/* -*- mode:C; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */ /* * Clutter. * * An OpenGL based 'interactive canvas' library. * * Authored By Tomas Frydrych * * Copyright (C) 2007 OpenedHand * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ /** * SECTION:clutter-behaviour-bspline * @short_description: A behaviour class interpolating actors along a path * defined by bezier spline. * * #ClutterBehaviourBspline interpolates actors along a defined bspline path. * * A bezier spline is a set of cubic bezier curves defined by a sequence of * control points given when creating a new #ClutterBehaviourBspline instance. * * Additional bezier curves can be added to the end of the bspline using * clutter_behaviour_bspline_append() family of functions, control points can * be moved using clutter_behaviour_bspline_adjust(). The bspline can be split * into two with clutter_behaviour_bspline_split(), and bsplines can be * concatenated using clutter_behaviour_bspline_join(). * * Each time the behaviour reaches a point on the path, the "knot-reached" * signal is emitted. * * Since: 0.4 */ #include "clutter-fixed.h" #include "clutter-marshal.h" #include "clutter-behaviour-bspline.h" #include "clutter-debug.h" #include "clutter-private.h" #include #include /* * We have some experimental code here to allow for constant velocity * movement of actors along the bezier path, this macro enables it. */ #undef CBZ_L2T_INTERPOLATION /**************************************************************************** * ClutterBezier -- represenation of a cubic bezier curve * * (private; a building block for the public bspline object) * ****************************************************************************/ /* * The t parameter of the bezier is from interval <0,1>, so we use * 14.18 fixed format to improve precission and simplify POW3 calculation. */ #define CBZ_T_Q 18 #define CBZ_T_ONE (1 << CBZ_T_Q) #define CBZ_T_POW2(x) ((x >> 9) * (x >> 9)) #define CBZ_T_POW3(x) ((x >> 12) * (x >> 12) * (x >> 12)) #define CBZ_T_MUL(x,y) ((x >> 9) * (y >> 9)) #define CBZ_T_DIV(x,y) ((((x) << 9)/(y)) << 9) /* * Constants for sampling of the bezier */ #define CBZ_T_SAMPLES 128 #define CBZ_T_STEP (CBZ_T_ONE / CBZ_T_SAMPLES) #define CBZ_L_STEP (CBZ_T_ONE / CBZ_T_SAMPLES) typedef gint32 _FixedT; /* * This is a private type representing a single cubic bezier */ typedef struct _ClutterBezier { /* * bezier coefficients -- these are calculated using multiplication and * addition from integer input, so these are also integers */ gint ax; gint bx; gint cx; gint dx; gint ay; gint by; gint cy; gint dy; /* length of the bezier */ guint length; #ifdef CBZ_L2T_INTERPOLATION /* * coefficients for the L -> t bezier; these are calculated from fixed * point input, and more specifically numbers that have been normalised * to fit <0,1>, so these are also fixed point, and we can used the * _FixedT type here. */ _FixedT La; _FixedT Lb; _FixedT Lc; /* _FixedT Ld; == 0 */ #endif } ClutterBezier; static ClutterBezier * clutter_bezier_new () { return g_slice_new0 (ClutterBezier); } static void clutter_bezier_free (ClutterBezier * b) { if (G_LIKELY (b)) { g_slice_free (ClutterBezier, b); } } static ClutterBezier * clutter_bezier_clone_and_move (ClutterBezier *b, gint x, gint y) { ClutterBezier * b2 = clutter_bezier_new (); memcpy (b2, b, sizeof (ClutterBezier)); b2->dx += x; b2->dy += y; return b2; } #ifdef CBZ_L2T_INTERPOLATION /* * L is relative advance along the bezier curve from interval <0,1> */ static _FixedT clutter_bezier_L2t (ClutterBezier *b, _FixedT L) { _FixedT t = CBZ_T_MUL (b->La, CBZ_T_POW3(L)) + CBZ_T_MUL (b->Lb, CBZ_T_POW2(L)) + CBZ_T_MUL (b->Lc, L); if (t > CBZ_T_ONE) t = CBZ_T_ONE; else if (t < 0) t = 0; return t; } #endif static gint clutter_bezier_t2x (ClutterBezier * b, _FixedT t) { /* * NB -- the int coefficients can be at most 8192 for the multiplication * to work in this fashion due to the limits of the 14.18 fixed. */ return ((b->ax*CBZ_T_POW3(t) + b->bx*CBZ_T_POW2(t) + b->cx*t) >> CBZ_T_Q) + b->dx; } static gint clutter_bezier_t2y (ClutterBezier * b, _FixedT t) { /* * NB -- the int coefficients can be at most 8192 for the multiplication * to work in this fashion due to the limits of the 14.18 fixed. */ return ((b->ay*CBZ_T_POW3(t) + b->by*CBZ_T_POW2(t) + b->cy*t) >> CBZ_T_Q) + b->dy; } /* * Advances along the bezier to relative length L and returns the coordinances * in knot */ static void clutter_bezier_advance (ClutterBezier *b, _FixedT L, ClutterKnot * knot) { #ifdef CBZ_L2T_INTERPOLATION _FixedT t = clutter_bezier_L2t (b, L); #else _FixedT t = L; #endif knot->x = clutter_bezier_t2x (b, t); knot->y = clutter_bezier_t2y (b, t); CLUTTER_NOTE (BEHAVIOUR, "advancing to relative pt %f: t %f, {%d,%d}", (double) L / (double) CBZ_T_ONE, (double) t / (double) CBZ_T_ONE, knot->x, knot->y); } static void clutter_bezier_init (ClutterBezier *b, gint x_0, gint y_0, gint x_1, gint y_1, gint x_2, gint y_2, gint x_3, gint y_3) { _FixedT t; int i; int xp = x_0; int yp = y_0; _FixedT length [CBZ_T_SAMPLES + 1]; #ifdef CBZ_L2T_INTERPOLATION int j, k; _FixedT L; _FixedT t_equalized [CBZ_T_SAMPLES + 1]; #endif #if 0 g_debug ("Initializing bezier at {{%d,%d},{%d,%d},{%d,%d},{%d,%d}}", x0, y0, x1, y1, x2, y2, x3, y3); #endif b->dx = x_0; b->dy = y_0; b->cx = 3 * (x_1 - x_0); b->cy = 3 * (y_1 - y_0); b->bx = 3 * (x_2 - x_1) - b->cx; b->by = 3 * (y_2 - y_1) - b->cy; b->ax = x_3 - 3 * x_2 + 3 * x_1 - x_0; b->ay = y_3 - 3 * y_2 + 3 * y_1 - y_0; #if 0 g_debug ("Cooeficients {{%d,%d},{%d,%d},{%d,%d},{%d,%d}}", b->ax, b->ay, b->bx, b->by, b->cx, b->cy, b->dx, b->dy); #endif /* * Because of the way we do the multiplication in bezeir_t2x,y * these coefficients need to be at most 0x1fff; this should be the case, * I think, but have added this warning to catch any problems -- if it * triggers, we need to change those two functions a bit. */ if (b->ax > 0x1fff || b->bx > 0x1fff || b->cx > 0x1fff) g_warning ("Calculated coefficents will result in multiplication " "overflow in clutter_bezier_t2x and clutter_bezier_t2y."); /* * Sample the bezier with CBZ_T_SAMPLES and calculate length at * each point. * * We are working with integers here, so we use the fast sqrti function. */ length[0] = 0; for (t = CBZ_T_STEP, i = 1; i <= CBZ_T_SAMPLES; ++i, t += CBZ_T_STEP) { int x = clutter_bezier_t2x (b, t); int y = clutter_bezier_t2y (b, t); guint l = clutter_sqrti ((y - yp)*(y - yp) + (x - xp)*(x - xp)); l += length[i-1]; length[i] = l; xp = x; yp = y; } b->length = length[CBZ_T_SAMPLES]; #if 0 g_debug ("length %d", b->length); #endif #ifdef CBZ_L2T_INTERPOLATION /* * Now normalize the length values, converting them into _FixedT */ for (i = 0; i <= CBZ_T_SAMPLES; ++i) { length[i] = (length[i] << CBZ_T_Q) / b->length; } /* * Now generate a L -> t table such that the L will equidistant * over <0,1> */ t_equalized[0] = 0; for (i = 1, j = 1, L = CBZ_L_STEP; i < CBZ_T_SAMPLES; ++i, L += CBZ_L_STEP) { _FixedT l1, l2; _FixedT d1, d2, d; _FixedT t1, t2; /* find the band for our L */ for (k = j; k < CBZ_T_SAMPLES; ++k) { if (L < length[k]) break; } /* * Now we know that L is from (length[k-1],length[k]> * We remember k-1 in order not to have to iterate over the * whole length array in the next iteration of the main loop */ j = k - 1; /* * Now interpolate equlised t as a weighted average */ l1 = length[k-1]; l2 = length[k]; d1 = l2 - L; d2 = L - l1; d = l2 - l1; t1 = (k - 1) * CBZ_T_STEP; t2 = k * CBZ_T_STEP; t_equalized[i] = (t1*d1 + t2*d2)/d; if (t_equalized[i] < t_equalized[i-1]) g_debug ("wrong t: L %f, l1 %f, l2 %f, t1 %f, t2 %f", (double) (L)/(double)CBZ_T_ONE, (double) (l1)/(double)CBZ_T_ONE, (double) (l2)/(double)CBZ_T_ONE, (double) (t1)/(double)CBZ_T_ONE, (double) (t2)/(double)CBZ_T_ONE); } t_equalized[CBZ_T_SAMPLES] = CBZ_T_ONE; /* We now fit a bezier -- at this stage, do a single fit through our values * at 0, 1/3, 2/3 and 1 * * FIXME -- do we need to use a better fitting approach to choose the best * beziere. The actual curve we acquire this way is not too bad shapwise, * but (probably due to rounding errors) the resulting curve no longer * satisfies the necessary condition that for L2 > L1, t2 > t1, which * causes oscilation. */ #if 0 /* * These are the control points we use to calculate the curve coefficients * for bezier t(L); these are not needed directly, but are implied in the * calculations below. * * (p0 is 0,0, and p3 is 1,1) */ p1 = (18 * t_equalized[CBZ_T_SAMPLES/3] - 9 * t_equalized[2*CBZ_T_SAMPLES/3] + 2 << CBZ_T_Q) / 6; p2 = (18 * t_equalized[2*CBZ_T_SAMPLES/3] - 9 * t_equalized[CBZ_T_SAMPLES/3] - (5 << CBZ_T_Q)) / 6; #endif b->Lc = (18 * t_equalized[CBZ_T_SAMPLES/3] - 9 * t_equalized[2*CBZ_T_SAMPLES/3] + (2 << CBZ_T_Q)) >> 1; b->Lb = (36 * t_equalized[2*CBZ_T_SAMPLES/3] - 45 * t_equalized[CBZ_T_SAMPLES/3] - (9 << CBZ_T_Q)) >> 1; b->La = ((27 * (t_equalized[CBZ_T_SAMPLES/3] - t_equalized[2*CBZ_T_SAMPLES/3]) + (7 << CBZ_T_Q)) >> 1) + CBZ_T_ONE; g_debug ("t(1/3) %f, t(2/3) %f", (double)t_equalized[CBZ_T_SAMPLES/3]/(double)CBZ_T_ONE, (double)t_equalized[2*CBZ_T_SAMPLES/3]/(double)CBZ_T_ONE); g_debug ("L -> t coefficients: %f, %f, %f", (double)b->La/(double)CBZ_T_ONE, (double)b->Lb/(double)CBZ_T_ONE, (double)b->Lc/(double)CBZ_T_ONE); /* * For debugging, you can load these values into a spreadsheet and graph * them to see how well the approximation matches the data */ for (i = 0; i < CBZ_T_SAMPLES; ++i) { g_print ("%f, %f, %f\n", (double)(i*CBZ_T_STEP)/(double)CBZ_T_ONE, (double)(t_equalized[i])/(double)CBZ_T_ONE, (double)(clutter_bezier_L2t(b,i*CBZ_T_STEP))/(double)CBZ_T_ONE); } #endif } /* * Moves a control point at indx to location represented by knot */ static void clutter_bezier_adjust (ClutterBezier * b, ClutterKnot * knot, guint indx) { guint x[4], y[4]; g_assert (indx < 4); x[0] = b->dx; y[0] = b->dy; x[1] = b->cx / 3 + x[0]; y[1] = b->cy / 3 + y[0]; x[2] = b->bx / 3 + b->cx + x[1]; y[2] = b->by / 3 + b->cy + y[1]; x[3] = b->ax + x[0] + b->cx + b->bx; y[3] = b->ay + y[0] + b->cy + b->by; x[indx] = knot->x; y[indx] = knot->y; clutter_bezier_init (b, x[0], y[0], x[1], y[1], x[2], y[2], x[3], y[3]); } /**************************************************************************** * * * ClutterBehaviourBspline * * * ****************************************************************************/ G_DEFINE_TYPE (ClutterBehaviourBspline, clutter_behaviour_bspline, CLUTTER_TYPE_BEHAVIOUR); #define CLUTTER_BEHAVIOUR_BSPLINE_GET_PRIVATE(obj) \ (G_TYPE_INSTANCE_GET_PRIVATE ((obj), \ CLUTTER_TYPE_BEHAVIOUR_BSPLINE, \ ClutterBehaviourBsplinePrivate)) enum { KNOT_REACHED, LAST_SIGNAL }; static guint bspline_signals[LAST_SIGNAL] = { 0, }; struct _ClutterBehaviourBsplinePrivate { /* * The individual bezier curves that make up this bspline */ GArray * splines; /* * The length of the bspline */ guint length; /* * Bspline offsets (these allow us to move the bspline without having to * mess about with the individual beziers). * * NB: this is not the actual origin, but an adjustment to the origin of * the first bezier; it defaults to 0 unless the user explicitely changes * the bspline offset. */ gint x; gint y; /* * A temporary stack of control points used by the append methods */ GArray * point_stack; }; static void clutter_behaviour_bspline_finalize (GObject *object) { ClutterBehaviourBspline *self = CLUTTER_BEHAVIOUR_BSPLINE (object); ClutterBehaviourBsplinePrivate *priv = self->priv; gint i; for (i = 0; i < priv->splines->len; ++i) clutter_bezier_free (g_array_index (priv->splines, ClutterBezier*, i)); g_array_free (priv->splines, TRUE); for (i = 0; i < priv->point_stack->len; ++i) clutter_knot_free (g_array_index (priv->point_stack, ClutterKnot*, i)); g_array_free (priv->point_stack, TRUE); G_OBJECT_CLASS (clutter_behaviour_bspline_parent_class)->finalize (object); } static void actor_apply_knot_foreach (ClutterBehaviour *behaviour, ClutterActor *actor, gpointer data) { ClutterKnot *knot = data; clutter_actor_set_position (actor, knot->x, knot->y); } /* * Advances to a point that is at distance 'to' along the spline; * * returns FALSE if the length is beyond the end of the bspline. */ static gboolean clutter_behaviour_bspline_advance (ClutterBehaviourBspline *bs, guint to) { ClutterBehaviourBsplinePrivate *priv = bs->priv; gint i; guint length = 0; ClutterKnot knot; if (to > priv->length) return FALSE; for (i = 0; i < priv->splines->len; ++i) { ClutterBezier *b = g_array_index (priv->splines, ClutterBezier*, i); if (length + b->length >= to) { _FixedT L = ((to - length) << CBZ_T_Q) / b->length; clutter_bezier_advance (b, L, &knot); knot.x += bs->priv->x; knot.y += bs->priv->y; CLUTTER_NOTE (BEHAVIOUR, "advancing to length %d: (%d, %d)", to, knot.x, knot.y); clutter_behaviour_actors_foreach (CLUTTER_BEHAVIOUR (bs), actor_apply_knot_foreach, &knot); g_signal_emit (bs, bspline_signals[KNOT_REACHED], 0, &knot); return TRUE; } length += b->length; } /* should not be reached */ return FALSE; } static void clutter_behaviour_bspline_alpha_notify (ClutterBehaviour * behave, guint32 alpha) { ClutterBehaviourBspline * bs = CLUTTER_BEHAVIOUR_BSPLINE (behave); gint to = (alpha * bs->priv->length) / CLUTTER_ALPHA_MAX_ALPHA; clutter_behaviour_bspline_advance (bs, to); } static void clutter_behaviour_bspline_class_init (ClutterBehaviourBsplineClass *klass) { GObjectClass * object_class = G_OBJECT_CLASS (klass); ClutterBehaviourClass * behave_class = CLUTTER_BEHAVIOUR_CLASS (klass); object_class->finalize = clutter_behaviour_bspline_finalize; behave_class->alpha_notify = clutter_behaviour_bspline_alpha_notify; /** * ClutterBehaviourBspline::knot-reached: * @pathb: the object which received the signal * @knot: the #ClutterKnot reached * * This signal is emitted at the end of each frame. * * Since: 0.2 */ bspline_signals[KNOT_REACHED] = g_signal_new ("knot-reached", G_TYPE_FROM_CLASS (object_class), G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (ClutterBehaviourBsplineClass, knot_reached), NULL, NULL, clutter_marshal_VOID__BOXED, G_TYPE_NONE, 1, CLUTTER_TYPE_KNOT); g_type_class_add_private (klass, sizeof (ClutterBehaviourBsplinePrivate)); } static void clutter_behaviour_bspline_init (ClutterBehaviourBspline * self) { ClutterBehaviourBsplinePrivate *priv; self->priv = priv = CLUTTER_BEHAVIOUR_BSPLINE_GET_PRIVATE (self); priv->splines = g_array_new (FALSE, FALSE, sizeof (ClutterBezier *)); priv->point_stack = g_array_new (FALSE, FALSE, sizeof (ClutterKnot *)); priv->length = 0; } /** * clutter_behaviour_bspline_new: * @alpha: a #ClutterAlpha, or %NULL * @knots: a list of #ClutterKnots representing individual control points * @n_knots: the number of control points * * Creates a new bezier spline behaviour. You can use this behaviour to drive * actors along the bezier spline, described by the @knots control points. * * Bspline is defined by 3n + 1 points, n >=1; any trailing points passed * into this function are stored internally and used during any subsequent * clutter_behaviour_bspline_append() operations. * * Return value: a #ClutterBehaviour * * Since: 0.4 */ ClutterBehaviour * clutter_behaviour_bspline_new (ClutterAlpha *alpha, const ClutterKnot *knots, guint n_knots) { ClutterBehaviourBspline *bs; gint i; g_return_val_if_fail (alpha == NULL || CLUTTER_IS_ALPHA (alpha), NULL); bs = g_object_new (CLUTTER_TYPE_BEHAVIOUR_BSPLINE, "alpha", alpha, NULL); for (i = 0; i < n_knots; ++i) clutter_behaviour_bspline_append_knot (bs, &knots[i]); return CLUTTER_BEHAVIOUR (bs); } /* * Appends a single spline; knots points to 4 knots if this is first * bezier in the spline, 3 subsequently */ static void clutter_behaviour_bspline_append_spline (ClutterBehaviourBspline * bs, const ClutterKnot ** knots) { ClutterBehaviourBsplinePrivate *priv; gint i; ClutterBezier * b; ClutterKnot knot0; g_return_if_fail (CLUTTER_IS_BEHAVIOUR_BSPLINE (bs)); priv = bs->priv; if (priv->splines->len) { /* Get the first point from the last curve */ ClutterBezier *b_last; b_last = g_array_index (priv->splines, ClutterBezier *, priv->splines->len - 1); knot0.x = b_last->ax + b_last->bx + b_last->cx + b_last->dx; knot0.y = b_last->ay + b_last->by + b_last->cy + b_last->dy; i = 0; } else { knot0.x = knots[0]->x; knot0.y = knots[0]->y; i = 1; } b = clutter_bezier_new (); clutter_bezier_init (b, knot0.x, knot0.y, knots[i]->x, knots[i]->y, knots[i + 1]->x, knots[i + 1]->y, knots[i + 2]->x, knots[i + 2]->y); priv->splines = g_array_append_val (priv->splines, b); priv->length += b->length; } /** * clutter_behaviour_bspline_append_knot: * @bs: a #ClutterBehaviourBspline * @knot: a #ClutterKnot control point to append. * * Appends a #ClutterKnot control point to the bezier spline bs. Note, that * since a bezier is defined by 4 control points, the point gets stored in * a temporary chache, and only when there are enough control points to * create a new bezier curve will the bspline extended. * * Since: 0.4 */ void clutter_behaviour_bspline_append_knot (ClutterBehaviourBspline * bs, const ClutterKnot * knot) { ClutterBehaviourBsplinePrivate *priv; ClutterKnot * k = clutter_knot_copy (knot); guint needed = 3; guint i; g_return_if_fail (CLUTTER_IS_BEHAVIOUR_BSPLINE (bs)); priv = bs->priv; g_array_append_val (priv->point_stack, k); if (priv->splines->len == 0) needed = 4; if (priv->point_stack->len == needed) { clutter_behaviour_bspline_append_spline (bs, (const ClutterKnot**) priv->point_stack->data); for (i = 0; i < needed; ++i) { clutter_knot_free (g_array_index (priv->point_stack, ClutterKnot *, i)); } g_array_set_size (priv->point_stack, 0); } } static void clutter_behaviour_bspline_append_knots_valist (ClutterBehaviourBspline *bs, const ClutterKnot *first_knot, va_list args) { const ClutterKnot * knot; knot = first_knot; while (knot) { clutter_behaviour_bspline_append_knot (bs, knot); knot = va_arg (args, ClutterKnot*); } } /** * clutter_behaviour_bspline_append: * @bs: a #ClutterBehaviourBspline * @first_knot: first #ClutterKnot * @VarArgs: a NULL-terminated array of #ClutterKnot control points. * * Appends a bezier spline defined by the last control point of bezier spline * bs and the array of #ClutterKnot control points to the orginal bezier spline * bs. * * Since: 0.4 */ void clutter_behaviour_bspline_append (ClutterBehaviourBspline * bs, const ClutterKnot * first_knot, ...) { va_list args; g_return_if_fail (CLUTTER_IS_BEHAVIOUR_BSPLINE (bs)); g_return_if_fail (first_knot != NULL); va_start (args, first_knot); clutter_behaviour_bspline_append_knots_valist (bs, first_knot, args); va_end (args); } /** * clutter_behaviour_bspline_truncate: * @bs: a #ClutterBehaviourBspline * @offset: offset of control where the bspline should be truncated * * Truncates the bezier spline at the control point; if the control point at * offset is not one of the on-curve points, the bspline will be * truncated at the nearest preceeding on-curve point. * * Since: 0.4 */ void clutter_behaviour_bspline_truncate (ClutterBehaviourBspline *bs, guint offset) { ClutterBehaviourBsplinePrivate *priv; guint i; g_return_if_fail (CLUTTER_IS_BEHAVIOUR_BSPLINE (bs)); if (!offset) { clutter_behaviour_bspline_clear (bs); return; } priv = bs->priv; /* convert control point offset to the offset of last spline to keep */ offset = (offset - 1) / 3; priv->splines = g_array_set_size (priv->splines, offset + 1); priv->length = 0; for (i = 0; i < priv->splines->len; ++i) { ClutterBezier *b; b = g_array_index (priv->splines, ClutterBezier*, i); priv->length += b->length; } } /** * clutter_behaviour_bspline_clear: * @bs: a #ClutterBehaviourBspline * * Empties a bspline. * * Since: 0.4 */ void clutter_behaviour_bspline_clear (ClutterBehaviourBspline *bs) { ClutterBehaviourBsplinePrivate *priv; gint i; g_return_if_fail (CLUTTER_IS_BEHAVIOUR_BSPLINE (bs)); priv = bs->priv; for (i = 0; i < priv->splines->len; ++i) clutter_bezier_free (g_array_index (priv->splines, ClutterBezier*, i)); g_array_set_size (priv->splines, 0); for (i = 0; i < priv->point_stack->len; ++i) clutter_knot_free (g_array_index (priv->point_stack, ClutterKnot*, i)); g_array_set_size (priv->point_stack, 0); priv->x = 0; priv->y = 0; priv->length = 0; } /** * clutter_behaviour_bspline_join: * @bs1: a #ClutterBehaviourBspline * @bs2: a #ClutterBehaviourBspline * * Joins a copy of bezier spline bs2 onto the end of bezier spline bs1; bs2 is * not modified. * * Since: 0.4 */ void clutter_behaviour_bspline_join (ClutterBehaviourBspline *bs1, ClutterBehaviourBspline *bs2) { ClutterBehaviourBsplinePrivate *priv; gint i, x_1, y_1; ClutterKnot knot; ClutterBezier *b, *b2; g_return_if_fail (CLUTTER_IS_BEHAVIOUR_BSPLINE (bs1)); g_return_if_fail (CLUTTER_IS_BEHAVIOUR_BSPLINE (bs2)); clutter_behaviour_bspline_get_origin (bs2, &knot); priv = bs1->priv; b = g_array_index (priv->splines, ClutterBezier*, priv->splines->len - 1); x_1 = clutter_bezier_t2x (b, CBZ_T_ONE); y_1 = clutter_bezier_t2y (b, CBZ_T_ONE); /* * need to move bs2 so it joins bs1 */ x_1 -= knot.x; y_1 -= knot.y; for (i = 0; i < priv->splines->len; ++i) { b = g_array_index (bs2->priv->splines, ClutterBezier*, i); b2 = clutter_bezier_clone_and_move (b, x_1, y_1); priv->length += b2->length; g_array_append_val (priv->splines, b2); } } /** * clutter_behaviour_bspline_split: * @bs: a #ClutterBehaviourBspline * @offset: an offset of the control point at which to split the spline. * * Splits a bezier spline into two at the control point at offset; if the * control point at offset is not one of the on-curve bezier points, the * bspline will be split at the nearest on-curve point before the offset. * The original bspline is shortened appropriately. * * Return value: new ClutterBehaviourBspline. * * Since: 0.4 */ ClutterBehaviour * clutter_behaviour_bspline_split (ClutterBehaviourBspline *bs, guint offset) { ClutterBehaviourBsplinePrivate *priv; ClutterBehaviourBspline * bs2 = NULL; ClutterAlpha * alpha; guint i, split, length2 = 0; g_return_val_if_fail (CLUTTER_IS_BEHAVIOUR_BSPLINE (bs), NULL); priv = bs->priv; split = offset / 3; if (split == 0 || split >= priv->splines->len) return NULL; alpha = clutter_behaviour_get_alpha (CLUTTER_BEHAVIOUR (bs)); bs2 = g_object_new (CLUTTER_TYPE_BEHAVIOUR_BSPLINE, "alpha", alpha, NULL); bs2->priv->x = priv->x; bs2->priv->y = priv->y; for (i = split; i < priv->splines->len; ++i) { ClutterBezier *b; b = g_array_index (priv->splines, ClutterBezier*, i); g_array_append_val (bs2->priv->splines, b); length2 += b->length; } bs2->priv->length -= length2; bs2->priv->length = length2; g_array_set_size (priv->splines, split); return CLUTTER_BEHAVIOUR (bs2); } /** * clutter_behaviour_bspline_adjust: * @bs: a #ClutterBehaviourBspline * @offset: an index of control point to ajdust * @knot: a #ClutterKnot with new coordinances for the control point. * * Change the coordinaces of control point at index to those represented by * the knot. * * Since: 0.4 */ void clutter_behaviour_bspline_adjust (ClutterBehaviourBspline *bs, guint offset, ClutterKnot *knot) { ClutterBehaviourBsplinePrivate *priv; ClutterBezier * b1 = NULL; ClutterBezier * b2 = NULL; guint p1_indx = 0; guint p2_indx = 0; guint old_length; g_return_if_fail (CLUTTER_IS_BEHAVIOUR_BSPLINE (bs)); priv = bs->priv; /* * Find the bezier(s) affected by change of this control point * and the relative position of the control point within them */ if (offset == 0) b1 = g_array_index (priv->splines, ClutterBezier*, 0); else if (offset + 1 == priv->splines->len) { b2 = g_array_index (priv->splines, ClutterBezier*, priv->splines->len - 1); p2_indx = 3; } else { guint mod3 = offset % 3; guint i = offset / 3; if (mod3 == 0) { /* on-curve point, i.e., two beziers */ b1 = g_array_index (priv->splines, ClutterBezier*, i - 1); b2 = g_array_index (priv->splines, ClutterBezier*, i); p1_indx = 3; } else { b1 = g_array_index (priv->splines, ClutterBezier*, i); p1_indx = mod3; } } /* * Adjust the bezier(s) and total bspline length */ if (b1) { old_length = b1->length; clutter_bezier_adjust (b1, knot, p1_indx); priv->length = priv->length - old_length + b1->length; } if (b2) { old_length = b2->length; clutter_bezier_adjust (b2, knot, p2_indx); priv->length = priv->length - old_length + b2->length; } } /** * clutter_behaviour_bspline_set_origin * @bs: a #ClutterBehaviourBspline * @knot: a #ClutterKnot origin for the bezier * * Sets the origin of the bezier to the point represented by knot. (Initially * the origin of a bspline is given by the position of the first control point * of the first bezier curve.) * * Since: 0.4 */ void clutter_behaviour_bspline_set_origin (ClutterBehaviourBspline * bs, ClutterKnot * knot) { ClutterBehaviourBsplinePrivate *priv; g_return_if_fail (CLUTTER_IS_BEHAVIOUR_BSPLINE (bs)); priv = bs->priv; if (priv->splines->len == 0) { priv->x = knot->x; priv->y = knot->y; } else { ClutterBezier *b; b = g_array_index (priv->splines, ClutterBezier*, 0); priv->x = knot->x - b->dx; priv->y = knot->y - b->dy; CLUTTER_NOTE (BEHAVIOUR, "setting origin to (%d, %d): " "b (%d, %d), adjustment (%d, %d)", knot->x, knot->y, b->dx, b->dy, priv->x, priv->y); } } /** * clutter_behaviour_bspline_get_origin * @bs: a #ClutterBehaviourBspline * @knot: a #ClutterKnot where to store the origin of the bezier * * Gets the origin of the bezier. * * Since: 0.4 */ void clutter_behaviour_bspline_get_origin (ClutterBehaviourBspline *bs, ClutterKnot *knot) { ClutterBehaviourBsplinePrivate *priv; g_return_if_fail (CLUTTER_IS_BEHAVIOUR_BSPLINE (bs)); g_return_if_fail (knot != NULL); priv = bs->priv; if (priv->splines->len == 0) { knot->x = priv->x; knot->y = priv->y; } else { ClutterBezier *b; b = g_array_index (priv->splines, ClutterBezier*, 0); knot->x = priv->x + b->dx; knot->y = priv->y + b->dy; } }