Paul Davis
590882f3c8
Items no longer need a parent group (they require a Canvas pointer instead), so all constructors have been rationalized and have two variants, one with a parent and one with a canvas. All Items now inherit from Fill and Outline, to banish diagonal inheritance and virtual base classes and all that. There were zero changes to the Ardour GUI arising from these changes.
263 lines
7.0 KiB
C++
263 lines
7.0 KiB
C++
/*
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Copyright (C) 2013 Paul Davis
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <cmath>
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#include <exception>
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#include <algorithm>
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#include "canvas/curve.h"
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using namespace ArdourCanvas;
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using std::min;
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using std::max;
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Curve::Curve (Canvas* c)
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: PolyItem (c)
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, n_samples (0)
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, points_per_segment (16)
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, curve_type (CatmullRomCentripetal)
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, curve_fill (None)
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{
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}
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Curve::Curve (Group* g)
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: PolyItem (g)
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, n_samples (0)
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, points_per_segment (16)
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, curve_type (CatmullRomCentripetal)
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, curve_fill (None)
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{
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}
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/** When rendering the curve, we will always draw a fixed number of straight
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* line segments to span the x-axis extent of the curve. More segments:
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* smoother visual rendering. Less rendering: closer to a visibily poly-line
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* render.
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*/
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void
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Curve::set_points_per_segment (uint32_t n)
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{
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/* this only changes our appearance rather than the bounding box, so we
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just need to schedule a redraw rather than notify the parent of any
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changes
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*/
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points_per_segment = n;
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interpolate ();
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redraw ();
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}
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void
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Curve::compute_bounding_box () const
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{
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PolyItem::compute_bounding_box ();
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/* possibly add extents of any point indicators here if we ever do that */
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}
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void
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Curve::set (Points const& p)
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{
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PolyItem::set (p);
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interpolate ();
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}
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void
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Curve::interpolate ()
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{
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samples.clear ();
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InterpolatedCurve::interpolate (_points, points_per_segment, CatmullRomCentripetal, false, samples);
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n_samples = samples.size();
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}
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void
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Curve::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
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{
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if (!_outline || _points.size() < 2 || !_bounding_box) {
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return;
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}
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Rect self = item_to_window (_bounding_box.get());
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boost::optional<Rect> d = self.intersection (area);
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assert (d);
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Rect draw = d.get ();
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/* Our approach is to always draw n_segments across our total size.
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*
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* This is very inefficient if we are asked to only draw a small
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* section of the curve. For now we rely on cairo clipping to help
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* with this.
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*/
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setup_outline_context (context);
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if (_points.size() == 2) {
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/* straight line */
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Duple window_space;
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window_space = item_to_window (_points.front());
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context->move_to (window_space.x, window_space.y);
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window_space = item_to_window (_points.back());
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context->line_to (window_space.x, window_space.y);
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switch (curve_fill) {
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case None:
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context->stroke();
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break;
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case Inside:
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context->stroke_preserve ();
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window_space = item_to_window (Duple(_points.back().x, draw.height()));
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context->line_to (window_space.x, window_space.y);
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window_space = item_to_window (Duple(_points.front().x, draw.height()));
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context->line_to (window_space.x, window_space.y);
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context->close_path();
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setup_fill_context(context);
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context->fill ();
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break;
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case Outside:
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context->stroke_preserve ();
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window_space = item_to_window (Duple(_points.back().x, 0.0));
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context->line_to (window_space.x, window_space.y);
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window_space = item_to_window (Duple(_points.front().x, 0.0));
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context->line_to (window_space.x, window_space.y);
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context->close_path();
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setup_fill_context(context);
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context->fill ();
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break;
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}
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} else {
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/* curve of at least 3 points */
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/* x-axis limits of the curve, in window space coordinates */
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Duple w1 = item_to_window (Duple (_points.front().x, 0.0));
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Duple w2 = item_to_window (Duple (_points.back().x, 0.0));
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/* clamp actual draw to area bound by points, rather than our bounding box which is slightly different */
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context->save ();
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context->rectangle (draw.x0, draw.y0, draw.width(), draw.height());
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context->clip ();
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/* expand drawing area by several pixels on each side to avoid cairo stroking effects at the boundary.
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they will still occur, but cairo's clipping will hide them.
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*/
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draw = draw.expand (4.0);
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/* now clip it to the actual points in the curve */
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if (draw.x0 < w1.x) {
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draw.x0 = w1.x;
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}
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if (draw.x1 >= w2.x) {
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draw.x1 = w2.x;
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}
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/* find left and right-most sample */
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Duple window_space;
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Points::size_type left = 0;
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Points::size_type right = n_samples;
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for (Points::size_type idx = 0; idx < n_samples - 1; ++idx) {
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left = idx;
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window_space = item_to_window (Duple (samples[idx].x, 0.0));
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if (window_space.x >= draw.x0) break;
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}
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for (Points::size_type idx = n_samples; idx > left + 1; --idx) {
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window_space = item_to_window (Duple (samples[idx].x, 0.0));
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if (window_space.x <= draw.x1) break;
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right = idx;
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}
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/* draw line between samples */
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window_space = item_to_window (Duple (samples[left].x, samples[left].y));
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context->move_to (window_space.x, window_space.y);
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for (uint32_t idx = left + 1; idx < right; ++idx) {
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window_space = item_to_window (Duple (samples[idx].x, samples[idx].y));
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context->line_to (window_space.x, window_space.y);
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}
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switch (curve_fill) {
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case None:
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context->stroke();
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break;
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case Inside:
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context->stroke_preserve ();
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window_space = item_to_window (Duple (samples[right-1].x, draw.height()));
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context->line_to (window_space.x, window_space.y);
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window_space = item_to_window (Duple (samples[left].x, draw.height()));
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context->line_to (window_space.x, window_space.y);
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context->close_path();
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setup_fill_context(context);
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context->fill ();
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break;
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case Outside:
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context->stroke_preserve ();
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window_space = item_to_window (Duple (samples[right-1].x, 0.0));
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context->line_to (window_space.x, window_space.y);
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window_space = item_to_window (Duple (samples[left].x, 0.0));
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context->line_to (window_space.x, window_space.y);
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context->close_path();
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setup_fill_context(context);
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context->fill ();
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break;
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}
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context->restore ();
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}
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#if 0
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/* add points */
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setup_outline_context (context);
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for (Points::const_iterator p = _points.begin(); p != _points.end(); ++p) {
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Duple window_space (item_to_window (*p));
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context->arc (window_space.x, window_space.y, 5.0, 0.0, 2 * M_PI);
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context->stroke ();
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}
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#endif
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}
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bool
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Curve::covers (Duple const & pc) const
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{
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Duple point = window_to_item (pc);
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/* O(N) N = number of points, and not accurate */
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for (Points::const_iterator p = _points.begin(); p != _points.end(); ++p) {
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const Coord dx = point.x - (*p).x;
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const Coord dy = point.y - (*p).y;
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const Coord dx2 = dx * dx;
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const Coord dy2 = dy * dy;
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if ((dx2 < 2.0 && dy2 < 2.0) || (dx2 + dy2 < 4.0)) {
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return true;
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}
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}
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return false;
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}
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