+/*
+ Copyright (C) 2011-2013 Paul Davis
+ Author: Carl Hetherington <cth@carlh.net>
+
+ 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include <algorithm>
+#include <cmath>
#include <stdint.h>
#include <cairomm/context.h>
+
#include "canvas/utils.h"
+using namespace std;
+using namespace ArdourCanvas;
+
void
ArdourCanvas::set_source_rgba (Cairo::RefPtr<Cairo::Context> context, Color color)
{
);
}
+void
+ArdourCanvas::set_source_rgb_a (Cairo::RefPtr<Cairo::Context> context, Color color, float alpha)
+{
+ context->set_source_rgba (
+ ((color >> 24) & 0xff) / 255.0,
+ ((color >> 16) & 0xff) / 255.0,
+ ((color >> 8) & 0xff) / 255.0,
+ alpha
+ );
+}
+
+void
+ArdourCanvas::set_source_rgba (cairo_t *cr, Color color)
+{
+ cairo_set_source_rgba ( cr,
+ ((color >> 24) & 0xff) / 255.0,
+ ((color >> 16) & 0xff) / 255.0,
+ ((color >> 8) & 0xff) / 255.0,
+ ((color >> 0) & 0xff) / 255.0
+ );
+}
+
+void
+ArdourCanvas::set_source_rgb_a (cairo_t *cr, Color color, float alpha)
+{
+ cairo_set_source_rgba ( cr,
+ ((color >> 24) & 0xff) / 255.0,
+ ((color >> 16) & 0xff) / 255.0,
+ ((color >> 8) & 0xff) / 255.0,
+ alpha
+ );
+}
+
+ArdourCanvas::Distance
+ArdourCanvas::distance_to_segment_squared (Duple const & p, Duple const & p1, Duple const & p2, double& t, Duple& at)
+{
+ static const double kMinSegmentLenSquared = 0.00000001; // adjust to suit. If you use float, you'll probably want something like 0.000001f
+ static const double kEpsilon = 1.0E-14; // adjust to suit. If you use floats, you'll probably want something like 1E-7f
+ double dx = p2.x - p1.x;
+ double dy = p2.y - p1.y;
+ double dp1x = p.x - p1.x;
+ double dp1y = p.y - p1.y;
+ const double segLenSquared = (dx * dx) + (dy * dy);
+
+ if (segLenSquared >= -kMinSegmentLenSquared && segLenSquared <= kMinSegmentLenSquared) {
+ // segment is a point.
+ at = p1;
+ t = 0.0;
+ return ((dp1x * dp1x) + (dp1y * dp1y));
+ }
+
+
+ // Project a line from p to the segment [p1,p2]. By considering the line
+ // extending the segment, parameterized as p1 + (t * (p2 - p1)),
+ // we find projection of point p onto the line.
+ // It falls where t = [(p - p1) . (p2 - p1)] / |p2 - p1|^2
+
+ t = ((dp1x * dx) + (dp1y * dy)) / segLenSquared;
+
+ if (t < kEpsilon) {
+ // intersects at or to the "left" of first segment vertex (p1.x, p1.y). If t is approximately 0.0, then
+ // intersection is at p1. If t is less than that, then there is no intersection (i.e. p is not within
+ // the 'bounds' of the segment)
+ if (t > -kEpsilon) {
+ // intersects at 1st segment vertex
+ t = 0.0;
+ }
+ // set our 'intersection' point to p1.
+ at = p1;
+ // Note: If you wanted the ACTUAL intersection point of where the projected lines would intersect if
+ // we were doing PointLineDistanceSquared, then qx would be (p1.x + (t * dx)) and qy would be (p1.y + (t * dy)).
+
+ } else if (t > (1.0 - kEpsilon)) {
+ // intersects at or to the "right" of second segment vertex (p2.x, p2.y). If t is approximately 1.0, then
+ // intersection is at p2. If t is greater than that, then there is no intersection (i.e. p is not within
+ // the 'bounds' of the segment)
+ if (t < (1.0 + kEpsilon)) {
+ // intersects at 2nd segment vertex
+ t = 1.0;
+ }
+ // set our 'intersection' point to p2.
+ at = p2;
+ // Note: If you wanted the ACTUAL intersection point of where the projected lines would intersect if
+ // we were doing PointLineDistanceSquared, then qx would be (p1.x + (t * dx)) and qy would be (p1.y + (t * dy)).
+ } else {
+ // The projection of the point to the point on the segment that is perpendicular succeeded and the point
+ // is 'within' the bounds of the segment. Set the intersection point as that projected point.
+ at = Duple (p1.x + (t * dx), p1.y + (t * dy));
+ }
+
+ // return the squared distance from p to the intersection point. Note that we return the squared distance
+ // as an optimization because many times you just need to compare relative distances and the squared values
+ // works fine for that. If you want the ACTUAL distance, just take the square root of this value.
+ double dpqx = p.x - at.x;
+ double dpqy = p.y - at.y;
+
+ return ((dpqx * dpqx) + (dpqy * dpqy));
+}
+
projects / ardour.git / blobdiff