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| -rw-r--r-- | src/live_effects/lpe-interpolate.cpp | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/src/live_effects/lpe-interpolate.cpp b/src/live_effects/lpe-interpolate.cpp new file mode 100644 index 0000000..7456c16 --- /dev/null +++ b/src/live_effects/lpe-interpolate.cpp @@ -0,0 +1,199 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/** \file + * LPE interpolate implementation + */ +/* + * Authors: + * Johan Engelen + * + * Copyright (C) Johan Engelen 2007-2008 <j.b.c.engelen@utwente.nl> + * + * Released under GNU GPL v2+, read the file 'COPYING' for more information. + */ +#include "live_effects/lpe-interpolate.h" +#include <2geom/sbasis-to-bezier.h> +#include "display/curve.h" +#include "object/sp-path.h" + +// TODO due to internal breakage in glibmm headers, this must be last: +#include <glibmm/i18n.h> + + +namespace Inkscape { +namespace LivePathEffect { + +LPEInterpolate::LPEInterpolate(LivePathEffectObject *lpeobject) + : Effect(lpeobject) + , trajectory_path(_("Trajectory:"), _("Path along which intermediate steps are created."), "trajectory", &wr, this, + "M0,0 L0,0") + , number_of_steps(_("Steps_:"), _("Determines the number of steps from start to end path."), "steps", &wr, this, 5) + , equidistant_spacing(_("E_quidistant spacing"), + _("If true, the spacing between intermediates is constant along the length of the path. If " + "false, the distance depends on the location of the nodes of the trajectory path."), + "equidistant_spacing", &wr, this, true) +{ + show_orig_path = true; + + registerParameter(&trajectory_path); + registerParameter(&equidistant_spacing); + registerParameter(&number_of_steps); + + number_of_steps.param_make_integer(); + number_of_steps.param_set_range(2, std::numeric_limits<gint>::max()); +} + +LPEInterpolate::~LPEInterpolate() = default; + + +bool +LPEInterpolate::doOnOpen(SPLPEItem const *lpeitem) +{ + if (!is_load || is_applied) { + return false; + } + trajectory_path.reload(); + return false; +} + + +void LPEInterpolate::transform_multiply(Geom::Affine const &postmul, bool /*set*/) +{ + if (sp_lpe_item && sp_lpe_item->pathEffectsEnabled() && sp_lpe_item->optimizeTransforms()) { + trajectory_path.param_transform_multiply(postmul, false); + } +} + +/* + * interpolate path_in[0] to path_in[1] + */ +Geom::PathVector LPEInterpolate::doEffect_path(Geom::PathVector const &path_in) +{ + if ((path_in.size() < 2) || (number_of_steps < 2)) { + return path_in; + } + // Don't allow empty path parameter: + if (trajectory_path.get_pathvector().empty()) { + return path_in; + } + if (is_load) { + trajectory_path.reload(); + } + + Geom::PathVector path_out; + + Geom::Piecewise<Geom::D2<Geom::SBasis> > pwd2_A = path_in[0].toPwSb(); + Geom::Piecewise<Geom::D2<Geom::SBasis> > pwd2_B = path_in[1].toPwSb(); + + // Transform both paths to (0,0) midpoint, so they can easily be positioned along interpolate_path + Geom::OptRect bounds_A = Geom::bounds_exact(pwd2_A); + if (bounds_A) { + pwd2_A -= bounds_A->midpoint(); + } + Geom::OptRect bounds_B = Geom::bounds_exact(pwd2_B); + if (bounds_B) { + pwd2_B -= bounds_B->midpoint(); + } + + // Make sure both paths have the same number of segments and cuts at the same locations + pwd2_B.setDomain(pwd2_A.domain()); + Geom::Piecewise<Geom::D2<Geom::SBasis> > pA = Geom::partition(pwd2_A, pwd2_B.cuts); + Geom::Piecewise<Geom::D2<Geom::SBasis> > pB = Geom::partition(pwd2_B, pwd2_A.cuts); + + auto trajectory = calculate_trajectory(bounds_A, bounds_B); + + Geom::Interval trajectory_domain = trajectory.domain(); + + for (int i = 0; i < number_of_steps; ++i) { + double fraction = i / (number_of_steps - 1); + + Geom::Piecewise<Geom::D2<Geom::SBasis> > pResult = pA * (1 - fraction) + pB * fraction; + pResult += trajectory.valueAt(trajectory_domain.min() + fraction * trajectory_domain.extent()); + + Geom::PathVector pathv = Geom::path_from_piecewise(pResult, LPE_CONVERSION_TOLERANCE); + path_out.push_back(pathv[0]); + } + + return path_out; +} + + +// returns the lpe parameter trajectory_path, transformed so that it starts at the +// bounding box center of the first path and ends at the bounding box center of the +// second path +Geom::Piecewise<Geom::D2<Geom::SBasis> > LPEInterpolate::calculate_trajectory(Geom::OptRect bounds_A, + Geom::OptRect bounds_B) +{ + Geom::Affine affine = trajectory_path.get_relative_affine(); + Geom::Piecewise<Geom::D2<Geom::SBasis> > trajectory = trajectory_path.get_pathvector()[0].toPwSb() * affine; + + if (equidistant_spacing) { + trajectory = Geom::arc_length_parametrization(trajectory); + } + + if (!bounds_A || !bounds_B) { + return trajectory; + } + + auto trajectory_start = trajectory.firstValue(); + auto trajectory_end = trajectory.lastValue(); + + auto midpoint_A = bounds_A->midpoint(); + auto midpoint_B = bounds_B->midpoint(); + + Geom::Ray original(trajectory_start, trajectory_end); + Geom::Ray transformed(midpoint_A, midpoint_B); + + double rotation = transformed.angle() - original.angle(); + double scale = Geom::distance(midpoint_A, midpoint_B) / Geom::distance(trajectory_start, trajectory_end); + + Geom::Affine transformation; + + transformation *= Geom::Translate(-trajectory_start); + transformation *= Geom::Scale(scale, scale); + transformation *= Geom::Rotate(rotation); + + transformation *= Geom::Translate(midpoint_A); + + return trajectory * transformation; +} + +void LPEInterpolate::resetDefaults(SPItem const *item) +{ + Effect::resetDefaults(item); + + if (!SP_IS_PATH(item)) + return; + + SPCurve const *crv = SP_PATH(item)->curveForEdit(); + Geom::PathVector const &pathv = crv->get_pathvector(); + if ((pathv.size() < 2)) + return; + + Geom::OptRect bounds_A = pathv[0].boundsExact(); + Geom::OptRect bounds_B = pathv[1].boundsExact(); + + if (bounds_A && bounds_B) { + Geom::PathVector traj_pathv; + traj_pathv.push_back(Geom::Path()); + traj_pathv[0].start(bounds_A->midpoint()); + traj_pathv[0].appendNew<Geom::LineSegment>(bounds_B->midpoint()); + trajectory_path.set_new_value(traj_pathv, true); + } + else { + trajectory_path.param_set_and_write_default(); + } +} + +} // 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 : |