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/*
* This file is part of gerbolyze, a vector image preprocessing toolchain
* Copyright (C) 2021 Jan Sebastian Götte <gerbolyze@jaseg.de>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include "svg_geom.h"
#include <cmath>
#include <string>
#include <sstream>
#include <queue>
#include <assert.h>
#include <cairo.h>
#include "svg_import_defs.h"
using namespace ClipperLib;
using namespace std;
/* Get bounding box of a Clipper Paths */
IntRect gerbolyze::get_paths_bounds(const Paths &paths) {
if (paths.empty()) {
return {0, 0, 0, 0};
}
if (paths[0].empty()) {
return {0, 0, 0, 0};
}
IntPoint p0 = paths[0][0];
cInt x0=p0.X, y0=p0.Y, x1=p0.X, y1=p0.Y;
for (const Path &p : paths) {
for (const IntPoint ip : p) {
if (ip.X < x0)
x0 = ip.X;
if (ip.Y < y0)
y0 = ip.Y;
if (ip.X > x1)
x1 = ip.X;
if (ip.Y > y1)
y1 = ip.Y;
}
}
return {x0, y0, x1, y1};
}
enum ClipperLib::PolyFillType gerbolyze::clipper_fill_rule(const pugi::xml_node &node) {
string val(node.attribute("fill-rule").value());
if (val == "evenodd")
return ClipperLib::pftEvenOdd;
else
return ClipperLib::pftNonZero; /* default */
}
enum ClipperLib::EndType gerbolyze::clipper_end_type(const pugi::xml_node &node) {
string val(node.attribute("stroke-linecap").value());
if (val == "round")
return ClipperLib::etOpenRound;
if (val == "square")
return ClipperLib::etOpenSquare;
return ClipperLib::etOpenButt;
}
enum ClipperLib::JoinType gerbolyze::clipper_join_type(const pugi::xml_node &node) {
string val(node.attribute("stroke-linejoin").value());
if (val == "round")
return ClipperLib::jtRound;
if (val == "bevel")
return ClipperLib::jtSquare;
return ClipperLib::jtMiter;
}
static void dehole_polytree_worker(PolyNode &ptree, Paths &out, queue<PolyTree> &todo) {
for (int i=0; i<ptree.ChildCount(); i++) {
PolyNode *nod = ptree.Childs[i];
assert(nod);
assert(!nod->IsHole());
/* First, recursively process inner polygons. */
for (int j=0; j<nod->ChildCount(); j++) {
PolyNode *child = nod->Childs[j];
assert(child);
assert(child->IsHole());
if (child->ChildCount() > 0) {
dehole_polytree_worker(*child, out, todo);
}
}
if (nod->ChildCount() == 0) {
out.push_back(nod->Contour);
} else {
/* Do not add children's children, those were handled in the recursive call above */
Clipper c;
c.AddPath(nod->Contour, ptSubject, /* closed= */ true);
for (int k=0; k<nod->ChildCount(); k++) {
c.AddPath(nod->Childs[k]->Contour, ptSubject, /* closed= */ true);
}
/* Find a viable cut: Cut from top-left bounding box corner, through two subsequent points on the hole
* outline and to top-right bbox corner. */
IntRect bbox = c.GetBounds();
Path tri = { { bbox.left, bbox.top }, nod->Childs[0]->Contour[0], nod->Childs[0]->Contour[1], { bbox.right, bbox.top } };
c.AddPath(tri, ptClip, true);
c.StrictlySimple(true);
/* Execute twice, once for intersection fragment and once for difference fragment. Note that this will yield
* at least two, but possibly more polygons. */
c.Execute(ctDifference, todo.emplace(), pftNonZero);
c.Execute(ctIntersection, todo.emplace(), pftNonZero);
}
}
}
/* Take a Clipper polytree, i.e. a description of a set of polygons, their holes and their inner polygons, and remove
* all holes from it. We remove holes by splitting each polygon that has a hole into two or more pieces so that the hole
* is no more. These pieces perfectly fit each other so there is no visual or functional difference.
*/
void gerbolyze::dehole_polytree(PolyTree &ptree, Paths &out) {
queue<PolyTree> todo;
dehole_polytree_worker(ptree, out, todo);
while (!todo.empty()) {
dehole_polytree_worker(todo.front(), out, todo);
todo.pop();
}
}
/* Intersect two clip paths. Both must share a coordinate system. */
void gerbolyze::combine_clip_paths(Paths &in_a, Paths &in_b, Paths &out) {
Clipper c;
c.StrictlySimple(true);
c.AddPaths(in_a, ptClip, /* closed */ true);
c.AddPaths(in_b, ptSubject, /* closed */ true);
/* Nonzero fill since both input clip paths must already have been preprocessed by clipper. */
c.Execute(ctIntersection, out, pftNonZero);
}
/* Transform given clipper paths under the given cairo transform. If no transform is given, use cairo's current
* user-to-device transform. */
void gerbolyze::transform_paths(cairo_t *cr, Paths &paths, cairo_matrix_t *mat) {
cairo_save(cr);
if (mat != nullptr) {
cairo_set_matrix(cr, mat);
}
for (Path &p : paths) {
transform(p.begin(), p.end(), p.begin(),
[cr](IntPoint p) -> IntPoint {
double x = p.X / clipper_scale, y = p.Y / clipper_scale;
cairo_user_to_device(cr, &x, &y);
return { (cInt)round(x * clipper_scale), (cInt)round(y * clipper_scale) };
});
}
cairo_restore(cr);
}
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