc, buf);

     #if 0
       /* using this form, might make more sense, since it would allow accurate
          sampling as needed by affine/perspective transforms that are scaling
          down as well as when scaling up/interpolating
        */
       gegl_sampler_get_quad (sampler, xc-0.5, yc-0.5,
                                       xc+0.5, yc-0.5,
                                       xc+0.5, yc+0.5,
                                       xc-0.5, yc+0.5,
                                       buf);
     #endif

       {
         int component;
         for (component = 0 ; component < 4 ; component++)
           dst_buf[dst_pos+component]= buf[component];
       }
       dst_pos+=4;
     }

 gegl_buffer_set_fmt (dst, dst_buf, babl_format ("RaGaBaA float"));
 g_object_unref (sampler);
 g_free (aux_buf);
 g_free (dst_buf);
}

--
«The future is already here. It's just not very evenly distributed»
                                                -- William Gibson
http://pippin.gimp.org/                            http://ffii.org/
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