mirror of https://github.com/CGAL/cgal
114 lines
4.0 KiB
C++
114 lines
4.0 KiB
C++
// Copyright (c) 2000,2001 Utrecht University (The Netherlands),
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// ETH Zurich (Switzerland), Freie Universitaet Berlin (Germany),
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// INRIA Sophia-Antipolis (France), Martin-Luther-University Halle-Wittenberg
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// (Germany), Max-Planck-Institute Saarbruecken (Germany), RISC Linz (Austria),
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// and Tel-Aviv University (Israel). All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public License as
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// published by the Free Software Foundation; version 2.1 of the License.
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// See the file LICENSE.LGPL distributed with CGAL.
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//
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// Licensees holding a valid commercial license may use this file in
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// accordance with the commercial license agreement provided with the software.
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//
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// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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//
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// $URL$
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// $Id$
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//
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//
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// Author(s) : Bernd Gaertner, Sven Schoenherr <sven@inf.ethz.ch>
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// Each of the following operators is individually
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// protected against multiple inclusion.
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// Window_stream I/O operators
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// ===========================
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// Conic_2
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// -------
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#ifdef CGAL_CONIC_2_H
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#ifndef CGAL_IO_WINDOW_STREAM_CONIC_2
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#define CGAL_IO_WINDOW_STREAM_CONIC_2
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template< class R >
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CGAL::Window_stream&
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operator << ( CGAL::Window_stream& ws, const CGAL::Conic_2<R>& c)
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{
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// length of a pixel in window-coordinates
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double pixel = 1/ws.scale();
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// pixel dimensions of window
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int width = (int)((ws.xmax() - ws.xmin()) * ws.scale()) + 1,
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height = (int)((ws.ymax() - ws.ymin()) * ws.scale()) + 1,
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dim = std::max( width, height);
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// pixel coordinates, stored for faster output
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double *X = new double [2*dim];
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double *Y = new double [2*dim];
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// actual number of pixels to be drawn
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int pixels;
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// conic coordinates
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double r = CGAL::to_double (c.r()),
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s = CGAL::to_double (c.s()),
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t = CGAL::to_double (c.t()),
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u = CGAL::to_double (c.u()),
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v = CGAL::to_double (c.v()),
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w = CGAL::to_double (c.w());
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// Phase I (drawing in x-direction)
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pixels = 0;
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// solve conic equation for y
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if (s != 0.0)
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for (double x = ws.xmin(); x <= ws.xmax(); x+=pixel) {
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double discr = (t*t-4.0*r*s)*(x*x) + (2.0*t*v-4.0*s*u)*x +
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v*v - 4.0*s*w;
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if (discr >= 0.0) {
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double y1 = (-t*x - v - CGAL::sqrt(discr))/(2.0*s);
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double y2 = (-t*x - v + CGAL::sqrt(discr))/(2.0*s);
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X[pixels] = x; Y[pixels++] = y1;
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X[pixels] = x; Y[pixels++] = y2; } }
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else
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for (double x = ws.xmin(); x <= ws.xmax(); x+=pixel) {
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double denom = t*x + v;
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if (denom != 0.0) {
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double y = -(r*x*x + u*x + w)/denom;
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X[pixels] = x; Y[pixels++] = y; } }
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ws.draw_pixels (pixels, X, Y);
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// Phase II (drawing in y-direction)
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pixels = 0;
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// solve conic equation for x
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if (r != 0.0)
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for (double y = ws.ymin(); y <= ws.ymax(); y+=pixel) {
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double discr = (t*t-4.0*r*s)*(y*y) + (2.0*t*u-4.0*r*v)*y +
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u*u - 4.0*r*w;
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if (discr >= 0.0) {
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double x1 = (-t*y - u - CGAL::sqrt(discr))/(2.0*r);
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double x2 = (-t*y - u + CGAL::sqrt(discr))/(2.0*r);
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X[pixels] = x1; Y[pixels++] = y;
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X[pixels] = x2; Y[pixels++] = y; } }
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else
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for (double y = ws.ymin(); y <= ws.ymax(); y+=pixel) {
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double denom = t*y + u;
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if (denom != 0.0) {
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double x = -(s*y*y + v*y + w)/denom;
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X[pixels] = x; Y[pixels++] = y; } }
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ws.draw_pixels (pixels, X, Y);
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// free memory
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delete[] Y;
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delete[] X;
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return( ws);
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}
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#endif // CGAL_IO_WINDOW_STREAM_CONIC_2
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#endif // CGAL_CONIC_2_H
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// ===== EOF ==================================================================
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