Commit 6a557996 authored by Simon Budig's avatar Simon Budig Committed by Simon Budig

untested and unused stuff for the interpolation of bezier curves. More to

222002-12-28  Simon Budig  <simon@gimp.org>

        * app/vectors/gimpbezierstroke.c: untested and unused stuff
        for the interpolation of bezier curves. More to come soon.
parent a498acb3
2002-12-28 Simon Budig <simon@gimp.org>
* app/vectors/gimpbezierstroke.c: untested and unused stuff
for the interpolation of bezier curves. More to come soon.
2002-12-27 Maurits Rijk <lpeek.mrijk@consunet.nl>
* plug-ins/common/smooth_palette.c (dialog): fix for #82490 (Smooth
......
......@@ -29,6 +29,8 @@
#include "gimpanchor.h"
#include "gimpbezierstroke.h"
#define INPUT_RESOLUTION 256
#define DETAIL 0.25
/* private variables */
......@@ -274,17 +276,172 @@ gimp_bezier_stroke_interpolate (const GimpStroke *stroke,
/* local helper functions for bezier subdivision */
/* amul * a + bmul * b */
static void
gimp_bezier_coords_mix (gdouble amul,
GimpCoords *a,
gdouble bmul,
GimpCoords *b,
GimpCoords *ret_val)
{
if (b)
{
ret_val->x = amul * a->x + bmul * b->x ;
ret_val->y = amul * a->y + bmul * b->x ;
ret_val->pressure = amul * a->pressure + bmul * b->x ;
ret_val->xtilt = amul * a->xtilt + bmul * b->x ;
ret_val->ytilt = amul * a->ytilt + bmul * b->x ;
ret_val->wheel = amul * a->wheel + bmul * b->x ;
}
else
{
ret_val->x = amul * a->x;
ret_val->y = amul * a->y;
ret_val->pressure = amul * a->pressure;
ret_val->xtilt = amul * a->xtilt;
ret_val->ytilt = amul * a->ytilt;
ret_val->wheel = amul * a->wheel;
}
}
/* (a+b)/2 */
static void
gimp_bezier_coords_average (GimpCoords *a,
GimpCoords *b,
GimpCoords *ret_average)
{
ret_average->x = (a->x + b->x ) / 2.0;
ret_average->y = (a->y + b->y ) / 2.0;
ret_average->pressure = (a->pressure + b->pressure) / 2.0;
ret_average->xtilt = (a->xtilt + b->xtilt ) / 2.0;
ret_average->ytilt = (a->ytilt + b->ytilt ) / 2.0;
ret_average->wheel = (a->wheel + b->wheel ) / 2.0;
gimp_bezier_coords_mix (0.5, a, 0.5, b, ret_average);
}
/* a - b */
static void
gimp_bezier_coords_difference (GimpCoords *a,
GimpCoords *b,
GimpCoords *ret_difference)
{
gimp_bezier_coords_mix (1.0, a, -1.0, b, ret_difference);
}
/* a * f = ret_product */
static void
gimp_bezier_coords_scale (gdouble f,
GimpCoords *a,
GimpCoords *ret_multiply)
{
gimp_bezier_coords_mix (f, a, 0.0, NULL, ret_multiply);
}
/* local helper for measuring the scalarproduct of two gimpcoords. */
static gdouble
gimp_bezier_coords_scalarprod (GimpCoords *a,
GimpCoords *b)
{
return (a->x * b->x +
a->y * b->y +
a->pressure * b->pressure +
a->xtilt * b->xtilt +
a->ytilt * b->ytilt +
a->wheel * b->wheel );
}
/*
* The "lenght" of the gimpcoord.
* Applies a metric that increases the weight on the
* pressure/xtilt/ytilt/wheel to ensure proper interpolation
*/
static gdouble
gimp_bezier_coords_length2 (GimpCoords *a)
{
GimpCoords upscaled_a;
upscaled_a.x = a->x;
upscaled_a.y = a->y;
upscaled_a.pressure = a->pressure * INPUT_RESOLUTION;
upscaled_a.xtilt = a->xtilt * INPUT_RESOLUTION;
upscaled_a.ytilt = a->ytilt * INPUT_RESOLUTION;
upscaled_a.wheel = a->wheel * INPUT_RESOLUTION;
return (gimp_bezier_coords_scalarprod (&upscaled_a, &upscaled_a));
}
static gdouble
gimp_bezier_coords_length (GimpCoords *a)
{
return (sqrt (gimp_bezier_coords_length2 (a)));
}
/*
* a helper function that determines if a bezier segment is "straight
* enough" to be approximated by a line.
*
* Needs four GimpCoords in an array.
*/
static gboolean
gimp_bezier_coords_is_straight (GimpCoords *beziercoords)
{
GimpCoords line, tan1, tan2, d1, d2;
gdouble l2, s1, s2;
gimp_bezier_coords_difference (&(beziercoords[3]),
&(beziercoords[0]),
&line);
if (gimp_bezier_coords_length2 (&line) < DETAIL * DETAIL)
{
gimp_bezier_coords_difference (&(beziercoords[1]),
&(beziercoords[0]),
&tan1);
gimp_bezier_coords_difference (&(beziercoords[2]),
&(beziercoords[3]),
&tan2);
if ((gimp_bezier_coords_length2 (&tan1) < DETAIL * DETAIL) &&
(gimp_bezier_coords_length2 (&tan2) < DETAIL * DETAIL))
{
return 1;
}
else
{
return 0;
}
}
else
{
gimp_bezier_coords_difference (&(beziercoords[1]),
&(beziercoords[0]),
&tan1);
gimp_bezier_coords_difference (&(beziercoords[2]),
&(beziercoords[0]),
&tan2);
l2 = gimp_bezier_coords_scalarprod (&line, &line);
s1 = gimp_bezier_coords_scalarprod (&line, &tan1) / l2;
s2 = gimp_bezier_coords_scalarprod (&line, &tan2) / l2;
if (s1 < 0 || s1 > 1 || s2 < 0 || s2 > 1 || s2 < s1)
return 0;
gimp_bezier_coords_mix (1.0, &tan1, - s1, &line, &d1);
gimp_bezier_coords_mix (1.0, &tan2, - s2, &line, &d2);
if ((gimp_bezier_coords_length2 (&d1) > DETAIL * DETAIL) ||
(gimp_bezier_coords_length2 (&d2) > DETAIL * DETAIL))
return 0;
return 1;
}
}
......@@ -300,7 +457,7 @@ gimp_bezier_coords_subdivide (GimpCoords *beziercoords,
*/
GimpCoords subdivided[8];
gint i, good_enough = 1;
gint i;
subdivided[0] = beziercoords[0];
subdivided[6] = beziercoords[3];
......@@ -333,7 +490,7 @@ gimp_bezier_coords_subdivide (GimpCoords *beziercoords,
* if the stroke is sufficiently close to a straight line.
*/
if ( good_enough /* stroke 1 */ )
if (gimp_bezier_coords_is_straight (&(subdivided[0])) /* stroke 1 */)
{
for (i=0; i < 3; i++)
{
......@@ -348,7 +505,7 @@ gimp_bezier_coords_subdivide (GimpCoords *beziercoords,
ret_ncoords, ret_coords);
}
if ( good_enough /* stroke 2 */ )
if (gimp_bezier_coords_is_straight (&(subdivided[3])) /* stroke 1 */)
{
for (i=0; i < 3; i++)
{
......
Makefile
Makefile.in
.xvpics
.thumbnails
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