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-rw-r--r--src/dialogs/unclump.cpp371
1 files changed, 371 insertions, 0 deletions
diff --git a/src/dialogs/unclump.cpp b/src/dialogs/unclump.cpp
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+#define __UNCLUMP_C__
+
+/*
+ * Unclumping objects
+ *
+ * Authors:
+ * bulia byak
+ *
+ * Copyright (C) 2005 Authors
+ * Released under GNU GPL
+ */
+
+
+#include <map>
+#include "libnr/nr-matrix-ops.h"
+#include "sp-item.h"
+
+
+// Taking bbox of an item is an expensive operation, and we need to do it many times, so here we
+// cache the centers, widths, and heights of items
+
+//FIXME: make a class with these cashes as members instead of globals
+std::map<const gchar *, NR::Point> c_cache;
+std::map<const gchar *, NR::Point> wh_cache;
+
+/**
+Center of bbox of item
+*/
+NR::Point
+unclump_center (SPItem *item)
+{
+ std::map<const gchar *, NR::Point>::iterator i = c_cache.find(SP_OBJECT_ID(item));
+ if ( i != c_cache.end() ) {
+ return i->second;
+ }
+
+ NR::Rect const r = item->invokeBbox(sp_item_i2d_affine(item));
+ NR::Point const c = r.midpoint();
+ c_cache[SP_OBJECT_ID(item)] = c;
+ return c;
+}
+
+NR::Point
+unclump_wh (SPItem *item)
+{
+ NR::Point wh;
+ std::map<const gchar *, NR::Point>::iterator i = wh_cache.find(SP_OBJECT_ID(item));
+ if ( i != wh_cache.end() ) {
+ wh = i->second;
+ } else {
+ NR::Rect const r = item->invokeBbox(sp_item_i2d_affine(item));
+ wh = r.dimensions();
+ wh_cache[SP_OBJECT_ID(item)] = wh;
+ }
+
+ return wh;
+}
+
+/**
+Distance between "edges" of item1 and item2. An item is considered to be an ellipse inscribed into its w/h,
+so its radius (distance from center to edge) depends on the w/h and the angle towards the other item.
+May be negative if the edge of item1 is between the center and the edge of item2.
+*/
+double
+unclump_dist (SPItem *item1, SPItem *item2)
+{
+ NR::Point c1 = unclump_center (item1);
+ NR::Point c2 = unclump_center (item2);
+
+ NR::Point wh1 = unclump_wh (item1);
+ NR::Point wh2 = unclump_wh (item2);
+
+ // angle from each item's center to the other's, unsqueezed by its w/h, normalized to 0..pi/2
+ double a1 = atan2 ((c2 - c1)[NR::Y], (c2 - c1)[NR::X] * wh1[NR::Y]/wh1[NR::X]);
+ a1 = fabs (a1);
+ if (a1 > M_PI/2) a1 = M_PI - a1;
+
+ double a2 = atan2 ((c1 - c2)[NR::Y], (c1 - c2)[NR::X] * wh2[NR::Y]/wh2[NR::X]);
+ a2 = fabs (a2);
+ if (a2 > M_PI/2) a2 = M_PI - a2;
+
+ // get the radius of each item for the given angle
+ double r1 = 0.5 * (wh1[NR::X] + (wh1[NR::Y] - wh1[NR::X]) * (a1/(M_PI/2)));
+ double r2 = 0.5 * (wh2[NR::X] + (wh2[NR::Y] - wh2[NR::X]) * (a2/(M_PI/2)));
+
+ // dist between centers minus angle-adjusted radii
+ double dist_r = (NR::L2 (c2 - c1) - r1 - r2);
+
+ double stretch1 = wh1[NR::Y]/wh1[NR::X];
+ double stretch2 = wh2[NR::Y]/wh2[NR::X];
+
+ if ((stretch1 > 1.5 || stretch1 < 0.66) && (stretch2 > 1.5 || stretch2 < 0.66)) {
+
+ std::vector<double> dists;
+ dists.push_back (dist_r);
+
+ // If both objects are not circle-like, find dists between four corners
+ std::vector<NR::Point> c1_points(2);
+ {
+ double y_closest;
+ if (c2[NR::Y] > c1[NR::Y] + wh1[NR::Y]/2) {
+ y_closest = c1[NR::Y] + wh1[NR::Y]/2;
+ } else if (c2[NR::Y] < c1[NR::Y] - wh1[NR::Y]/2) {
+ y_closest = c1[NR::Y] - wh1[NR::Y]/2;
+ } else {
+ y_closest = c2[NR::Y];
+ }
+ c1_points[0] = NR::Point (c1[NR::X], y_closest);
+ double x_closest;
+ if (c2[NR::X] > c1[NR::X] + wh1[NR::X]/2) {
+ x_closest = c1[NR::X] + wh1[NR::X]/2;
+ } else if (c2[NR::X] < c1[NR::X] - wh1[NR::X]/2) {
+ x_closest = c1[NR::X] - wh1[NR::X]/2;
+ } else {
+ x_closest = c2[NR::X];
+ }
+ c1_points[1] = NR::Point (x_closest, c1[NR::Y]);
+ }
+
+
+ std::vector<NR::Point> c2_points(2);
+ {
+ double y_closest;
+ if (c1[NR::Y] > c2[NR::Y] + wh2[NR::Y]/2) {
+ y_closest = c2[NR::Y] + wh2[NR::Y]/2;
+ } else if (c1[NR::Y] < c2[NR::Y] - wh2[NR::Y]/2) {
+ y_closest = c2[NR::Y] - wh2[NR::Y]/2;
+ } else {
+ y_closest = c1[NR::Y];
+ }
+ c2_points[0] = NR::Point (c2[NR::X], y_closest);
+ double x_closest;
+ if (c1[NR::X] > c2[NR::X] + wh2[NR::X]/2) {
+ x_closest = c2[NR::X] + wh2[NR::X]/2;
+ } else if (c1[NR::X] < c2[NR::X] - wh2[NR::X]/2) {
+ x_closest = c2[NR::X] - wh2[NR::X]/2;
+ } else {
+ x_closest = c1[NR::X];
+ }
+ c2_points[1] = NR::Point (x_closest, c2[NR::Y]);
+ }
+
+ for (int i = 0; i < 2; i ++) {
+ for (int j = 0; j < 2; j ++) {
+ dists.push_back (NR::L2 (c1_points[i] - c2_points[j]));
+ }
+ }
+
+ // return the minimum of all dists
+ return *std::min_element(dists.begin(), dists.end());
+ } else {
+ return dist_r;
+ }
+}
+
+/**
+Average unclump_dist from item to others
+*/
+double unclump_average (SPItem *item, GSList *others)
+{
+ int n = 0;
+ double sum = 0;
+
+ for (GSList *i = others; i != NULL; i = i->next) {
+ SPItem *other = SP_ITEM (i->data);
+
+ if (other == item)
+ continue;
+
+ n++;
+ sum += unclump_dist (item, other);
+ }
+
+ if (n != 0)
+ return sum/n;
+ else
+ return 0;
+}
+
+/**
+Closest to item among others
+ */
+SPItem *unclump_closest (SPItem *item, GSList *others)
+{
+ double min = HUGE_VAL;
+ SPItem *closest = NULL;
+
+ for (GSList *i = others; i != NULL; i = i->next) {
+ SPItem *other = SP_ITEM (i->data);
+
+ if (other == item)
+ continue;
+
+ double dist = unclump_dist (item, other);
+ if (dist < min && fabs (dist) < 1e6) {
+ min = dist;
+ closest = other;
+ }
+ }
+
+ return closest;
+}
+
+/**
+Most distant from item among others
+ */
+SPItem *unclump_farest (SPItem *item, GSList *others)
+{
+ double max = -HUGE_VAL;
+ SPItem *farest = NULL;
+
+ for (GSList *i = others; i != NULL; i = i->next) {
+ SPItem *other = SP_ITEM (i->data);
+
+ if (other == item)
+ continue;
+
+ double dist = unclump_dist (item, other);
+ if (dist > max && fabs (dist) < 1e6) {
+ max = dist;
+ farest = other;
+ }
+ }
+
+ return farest;
+}
+
+/**
+Removes from the \a rest list those items that are "behind" \a closest as seen from \a item,
+i.e. those on the other side of the line through \a closest perpendicular to the direction from \a
+item to \a closest. Returns a newly created list which must be freed.
+ */
+GSList *
+unclump_remove_behind (SPItem *item, SPItem *closest, GSList *rest)
+{
+ NR::Point it = unclump_center (item);
+ NR::Point p1 = unclump_center (closest);
+
+ // perpendicular through closest to the direction to item:
+ NR::Point perp = NR::rot90(it - p1);
+ NR::Point p2 = p1 + perp;
+
+ // get the standard Ax + By + C = 0 form for p1-p2:
+ double A = p1[NR::Y] - p2[NR::Y];
+ double B = p2[NR::X] - p1[NR::X];
+ double C = p2[NR::Y] * p1[NR::X] - p1[NR::Y] * p2[NR::X];
+
+ // substitute the item into it:
+ double val_item = A * it[NR::X] + B * it[NR::Y] + C;
+
+ GSList *out = NULL;
+
+ for (GSList *i = rest; i != NULL; i = i->next) {
+ SPItem *other = SP_ITEM (i->data);
+
+ if (other == item)
+ continue;
+
+ NR::Point o = unclump_center (other);
+ double val_other = A * o[NR::X] + B * o[NR::Y] + C;
+
+ if (val_item * val_other <= 1e-6) {
+ // different signs, which means item and other are on the different sides of p1-p2 line; skip
+ } else {
+ out = g_slist_prepend (out, other);
+ }
+ }
+
+ return out;
+}
+
+/**
+Moves \a what away from \a from by \a dist
+ */
+void
+unclump_push (SPItem *from, SPItem *what, double dist)
+{
+ NR::Point it = unclump_center (what);
+ NR::Point p = unclump_center (from);
+ NR::Point by = dist * NR::unit_vector (- (p - it));
+
+ NR::Matrix move = NR::Matrix (NR::translate (by));
+
+ std::map<const gchar *, NR::Point>::iterator i = c_cache.find(SP_OBJECT_ID(what));
+ if ( i != c_cache.end() ) {
+ i->second *= move;
+ }
+
+ //g_print ("push %s at %g,%g from %g,%g by %g,%g, dist %g\n", SP_OBJECT_ID(what), it[NR::X],it[NR::Y], p[NR::X],p[NR::Y], by[NR::X],by[NR::Y], dist);
+
+ sp_item_set_i2d_affine(what, sp_item_i2d_affine(what) * move);
+ sp_item_write_transform(what, SP_OBJECT_REPR(what), what->transform, NULL);
+}
+
+/**
+Moves \a what towards \a to by \a dist
+ */
+void
+unclump_pull (SPItem *to, SPItem *what, double dist)
+{
+ NR::Point it = unclump_center (what);
+ NR::Point p = unclump_center (to);
+ NR::Point by = dist * NR::unit_vector (p - it);
+
+ NR::Matrix move = NR::Matrix (NR::translate (by));
+
+ std::map<const gchar *, NR::Point>::iterator i = c_cache.find(SP_OBJECT_ID(what));
+ if ( i != c_cache.end() ) {
+ i->second *= move;
+ }
+
+ //g_print ("pull %s at %g,%g to %g,%g by %g,%g, dist %g\n", SP_OBJECT_ID(what), it[NR::X],it[NR::Y], p[NR::X],p[NR::Y], by[NR::X],by[NR::Y], dist);
+
+ sp_item_set_i2d_affine(what, sp_item_i2d_affine(what) * move);
+ sp_item_write_transform(what, SP_OBJECT_REPR(what), what->transform, NULL);
+}
+
+
+/**
+Unclumps the items in \a items, reducing local unevenness in their distribution. Produces an effect
+similar to "engraver dots". The only distribution which is unchanged by unclumping is a hexagonal
+grid. May be called repeatedly for stronger effect.
+ */
+void
+unclump (GSList *items)
+{
+ c_cache.clear();
+ wh_cache.clear();
+
+ for (GSList *i = items; i != NULL; i = i->next) { // for each original/clone x:
+ SPItem *item = SP_ITEM (i->data);
+
+ GSList *nei = NULL;
+
+ GSList *rest = g_slist_copy (items);
+ rest = g_slist_remove (rest, item);
+
+ while (rest != NULL) {
+ SPItem *closest = unclump_closest (item, rest);
+ if (closest) {
+ nei = g_slist_prepend (nei, closest);
+ rest = g_slist_remove (rest, closest);
+ GSList *new_rest = unclump_remove_behind (item, closest, rest);
+ g_slist_free (rest);
+ rest = new_rest;
+ } else {
+ g_slist_free (rest);
+ break;
+ }
+ }
+
+ if (g_slist_length (nei) >= 2) {
+ double ave = unclump_average (item, nei);
+
+ SPItem *closest = unclump_closest (item, nei);
+ SPItem *farest = unclump_farest (item, nei);
+
+ double dist_closest = unclump_dist (closest, item);
+ double dist_farest = unclump_dist (farest, item);
+
+ //g_print ("NEI %d for item %s closest %s at %g farest %s at %g ave %g\n", g_slist_length(nei), SP_OBJECT_ID(item), SP_OBJECT_ID(closest), dist_closest, SP_OBJECT_ID(farest), dist_farest, ave);
+
+ if (fabs (ave) < 1e6 && fabs (dist_closest) < 1e6 && fabs (dist_farest) < 1e6) { // otherwise the items are bogus
+ // increase these coefficients to make unclumping more aggressive and less stable
+ // the pull coefficient is a bit bigger to counteract the long-term expansion trend
+ unclump_push (closest, item, 0.3 * (ave - dist_closest));
+ unclump_pull (farest, item, 0.35 * (dist_farest - ave));
+ }
+ }
+ }
+}
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