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Diffstat (limited to '')
| -rw-r--r-- | src/toys/auto-cross.cpp | 321 |
1 files changed, 321 insertions, 0 deletions
diff --git a/src/toys/auto-cross.cpp b/src/toys/auto-cross.cpp new file mode 100644 index 0000000..00b5b25 --- /dev/null +++ b/src/toys/auto-cross.cpp @@ -0,0 +1,321 @@ +/* @brief + * A toy for playing around with Path::intersectSelf(). + * + * Authors: + * Rafał Siejakowski <rs@rs-math.net> + * + * Copyright 2022 the Authors. + * + * This library is free software; you can redistribute it and/or + * modify it either under the terms of the GNU Lesser General Public + * License version 2.1 as published by the Free Software Foundation + * (the "LGPL") or, at your option, under the terms of the Mozilla + * Public License Version 1.1 (the "MPL"). If you do not alter this + * notice, a recipient may use your version of this file under either + * the MPL or the LGPL. + * + * You should have received a copy of the LGPL along with this library + * in the file COPYING-LGPL-2.1; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * You should have received a copy of the MPL along with this library + * in the file COPYING-MPL-1.1 + * + * The contents of this file are subject to the Mozilla Public License + * Version 1.1 (the "License"); you may not use this file except in + * compliance with the License. You may obtain a copy of the License at + * http://www.mozilla.org/MPL/ + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY + * OF ANY KIND, either express or implied. See the LGPL or the MPL for + * the specific language governing rights and limitations. + */ + +#include <toys/toy-framework-2.h> +#include <2geom/path.h> +#include <2geom/elliptical-arc.h> +#include <2geom/svg-path-parser.h> + +using namespace Geom; +using Color = uint32_t; + +Color const RED = 0x80000000; +Color const GREEN = 0x00800000; +Color const BROWN = 0x90500000; +Color const BLUE = 0x0000ff00; +Color const BLACK = 0x00000000; + +static void set_cairo_rgb(cairo_t *c, Color rgb) +{ + cairo_set_source_rgba(c, (double)((rgb & 0xFF000000) >> 24) / 255.0, + (double)((rgb & 0x00FF0000) >> 16) / 255.0, + (double)((rgb & 0x0000FF00) >> 8) / 255.0, + 1.0); +} + +static void write_text(cairo_t *c, const char *text, Point const &position, Color color) +{ + cairo_move_to(c, position); + cairo_set_font_size(c, 12); + set_cairo_rgb(c, color); + cairo_show_text(c, text); +} + +static std::string format_point(Point const &pt) +{ + std::ostringstream ss; + ss.precision(4); + ss << pt; + return ss.str(); +} + +static EllipticalArc random_arc(Point from, Point to) +{ + double const dist = distance(from, to); + auto angle = atan2(to - from); + bool sweep = std::abs(angle) > M_PI_2; + angle *= 2; + angle = std::fmod(angle, 2.0 * M_PI); + return EllipticalArc(from, Point(0.5 * dist, 2.0 * dist), angle, false, sweep, to); +} + +class Item +{ +private: + Path _path; + Color _color; + std::string _d; + +public: + Item(Color color) + : _color{color} + {} + + void setPath(Path &&new_path) + { + _path = std::forward<Path>(new_path); + std::ostringstream oss; + oss << _path; + _d = oss.str(); + } + + void draw(cairo_t *cr) const + { + cairo_set_line_width(cr, 2); + set_cairo_rgb(cr, _color); + cairo_path(cr, _path); + cairo_stroke(cr); + _drawBezierTangents(cr); + _drawSelfIntersections(cr); + } + + void write(cairo_t *cr, Point const &pos) const + { + write_text(cr, _d.c_str(), pos, _color); + } + + std::string const& getSVGD() const { return _d; } + +private: + void _drawBezierTangents(cairo_t *c) const + { + cairo_set_line_width(c, 1); + set_cairo_rgb(c, 0x0000b000); + // Draw tangents for Beziers: + for (auto const &curve : _path) { + if (auto const *bezier = dynamic_cast<BezierCurve const *>(&curve)) { + if (bezier->order() > 1) { + auto points = bezier->controlPoints(); + cairo_move_to(c, points[0]); + cairo_line_to(c, points[1]); + cairo_stroke(c); + cairo_move_to(c, points.back()); + cairo_line_to(c, points[points.size() - 2]); + cairo_stroke(c); + } + } + } + } + + void _drawSelfIntersections(cairo_t *cr) const + { + set_cairo_rgb(cr, BLACK); + for (auto const &xing : _path.intersectSelf()) { + draw_cross(cr, xing.point()); + auto const coords = format_point(xing.point()); + write_text(cr, coords.c_str(), xing.point() + Point(8, -8), BLACK); + } + } +}; + +class AutoCross : public Toy +{ +public: + AutoCross() + : items{Item(RED), Item(GREEN), Item(BROWN)} + { + bezier_handles.pts = { {200, 400}, {100, 300}, {300, 400}, {300, 300}, {450, 300}, {500, 500}, {400, 400} }; + elliptical_handles.pts = { {500, 200}, {700, 400}, {600, 500} }; + mixed_handles.pts = { {100, 600}, {120, 690}, {300, 650}, {330, 600}, {500, 800} }; + handles.push_back(&bezier_handles); + handles.push_back(&elliptical_handles); + handles.push_back(&mixed_handles); + } + + void draw(cairo_t *cr, std::ostringstream *notify, int width, int height, bool save, + std::ostringstream *timer_stream) override + { + if (crashed) { + draw_error(cr, width, height); + } else { + try { + draw_impl(cr, width, height); + } catch (Exception &e) { + error = e.what(); + handles.clear(); + crashed = true; + } + } + Toy::draw(cr, notify, width, height, save, timer_stream); + } + + void key_hit(GdkEventKey *ev) override + { + if (ev->keyval == GDK_KEY_space) { + print_path_d(); + } else if ((ev->keyval == GDK_KEY_V || ev->keyval == GDK_KEY_v) && (ev->state & GDK_CONTROL_MASK)) { + paste_d(); + } + + } + +private: + std::string error; + std::vector<Item> items; + PointSetHandle bezier_handles, elliptical_handles, mixed_handles; + bool crashed = false; + + void paste_d() + { + auto *clipboard = gtk_clipboard_get(GDK_SELECTION_CLIPBOARD); + auto *text = gtk_clipboard_wait_for_text(clipboard); + if (!text) { + return; + } + PathVector pv; + try { + pv = parse_svg_path(text); + } catch (SVGPathParseError &error) { + std::cerr << "Error pasting path d: " << error.what() << std::endl; + return; + } + if (pv.empty()) { + return; + } + Item paste_item{RED}; // TODO: cycle through a color palette. + paste_item.setPath(std::move(pv[0])); + items.push_back(paste_item); + redraw(); + } + + void print_path_d() + { + std::cout << "Path snapshots:\n"; + for (auto it = items.rbegin(); it != items.rend(); ++it) { + std::cout << it->getSVGD() << '\n'; + } + } + + void refresh_geometry() + { + // Construct the 2-segment Bézier path + auto const &cp = bezier_handles.pts; + Path bezier; + bezier.append(BezierCurveN<3>(cp[0].round(), cp[1].round(), cp[2].round(), cp[3].round())); + bezier.append(BezierCurveN<3>(cp[3].round(), cp[4].round(), cp[5].round(), cp[6].round())); + items[0].setPath(std::move(bezier)); + + // Construct the elliptical arcs + auto const &ae = elliptical_handles.pts; + Path elliptical; + elliptical.append(random_arc(ae[0], ae[1])); + elliptical.append(random_arc(ae[1], ae[2])); + items[1].setPath(std::move(elliptical)); + + // Construct a mixed path + auto const &mh = mixed_handles.pts; + Path mixed; + mixed.append(BezierCurveN<3>(mh[0], mh[1], mh[2], mh[3])); + mixed.append(random_arc(mh[3], mh[4])); + mixed.close(); + items[2].setPath(std::move(mixed)); + } + + void draw_impl(cairo_t *cr, int width, int height) + { + refresh_geometry(); + write_title(cr); + + auto text_pos = Point(20, height - 20); + for (auto const &item : items) { + item.draw(cr); + item.write(cr, text_pos); + text_pos -= Point(0, 20); + } + } + + void write_title(cairo_t *c) + { + cairo_move_to(c, 10, 40); + cairo_set_font_size(c, 30); + set_cairo_rgb(c, 0x0); + cairo_show_text(c, "Self-intersection of paths in lib2geom!"); + cairo_set_font_size(c, 14); + cairo_move_to(c, 10, 60); + cairo_show_text(c, "[Space]: Print SVG 'd' attributes to stdout"); + cairo_move_to(c, 10, 80); + cairo_show_text(c, "[Ctrl-V]: Paste a 'd' attribute from clipboard"); + } + + void draw_error(cairo_t *cr, int width, int height) + { + auto center = Point(0.5 * (double)width, 0.5 * (double)height); + cairo_move_to(cr, center + Point(-90, -100)); + cairo_line_to(cr, center + Point(100, 90)); + cairo_line_to(cr, center + Point(90, 100)); + cairo_line_to(cr, center + Point(-100, -90)); + cairo_close_path(cr); + cairo_set_source_rgb(cr, 1, 0, 0); + cairo_fill(cr); + + cairo_move_to(cr, center + Point(90, -100)); + cairo_line_to(cr, center + Point(100, -90)); + cairo_line_to(cr, center + Point(-90, 100)); + cairo_line_to(cr, center + Point(-100, 90)); + cairo_close_path(cr); + cairo_set_source_rgb(cr, 1, 0, 0); + cairo_fill(cr); + + cairo_move_to(cr, center + Point(-90, 120)); + cairo_show_text(cr, "Sorry, your toy has just broken :-/"); + cairo_move_to(cr, Point(10, center[Y] + 150)); + cairo_show_text(cr, error.c_str()); + } +}; + +int main(int argc, char **argv) +{ + auto toy = AutoCross(); + init(argc, argv, &toy, 800, 800); + 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=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :
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