261 lines
6.9 KiB
C++
261 lines
6.9 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_fill (None)
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{
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}
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Curve::Curve (Item* parent)
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: PolyItem (parent)
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, n_samples (0)
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, points_per_segment (16)
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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), false);
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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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