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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:30:19 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:30:19 +0000 |
commit | 5c1676dfe6d2f3c837a5e074117b45613fd29a72 (patch) | |
tree | cbffb45144febf451e54061db2b21395faf94bfe /app/core/gimpcoords-interpolate.c | |
parent | Initial commit. (diff) | |
download | gimp-5c1676dfe6d2f3c837a5e074117b45613fd29a72.tar.xz gimp-5c1676dfe6d2f3c837a5e074117b45613fd29a72.zip |
Adding upstream version 2.10.34.upstream/2.10.34upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | app/core/gimpcoords-interpolate.c | 371 |
1 files changed, 371 insertions, 0 deletions
diff --git a/app/core/gimpcoords-interpolate.c b/app/core/gimpcoords-interpolate.c new file mode 100644 index 0000000..f667e57 --- /dev/null +++ b/app/core/gimpcoords-interpolate.c @@ -0,0 +1,371 @@ +/* GIMP - The GNU Image Manipulation Program + * Copyright (C) 1995 Spencer Kimball and Peter Mattis + * + * gimpcoords-interpolate.c + * + * 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 <glib-object.h> + +#include "libgimpmath/gimpmath.h" + +#include "core-types.h" + +#include "gimpcoords.h" +#include "gimpcoords-interpolate.h" + + +/* Local helper functions declarations*/ +static void gimp_coords_interpolate_bezier_internal (const GimpCoords bezier_pt[4], + const gdouble start_t, + const gdouble end_t, + const gdouble precision, + GArray *ret_coords, + GArray *ret_params, + gint depth); +static gdouble gimp_coords_get_catmull_spline_point (const gdouble t, + const gdouble p0, + const gdouble p1, + const gdouble p2, + const gdouble p3); + +/* Functions for bezier subdivision */ + +void +gimp_coords_interpolate_bezier (const GimpCoords bezier_pt[4], + const gdouble precision, + GArray *ret_coords, + GArray *ret_params) +{ + g_return_if_fail (bezier_pt != NULL); + g_return_if_fail (precision > 0.0); + g_return_if_fail (ret_coords != NULL); + + gimp_coords_interpolate_bezier_internal (bezier_pt, + 0.0, 1.0, + precision, + ret_coords, ret_params, 10); +} + +/* Recursive subdivision helper function */ +static void +gimp_coords_interpolate_bezier_internal (const GimpCoords bezier_pt[4], + const gdouble start_t, + const gdouble end_t, + const gdouble precision, + GArray *ret_coords, + GArray *ret_params, + gint depth) +{ + /* + * bezier_pt has to contain four GimpCoords with the four control points + * of the bezier segment. We subdivide it at the parameter 0.5. + */ + + GimpCoords subdivided[8]; + gdouble middle_t = (start_t + end_t) / 2; + + subdivided[0] = bezier_pt[0]; + subdivided[6] = bezier_pt[3]; + + /* if (!depth) g_printerr ("Hit recursion depth limit!\n"); */ + + gimp_coords_average (&bezier_pt[0], &bezier_pt[1], &subdivided[1]); + gimp_coords_average (&bezier_pt[1], &bezier_pt[2], &subdivided[7]); + gimp_coords_average (&bezier_pt[2], &bezier_pt[3], &subdivided[5]); + + gimp_coords_average (&subdivided[1], &subdivided[7], &subdivided[2]); + gimp_coords_average (&subdivided[7], &subdivided[5], &subdivided[4]); + gimp_coords_average (&subdivided[2], &subdivided[4], &subdivided[3]); + + /* + * We now have the coordinates of the two bezier segments in + * subdivided [0-3] and subdivided [3-6] + */ + + /* + * Here we need to check, if we have sufficiently subdivided, i.e. + * if the stroke is sufficiently close to a straight line. + */ + + if (! depth || + gimp_coords_bezier_is_straight (subdivided, precision)) /* 1st half */ + { + g_array_append_vals (ret_coords, subdivided, 3); + + if (ret_params) + { + gdouble params[3]; + + params[0] = start_t; + params[1] = (2 * start_t + middle_t) / 3; + params[2] = (start_t + 2 * middle_t) / 3; + + g_array_append_vals (ret_params, params, 3); + } + } + else + { + gimp_coords_interpolate_bezier_internal (subdivided, + start_t, (start_t + end_t) / 2, + precision, + ret_coords, ret_params, + depth - 1); + } + + if (! depth || + gimp_coords_bezier_is_straight (subdivided + 3, precision)) /* 2nd half */ + { + g_array_append_vals (ret_coords, subdivided + 3, 3); + + if (ret_params) + { + gdouble params[3]; + + params[0] = middle_t; + params[1] = (2 * middle_t + end_t) / 3; + params[2] = (middle_t + 2 * end_t) / 3; + + g_array_append_vals (ret_params, params, 3); + } + } + else + { + gimp_coords_interpolate_bezier_internal (subdivided + 3, + (start_t + end_t) / 2, end_t, + precision, + ret_coords, ret_params, + depth - 1); + } +} + + +/* + * Returns the position and/or velocity of a Bezier curve at time 't'. + */ + +void +gimp_coords_interpolate_bezier_at (const GimpCoords bezier_pt[4], + gdouble t, + GimpCoords *position, + GimpCoords *velocity) +{ + gdouble u = 1.0 - t; + + g_return_if_fail (bezier_pt != NULL); + + if (position) + { + GimpCoords a; + GimpCoords b; + + gimp_coords_mix ( u * u * u, &bezier_pt[0], + 3.0 * u * u * t, &bezier_pt[1], + &a); + gimp_coords_mix (3.0 * u * t * t, &bezier_pt[2], + t * t * t, &bezier_pt[3], + &b); + + gimp_coords_add (&a, &b, position); + } + + if (velocity) + { + GimpCoords a; + GimpCoords b; + + gimp_coords_mix (-3.0 * u * u, &bezier_pt[0], + 3.0 * (u - 2.0 * t) * u, &bezier_pt[1], + &a); + gimp_coords_mix (-3.0 * (t - 2.0 * u) * t, &bezier_pt[2], + 3.0 * t * t, &bezier_pt[3], + &b); + + gimp_coords_add (&a, &b, velocity); + } +} + +/* + * a helper function that determines if a bezier segment is "straight + * enough" to be approximated by a line. + * + * To be more exact, it also checks for the control points to be distributed + * evenly along the line. This makes it easier to reconstruct parameters for + * a given point along the segment. + * + * Needs four GimpCoords in an array. + */ + +gboolean +gimp_coords_bezier_is_straight (const GimpCoords bezier_pt[4], + gdouble precision) +{ + GimpCoords pt1, pt2; + + g_return_val_if_fail (bezier_pt != NULL, FALSE); + g_return_val_if_fail (precision > 0.0, FALSE); + + /* calculate the "ideal" positions for the control points */ + + gimp_coords_mix (2.0 / 3.0, &bezier_pt[0], + 1.0 / 3.0, &bezier_pt[3], + &pt1); + gimp_coords_mix (1.0 / 3.0, &bezier_pt[0], + 2.0 / 3.0, &bezier_pt[3], + &pt2); + + /* calculate the deviation of the actual control points */ + + return (gimp_coords_manhattan_dist (&bezier_pt[1], &pt1) < precision && + gimp_coords_manhattan_dist (&bezier_pt[2], &pt2) < precision); +} + + +/* Functions for catmull-rom interpolation */ + +void +gimp_coords_interpolate_catmull (const GimpCoords catmull_pt[4], + gdouble precision, + GArray *ret_coords, + GArray *ret_params) +{ + gdouble delta_x, delta_y; + gdouble distance; + gdouble dir_step; + gdouble delta_dir; + gint num_points; + gint n; + + GimpCoords past_coords; + GimpCoords start_coords; + GimpCoords end_coords; + GimpCoords future_coords; + + g_return_if_fail (catmull_pt != NULL); + g_return_if_fail (precision > 0.0); + g_return_if_fail (ret_coords != NULL); + + delta_x = catmull_pt[2].x - catmull_pt[1].x; + delta_y = catmull_pt[2].y - catmull_pt[1].y; + + /* Catmull-Rom interpolation requires 4 points. + * Two endpoints plus one more at each end. + */ + + past_coords = catmull_pt[0]; + start_coords = catmull_pt[1]; + end_coords = catmull_pt[2]; + future_coords = catmull_pt[3]; + + distance = sqrt (SQR (delta_x) + SQR (delta_y)); + + num_points = distance / precision; + + delta_dir = end_coords.direction - start_coords.direction; + + if (delta_dir <= -0.5) + delta_dir += 1.0; + else if (delta_dir >= 0.5) + delta_dir -= 1.0; + + dir_step = delta_dir / num_points; + + for (n = 1; n <= num_points; n++) + { + GimpCoords coords = past_coords; /* Make sure we carry over things + * we do not interpolate */ + gdouble velocity; + gdouble pressure; + gdouble p = (gdouble) n / num_points; + + coords.x = + gimp_coords_get_catmull_spline_point (p, + past_coords.x, + start_coords.x, + end_coords.x, + future_coords.x); + + coords.y = + gimp_coords_get_catmull_spline_point (p, + past_coords.y, + start_coords.y, + end_coords.y, + future_coords.y); + + pressure = + gimp_coords_get_catmull_spline_point (p, + past_coords.pressure, + start_coords.pressure, + end_coords.pressure, + future_coords.pressure); + coords.pressure = CLAMP (pressure, 0.0, 1.0); + + coords.xtilt = + gimp_coords_get_catmull_spline_point (p, + past_coords.xtilt, + start_coords.xtilt, + end_coords.xtilt, + future_coords.xtilt); + coords.ytilt = + gimp_coords_get_catmull_spline_point (p, + past_coords.ytilt, + start_coords.ytilt, + end_coords.ytilt, + future_coords.ytilt); + + coords.wheel = + gimp_coords_get_catmull_spline_point (p, + past_coords.wheel, + start_coords.wheel, + end_coords.wheel, + future_coords.wheel); + + velocity = gimp_coords_get_catmull_spline_point (p, + past_coords.velocity, + start_coords.velocity, + end_coords.velocity, + future_coords.velocity); + coords.velocity = CLAMP (velocity, 0.0, 1.0); + + coords.direction = start_coords.direction + dir_step * n; + + coords.direction = coords.direction - floor (coords.direction); + + coords.xscale = end_coords.xscale; + coords.yscale = end_coords.yscale; + coords.angle = end_coords.angle; + coords.reflect = end_coords.reflect; + + g_array_append_val (ret_coords, coords); + + if (ret_params) + g_array_append_val (ret_params, p); + } +} + +static gdouble +gimp_coords_get_catmull_spline_point (const gdouble t, + const gdouble p0, + const gdouble p1, + const gdouble p2, + const gdouble p3) +{ + return ((((-t + 2.0) * t - 1.0) * t / 2.0) * p0 + + ((((3.0 * t - 5.0) * t) * t + 2.0) / 2.0) * p1 + + (((-3.0 * t + 4.0) * t + 1.0) * t / 2.0) * p2 + + (((t - 1) * t * t) / 2.0) * p3); +} |