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Diffstat (limited to 'src/object/sp-polygon.cpp')
| -rw-r--r-- | src/object/sp-polygon.cpp | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/src/object/sp-polygon.cpp b/src/object/sp-polygon.cpp new file mode 100644 index 0000000..3f07bbc --- /dev/null +++ b/src/object/sp-polygon.cpp @@ -0,0 +1,228 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * SVG <polygon> implementation + * + * Authors: + * Lauris Kaplinski <lauris@kaplinski.com> + * Abhishek Sharma + * + * Copyright (C) 1999-2002 Lauris Kaplinski + * Copyright (C) 2000-2001 Ximian, Inc. + * + * Released under GNU GPL v2+, read the file 'COPYING' for more information. + */ + +#include "attributes.h" +#include "sp-polygon.h" +#include "display/curve.h" +#include <glibmm/i18n.h> +#include <2geom/curves.h> +#include "helper/geom-curves.h" +#include "svg/stringstream.h" +#include "xml/repr.h" +#include "document.h" + +SPPolygon::SPPolygon() : SPShape() { +} + +SPPolygon::~SPPolygon() = default; + +void SPPolygon::build(SPDocument *document, Inkscape::XML::Node *repr) { + SPPolygon* object = this; + + SPShape::build(document, repr); + + object->readAttr(SPAttr::POINTS); +} + +/* + * sp_svg_write_polygon: Write points attribute for polygon tag. + * pathv may only contain paths with only straight line segments + * Return value: points attribute string. + */ +static gchar *sp_svg_write_polygon(Geom::PathVector const & pathv) +{ + Inkscape::SVGOStringStream os; + + for (const auto & pit : pathv) { + for (Geom::Path::const_iterator cit = pit.begin(); cit != pit.end_default(); ++cit) { + if ( is_straight_curve(*cit) ) + { + os << cit->finalPoint()[0] << "," << cit->finalPoint()[1] << " "; + } else { + g_error("sp_svg_write_polygon: polygon path contains non-straight line segments"); + } + } + } + + return g_strdup(os.str().c_str()); +} + +Inkscape::XML::Node* SPPolygon::write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags) { + // Tolerable workaround: we need to update the object's curve before we set points= + // because it's out of sync when e.g. some extension attrs of the polygon or star are changed in XML editor + this->set_shape(); + + if ((flags & SP_OBJECT_WRITE_BUILD) && !repr) { + repr = xml_doc->createElement("svg:polygon"); + } + + /* We can safely write points here, because all subclasses require it too (Lauris) */ + /* While saving polygon element without points attribute _curve is NULL (see bug 1202753) */ + if (this->_curve != nullptr) { + gchar *str = sp_svg_write_polygon(this->_curve->get_pathvector()); + repr->setAttribute("points", str); + g_free(str); + } + + SPShape::write(xml_doc, repr, flags); + + return repr; +} + +/** + * @brief Parse a double from the string passed by pointer and advance the string start. + * + * @param[in,out] p A pointer to a string (representing a piece of the `points` attribute). + * @param[out] v The parsed value. + * @return Parse status. + */ +SPPolyParseError sp_poly_get_value(char const **p, double *v) +{ + while (**p != '\0' && (**p == ',' || **p == '\x20' || **p == '\x9' || **p == '\xD' || **p == '\xA')) { + (*p)++; + } + + if (**p == '\0') { + return POLY_END_OF_STRING; + } + + gchar *e = nullptr; + double value = g_ascii_strtod(*p, &e); + if (e == *p) { + return POLY_INVALID_NUMBER; + } + if (std::isnan(value)) { + return POLY_NOT_A_NUMBER; + } + if (std::isinf(value)) { + return POLY_INFINITE_VALUE; + } + + *p = e; + *v = value; + return POLY_OK; +} + +/** + * @brief Print a warning message related to the parsing of a 'points' attribute. + */ +static void sp_poly_print_warning(char const *points, char const *error_location, SPPolyParseError error) +{ + switch (error) { + case POLY_END_OF_STRING: // Unexpected end of string! + { + size_t constexpr MAX_DISPLAY_SIZE = 64; + Glib::ustring s{points}; + if (s.size() > MAX_DISPLAY_SIZE) { + s = "... " + s.substr(s.size() - MAX_DISPLAY_SIZE); + } + g_warning("Error parsing a 'points' attribute: string ended unexpectedly!\n\t\"%s\"", s.c_str()); + break; + } + case POLY_INVALID_NUMBER: + g_warning("Invalid number in the 'points' attribute:\n\t\"(...) %s\"", error_location); + break; + + case POLY_INFINITE_VALUE: + g_warning("Infinity is not allowed in the 'points' attribute:\n\t\"(...) %s\"", error_location); + break; + + case POLY_NOT_A_NUMBER: + g_warning("NaN-value is not allowed in the 'points' attribute:\n\t\"(...) %s\"", error_location); + break; + + case POLY_OK: + default: + break; + } +} + +/** + * @brief Parse a 'points' attribute, printing a warning when an error occurs. + * + * @param points The points attribute. + * @return The corresponding polyline curve (open). + */ +SPCurve sp_poly_parse_curve(char const *points) +{ + SPCurve result; + char const *cptr = points; + bool has_pt = false; + + while (true) { + double x, y; + + if (auto error = sp_poly_get_value(&cptr, &x)) { + // If the error is something other than end of input, we must report it. + // End of input is allowed when scanning for the next x coordinate: it + // simply means that we have reached the end of the coordinate list. + if (error != POLY_END_OF_STRING) { + sp_poly_print_warning(points, cptr, error); + } + break; + } + if (auto error = sp_poly_get_value(&cptr, &y)) { + // End of input is not allowed when scanning for y. + sp_poly_print_warning(points, cptr, error); + break; + } + + if (has_pt) { + result.lineto(x, y); + } else { + result.moveto(x, y); + has_pt = true; + } + } + return result; +} + +void SPPolygon::set(SPAttr key, const gchar* value) { + switch (key) { + case SPAttr::POINTS: { + if (!value) { + /* fixme: The points attribute is required. We should handle its absence as per + * http://www.w3.org/TR/SVG11/implnote.html#ErrorProcessing. */ + break; + } + + auto curve = sp_poly_parse_curve(value); + curve.closepath(); + setCurve(std::move(curve)); + break; + } + default: + SPShape::set(key, value); + break; + } +} + +const char* SPPolygon::typeName() const { + return "path"; +} + +gchar* SPPolygon::description() const { + return g_strdup(_("<b>Polygon</b>")); +} + +/* + 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 : |