Paul Davis
6473cc7cb4
Default implementation for Item still uses bounding box, but specializations for Arc (Circle), Polygon, Line and PolyLine have been added
171 lines
3.6 KiB
C++
171 lines
3.6 KiB
C++
/*
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Copyright (C) 2011-2013 Paul Davis
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Author: Carl Hetherington <cth@carlh.net>
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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 <algorithm>
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#include <cairomm/context.h>
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#include "pbd/compose.h"
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#include "canvas/line.h"
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#include "canvas/types.h"
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#include "canvas/debug.h"
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#include "canvas/utils.h"
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#include "canvas/canvas.h"
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using namespace std;
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using namespace ArdourCanvas;
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Line::Line (Group* parent)
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: Item (parent)
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, Outline (parent)
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{
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}
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void
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Line::compute_bounding_box () const
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{
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Rect bbox;
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bbox.x0 = min (_points[0].x, _points[1].x);
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bbox.y0 = min (_points[0].y, _points[1].y);
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bbox.x1 = max (_points[0].x, _points[1].x);
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bbox.y1 = max (_points[0].y, _points[1].y);
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bbox = bbox.expand (0.5 + (_outline_width / 2));
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_bounding_box = bbox;
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_bounding_box_dirty = false;
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}
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void
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Line::render (Rect const & /*area*/, Cairo::RefPtr<Cairo::Context> context) const
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{
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setup_outline_context (context);
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Duple p0 = item_to_window (Duple (_points[0].x, _points[0].y));
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Duple p1 = item_to_window (Duple (_points[1].x, _points[1].y));
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/* See Cairo FAQ on single pixel lines to understand why we add 0.5
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*/
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context->move_to (p0.x + 0.5, p0.y + 0.5);
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context->line_to (p1.x + 0.5, p1.y + 0.5);
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context->stroke ();
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}
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void
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Line::set (Duple a, Duple b)
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{
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begin_change ();
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_points[0] = a;
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_points[1] = b;
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_bounding_box_dirty = true;
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end_change ();
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DEBUG_TRACE (PBD::DEBUG::CanvasItemsDirtied, "canvas item dirty: line change\n");
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}
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void
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Line::set_x (Coord x0, Coord x1)
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{
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begin_change ();
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_points[0].x = x0;
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_points[1].x = x1;
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_bounding_box_dirty = true;
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end_change ();
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DEBUG_TRACE (PBD::DEBUG::CanvasItemsDirtied, "canvas item dirty: line change\n");
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}
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void
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Line::set_x0 (Coord x0)
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{
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begin_change ();
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_points[0].x = x0;
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_bounding_box_dirty = true;
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end_change ();
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DEBUG_TRACE (PBD::DEBUG::CanvasItemsDirtied, "canvas item dirty: line change\n");
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}
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void
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Line::set_y0 (Coord y0)
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{
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begin_change ();
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_points[0].y = y0;
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_bounding_box_dirty = true;
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end_change ();
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DEBUG_TRACE (PBD::DEBUG::CanvasItemsDirtied, "canvas item dirty: line change\n");
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}
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void
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Line::set_x1 (Coord x1)
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{
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begin_change ();
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_points[1].x = x1;
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_bounding_box_dirty = true;
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end_change ();
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DEBUG_TRACE (PBD::DEBUG::CanvasItemsDirtied, "canvas item dirty: line change\n");
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}
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void
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Line::set_y1 (Coord y1)
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{
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begin_change ();
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_points[1].y = y1;
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_bounding_box_dirty = true;
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end_change ();
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DEBUG_TRACE (PBD::DEBUG::CanvasItemsDirtied, "canvas item dirty: line change\n");
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}
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bool
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Line::covers (Duple const & point) const
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{
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Duple p = canvas_to_item (point);
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/* compute area of triangle computed by the two line points and the one
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we are being asked about. If zero (within a given tolerance), the
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points are co-linear and the argument is on the line.
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*/
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double area = fabs (_points[0].x * (_points[0].y - p.y)) +
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(_points[1].x * (p.y - _points[0].y)) +
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(p.x * (_points[0].y - _points[1].y));
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if (area < 0.001) {
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return true;
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}
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return false;
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}
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