9d5f99bc30
git-svn-id: http://skia.googlecode.com/svn/trunk@7303 2bbb7eff-a529-9590-31e7-b0007b416f81
39 lines
1.2 KiB
C
39 lines
1.2 KiB
C
/*
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* Copyright 2012 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#if !defined QUADRATIC_UTILITIES_H
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#define QUADRATIC_UTILITIES_H
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#include "DataTypes.h"
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void chop_at(const Quadratic& src, QuadraticPair& dst, double t);
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double dx_at_t(const Quadratic& , double t);
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double dy_at_t(const Quadratic& , double t);
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void dxdy_at_t(const Quadratic& , double t, _Point& xy);
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/* Parameterization form, given A*t*t + 2*B*t*(1-t) + C*(1-t)*(1-t)
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*
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* a = A - 2*B + C
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* b = 2*B - 2*C
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* c = C
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*/
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inline void set_abc(const double* quad, double& a, double& b, double& c) {
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a = quad[0]; // a = A
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b = 2 * quad[2]; // b = 2*B
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c = quad[4]; // c = C
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b -= c; // b = 2*B - C
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a -= b; // a = A - 2*B + C
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b -= c; // b = 2*B - 2*C
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}
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int quadraticRoots(double A, double B, double C, double t[2]);
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int quadraticRootsX(const double A, const double B, const double C, double s[2]);
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void sub_divide(const Quadratic& src, double t1, double t2, Quadratic& dst);
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void xy_at_t(const Quadratic& , double t, double& x, double& y);
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#endif
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