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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-13 11:57:42 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-13 11:57:42 +0000 |
commit | 61f3ab8f23f4c924d455757bf3e65f8487521b5a (patch) | |
tree | 885599a36a308f422af98616bc733a0494fe149a /src/toys/ellipse-intersect-toy.cpp | |
parent | Initial commit. (diff) | |
download | lib2geom-upstream.tar.xz lib2geom-upstream.zip |
Adding upstream version 1.3.upstream/1.3upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/toys/ellipse-intersect-toy.cpp')
-rw-r--r-- | src/toys/ellipse-intersect-toy.cpp | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/src/toys/ellipse-intersect-toy.cpp b/src/toys/ellipse-intersect-toy.cpp new file mode 100644 index 0000000..3d65baa --- /dev/null +++ b/src/toys/ellipse-intersect-toy.cpp @@ -0,0 +1,158 @@ +#include <2geom/cairo-path-sink.h> +#include <2geom/ellipse.h> +#include <2geom/line.h> +#include <2geom/polynomial.h> +#include <toys/toy-framework-2.h> + +using namespace Geom; + +class CircleIntersect : public Toy { + PointSetHandle psh[2]; + Ellipse ea, eb; + Line l[6]; + + void intersect() { + // This is code is almost the same as in ellipse.cpp. + // We use it here to get the lines. + double A, B, C, D, E, F; + double a, b, c, d, e, f; + + ea.coefficients(A, E, B, C, D, F); + eb.coefficients(a, e, b, c, d, f); + + double I, J, K, L; + I = (-E*E*F + 4*A*B*F + C*D*E - A*D*D - B*C*C) / 4; + J = -((E*E - 4*A*B) * f + (2*E*F - C*D) * e + (2*A*D - C*E) * d + + (2*B*C - D*E) * c + (C*C - 4*A*F) * b + (D*D - 4*B*F) * a) / 4; + K = -((e*e - 4*a*b) * F + (2*e*f - c*d) * E + (2*a*d - c*e) * D + + (2*b*c - d*e) * C + (c*c - 4*a*f) * B + (d*d - 4*b*f) * A) / 4; + L = (-e*e*f + 4*a*b*f + c*d*e - a*d*d - b*c*c) / 4; + + std::vector<double> mu = solve_cubic(I, J, K, L); + + for (unsigned i = 0; i < mu.size(); ++i) { + double aa = mu[i] * A + a; + double bb = mu[i] * B + b; + double cc = mu[i] * C + c; + double dd = mu[i] * D + d; + double ee = mu[i] * E + e; + double ff = mu[i] * F + f; + double delta = ee*ee - 4*aa*bb; + if (delta < 0) { + continue; + } + + if (aa != 0) { + bb /= aa; cc /= aa; dd /= aa; ee /= aa; ff /= aa; + double s = (ee + std::sqrt(ee*ee - 4*bb)) / 2; + double q = ee - s; + double alpha = (dd - cc*q) / (s - q); + double beta = cc - alpha; + + l[i*2] = Line(1, q, alpha); + l[i*2+1] = Line(1, s, beta); + } else if (bb != 0) { + cc /= bb; dd /= bb; ee /= bb; ff /= bb; + double s = ee; + double q = 0; + double alpha = cc / ee; + double beta = ff * ee / cc; + + l[i*2] = Line(q, 1, alpha); + l[i*2+1] = Line(s, 1, beta); + } else { + // both aa and bb are zero + l[i*2] = Line(ee, 1, dd); + l[i*2+1] = Line(0, 1, cc/ee); + } + } + } + + void draw(cairo_t *cr, std::ostringstream *notify, int width, int height, bool save, std::ostringstream *timer_stream) override { + + Rect all(Point(0,0), Point(width, height)); + + double r1x = Geom::distance(psh[0].pts[0], psh[0].pts[1]); + double r1y = Geom::distance(psh[0].pts[0], psh[0].pts[2]); + double rot1 = Geom::atan2(psh[0].pts[1] - psh[0].pts[0]); + + double r2x = Geom::distance(psh[1].pts[0], psh[1].pts[1]); + double r2y = Geom::distance(psh[1].pts[0], psh[1].pts[2]); + double rot2 = Geom::atan2(psh[1].pts[1] - psh[1].pts[0]); + + ea = Ellipse(psh[0].pts[0], Point(r1x, r1y), rot1); + eb = Ellipse(psh[1].pts[0], Point(r2x, r2y), rot2); + + for (auto & i : l) { + i = Line(0, 0, 0); + } + + cairo_set_line_width(cr, 1.0); + + cairo_set_source_rgb(cr, 0, 0, 0); + Geom::CairoPathSink cps(cr); + cps.feed(ea); + cps.feed(eb); + cairo_stroke(cr); + + try { + intersect(); + std::vector<ShapeIntersection> result = ea.intersect(eb); + + if (!l[0].isDegenerate() && !l[1].isDegenerate()) { + cairo_set_source_rgba(cr, 1, 0, 0, 0.2); + draw_line(cr, l[0], all); + draw_line(cr, l[1], all); + cairo_stroke(cr); + } + if (!l[2].isDegenerate() && !l[3].isDegenerate()) { + cairo_set_source_rgba(cr, 0, 1, 0, 0.2); + draw_line(cr, l[2], all); + draw_line(cr, l[3], all); + cairo_stroke(cr); + } + if (!l[4].isDegenerate() && !l[5].isDegenerate()) { + cairo_set_source_rgba(cr, 0, 0, 1, 0.2); + draw_line(cr, l[4], all); + draw_line(cr, l[5], all); + cairo_stroke(cr); + } + + cairo_set_source_rgb(cr, 1, 0, 0); + for (auto & i : result) { + draw_handle(cr, i.point()); + } + cairo_stroke(cr); + } catch(...) { + *notify << "Exception"; + } + + // TODO: draw_handle at intersections + + Toy::draw(cr, notify, width, height, save,timer_stream); + } + + public: + CircleIntersect(){ + psh[0].push_back(300,300); psh[0].push_back(450,150); psh[0].push_back(250, 250); + psh[1].push_back(350,300); psh[1].push_back(500,500); psh[1].push_back(300, 350); + handles.push_back(&psh[0]); + handles.push_back(&psh[1]); + } +}; + +int main(int argc, char **argv) { + init(argc, argv, new CircleIntersect()); + return 0; +} + +/* + 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=4:softtabstop=4:fileencoding=utf-8:textwidth=99 : |