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| author | craig <craig@11d20701-8431-0410-a711-e3c959e3b870> | 2012-01-01 11:40:09 +0000 |
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| committer | craig <craig@11d20701-8431-0410-a711-e3c959e3b870> | 2012-01-01 11:40:09 +0000 |
| commit | 7ed83b6c6666eb8b6b104c211ae7e52907350372 (patch) | |
| tree | 4430b556abac0ad660a0aacf1887d77f85d8be02 /scribus/plugins/tools/2geomtools/lib2geom/sbasis.cpp | |
| download | scribus-7ed83b6c6666eb8b6b104c211ae7e52907350372.tar.gz scribus-7ed83b6c6666eb8b6b104c211ae7e52907350372.tar.xz scribus-7ed83b6c6666eb8b6b104c211ae7e52907350372.zip | |
Branch 1.3.5 tree to 1.4.x tree, goodbye 1.3.x
git-svn-id: svn://scribus.net/branches/Version14x/Scribus@17163 11d20701-8431-0410-a711-e3c959e3b870
Diffstat (limited to 'scribus/plugins/tools/2geomtools/lib2geom/sbasis.cpp')
| -rw-r--r-- | scribus/plugins/tools/2geomtools/lib2geom/sbasis.cpp | 492 |
1 files changed, 492 insertions, 0 deletions
diff --git a/scribus/plugins/tools/2geomtools/lib2geom/sbasis.cpp b/scribus/plugins/tools/2geomtools/lib2geom/sbasis.cpp new file mode 100644 index 0000000..3f133ec --- /dev/null +++ b/scribus/plugins/tools/2geomtools/lib2geom/sbasis.cpp @@ -0,0 +1,492 @@ +/* + * sbasis.cpp - S-power basis function class + supporting classes + * + * Authors: + * Nathan Hurst <njh@mail.csse.monash.edu.au> + * Michael Sloan <mgsloan@gmail.com> + * + * Copyright (C) 2006-2007 authors + * + * This library is free software; you can redistribute it and/or + * modify it either under the terms of the GNU Lesser General Public + * License version 2.1 as published by the Free Software Foundation + * (the "LGPL") or, at your option, under the terms of the Mozilla + * Public License Version 1.1 (the "MPL"). If you do not alter this + * notice, a recipient may use your version of this file under either + * the MPL or the LGPL. + * + * You should have received a copy of the LGPL along with this library + * in the file COPYING-LGPL-2.1; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * You should have received a copy of the MPL along with this library + * in the file COPYING-MPL-1.1 + * + * The contents of this file are subject to the Mozilla Public License + * Version 1.1 (the "License"); you may not use this file except in + * compliance with the License. You may obtain a copy of the License at + * http://www.mozilla.org/MPL/ + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY + * OF ANY KIND, either express or implied. See the LGPL or the MPL for + * the specific language governing rights and limitations. + */ + +#include <cmath> + +#include "sbasis.h" +#include "isnan.h" +#include "angle.h" + + +namespace Geom{ + +/*** At some point we should work on tighter bounds for the error. It is clear that the error is + * bounded by the L1 norm over the tail of the series, but this is very loose, leading to far too + * many cubic beziers. I've changed this to be \sum _i=tail ^\infty |hat a_i| 2^-i but I have no + * evidence that this is correct. + */ + +/* +double SBasis::tail_error(unsigned tail) const { + double err = 0, s = 1./(1<<(2*tail)); // rough + for(unsigned i = tail; i < size(); i++) { + err += (fabs((*this)[i][0]) + fabs((*this)[i][1]))*s; + s /= 4; + } + return err; +} +*/ + +double SBasis::tailError(unsigned tail) const { + Interval bs = bounds_fast(*this, tail); + return std::max(fabs(bs.min()),fabs(bs.max())); +} + +bool SBasis::isFinite() const { + for(unsigned i = 0; i < size(); i++) { + if(!(*this)[i].isFinite()) + return false; + } + return true; +} + +SBasis operator+(const SBasis& a, const SBasis& b) { + SBasis result; + const unsigned out_size = std::max(a.size(), b.size()); + const unsigned min_size = std::min(a.size(), b.size()); + result.reserve(out_size); + + for(unsigned i = 0; i < min_size; i++) { + result.push_back(a[i] + b[i]); + } + for(unsigned i = min_size; i < a.size(); i++) + result.push_back(a[i]); + for(unsigned i = min_size; i < b.size(); i++) + result.push_back(b[i]); + + assert(result.size() == out_size); + return result; +} + +SBasis operator-(const SBasis& a, const SBasis& b) { + SBasis result; + const unsigned out_size = std::max(a.size(), b.size()); + const unsigned min_size = std::min(a.size(), b.size()); + result.reserve(out_size); + + for(unsigned i = 0; i < min_size; i++) { + result.push_back(a[i] - b[i]); + } + for(unsigned i = min_size; i < a.size(); i++) + result.push_back(a[i]); + for(unsigned i = min_size; i < b.size(); i++) + result.push_back(-b[i]); + + assert(result.size() == out_size); + return result; +} + +SBasis& operator+=(SBasis& a, const SBasis& b) { + const unsigned out_size = std::max(a.size(), b.size()); + const unsigned min_size = std::min(a.size(), b.size()); + a.reserve(out_size); + + for(unsigned i = 0; i < min_size; i++) + a[i] += b[i]; + for(unsigned i = min_size; i < b.size(); i++) + a.push_back(b[i]); + + assert(a.size() == out_size); + return a; +} + +SBasis& operator-=(SBasis& a, const SBasis& b) { + const unsigned out_size = std::max(a.size(), b.size()); + const unsigned min_size = std::min(a.size(), b.size()); + a.reserve(out_size); + + for(unsigned i = 0; i < min_size; i++) + a[i] -= b[i]; + for(unsigned i = min_size; i < b.size(); i++) + a.push_back(-b[i]); + + assert(a.size() == out_size); + return a; +} + +SBasis operator*(SBasis const &a, double k) { + SBasis c; + c.reserve(a.size()); + for(unsigned i = 0; i < a.size(); i++) + c.push_back(a[i] * k); + return c; +} + +SBasis& operator*=(SBasis& a, double b) { + if (a.isZero()) return a; + if (b == 0) + a.clear(); + else + for(unsigned i = 0; i < a.size(); i++) + a[i] *= b; + return a; +} + +SBasis shift(SBasis const &a, int sh) { + SBasis c = a; + if(sh > 0) { + c.insert(c.begin(), sh, Linear(0,0)); + } else { + //TODO: truncate + } + return c; +} + +SBasis shift(Linear const &a, int sh) { + SBasis c; + if(sh > 0) { + c.insert(c.begin(), sh, Linear(0,0)); + c.push_back(a); + } + return c; +} + +SBasis multiply(SBasis const &a, SBasis const &b) { + // c = {a0*b0 - shift(1, a.Tri*b.Tri), a1*b1 - shift(1, a.Tri*b.Tri)} + + // shift(1, a.Tri*b.Tri) + SBasis c; + if(a.isZero() || b.isZero()) + return c; + c.resize(a.size() + b.size(), Linear(0,0)); + c[0] = Linear(0,0); + for(unsigned j = 0; j < b.size(); j++) { + for(unsigned i = j; i < a.size()+j; i++) { + double tri = Tri(b[j])*Tri(a[i-j]); + c[i+1/*shift*/] += Linear(Hat(-tri)); + } + } + for(unsigned j = 0; j < b.size(); j++) { + for(unsigned i = j; i < a.size()+j; i++) { + for(unsigned dim = 0; dim < 2; dim++) + c[i][dim] += b[j][dim]*a[i-j][dim]; + } + } + c.normalize(); + //assert(!(0 == c.back()[0] && 0 == c.back()[1])); + return c; +} + +SBasis integral(SBasis const &c) { + SBasis a; + a.resize(c.size() + 1, Linear(0,0)); + a[0] = Linear(0,0); + + for(unsigned k = 1; k < c.size() + 1; k++) { + double ahat = -Tri(c[k-1])/(2*k); + a[k] = Hat(ahat); + } + double aTri = 0; + for(int k = c.size()-1; k >= 0; k--) { + aTri = (Hat(c[k]).d + (k+1)*aTri/2)/(2*k+1); + a[k][0] -= aTri/2; + a[k][1] += aTri/2; + } + a.normalize(); + return a; +} + +SBasis derivative(SBasis const &a) { + SBasis c; + c.resize(a.size(), Linear(0,0)); + + for(unsigned k = 0; k < a.size(); k++) { + double d = (2*k+1)*Tri(a[k]); + + for(unsigned dim = 0; dim < 2; dim++) { + c[k][dim] = d; + if(k+1 < a.size()) { + if(dim) + c[k][dim] = d - (k+1)*a[k+1][dim]; + else + c[k][dim] = d + (k+1)*a[k+1][dim]; + } + } + } + + return c; +} + +//TODO: convert int k to unsigned k, and remove cast +SBasis sqrt(SBasis const &a, int k) { + SBasis c; + if(a.isZero() || k == 0) + return c; + c.resize(k, Linear(0,0)); + c[0] = Linear(std::sqrt(a[0][0]), std::sqrt(a[0][1])); + SBasis r = a - multiply(c, c); // remainder + + for(unsigned i = 1; i <= (unsigned)k && i<r.size(); i++) { + Linear ci(r[i][0]/(2*c[0][0]), r[i][1]/(2*c[0][1])); + SBasis cisi = shift(ci, i); + r -= multiply(shift((c*2 + cisi), i), SBasis(ci)); + r.truncate(k+1); + c += cisi; + if(r.tailError(i) == 0) // if exact + break; + } + + return c; +} + +// return a kth order approx to 1/a) +SBasis reciprocal(Linear const &a, int k) { + SBasis c; + assert(!a.isZero()); + c.resize(k, Linear(0,0)); + double r_s0 = (Tri(a)*Tri(a))/(-a[0]*a[1]); + double r_s0k = 1; + for(unsigned i = 0; i < (unsigned)k; i++) { + c[i] = Linear(r_s0k/a[0], r_s0k/a[1]); + r_s0k *= r_s0; + } + return c; +} + +SBasis divide(SBasis const &a, SBasis const &b, int k) { + SBasis c; + assert(!a.isZero()); + SBasis r = a; // remainder + + k++; + r.resize(k, Linear(0,0)); + c.resize(k, Linear(0,0)); + + for(unsigned i = 0; i < (unsigned)k; i++) { + Linear ci(r[i][0]/b[0][0], r[i][1]/b[0][1]); //H0 + c[i] += ci; + r -= shift(multiply(ci,b), i); + r.truncate(k+1); + if(r.tailError(i) == 0) // if exact + break; + } + + return c; +} + +// a(b) +// return a0 + s(a1 + s(a2 +... where s = (1-u)u; ak =(1 - u)a^0_k + ua^1_k +SBasis compose(SBasis const &a, SBasis const &b) { + SBasis s = multiply((SBasis(Linear(1,1))-b), b); + SBasis r; + + for(int i = a.size()-1; i >= 0; i--) { + r = SBasis(Linear(Hat(a[i][0]))) - b*a[i][0] + b*a[i][1] + multiply(r,s); + } + return r; +} + +// a(b) +// return a0 + s(a1 + s(a2 +... where s = (1-u)u; ak =(1 - u)a^0_k + ua^1_k +SBasis compose(SBasis const &a, SBasis const &b, unsigned k) { + SBasis s = multiply((SBasis(Linear(1,1))-b), b); + SBasis r; + + for(int i = a.size()-1; i >= 0; i--) { + r = SBasis(Linear(Hat(a[i][0]))) - b*a[i][0] + b*a[i][1] + multiply(r,s); + } + r.truncate(k); + return r; +} + +/* +Inversion algorithm. The notation is certainly very misleading. The +pseudocode should say: + +c(v) := 0 +r(u) := r_0(u) := u +for i:=0 to k do + c_i(v) := H_0(r_i(u)/(t_1)^i; u) + c(v) := c(v) + c_i(v)*t^i + r(u) := r(u) ? c_i(u)*(t(u))^i +endfor +*/ + +//#define DEBUG_INVERSION 1 + +SBasis inverse(SBasis a, int k) { + assert(a.size() > 0); +// the function should have 'unit range'("a00 = 0 and a01 = 1") and be monotonic. + double a0 = a[0][0]; + if(a0 != 0) { + a -= a0; + } + double a1 = a[0][1]; + assert(a1 != 0); // not invertable. + + if(a1 != 1) { + a /= a1; + } + SBasis c; // c(v) := 0 + if(a.size() >= 2 && k == 2) { + c.push_back(Linear(0,1)); + Linear t1(1+a[1][0], 1-a[1][1]); // t_1 + c.push_back(Linear(-a[1][0]/t1[0], -a[1][1]/t1[1])); + } else if(a.size() >= 2) { // non linear + SBasis r = Linear(0,1); // r(u) := r_0(u) := u + Linear t1(1./(1+a[1][0]), 1./(1-a[1][1])); // 1./t_1 + Linear one(1,1); + Linear t1i = one; // t_1^0 + SBasis one_minus_a = SBasis(one) - a; + SBasis t = multiply(one_minus_a, a); // t(u) + SBasis ti(one); // t(u)^0 +#ifdef DEBUG_INVERSION + std::cout << "a=" << a << std::endl; + std::cout << "1-a=" << one_minus_a << std::endl; + std::cout << "t1=" << t1 << std::endl; + //assert(t1 == t[1]); +#endif + + c.resize(k+1, Linear(0,0)); + for(unsigned i = 0; i < (unsigned)k; i++) { // for i:=0 to k do +#ifdef DEBUG_INVERSION + std::cout << "-------" << i << ": ---------" <<std::endl; + std::cout << "r=" << r << std::endl + << "c=" << c << std::endl + << "ti=" << ti << std::endl + << std::endl; +#endif + if(r.size() <= i) // ensure enough space in the remainder, probably not needed + r.resize(i+1, Linear(0,0)); + Linear ci(r[i][0]*t1i[0], r[i][1]*t1i[1]); // c_i(v) := H_0(r_i(u)/(t_1)^i; u) +#ifdef DEBUG_INVERSION + std::cout << "t1i=" << t1i << std::endl; + std::cout << "ci=" << ci << std::endl; +#endif + for(int dim = 0; dim < 2; dim++) // t1^-i *= 1./t1 + t1i[dim] *= t1[dim]; + c[i] = ci; // c(v) := c(v) + c_i(v)*t^i + // change from v to u parameterisation + SBasis civ = one_minus_a*ci[0] + a*ci[1]; + // r(u) := r(u) - c_i(u)*(t(u))^i + // We can truncate this to the number of final terms, as no following terms can + // contribute to the result. + r -= multiply(civ,ti); + r.truncate(k); + if(r.tailError(i) == 0) + break; // yay! + ti = multiply(ti,t); + } +#ifdef DEBUG_INVERSION + std::cout << "##########################" << std::endl; +#endif + } else + c = Linear(0,1); // linear + c -= a0; // invert the offset + c /= a1; // invert the slope + return c; +} + +SBasis sin(Linear b, int k) { + SBasis s = Linear(std::sin(b[0]), std::sin(b[1])); + Tri tr(s[0]); + double t2 = Tri(b); + s.push_back(Linear(std::cos(b[0])*t2 - tr, -std::cos(b[1])*t2 + tr)); + + t2 *= t2; + for(int i = 0; i < k; i++) { + Linear bo(4*(i+1)*s[i+1][0] - 2*s[i+1][1], + -2*s[i+1][0] + 4*(i+1)*s[i+1][1]); + bo -= s[i]*(t2/(i+1)); + + + s.push_back(bo/double(i+2)); + } + + return s; +} + +SBasis cos(Linear bo, int k) { + return sin(Linear(bo[0] + M_PI_2, + bo[1] + M_PI_2), + k); +} + +//compute fog^-1. ("zero" = double comparison threshold. *!*we might divide by "zero"*!*) +//TODO: compute order according to tol? +//TODO: requires g(0)=0 & g(1)=1 atm... adaptation to other cases should be obvious! +SBasis compose_inverse(SBasis const &f, SBasis const &g, unsigned order, double zero){ + SBasis result; //result + SBasis r=f; //remainder + SBasis Pk=Linear(1)-g,Qk=g,sg=Pk*Qk; + Pk.truncate(order); + Qk.truncate(order); + Pk.resize(order,Linear(0.)); + Qk.resize(order,Linear(0.)); + r.resize(order,Linear(0.)); + + int vs= valuation(sg,zero); + + for (unsigned k=0; k<order; k+=vs){ + double p10 = Pk.at(k)[0];// we have to solve the linear system: + double p01 = Pk.at(k)[1];// + double q10 = Qk.at(k)[0];// p10*a + q10*b = r10 + double q01 = Qk.at(k)[1];// & + double r10 = r.at(k)[0];// p01*a + q01*b = r01 + double r01 = r.at(k)[1];// + double a,b; + double det = p10*q01-p01*q10; + + //TODO: handle det~0!! + if (fabs(det)<zero){ + det = zero; + a=b=0; + }else{ + a=( q01*r10-q10*r01)/det; + b=(-p01*r10+p10*r01)/det; + } + result.push_back(Linear(a,b)); + r=r-Pk*a-Qk*b; + + Pk=Pk*sg; + Qk=Qk*sg; + Pk.truncate(order); + Qk.truncate(order); + r.truncate(order); + } + result.normalize(); + return result; +} + +} + +/* + Local Variables: + mode:c++ + c-file-style:"stroustrup" + c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +)) + indent-tabs-mode:nil + fill-column:99 + End: +*/ +// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 : |
