diff options
Diffstat (limited to 'src/live_effects/lpe-ellipse_5pts.cpp')
| -rw-r--r-- | src/live_effects/lpe-ellipse_5pts.cpp | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/src/live_effects/lpe-ellipse_5pts.cpp b/src/live_effects/lpe-ellipse_5pts.cpp new file mode 100644 index 0000000..29288f8 --- /dev/null +++ b/src/live_effects/lpe-ellipse_5pts.cpp @@ -0,0 +1,212 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/** \file + * LPE "Ellipse through 5 points" implementation + */ + +/* + * Authors: + * Theodore Janeczko + * + * Copyright (C) Theodore Janeczko 2012 <flutterguy317@gmail.com> + * + * Released under GNU GPL v2+, read the file 'COPYING' for more information. + */ + +#include "live_effects/lpe-ellipse_5pts.h" +#include <2geom/circle.h> +#include <2geom/ellipse.h> +#include <2geom/path-sink.h> +#include "inkscape.h" +#include "desktop.h" +#include "message-stack.h" +// TODO due to internal breakage in glibmm headers, this must be last: +#include <glibmm/i18n.h> + +namespace Inkscape { +namespace LivePathEffect { + +LPEEllipse5Pts::LPEEllipse5Pts(LivePathEffectObject *lpeobject) : + Effect(lpeobject) +{ + //perceived_path = true; +} + +LPEEllipse5Pts::~LPEEllipse5Pts() += default; + +static double _det3(double (*mat)[3]) +{ + for (int i = 0; i < 2; i++) + { + for (int j = i + 1; j < 3; j++) + { + for (int k = i + 1; k < 3; k++) + { + mat[j][k] = (mat[j][k] * mat[i][i] - mat[j][i] * mat[i][k]); + if (i) mat[j][k] /= mat[i-1][i-1]; + } + } + } + return mat[2][2]; +} +static double _det5(double (*mat)[5]) +{ + for (int i = 0; i < 4; i++) + { + for (int j = i + 1; j < 5; j++) + { + for (int k = i + 1; k < 5; k++) + { + mat[j][k] = (mat[j][k] * mat[i][i] - mat[j][i] * mat[i][k]); + if (i) mat[j][k] /= mat[i-1][i-1]; + } + } + } + return mat[4][4]; +} + +Geom::PathVector +LPEEllipse5Pts::doEffect_path (Geom::PathVector const & path_in) +{ + Geom::PathVector path_out = Geom::PathVector(); + + if (path_in[0].size() < 4) { + + SP_ACTIVE_DESKTOP->messageStack()->flash(Inkscape::WARNING_MESSAGE, _("Five points required for constructing an ellipse")); + return path_in; + } + // we assume that the path has >= 3 nodes + Geom::Point A = path_in[0].initialPoint(); + Geom::Point B = path_in[0].pointAt(1); + Geom::Point C = path_in[0].pointAt(2); + Geom::Point D = path_in[0].pointAt(3); + Geom::Point E = path_in[0].pointAt(4); + + using namespace Geom; + + double rowmajor_matrix[5][6] = + { + {A.x()*A.x(), A.x()*A.y(), A.y()*A.y(), A.x(), A.y(), 1}, + {B.x()*B.x(), B.x()*B.y(), B.y()*B.y(), B.x(), B.y(), 1}, + {C.x()*C.x(), C.x()*C.y(), C.y()*C.y(), C.x(), C.y(), 1}, + {D.x()*D.x(), D.x()*D.y(), D.y()*D.y(), D.x(), D.y(), 1}, + {E.x()*E.x(), E.x()*E.y(), E.y()*E.y(), E.x(), E.y(), 1} + }; + + double mat_a[5][5] = + { + {rowmajor_matrix[0][1], rowmajor_matrix[1][1], rowmajor_matrix[2][1], rowmajor_matrix[3][1], rowmajor_matrix[4][1]}, + {rowmajor_matrix[0][2], rowmajor_matrix[1][2], rowmajor_matrix[2][2], rowmajor_matrix[3][2], rowmajor_matrix[4][2]}, + {rowmajor_matrix[0][3], rowmajor_matrix[1][3], rowmajor_matrix[2][3], rowmajor_matrix[3][3], rowmajor_matrix[4][3]}, + {rowmajor_matrix[0][4], rowmajor_matrix[1][4], rowmajor_matrix[2][4], rowmajor_matrix[3][4], rowmajor_matrix[4][4]}, + {rowmajor_matrix[0][5], rowmajor_matrix[1][5], rowmajor_matrix[2][5], rowmajor_matrix[3][5], rowmajor_matrix[4][5]} + }; + double mat_b[5][5] = + { + {rowmajor_matrix[0][0], rowmajor_matrix[1][0], rowmajor_matrix[2][0], rowmajor_matrix[3][0], rowmajor_matrix[4][0]}, + {rowmajor_matrix[0][2], rowmajor_matrix[1][2], rowmajor_matrix[2][2], rowmajor_matrix[3][2], rowmajor_matrix[4][2]}, + {rowmajor_matrix[0][3], rowmajor_matrix[1][3], rowmajor_matrix[2][3], rowmajor_matrix[3][3], rowmajor_matrix[4][3]}, + {rowmajor_matrix[0][4], rowmajor_matrix[1][4], rowmajor_matrix[2][4], rowmajor_matrix[3][4], rowmajor_matrix[4][4]}, + {rowmajor_matrix[0][5], rowmajor_matrix[1][5], rowmajor_matrix[2][5], rowmajor_matrix[3][5], rowmajor_matrix[4][5]} + }; + double mat_c[5][5] = + { + {rowmajor_matrix[0][0], rowmajor_matrix[1][0], rowmajor_matrix[2][0], rowmajor_matrix[3][0], rowmajor_matrix[4][0]}, + {rowmajor_matrix[0][1], rowmajor_matrix[1][1], rowmajor_matrix[2][1], rowmajor_matrix[3][1], rowmajor_matrix[4][1]}, + {rowmajor_matrix[0][3], rowmajor_matrix[1][3], rowmajor_matrix[2][3], rowmajor_matrix[3][3], rowmajor_matrix[4][3]}, + {rowmajor_matrix[0][4], rowmajor_matrix[1][4], rowmajor_matrix[2][4], rowmajor_matrix[3][4], rowmajor_matrix[4][4]}, + {rowmajor_matrix[0][5], rowmajor_matrix[1][5], rowmajor_matrix[2][5], rowmajor_matrix[3][5], rowmajor_matrix[4][5]} + }; + double mat_d[5][5] = + { + {rowmajor_matrix[0][0], rowmajor_matrix[1][0], rowmajor_matrix[2][0], rowmajor_matrix[3][0], rowmajor_matrix[4][0]}, + {rowmajor_matrix[0][1], rowmajor_matrix[1][1], rowmajor_matrix[2][1], rowmajor_matrix[3][1], rowmajor_matrix[4][1]}, + {rowmajor_matrix[0][2], rowmajor_matrix[1][2], rowmajor_matrix[2][2], rowmajor_matrix[3][2], rowmajor_matrix[4][2]}, + {rowmajor_matrix[0][4], rowmajor_matrix[1][4], rowmajor_matrix[2][4], rowmajor_matrix[3][4], rowmajor_matrix[4][4]}, + {rowmajor_matrix[0][5], rowmajor_matrix[1][5], rowmajor_matrix[2][5], rowmajor_matrix[3][5], rowmajor_matrix[4][5]} + }; + double mat_e[5][5] = + { + {rowmajor_matrix[0][0], rowmajor_matrix[1][0], rowmajor_matrix[2][0], rowmajor_matrix[3][0], rowmajor_matrix[4][0]}, + {rowmajor_matrix[0][1], rowmajor_matrix[1][1], rowmajor_matrix[2][1], rowmajor_matrix[3][1], rowmajor_matrix[4][1]}, + {rowmajor_matrix[0][2], rowmajor_matrix[1][2], rowmajor_matrix[2][2], rowmajor_matrix[3][2], rowmajor_matrix[4][2]}, + {rowmajor_matrix[0][3], rowmajor_matrix[1][3], rowmajor_matrix[2][3], rowmajor_matrix[3][3], rowmajor_matrix[4][3]}, + {rowmajor_matrix[0][5], rowmajor_matrix[1][5], rowmajor_matrix[2][5], rowmajor_matrix[3][5], rowmajor_matrix[4][5]} + }; + double mat_f[5][5] = + { + {rowmajor_matrix[0][0], rowmajor_matrix[1][0], rowmajor_matrix[2][0], rowmajor_matrix[3][0], rowmajor_matrix[4][0]}, + {rowmajor_matrix[0][1], rowmajor_matrix[1][1], rowmajor_matrix[2][1], rowmajor_matrix[3][1], rowmajor_matrix[4][1]}, + {rowmajor_matrix[0][2], rowmajor_matrix[1][2], rowmajor_matrix[2][2], rowmajor_matrix[3][2], rowmajor_matrix[4][2]}, + {rowmajor_matrix[0][3], rowmajor_matrix[1][3], rowmajor_matrix[2][3], rowmajor_matrix[3][3], rowmajor_matrix[4][3]}, + {rowmajor_matrix[0][4], rowmajor_matrix[1][4], rowmajor_matrix[2][4], rowmajor_matrix[3][4], rowmajor_matrix[4][4]} + }; + + double a1 = _det5(mat_a); + double b1 = -_det5(mat_b); + double c1 = _det5(mat_c); + double d1 = -_det5(mat_d); + double e1 = _det5(mat_e); + double f1 = -_det5(mat_f); + + double mat_check[][3] = + { + {a1, b1/2, d1/2}, + {b1/2, c1, e1/2}, + {d1/2, e1/2, f1} + }; + + if (_det3(mat_check) == 0 || a1*c1 - b1*b1/4 <= 0) { + SP_ACTIVE_DESKTOP->messageStack()->flash(Inkscape::WARNING_MESSAGE, _("No ellipse found for specified points")); + return path_in; + } + + Geom::Ellipse el(a1, b1, c1, d1, e1, f1); + + double s, e; + double x0, y0, x1, y1, x2, y2, x3, y3; + double len; + + // figure out if we have a slice, guarding against rounding errors + + Geom::Path p(Geom::Point(cos(0), sin(0))); + + double end = 2 * M_PI; + for (s = 0; s < end; s += M_PI_2) { + e = s + M_PI_2; + if (e > end) + e = end; + len = 4*tan((e - s)/4)/3; + x0 = cos(s); + y0 = sin(s); + x1 = x0 + len * cos(s + M_PI_2); + y1 = y0 + len * sin(s + M_PI_2); + x3 = cos(e); + y3 = sin(e); + x2 = x3 + len * cos(e - M_PI_2); + y2 = y3 + len * sin(e - M_PI_2); + p.appendNew<Geom::CubicBezier>(Geom::Point(x1,y1), Geom::Point(x2,y2), Geom::Point(x3,y3)); + } + + Geom::Affine aff = Geom::Scale(el.rays()) * Geom::Rotate(el.rotationAngle()) * Geom::Translate(el.center()); + + path_out.push_back(p * aff); + + return path_out; +} + +/* ######################## */ + +} //namespace LivePathEffect +} /* namespace Inkscape */ + +/* + 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 : |