/*
This file is part of LilyPond, the GNU music typesetter.
- Copyright (C) 2006--2011 Joe Neeman <joeneeman@gmail.com>
+ Copyright (C) 2006--2012 Joe Neeman <joeneeman@gmail.com>
LilyPond is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
*/
#include "skyline.hh"
+#include "skyline-pair.hh"
#include <deque>
#include <cstdio>
a DOWN skyline with an UP skyline, we need to flip the DOWN skyline first.
This means that the merging routine doesn't need to be aware of direction,
but the distance routine does.
-*/
-/* If we start including very thin buildings, numerical accuracy errors can
- arise. Therefore, we ignore all buildings that are less than epsilon wide. */
-#define EPS 1e-5
+ Be careful about numerical accuracy. When dealing with extremely small values,
+ computation errors may arise due to the use of floating point arithmetic.
+ For example, if left and right have equal values to start with, in C++
+ they may not receive the same value after
+
+ left = left*factor + offset;
+ right = right*factor + offset;
+
+ Which is very unfortunate. Maybe using GCC compiler options to disallow
+ extended precision for intermediate results and/or the choice to store
+ intermediates with less than full precision would retain some kind of
+ deterministic behavior that way.
+
+ Anyway, it seems that accepting extremely narrow building in skylines
+ doesn't cause accuracy problems to us, so we allow arbitrarily small buildings.
+ However, as Keith pointed out, problems may appear if more than one operation
+ is done before storing the result, and/or there are different code paths
+ for doing the operations to the different ends of an interval.
+*/
static void
print_buildings (list<Building> const &b)
vector<Offset> ps (to_points (X_AXIS));
for (vsize i = 0; i < ps.size (); i++)
- printf ("(%f,%f)%s" , ps[i][X_AXIS], ps[i][Y_AXIS],
- (i%2)==1 ? "\n" : " ");
+ printf ("(%f,%f)%s", ps[i][X_AXIS], ps[i][Y_AXIS],
+ (i % 2) == 1 ? "\n" : " ");
}
Building::Building (Real start, Real start_height, Real end_height, Real end)
if (isinf (start) || isinf (end))
assert (start_height == end_height);
+ start_ = start;
end_ = end;
precompute (start, start_height, end_height, end);
}
-Building::Building (Box const &b, Real horizon_padding, Axis horizon_axis, Direction sky)
+Building::Building (Box const &b, Axis horizon_axis, Direction sky)
{
- Real start = b[horizon_axis][LEFT] - horizon_padding;
- Real end = b[horizon_axis][RIGHT] + horizon_padding;
+ Real start = b[horizon_axis][LEFT];
+ Real end = b[horizon_axis][RIGHT];
Real height = sky * b[other_axis (horizon_axis)][sky];
+ start_ = start;
end_ = end;
precompute (start, height, height, end);
}
void
Building::precompute (Real start, Real start_height, Real end_height, Real end)
{
- slope_ = (end_height - start_height) / (end - start);
- if (start_height == end_height) /* if they were both infinite, we would get nan, not 0, from the prev line */
- slope_ = 0;
+ slope_ = 0.0; /* if they were both infinite, we would get nan, not 0, from the prev line */
+ if (start_height != end_height)
+ slope_ = (end_height - start_height) / (end - start);
assert (!isinf (slope_) && !isnan (slope_));
y_intercept_ = start_height - slope_ * start;
}
-Real
+inline Real
Building::height (Real x) const
{
- return isinf (x) ? y_intercept_ : slope_*x + y_intercept_;
+ return isinf (x) ? y_intercept_ : slope_ * x + y_intercept_;
}
void
Building::print () const
{
- printf ("%f x + %f ends at %f\n", slope_, y_intercept_, end_);
+ printf ("%f x + %f from %f to %f\n", slope_, y_intercept_, start_, end_);
}
-Real
+inline Real
Building::intersection_x (Building const &other) const
{
Real ret = (y_intercept_ - other.y_intercept_) / (other.slope_ - slope_);
end_ = chop;
}
-Building
-Building::sloped_neighbour (Real start, Real horizon_padding, Direction d) const
+// Returns a shift s such that (x + s, y) intersects the roof of
+// this building. If no such shift exists, returns infinity_f.
+Real
+Building::shift_to_intersect (Real x, Real y) const
{
- Real x = (d == LEFT) ? start : end_;
- Real left = x;
- Real right = x + d * horizon_padding;
- Real left_height = height (x);
- Real right_height = left_height - horizon_padding;
- if (d == LEFT)
- {
- swap (left, right);
- swap (left_height, right_height);
- }
- return Building (left, left_height, right_height, right);
+ // Solve for s: y = (x + s)*m + b
+ Real ret = (y - y_intercept_ - slope_ * x) / slope_;
+
+ if (ret >= start_ && ret <= end_ && !isinf (ret))
+ return ret;
+ return infinity_f;
}
static Real
while (!s->empty () && start_x < b.end_)
{
Building c = s->front ();
+
+ // conceals and intersection_x involve multiplication and
+ // division. Avoid that, if we can.
+ if (c.y_intercept_ == -infinity_f)
+ {
+ if (c.end_ > b.end_)
+ return b.end_;
+ start_x = c.end_;
+ s->pop_front ();
+ continue;
+ }
+
if (c.conceals (b, start_x))
- return start_x;
+ return start_x;
Real i = b.intersection_x (c);
if (i > start_x && i <= b.end_ && i <= c.end_)
- return i;
+ return i;
start_x = c.end_;
if (b.end_ > c.end_)
- s->pop_front ();
+ s->pop_front ();
}
return b.end_;
}
/* their slopes were not equal, so there is an intersection point */
Real i = intersection_x (other);
return (i <= x && slope_ > other.slope_)
- || (i > x && slope_ < other.slope_);
+ || (i > x && slope_ < other.slope_);
+}
+
+// Remove redundant empty buildings from the skyline.
+// If there are two adjacent empty buildings, they can be
+// turned into one.
+void
+Skyline::normalize ()
+{
+ bool last_empty = false;
+ list<Building>::iterator i;
+
+ for (i = buildings_.begin (); i != buildings_.end (); i++)
+ {
+ if (last_empty && i->y_intercept_ == -infinity_f)
+ {
+ list<Building>::iterator last = i;
+ last--;
+ last->end_ = i->end_;
+ buildings_.erase (i);
+ i = last;
+ }
+ last_empty = (i->y_intercept_ == -infinity_f);
+ }
+
+ assert (buildings_.front ().start_ == -infinity_f);
+ assert (buildings_.back ().end_ == infinity_f);
+}
+
+void
+Skyline::deholify ()
+{
+ // Since a skyline should always be normalized, we can
+ // assume that there are never two adjacent empty buildings.
+ // That is, if center is empty then left and right are not.
+ list<Building>::iterator left = buildings_.begin ();
+ list<Building>::iterator center = buildings_.begin ();
+ list<Building>::iterator right;
+
+ for (right = buildings_.begin (); right != buildings_.end (); right++)
+ {
+ if (center != buildings_.begin () && center->y_intercept_ == -infinity_f)
+ {
+ Real p1 = left->height (left->end_);
+ Real p2 = right->height (right->start_);
+ *center = Building (center->start_, p1, p2, center->end_);
+
+ left = center;
+ center = right;
+ }
+ }
}
void
Skyline::internal_merge_skyline (list<Building> *s1, list<Building> *s2,
- list<Building> *const result)
+ list<Building> *const result) const
{
if (s1->empty () || s2->empty ())
{
}
Real x = -infinity_f;
+ Real last_end = -infinity_f;
while (!s1->empty ())
{
if (s2->front ().conceals (s1->front (), x))
- swap (s1, s2);
+ swap (s1, s2);
Building b = s1->front ();
- Real end = first_intersection (b, s2, x);
+ Building c = s2->front ();
+
+ // Optimization: if the other skyline is empty at this point,
+ // we can avoid testing some intersections. Just grab as many
+ // buildings from s1 as we can, and shove them onto the output.
+ if (c.y_intercept_ == -infinity_f
+ && c.end_ >= b.end_)
+ {
+ list<Building>::iterator i = s1->begin ();
+ i++;
+ while (i != s1->end () && i->end_ <= c.end_)
+ i++;
+
+ s1->front ().start_ = x;
+ result->splice (result->end (), *s1, s1->begin (), i);
+ x = result->back ().end_;
+ last_end = x;
+ continue;
+ }
+ Real end = first_intersection (b, s2, x);
if (s2->empty ())
- {
- result->push_front (b);
- break;
- }
-
- /* only include buildings wider than epsilon */
- if (end > x + EPS)
- {
- b.leading_part (end);
- result->push_front (b);
- }
+ {
+ b.start_ = last_end;
+ result->push_back (b);
+ break;
+ }
+
+ if (end >= x)
+ {
+ b.leading_part (end);
+ b.start_ = last_end;
+ last_end = b.end_;
+ result->push_back (b);
+ }
if (end >= s1->front ().end_)
- s1->pop_front ();
+ s1->pop_front ();
x = end;
}
- result->reverse ();
}
static void
}
/*
- Given Building 'b' with starting wall location 'start', extend each side
- with a sloped roofline of width 'horizon_padding'; put the skyline in 'ret'
+ Given Building 'b', build a skyline containing only that building.
*/
static void
-single_skyline (Building b, Real start, Real horizon_padding, list<Building> *const ret)
+single_skyline (Building b, list<Building> *const ret)
{
- bool sloped_neighbours = horizon_padding > 0 && !isinf (start) && !isinf (b.end_);
- if (!isinf (b.end_))
- ret->push_front (Building (b.end_ + horizon_padding, -infinity_f,
- -infinity_f, infinity_f));
- if (sloped_neighbours)
- ret->push_front (b.sloped_neighbour (start, horizon_padding, RIGHT));
-
- if (b.end_ > start + EPS)
- ret->push_front (b);
-
- if (sloped_neighbours)
- ret->push_front (b.sloped_neighbour (start, horizon_padding, LEFT));
+ assert (b.end_ >= b.start_);
- if (!isinf (start))
- ret->push_front (Building (-infinity_f, -infinity_f,
- -infinity_f, start - horizon_padding));
+ if (b.start_ != -infinity_f)
+ ret->push_back (Building (-infinity_f, -infinity_f,
+ -infinity_f, b.start_));
+ ret->push_back (b);
+ if (b.end_ != infinity_f)
+ ret->push_back (Building (b.end_, -infinity_f,
+ -infinity_f, infinity_f));
}
/* remove a non-overlapping set of boxes from BOXES and build a skyline
out of them */
static list<Building>
-non_overlapping_skyline (list<Box> *const boxes, Real horizon_padding, Axis horizon_axis, Direction sky)
+non_overlapping_skyline (list<Building> *const buildings)
{
list<Building> result;
Real last_end = -infinity_f;
- list<Box>::iterator i = boxes->begin ();
- while (i != boxes->end ())
+ Building last_building (-infinity_f, -infinity_f, -infinity_f, infinity_f);
+ list<Building>::iterator i = buildings->begin ();
+ while (i != buildings->end ())
{
- Interval iv = (*i)[horizon_axis];
-
- if (iv[LEFT] - horizon_padding < last_end)
- {
- i++;
- continue;
- }
-
- if (iv[LEFT] - horizon_padding > last_end + EPS)
- result.push_front (Building (last_end, -infinity_f, -infinity_f, iv[LEFT] - 2*horizon_padding));
-
- Building b (*i, horizon_padding, horizon_axis, sky);
- bool sloped_neighbours = horizon_padding > 0 && !isinf (iv.length ());
- if (sloped_neighbours)
- result.push_front (b.sloped_neighbour (iv[LEFT] - horizon_padding, horizon_padding, LEFT));
- result.push_front (b);
- if (sloped_neighbours)
- result.push_front (b.sloped_neighbour (iv[LEFT] - horizon_padding, horizon_padding, RIGHT));
-
- list<Box>::iterator j = i++;
- boxes->erase (j);
- last_end = result.front ().end_;
+ Real x1 = i->start_;
+ Real y1 = i->height (i->start_);
+ Real x2 = i->end_;
+ Real y2 = i->height (i->end_);
+
+ // Drop buildings that will obviously have no effect.
+ if (last_building.height (x1) >= y1
+ && last_building.end_ >= x2
+ && last_building.height (x2) >= y2)
+ {
+ list<Building>::iterator j = i++;
+ buildings->erase (j);
+ continue;
+ }
+
+ if (x1 < last_end)
+ {
+ i++;
+ continue;
+ }
+
+ if (x1 >= last_end)
+ result.push_back (Building (last_end, -infinity_f, -infinity_f, x1));
+
+ result.push_back (*i);
+ last_building = *i;
+ last_end = i->end_;
+
+ list<Building>::iterator j = i++;
+ buildings->erase (j);
}
+
if (last_end < infinity_f)
- result.push_front (Building (last_end, -infinity_f, -infinity_f, infinity_f));
- result.reverse ();
+ result.push_back (Building (last_end, -infinity_f, -infinity_f, infinity_f));
return result;
}
-class LessThanBox
+class LessThanBuilding
{
- Axis a_;
-
public:
- LessThanBox (Axis a)
+ bool operator () (Building const &b1, Building const &b2)
{
- a_ = a;
- }
-
- bool operator() (Box const &b1, Box const &b2)
- {
- return b1[a_][LEFT] < b2[a_][LEFT];
+ return b1.start_ < b2.start_
+ || (b1.start_ == b2.start_ && b1.height (b1.start_) > b2.height (b1.start_));
}
};
+/**
+ BUILDINGS is a list of buildings, but they could be overlapping
+ and in any order. The returned list of buildings is ordered and non-overlapping.
+*/
list<Building>
-Skyline::internal_build_skyline (list<Box> *boxes, Real horizon_padding, Axis horizon_axis, Direction sky)
+Skyline::internal_build_skyline (list<Building> *buildings) const
{
- vsize size = boxes->size ();
+ vsize size = buildings->size ();
if (size == 0)
{
else if (size == 1)
{
list<Building> result;
- single_skyline (Building (boxes->front (), horizon_padding, horizon_axis, sky),
- boxes->front ()[horizon_axis][LEFT] - horizon_padding,
- horizon_padding, &result);
+ single_skyline (buildings->front (), &result);
return result;
}
deque<list<Building> > partials;
- boxes->sort (LessThanBox (horizon_axis));
- while (!boxes->empty ())
- partials.push_back (non_overlapping_skyline (boxes, horizon_padding, horizon_axis, sky));
+ buildings->sort (LessThanBuilding ());
+ while (!buildings->empty ())
+ partials.push_back (non_overlapping_skyline (buildings));
/* we'd like to say while (partials->size () > 1) but that's O (n).
Instead, we exit in the middle of the loop */
list<Building> one = partials.front ();
partials.pop_front ();
if (partials.empty ())
- return one;
+ return one;
list<Building> two = partials.front ();
partials.pop_front ();
}
/*
- build padded skyline from an existing skyline with padding
- added to it.
-*/
+ Build skyline from a set of boxes.
-Skyline::Skyline (Skyline const &src, Real horizon_padding, Axis a)
+ Boxes should be non-empty on both axes. Otherwise, they will be ignored
+ */
+Skyline::Skyline (vector<Box> const &boxes, Axis horizon_axis, Direction sky)
{
- /*
- We extract boxes from the skyline, then build a new skyline from
- the boxes.
- A box is created for every horizontal portion of the skyline
- Because skylines are defined positive, and then inverted if they
- are to be down-facing, we create the new skyline in the UP
- direction, then give it the down direction if needed.
- */
- Real start = -infinity_f;
- list<Box> boxes;
-
- // establish a baseline box
- boxes.push_back (Box (Interval (-infinity_f, infinity_f),
- Interval (0, 0)));
- list<Building>::const_iterator end = src.buildings_.end ();
- for (list<Building>::const_iterator i = src.buildings_.begin (); i != end; start=i->end_, i++ )
- if ((i->slope_ == 0) && !isinf (i->y_intercept_))
- boxes.push_back (Box (Interval (start, i->end_),
- Interval (-infinity_f , i->y_intercept_)));
- buildings_ = internal_build_skyline (&boxes, horizon_padding, X_AXIS, UP);
- sky_ = src.sky_;
-}
+ list<Building> buildings;
+ sky_ = sky;
+ for (vsize i = 0; i < boxes.size (); i++)
+ if (!boxes[i].is_empty ())
+ buildings.push_front (Building (boxes[i], horizon_axis, sky));
+
+ buildings_ = internal_build_skyline (&buildings);
+ normalize ();
+}
/*
- build skyline from a set of boxes. If horizon_padding > 0, expand all the boxes
- by that amount and add 45-degree sloped boxes to the edges of each box (of
- width horizon_padding). That is, the total amount of horizontal expansion is
- horizon_padding*4, half of which is sloped and half of which is flat.
+ build skyline from a set of line segments.
- Boxes should have fatness in the horizon_axis (after they are expanded by
- horizon_padding), otherwise they are ignored.
+ Segments can be articulated from left to right or right to left.
+ In the case of the latter, they will be stored internally as left to right.
*/
-Skyline::Skyline (vector<Box> const &boxes, Real horizon_padding, Axis horizon_axis, Direction sky)
+Skyline::Skyline (vector<Drul_array<Offset> > const &segments, Axis horizon_axis, Direction sky)
{
- list<Box> filtered_boxes;
+ list<Building> buildings;
sky_ = sky;
- Axis vert_axis = other_axis (horizon_axis);
- for (vsize i = 0; i < boxes.size (); i++)
+ for (vsize i = 0; i < segments.size (); i++)
{
- Interval iv = boxes[i][horizon_axis];
- iv.widen (horizon_padding);
- if (iv.length () > EPS && !boxes[i][vert_axis].is_empty ())
- filtered_boxes.push_front (boxes[i]);
+ Drul_array<Offset> const &seg = segments[i];
+ Offset left = seg[LEFT];
+ Offset right = seg[RIGHT];
+ if (left[horizon_axis] > right[horizon_axis])
+ swap (left, right);
+
+ Real x1 = left[horizon_axis];
+ Real x2 = right[horizon_axis];
+ Real y1 = left[other_axis (horizon_axis)] * sky;
+ Real y2 = right[other_axis (horizon_axis)] * sky;
+
+ if (x1 <= x2)
+ buildings.push_back (Building (x1, y1, y2, x2));
}
- buildings_ = internal_build_skyline (&filtered_boxes, horizon_padding, horizon_axis, sky);
+ buildings_ = internal_build_skyline (&buildings);
+ normalize ();
}
-Skyline::Skyline (Box const &b, Real horizon_padding, Axis horizon_axis, Direction sky)
+Skyline::Skyline (vector<Skyline_pair> const &skypairs, Direction sky)
{
sky_ = sky;
- Building front (b, horizon_padding, horizon_axis, sky);
- single_skyline (front, b[horizon_axis][LEFT] - horizon_padding,
- horizon_padding, &buildings_);
+
+ deque<Skyline> partials;
+ for (vsize i = 0; i < skypairs.size (); i++)
+ partials.push_back (Skyline ((skypairs[i])[sky]));
+
+ while (partials.size () > 1)
+ {
+ Skyline one = partials.front ();
+ partials.pop_front ();
+ Skyline two = partials.front ();
+ partials.pop_front ();
+
+ one.merge (two);
+ partials.push_back (one);
+ }
+
+ if (partials.size ())
+ buildings_.swap (partials.front ().buildings_);
+ else
+ buildings_.clear ();
+}
+
+Skyline::Skyline (Box const &b, Axis horizon_axis, Direction sky)
+{
+ sky_ = sky;
+ Building front (b, horizon_axis, sky);
+ single_skyline (front, &buildings_);
+ normalize ();
}
void
{
assert (sky_ == other.sky_);
+ if (other.is_empty ())
+ return;
+
+ if (is_empty ())
+ {
+ buildings_ = other.buildings_;
+ return;
+ }
+
list<Building> other_bld (other.buildings_);
list<Building> my_bld;
my_bld.splice (my_bld.begin (), buildings_);
internal_merge_skyline (&other_bld, &my_bld, &buildings_);
+ normalize ();
}
void
-Skyline::insert (Box const &b, Real horizon_padding, Axis a)
+Skyline::insert (Box const &b, Axis a)
{
list<Building> other_bld;
list<Building> my_bld;
}
/* do the same filtering as in Skyline (vector<Box> const&, etc.) */
- Interval iv = b[a];
- iv.widen (horizon_padding);
- if (iv.length () <= EPS || b[other_axis (a)].is_empty ())
+ if (b.is_empty ())
return;
my_bld.splice (my_bld.begin (), buildings_);
- single_skyline (Building (b, horizon_padding, a, sky_), b[a][LEFT] - horizon_padding,
- horizon_padding, &other_bld);
+ single_skyline (Building (b, a, sky_), &other_bld);
internal_merge_skyline (&other_bld, &my_bld, &buildings_);
+ normalize ();
}
void
list<Building>::iterator end = buildings_.end ();
for (list<Building>::iterator i = buildings_.begin (); i != end; i++)
{
+ i->start_ += s;
i->end_ += s;
i->y_intercept_ -= s * i->slope_;
}
Real
Skyline::distance (Skyline const &other, Real horizon_padding) const
{
- assert (sky_ == -other.sky_);
+ Real dummy;
+ return internal_distance (other, horizon_padding, &dummy);
+}
+
+Real
+Skyline::touching_point (Skyline const &other, Real horizon_padding) const
+{
+ Real touch;
+ internal_distance (other, horizon_padding, &touch);
+ return touch;
+}
- Skyline const *padded_this = this;
- Skyline const *padded_other = &other;
+Real
+Skyline::internal_distance (Skyline const &other, Real horizon_padding, Real *touch_point) const
+{
+ if (horizon_padding == 0.0)
+ return internal_distance (other, touch_point);
+
+ // Note that it is not necessary to build a padded version of other,
+ // because the same effect can be achieved just by doubling horizon_padding.
+ Skyline padded_this = padded (horizon_padding);
+ return padded_this.internal_distance (other, touch_point);
+}
+
+Skyline
+Skyline::padded (Real horizon_padding) const
+{
+ if (horizon_padding < 0.0)
+ warning ("Cannot have negative horizon padding. Junking.");
+
+ if (horizon_padding <= 0.0)
+ return *this;
- /*
- For systems, padding is not added at creation time. Padding is
- added to AxisGroup objects when outside-staff objects are added.
- Thus, when we want to place systems with horizontal padding,
- we do it at distance calculation time.
- */
- if (horizon_padding != 0.0)
+ list<Building> pad_buildings;
+ for (list<Building>::const_iterator i = buildings_.begin (); i != buildings_.end (); ++i)
{
- padded_this = new Skyline (*padded_this, horizon_padding, X_AXIS);
- padded_other = new Skyline (*padded_other, horizon_padding, X_AXIS);
+ if (i->start_ > -infinity_f)
+ {
+ Real height = i->height (i->start_);
+ if (height > -infinity_f)
+ {
+ // Add the sloped building that pads the left side of the current building.
+ Real start = i->start_ - 2 * horizon_padding;
+ Real end = i->start_ - horizon_padding;
+ pad_buildings.push_back (Building (start, height - horizon_padding, height, end));
+
+ // Add the flat building that pads the left side of the current building.
+ start = i->start_ - horizon_padding;
+ end = i->start_;
+ pad_buildings.push_back (Building (start, height, height, end));
+ }
+ }
+
+ if (i->end_ < infinity_f)
+ {
+ Real height = i->height (i->end_);
+ if (height > -infinity_f)
+ {
+ // Add the flat building that pads the right side of the current building.
+ Real start = i->end_;
+ Real end = start + horizon_padding;
+ pad_buildings.push_back (Building (start, height, height, end));
+
+ // Add the sloped building that pads the right side of the current building.
+ start = end;
+ end += horizon_padding;
+ pad_buildings.push_back (Building (start, height, height - horizon_padding, end));
+ }
+ }
}
- list<Building>::const_iterator i = padded_this->buildings_.begin ();
- list<Building>::const_iterator j = padded_other->buildings_.begin ();
+ // The buildings may be overlapping, so resolve that.
+ list<Building> pad_skyline = internal_build_skyline (&pad_buildings);
+
+ // Merge the padding with the original, to make a new skyline.
+ Skyline padded (sky_);
+ list<Building> my_buildings = buildings_;
+ padded.buildings_.clear ();
+ internal_merge_skyline (&pad_skyline, &my_buildings, &padded.buildings_);
+ padded.normalize ();
+
+ return padded;
+}
+
+Real
+Skyline::internal_distance (Skyline const &other, Real *touch_point) const
+{
+ assert (sky_ == -other.sky_);
+
+ list<Building>::const_iterator i = buildings_.begin ();
+ list<Building>::const_iterator j = other.buildings_.begin ();
Real dist = -infinity_f;
Real start = -infinity_f;
- while (i != padded_this->buildings_.end () && j != padded_other->buildings_.end ())
+ Real touch = -infinity_f;
+ while (i != buildings_.end () && j != other.buildings_.end ())
{
Real end = min (i->end_, j->end_);
Real start_dist = i->height (start) + j->height (start);
Real end_dist = i->height (end) + j->height (end);
dist = max (dist, max (start_dist, end_dist));
+
+ if (end_dist == dist)
+ touch = end;
+ else if (start_dist == dist)
+ touch = start;
+
if (i->end_ <= j->end_)
- i++;
+ i++;
else
- j++;
+ j++;
start = end;
}
+
+ *touch_point = touch;
return dist;
}
for (i = buildings_.begin (); i != buildings_.end (); i++)
{
if (i->end_ >= airplane)
- return sky_ * i->height (airplane);
+ return sky_ * i->height (airplane);
}
assert (0);
Real
Skyline::max_height () const
+{
+ Real ret = -infinity_f;
+
+ list<Building>::const_iterator i;
+ for (i = buildings_.begin (); i != buildings_.end (); ++i)
+ {
+ ret = max (ret, i->height (i->start_));
+ ret = max (ret, i->height (i->end_));
+ }
+
+ return sky_ * ret;
+}
+
+Direction
+Skyline::direction () const
+{
+ return sky_;
+}
+
+Real
+Skyline::left () const
+{
+ for (list<Building>::const_iterator i (buildings_.begin ());
+ i != buildings_.end (); i++)
+ if (i->y_intercept_ > -infinity_f)
+ return i->start_;
+
+ return infinity_f;
+}
+
+Real
+Skyline::right () const
+{
+ for (list<Building>::const_reverse_iterator i (buildings_.rbegin ());
+ i != buildings_.rend (); ++i)
+ if (i->y_intercept_ > -infinity_f)
+ return i->end_;
+
+ return -infinity_f;
+}
+
+Real
+Skyline::max_height_position () const
{
Skyline s (-sky_);
s.set_minimum_height (0);
- return sky_ * distance (s);
+ return touching_point (s);
}
void
merge (s);
}
-
vector<Offset>
Skyline::to_points (Axis horizon_axis) const
{
bool
Skyline::is_empty () const
{
+ if (!buildings_.size ())
+ return true;
Building b = buildings_.front ();
return b.end_ == infinity_f && b.y_intercept_ == -infinity_f;
}
/****************************************************************/
-
IMPLEMENT_SIMPLE_SMOBS (Skyline);
IMPLEMENT_TYPE_P (Skyline, "ly:skyline?");
IMPLEMENT_DEFAULT_EQUAL_P (Skyline);
SCM
-Skyline::mark_smob (SCM)
+Skyline::mark_smob (SCM s)
{
- ASSERT_LIVE_IS_ALLOWED ();
+ ASSERT_LIVE_IS_ALLOWED (s);
return SCM_EOL;
}
return 1;
}
+
+MAKE_SCHEME_CALLBACK_WITH_OPTARGS (Skyline, get_touching_point, 3, 1, "")
+SCM
+Skyline::get_touching_point (SCM skyline_scm, SCM other_skyline_scm, SCM horizon_padding_scm)
+{
+ LY_ASSERT_SMOB (Skyline, other_skyline_scm, 1);
+
+ Real horizon_padding = 0;
+ if (horizon_padding_scm != SCM_UNDEFINED)
+ {
+ LY_ASSERT_TYPE (scm_is_number, horizon_padding_scm, 3);
+ horizon_padding = scm_to_double (horizon_padding_scm);
+ }
+
+ Skyline *skyline = Skyline::unsmob (skyline_scm);
+ Skyline *other_skyline = Skyline::unsmob (other_skyline_scm);
+ return scm_from_double (skyline->touching_point (*other_skyline, horizon_padding));
+}
+
+MAKE_SCHEME_CALLBACK_WITH_OPTARGS (Skyline, get_distance, 3, 1, "")
+SCM
+Skyline::get_distance (SCM skyline_scm, SCM other_skyline_scm, SCM horizon_padding_scm)
+{
+ LY_ASSERT_SMOB (Skyline, other_skyline_scm, 1);
+
+ Real horizon_padding = 0;
+ if (horizon_padding_scm != SCM_UNDEFINED)
+ {
+ LY_ASSERT_TYPE (scm_is_number, horizon_padding_scm, 3);
+ horizon_padding = scm_to_double (horizon_padding_scm);
+ }
+
+ Skyline *skyline = Skyline::unsmob (skyline_scm);
+ Skyline *other_skyline = Skyline::unsmob (other_skyline_scm);
+ return scm_from_double (skyline->distance (*other_skyline, horizon_padding));
+}
+
+MAKE_SCHEME_CALLBACK (Skyline, get_max_height, 1)
+SCM
+Skyline::get_max_height (SCM skyline_scm)
+{
+ return scm_from_double (Skyline::unsmob (skyline_scm)->max_height ());
+}
+
+MAKE_SCHEME_CALLBACK (Skyline, get_max_height_position, 1)
+SCM
+Skyline::get_max_height_position (SCM skyline_scm)
+{
+ return scm_from_double (Skyline::unsmob (skyline_scm)->max_height_position ());
+}
+
+MAKE_SCHEME_CALLBACK (Skyline, get_height, 2)
+SCM
+Skyline::get_height (SCM skyline_scm, SCM x_scm)
+{
+ Real x = robust_scm2double (x_scm, 0.0);
+ return scm_from_double (Skyline::unsmob (skyline_scm)->height (x));
+}
+
+LY_DEFINE (ly_skyline_empty_p, "ly:skyline-empty?",
+ 1, 0, 0, (SCM sky),
+ "Return whether @var{sky} is empty.")
+{
+ Skyline *s = Skyline::unsmob (sky);
+ LY_ASSERT_SMOB (Skyline, sky, 1);
+ return scm_from_bool (s->is_empty ());
+}
projects / lilypond.git / blobdiff