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livetrax/libs/canvas/line_set.cc

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/*
Copyright (C) 2011-2013 Paul Davis
Author: Carl Hetherington <cth@carlh.net>
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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "canvas/line_set.h"
#include "canvas/utils.h"
using namespace std;
using namespace ArdourCanvas;
class LineSorter {
public:
bool operator() (LineSet::Line const & a, LineSet::Line const & b) {
return a.pos < b.pos;
}
};
LineSet::LineSet (Canvas* c, Orientation o)
: Item (c)
, _extent (0)
, _orientation (o)
{
}
LineSet::LineSet (Item* parent, Orientation o)
: Item (parent)
, _extent (0)
, _orientation (o)
{
}
void
LineSet::compute_bounding_box () const
{
if (_lines.empty ()) {
_bounding_box = boost::optional<Rect> ();
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} else {
if (_orientation == Horizontal) {
_bounding_box = Rect (0, /* x0 */
_lines.front().pos - (_lines.front().width/2.0), /* y0 */
_extent, /* x1 */
_lines.back().pos - (_lines.back().width/2.0) /* y1 */
);
} else {
_bounding_box = Rect (_lines.front().pos - _lines.front().width/2.0, /* x0 */
0, /* y0 */
_lines.back().pos + _lines.back().width/2.0, /* x1 */
_extent /* y1 */
);
}
}
_bounding_box_dirty = false;
}
void
LineSet::set_extent (Distance e)
{
begin_change ();
_extent = e;
_bounding_box_dirty = true;
end_change ();
}
void
LineSet::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
{
/* area is in window coordinates */
for (vector<Line>::const_iterator i = _lines.begin(); i != _lines.end(); ++i) {
Rect self;
if (_orientation == Horizontal) {
self = item_to_window (Rect (0, i->pos - (i->width/2.0), _extent, i->pos + (i->width/2.0)));
} else {
self = item_to_window (Rect (i->pos - (i->width/2.0), 0, i->pos + (i->width/2.0), _extent));
}
boost::optional<Rect> isect = self.intersection (area);
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if (!isect) {
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continue;
}
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Rect intersection (isect.get());
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set_source_rgba (context, i->color);
context->set_line_width (i->width);
/* Not 100% sure that the computation of the invariant
* positions (y and x) below work correctly if the line width
* is not 1.0, but visual inspection suggests it is OK.
*/
if (_orientation == Horizontal) {
double y = self.y0 + ((self.y1 - self.y0)/2.0);
context->move_to (intersection.x0, y);
context->line_to (intersection.x1, y);
} else {
double x = self.x0 + ((self.x1 - self.x0)/2.0);
context->move_to (x, intersection.y0);
context->line_to (x, intersection.y1);
}
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context->stroke ();
}
}
void
LineSet::add (Coord y, Distance width, Color color)
{
begin_change ();
_lines.push_back (Line (y, width, color));
sort (_lines.begin(), _lines.end(), LineSorter());
_bounding_box_dirty = true;
end_change ();
}
void
LineSet::clear ()
{
begin_change ();
_lines.clear ();
_bounding_box_dirty = true;
end_change ();
}
bool
LineSet::covers (Duple const & /*point*/) const
{
/* lines are ordered by position along primary axis, so binary search
* to find the place to start looking.
*
* XXX but not yet.
*/
return false;
}