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livetrax/libs/canvas/xfade_curve.cc

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/*
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Copyright (C) 2013 Paul Davis
Copyright (C) 2014 Robin Gareus <robin@gareus.org>
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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.
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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.
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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 <cmath>
#include <exception>
#include <algorithm>
#include "canvas/xfade_curve.h"
#include "canvas/interpolated_curve.h"
#include "canvas/utils.h"
using namespace ArdourCanvas;
using std::min;
using std::max;
#ifdef USE_TRACKS_CODE_FEATURES
static const bool show_bg_fades = false;
#else
static const bool show_bg_fades = true;
#endif
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XFadeCurve::XFadeCurve (Canvas* c)
: Item (c)
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, points_per_segment (32)
, _xfadeposition (Start)
, _outline_color (0x000000ff)
, _fill_color (0x22448880)
, show_background_fade (show_bg_fades)
{
}
XFadeCurve::XFadeCurve (Canvas* c, XFadePosition pos)
: Item (c)
, points_per_segment (32)
, _xfadeposition (pos)
, _outline_color (0x000000ff)
, _fill_color (0x22448880)
, show_background_fade (show_bg_fades)
{
}
XFadeCurve::XFadeCurve (Item* parent)
: Item (parent)
, points_per_segment (32)
, _xfadeposition (Start)
, _outline_color (0x000000ff)
, _fill_color (0x22448880)
, show_background_fade (show_bg_fades)
{
}
XFadeCurve::XFadeCurve (Item* parent, XFadePosition pos)
: Item (parent)
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, points_per_segment (32)
, _xfadeposition (pos)
, _outline_color (0x000000ff)
, _fill_color (0x22448880)
, show_background_fade (show_bg_fades)
{
}
void
XFadeCurve::compute_bounding_box () const
{
if (!_in.points.empty() && !_out.points.empty()) {
Rect bbox;
Points::const_iterator i;
if (!_in.points.empty()) {
i = _in.points.begin();
bbox.x0 = bbox.x1 = i->x;
bbox.y0 = bbox.y1 = i->y;
++i;
while (i != _in.points.end()) {
bbox.x0 = min (bbox.x0, i->x);
bbox.y0 = min (bbox.y0, i->y);
bbox.x1 = max (bbox.x1, i->x);
bbox.y1 = max (bbox.y1, i->y);
++i;
}
} else {
i = _out.points.begin();
bbox.x0 = bbox.x1 = i->x;
bbox.y0 = bbox.y1 = i->y;
}
if (!_out.points.empty()) {
i = _out.points.begin();
while (i != _out.points.end()) {
bbox.x0 = min (bbox.x0, i->x);
bbox.y0 = min (bbox.y0, i->y);
bbox.x1 = max (bbox.x1, i->x);
bbox.y1 = max (bbox.y1, i->y);
++i;
}
}
_bounding_box = bbox.expand (1.0);
} else {
_bounding_box = Rect ();
}
_bounding_box_dirty = false;
}
void
XFadeCurve::set_inout (Points const & in, Points const & out)
{
if (_in.points == in && _out.points == out) {
return;
}
begin_change ();
_in.points = in;
_out.points = out;
_bounding_box_dirty = true;
interpolate ();
end_change ();
}
void
XFadeCurve::set_points_per_segment (uint32_t n)
{
points_per_segment = n;
interpolate ();
redraw ();
}
void
XFadeCurve::interpolate ()
{
_in.samples.clear ();
InterpolatedCurve::interpolate (_in.points, points_per_segment, CatmullRomCentripetal, false, _in.samples);
_in.n_samples = _in.samples.size();
_out.samples.clear ();
InterpolatedCurve::interpolate (_out.points, points_per_segment, CatmullRomCentripetal, false, _out.samples);
_out.n_samples = _out.samples.size();
}
Cairo::Path *
XFadeCurve::get_path(Rect const & area, Cairo::RefPtr<Cairo::Context> context, CanvasCurve const &c) const
{
assert(c.points.size() > 1);
context->begin_new_path ();
Duple window_space;
if (c.points.size () == 2) {
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window_space = item_to_window (c.points.front(), false);
context->move_to (window_space.x, window_space.y);
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window_space = item_to_window (c.points.back(), false);
context->line_to (window_space.x, window_space.y);
} else {
/* find left and right-most sample */
Points::size_type left = 0;
Points::size_type right = c.n_samples - 1;
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assert (left < right);
// we should really really do a binary search rather than iterate
for (Points::size_type idx = 0; idx < c.n_samples - 1; ++idx) {
left = idx;
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window_space = item_to_window (Duple (c.samples[idx].x, 0.0), false);
if (window_space.x >= area.x0) break;
}
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for (Points::size_type idx = c.n_samples - 1; right > left;) {
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if (--idx <= left) break;
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window_space = item_to_window (Duple (c.samples[idx].x, 0.0), false);
if (window_space.x <= area.x1) break;
right = idx;
}
assert(left < right);
assert(left < c.n_samples);
assert(right < c.n_samples);
/* draw line between samples */
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window_space = item_to_window (Duple (c.samples[left].x, c.samples[left].y), false);
context->move_to (window_space.x, window_space.y);
for (uint32_t idx = left + 1; idx <= right; ++idx) {
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window_space = item_to_window (Duple (c.samples[idx].x, c.samples[idx].y), false);
context->line_to (window_space.x, window_space.y);
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}
}
return context->copy_path ();
}
void
XFadeCurve::close_path(Rect const & area, Cairo::RefPtr<Cairo::Context> context, CanvasCurve const &c, bool inside) const
{
Duple window_space;
if (inside) {
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window_space = item_to_window (Duple(c.points.back().x, area.height()), false);
context->line_to (window_space.x, window_space.y);
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window_space = item_to_window (Duple(c.points.front().x, area.height()), false);
context->line_to (window_space.x, window_space.y);
context->close_path();
} else {
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window_space = item_to_window (Duple(c.points.back().x, 0.0), false);
context->line_to (window_space.x, window_space.y);
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window_space = item_to_window (Duple(c.points.front().x, 0.0), false);
context->line_to (window_space.x, window_space.y);
context->close_path();
}
}
void
XFadeCurve::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
{
if (!_bounding_box) { return; }
if (_in.points.size() < 2) { return; }
if (_out.points.size() < 2) { return; }
Rect self = item_to_window (_bounding_box);
Rect d = self.intersection (area);
assert (d);
Rect draw = d;
context->save ();
context->rectangle (draw.x0, draw.y0, draw.width(), draw.height());
context->clip ();
/* expand drawing area by several pixels on each side to avoid cairo stroking effects at the boundary.
* they will still occur, but cairo's clipping will hide them.
*/
draw = draw.expand (4.0);
Cairo::Path *path_in = get_path(draw, context, _in);
Cairo::Path *path_out = get_path(draw, context, _out);
Color outline_shaded = _outline_color;
outline_shaded = 0.5 * (outline_shaded & 0xff) + (outline_shaded & ~0xff);
Color fill_shaded = _fill_color;
fill_shaded = 0.5 * (fill_shaded & 0xff) + (fill_shaded & ~0xff);
#define IS_START (_xfadeposition == Start)
/* fill primary fade */
context->begin_new_path ();
context->append_path (IS_START ? *path_in : *path_out);
close_path(draw, context, IS_START ?_in : _out, false);
set_source_rgba (context, _fill_color);
context->fill ();
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if (show_background_fade) {
/* fill background fade */
context->save ();
context->begin_new_path ();
context->append_path (IS_START ? *path_in : *path_out);
close_path(draw, context, IS_START ? _in : _out, true);
context->set_fill_rule (Cairo::FILL_RULE_EVEN_ODD);
context->clip ();
context->begin_new_path ();
context->append_path (IS_START ? *path_out: *path_in);
close_path(draw, context, IS_START ? _out : _in, true);
set_source_rgba (context, fill_shaded);
context->set_fill_rule (Cairo::FILL_RULE_WINDING);
context->fill ();
context->restore ();
}
/* draw lines over fills */
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/* fade in line */
if (IS_START || show_background_fade) {
set_source_rgba (context, IS_START ? _outline_color : outline_shaded);
context->set_line_width (IS_START ? 1.0 : .5);
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context->begin_new_path ();
context->append_path (*path_in);
context->stroke();
}
/* fade out line */
if (!IS_START || show_background_fade) {
set_source_rgba (context, IS_START ? outline_shaded :_outline_color);
context->set_line_width (IS_START ? .5 : 1.0);
context->begin_new_path ();
context->append_path (*path_out);
context->stroke();
}
context->restore ();
delete path_in;
delete path_out;
}