dashing/dashing.cc

87 lines
2.4 KiB
C++

#include "parse_numbers.hh"
#include "dashing.hh"
namespace dashing
{
std::vector<F> parse_numbers(std::string line) {
std::istringstream fi(line);
std::vector<F> result;
F d;
while((fi >> d)) {
result.push_back(d);
for (auto p = fi.peek(); p == ',' || isspace(p); p = fi.peek()) {
fi.get();
}
}
return result;
}
PSMatrix PSMatrix::inverse() const {
auto i = F(1.) / determinant();
return PSMatrix{d*i, -b*i, -c*i, a*i, i*(c*f-e*d), i*(b*e-a*f)};
}
PSMatrix Translation(F x, F y) {
PSMatrix r{1.,0.,0.,1.,x,y};
return r;
}
PSMatrix Rotation(F theta) {
F c = cos(theta), s = sin(theta);
PSMatrix r{c,s,-s,c,0.,0.};
return r;
}
PSMatrix XSkew(F xk) {
PSMatrix r{1.,0.,xk,1.,0.,0.};
return r;
}
PSMatrix YScale(F ys) {
PSMatrix r{1.,0.,0.,ys,0.,0.};
return r;
}
PSMatrix operator*(const PSMatrix &m1, const PSMatrix m2) {
PSMatrix r{
m2.a * m1.a + m2.b * m1.c,
m2.a * m1.b + m2.b * m1.d,
m2.c * m1.a + m2.d * m1.c,
m2.c * m1.b + m2.d * m1.d,
m2.e * m1.a + m2.f * m1.c + m1.e,
m2.e * m1.b + m2.f * m1.d + m1.f};
return r;
}
static F radians(F degrees) { return degrees * acos(0) / 90.; }
Dash::Dash(F th, F x0, F y0, F dx, F dy,
const std::vector<F>::const_iterator dbegin,
const std::vector<F>::const_iterator dend)
: dash{dbegin, dend} {
auto s = 0.;
for(size_t i = 0; i < dash.size(); i++) {
bool is_negative = std::signbit(dash[i]);
bool index_is_odd = (i % 2) != 0;
if(is_negative != index_is_odd) {
throw std::invalid_argument("not a supported dash specification (but probably valid)");
}
dash[i] = std::abs(dash[i]);
}
if (dash.size() % 2) dash.push_back(0);
for(auto d : dash) { sum.push_back(s); s += d; }
sum.push_back(s);
tr = Translation(x0, y0) * Rotation(th) * XSkew(dx / dy) * YScale(dy);
tf = tr.inverse();
}
Dash Dash::FromString(const std::string &line, F scale) {
std::vector<F> words = parse_numbers(line);
if(words.size() < 5)
throw std::invalid_argument("not a valid dash specification");
for(auto i = words.begin() + 1; i != words.end(); i++) *i *= scale;
return Dash(radians(words.at(0)), words.at(1), words.at(2), words.at(3),
words.at(4), words.begin() + 5, words.end());
}
}