gimp/app/vectors/gimppath-warp.c

211 lines
5.3 KiB
C

/* GIMP - The GNU Image Manipulation Program
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* gimppath-warp.c
* Copyright (C) 2005 Bill Skaggs <weskaggs@primate.ucdavis.edu>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <gdk-pixbuf/gdk-pixbuf.h>
#include <gegl.h>
#include "vectors-types.h"
#include "libgimpmath/gimpmath.h"
#include "core/gimp-utils.h"
#include "core/gimpcoords.h"
#include "gimpanchor.h"
#include "gimpstroke.h"
#include "gimppath.h"
#include "gimppath-warp.h"
#define EPSILON 0.2
#define DX 2.0
static void gimp_stroke_warp_point (GimpStroke *stroke,
gdouble x,
gdouble y,
GimpCoords *point_warped,
gdouble y_offset,
gdouble x_len);
static void gimp_path_warp_stroke (GimpPath *path,
GimpStroke *stroke,
gdouble y_offset);
void
gimp_path_warp_point (GimpPath *path,
GimpCoords *point,
GimpCoords *point_warped,
gdouble y_offset)
{
gdouble x = point->x;
gdouble y = point->y;
gdouble len;
GList *list;
GimpStroke *stroke;
for (list = path->strokes->head;
list;
list = g_list_next (list))
{
stroke = list->data;
len = gimp_path_stroke_get_length (path, stroke);
if (x < len || ! list->next)
break;
x -= len;
}
if (! list)
{
point_warped->x = 0;
point_warped->y = 0;
return;
}
gimp_stroke_warp_point (stroke, x, y, point_warped, y_offset, len);
}
static void
gimp_stroke_warp_point (GimpStroke *stroke,
gdouble x,
gdouble y,
GimpCoords *point_warped,
gdouble y_offset,
gdouble x_len)
{
GimpCoords point_zero = { 0, };
GimpCoords point_minus = { 0, };
GimpCoords point_plus = { 0, };
gdouble slope;
gdouble dx, dy, nx, ny, len;
if (x + DX >= x_len)
{
gdouble tx, ty;
if (! gimp_stroke_get_point_at_dist (stroke, x_len, EPSILON,
&point_zero, &slope))
{
point_warped->x = 0;
point_warped->y = 0;
return;
}
point_warped->x = point_zero.x;
point_warped->y = point_zero.y;
if (! gimp_stroke_get_point_at_dist (stroke, x_len - DX, EPSILON,
&point_minus, &slope))
return;
dx = point_zero.x - point_minus.x;
dy = point_zero.y - point_minus.y;
len = hypot (dx, dy);
if (len < 0.01)
return;
tx = dx / len;
ty = dy / len;
nx = - dy / len;
ny = dx / len;
point_warped->x += tx * (x - x_len) + nx * (y - y_offset);
point_warped->y += ty * (x - x_len) + ny * (y - y_offset);
return;
}
if (! gimp_stroke_get_point_at_dist (stroke, x, EPSILON,
&point_zero, &slope))
{
point_warped->x = 0;
point_warped->y = 0;
return;
}
point_warped->x = point_zero.x;
point_warped->y = point_zero.y;
if (! gimp_stroke_get_point_at_dist (stroke, x - DX, EPSILON,
&point_minus, &slope))
return;
if (! gimp_stroke_get_point_at_dist (stroke, x + DX, EPSILON,
&point_plus, &slope))
return;
dx = point_plus.x - point_minus.x;
dy = point_plus.y - point_minus.y;
len = hypot (dx, dy);
if (len < 0.01)
return;
nx = - dy / len;
ny = dx / len;
point_warped->x = point_zero.x + nx * (y - y_offset);
point_warped->y = point_zero.y + ny * (y - y_offset);
}
static void
gimp_path_warp_stroke (GimpPath *path,
GimpStroke *stroke,
gdouble y_offset)
{
GList *list;
for (list = stroke->anchors->head; list; list = g_list_next (list))
{
GimpAnchor *anchor = list->data;
gimp_path_warp_point (path,
&anchor->position, &anchor->position,
y_offset);
}
}
void
gimp_path_warp_path (GimpPath *path,
GimpPath *path_in,
gdouble y_offset)
{
GList *list;
for (list = path_in->strokes->head;
list;
list = g_list_next (list))
{
GimpStroke *stroke = list->data;
gimp_path_warp_stroke (path, stroke, y_offset);
}
}