gimp/app/path_curves.c

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/* The GIMP -- an image manipulation program
*
* This file Copyright (C) 1999 Simon Budig
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <math.h>
#include <glib.h>
#include <gdk/gdk.h>
#include "apptypes.h"
#include "path_curves.h"
#include "path_bezier.h"
#include "tools/gimpdrawtool.h"
/* only here temporarily */
PathSegment * path_split_segment (PathSegment *, gdouble);
/* Here the different curves register their functions */
static CurveDescription CurveTypes[] =
{
/* SEGMENT_LINE */
{
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
},
/* SEGMENT_BEZIER */
{
NULL, /* path_bezier_get_points, */
path_bezier_get_point,
NULL, /* path_bezier_draw_handles, */
NULL, /* path_bezier_draw_segment, */
NULL, /* path_bezier_on_segment, */
path_bezier_drag_segment,
path_bezier_on_handles,
path_bezier_drag_handles,
NULL, /* path_bezier_insert_anchor, */
NULL, /* path_bezier_update_segment, */
path_bezier_flip_segment,
path_bezier_init_segment,
NULL /* path_bezier_cleanup_segment */
}
};
/*
* these functions implement the dispatching for the different
* curve-types. It implements default actions, which happen
* to work with straight lines.
*/
guint
path_curve_get_points (PathSegment *segment,
gdouble *points,
guint npoints,
gdouble start,
gdouble end)
{
gdouble pos, x, y;
gint index=0;
if (segment && segment->next) {
if (CurveTypes[segment->type].get_points)
return (* CurveTypes[segment->type].get_points) (segment, points, npoints, start, end);
else {
if (npoints > 1 && segment && segment->next) {
for (pos = start; pos <= end; pos += (end - start) / (npoints -1)) {
path_curve_get_point (segment, pos, &points[index*2],
&points[index*2+1]);
index++;
}
return index;
} else
return 0;
}
}
#ifdef PATH_TOOL_DEBUG
else
fprintf (stderr, "path_curve_get_points called without valid curve");
#endif
return 0;
}
void
path_curve_get_point (PathSegment *segment,
gdouble position,
gdouble *x,
gdouble *y)
{
if (segment && segment->next) {
if (CurveTypes[segment->type].get_point)
(* CurveTypes[segment->type].get_point) (segment, position, x, y);
else {
#if 1
*x = segment->x + (segment->next->x - segment->x) * position;
*y = segment->y + (segment->next->y - segment->y) * position;
#else
/* Only here for debugging purposes: A bezier curve with fixed tangents */
*x = (1-position)*(1-position)*(1-position) * segment->x +
3 * position *(1-position)*(1-position) * (segment->x - 60) +
3 * position * position *(1-position) * (segment->next->x + 60) +
position * position * position * (segment->next->x);
*y = (1-position)*(1-position)*(1-position) * segment->y +
3 * position *(1-position)*(1-position) * (segment->y + 60) +
3 * position * position *(1-position) * (segment->next->y + 60) +
position * position * position * (segment->next->y);
#endif
}
}
#ifdef PATH_TOOL_DEBUG
else
fprintf (stderr, "path_curve_get_point called without valid curve");
#endif
return;
}
void
path_curve_draw_handles (GimpDrawTool *tool,
PathSegment *segment)
{
if (segment && CurveTypes[segment->type].draw_handles)
(* CurveTypes[segment->type].draw_handles) (tool, segment);
/* straight lines do not have handles... */
return;
}
void
path_curve_draw_segment (GimpDrawTool *tool,
PathSegment *segment)
{
gint x, y, numpts, index;
if (segment && segment->next) {
if (CurveTypes[segment->type].draw_segment) {
(* CurveTypes[segment->type].draw_segment) (tool, segment);
return;
} else {
gdouble *coordinates = g_new (gdouble, 200);
numpts = path_curve_get_points (segment, coordinates, 100, 0, 1);
gimp_draw_tool_draw_lines (tool, coordinates, 100, FALSE);
g_free (coordinates);
}
#ifdef PATH_TOOL_DEBUG
} else {
fprintf (stderr, "Fatal Error: path_curve_draw_segment called without valid segment *\n");
#endif
}
return;
}
gdouble
path_curve_on_segment (PathSegment *segment,
gint x,
gint y,
gint halfwidth,
gint *distance)
{
if (segment && CurveTypes[segment->type].on_segment)
return (* CurveTypes[segment->type].on_segment) (segment, x, y, halfwidth, distance);
else {
if (segment && segment->next) {
#if 1
gint x1, y1, numpts, index;
gdouble *coordinates;
gint bestindex = -1;
coordinates = g_new (gdouble, 200);
*distance = halfwidth * halfwidth + 1;
numpts = path_curve_get_points (segment, coordinates, 100, 0, 1);
for (index=0; index < numpts; index++) {
x1 = coordinates[2*index];
y1 = coordinates[2*index+1];
if (((x - x1) * (x - x1) + (y - y1) * (y - y1)) < *distance) {
*distance = (x - x1) * (x - x1) + (y - y1) * (y - y1);
bestindex = index;
}
}
g_free (coordinates);
if (numpts == 1) {
*distance = (gint) sqrt ((gdouble) *distance);
return bestindex;
}
if (bestindex >= 0 && (*distance <= halfwidth * halfwidth)) {
*distance = (gint) sqrt ((gdouble) *distance);
return bestindex == 0 ? 0 : ((gdouble) bestindex) / (numpts - 1);
}
#else
/* Special case for lines */
gdouble Ax, Ay, Bx, By, r, d;
Ax = segment->x;
Ay = segment->y;
Bx = segment->next->x;
By = segment->next->y;
r = (( x - Ax)*(Bx - Ax) + ( y - Ay)* (By - Ay)) /
((Bx - Ax)*(Bx - Ax) + (By - Ay)* (By - Ay)) ;
if (r >= 0 && r <= 1) {
d = (((Ax + (Bx - Ax) * r) - x) * ((Ax + (Bx - Ax) * r) - x) +
((Ay + (By - Ay) * r) - y) * ((Ay + (By - Ay) * r) - y));
if (d <= halfwidth * halfwidth) {
*distance = (gint) (d + 0.5);
return r;
}
}
#endif
}
}
return -1;
}
void
path_curve_drag_segment (PathSegment *segment,
gdouble position,
gdouble dx,
gdouble dy)
{
if (segment && CurveTypes[segment->type].drag_segment)
(* CurveTypes[segment->type].drag_segment) (segment, position, dx, dy);
return;
}
gint
path_curve_on_handle (PathSegment *segment,
gdouble x,
gdouble y,
gdouble halfwidth)
{
if (segment && CurveTypes[segment->type].on_handles)
return (* CurveTypes[segment->type].on_handles) (segment, x, y, halfwidth);
return FALSE;
}
void
path_curve_drag_handle (PathSegment *segment,
gdouble dx,
gdouble dy,
gint handle_id)
{
if (segment && CurveTypes[segment->type].drag_handle)
(* CurveTypes[segment->type].drag_handle) (segment, dx, dy, handle_id);
}
PathSegment *
path_curve_insert_anchor (PathSegment *segment,
gdouble position)
{
if (segment && CurveTypes[segment->type].insert_anchor)
return (* CurveTypes[segment->type].insert_anchor) (segment, position);
else {
return path_split_segment (segment, position);
}
}
void
path_curve_flip_segment (PathSegment *segment)
{
if (segment && CurveTypes[segment->type].flip_segment)
(* CurveTypes[segment->type].flip_segment) (segment);
return;
}
void
path_curve_update_segment (PathSegment *segment)
{
if (segment && CurveTypes[segment->type].update_segment)
(* CurveTypes[segment->type].update_segment) (segment);
return;
}
void
path_curve_init_segment (PathSegment *segment)
{
if (segment && CurveTypes[segment->type].init_segment)
(* CurveTypes[segment->type].init_segment) (segment);
return;
}
void
path_curve_cleanup_segment (PathSegment *segment)
{
if (segment && CurveTypes[segment->type].cleanup_segment)
(* CurveTypes[segment->type].cleanup_segment) (segment);
return;
}