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/*
* Copyright (C) 2013-2017 Paul Davis <paul@linuxaudiosystems.com>
* Copyright (C) 2014-2015 Robin Gareus <robin@gareus.org>
* Copyright (C) 2016 Nick Mainsbridge <mainsbridge@gmail.com>
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <cmath>
#include <exception>
#include <algorithm>
#include "canvas/curve.h"
using namespace ArdourCanvas;
using std::min;
using std::max;
Curve::Curve (Canvas* c)
: PolyItem (c)
, n_samples (0)
, points_per_segment (16)
, curve_fill (None)
{
}
Curve::Curve (Item* parent)
: PolyItem (parent)
, n_samples (0)
, points_per_segment (16)
, curve_fill (None)
{
}
/** When rendering the curve, we will always draw a fixed number of straight
* line segments to span the x-axis extent of the curve. More segments:
* smoother visual rendering. Less rendering: closer to a visibily poly-line
* render.
*/
void
Curve::set_points_per_segment (uint32_t n)
{
/* this only changes our appearance rather than the bounding box, so we
just need to schedule a redraw rather than notify the parent of any
changes
*/
points_per_segment = n;
interpolate ();
redraw ();
}
void
Curve::compute_bounding_box () const
{
PolyItem::compute_bounding_box ();
/* possibly add extents of any point indicators here if we ever do that */
}
void
Curve::set (Points const& p)
{
PolyItem::set (p);
interpolate ();
}
void
Curve::interpolate ()
{
samples.clear ();
InterpolatedCurve::interpolate (_points, points_per_segment, CatmullRomCentripetal, false, samples);
n_samples = samples.size();
}
void
Curve::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
{
if (!_outline || _points.size() < 2 || !_bounding_box) {
return;
}
Rect self = item_to_window (_bounding_box);
Rect d = self.intersection (area);
assert (d);
Rect draw = d;
/* Our approach is to always draw n_segments across our total size.
*
* This is very inefficient if we are asked to only draw a small
* section of the curve. For now we rely on cairo clipping to help
* with this.
*/
setup_outline_context (context);
if (_points.size() == 2) {
/* straight line */
Duple window_space;
window_space = item_to_window (_points.front());
context->move_to (window_space.x, window_space.y);
window_space = item_to_window (_points.back());
context->line_to (window_space.x, window_space.y);
switch (curve_fill) {
case None:
context->stroke();
break;
case Inside:
context->stroke_preserve ();
window_space = item_to_window (Duple(_points.back().x, draw.height()));
context->line_to (window_space.x, window_space.y);
window_space = item_to_window (Duple(_points.front().x, draw.height()));
context->line_to (window_space.x, window_space.y);
context->close_path();
setup_fill_context(context);
context->fill ();
break;
case Outside:
context->stroke_preserve ();
window_space = item_to_window (Duple(_points.back().x, 0.0));
context->line_to (window_space.x, window_space.y);
window_space = item_to_window (Duple(_points.front().x, 0.0));
context->line_to (window_space.x, window_space.y);
context->close_path();
setup_fill_context(context);
context->fill ();
break;
}
} else {
/* curve of at least 3 points */
/* x-axis limits of the curve, in window space coordinates */
Duple w1 = item_to_window (Duple (_points.front().x, 0.0));
Duple w2 = item_to_window (Duple (_points.back().x, 0.0));
/* clamp actual draw to area bound by points, rather than our bounding box which is slightly different */
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);
/* now clip it to the actual points in the curve */
if (draw.x0 < w1.x) {
draw.x0 = w1.x;
}
if (draw.x1 >= w2.x) {
draw.x1 = w2.x;
}
/* find left and right-most sample */
Duple window_space;
Points::size_type left = 0;
Points::size_type right = n_samples;
for (Points::size_type idx = 0; idx < n_samples - 1; ++idx) {
left = idx;
window_space = item_to_window (Duple (samples[idx].x, 0.0));
if (window_space.x >= draw.x0) break;
}
for (Points::size_type idx = n_samples; idx > left + 1; --idx) {
window_space = item_to_window (Duple (samples[idx].x, 0.0));
if (window_space.x <= draw.x1) break;
right = idx;
}
/* draw line between samples */
window_space = item_to_window (Duple (samples[left].x, samples[left].y));
context->move_to (window_space.x, window_space.y);
for (uint32_t idx = left + 1; idx < right; ++idx) {
window_space = item_to_window (Duple (samples[idx].x, samples[idx].y));
context->line_to (window_space.x, window_space.y);
}
switch (curve_fill) {
case None:
context->stroke();
break;
case Inside:
context->stroke_preserve ();
window_space = item_to_window (Duple (samples[right-1].x, draw.height()));
context->line_to (window_space.x, window_space.y);
window_space = item_to_window (Duple (samples[left].x, draw.height()));
context->line_to (window_space.x, window_space.y);
context->close_path();
setup_fill_context(context);
context->fill ();
break;
case Outside:
context->stroke_preserve ();
window_space = item_to_window (Duple (samples[right-1].x, 0.0));
context->line_to (window_space.x, window_space.y);
window_space = item_to_window (Duple (samples[left].x, 0.0));
context->line_to (window_space.x, window_space.y);
context->close_path();
setup_fill_context(context);
context->fill ();
break;
}
context->restore ();
}
#if 0
/* add points */
setup_outline_context (context);
for (Points::const_iterator p = _points.begin(); p != _points.end(); ++p) {
Duple window_space (item_to_window (*p));
context->arc (window_space.x, window_space.y, 5.0, 0.0, 2 * M_PI);
context->stroke ();
}
#endif
}
bool
Curve::covers (Duple const & pc) const
{
Duple point = window_to_item (pc);
/* O(N) N = number of points, and not accurate */
for (Points::const_iterator p = _points.begin(); p != _points.end(); ++p) {
const Coord dx = point.x - (*p).x;
const Coord dy = point.y - (*p).y;
const Coord dx2 = dx * dx;
const Coord dy2 = dy * dy;
if ((dx2 < 2.0 && dy2 < 2.0) || (dx2 + dy2 < 4.0)) {
return true;
}
}
return false;
}
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