SVG drawing center option

src/ifcconvert/IfcConvert.cpp

@@ -344,7 +344,7 @@ int main(int argc, char** argv) {
 #endif
     short precision;
 	double section_height;
-	std::string svg_scale;
+	std::string svg_scale, svg_center;
 	std::string section_ref, elevation_ref;
 
     po::options_description serializer_options("Serialization options");
@@ -360,6 +360,9 @@ int main(int argc, char** argv) {
 		("scale", po::value<std::string>(&svg_scale),
 			"Interprets SVG bounds in mm, centers layout and draw elements to scale. "
 			"Only used when converting to SVG. Example 1:100.")
+		("center", po::value<std::string>(&svg_center),
+			"When using --scale, specifies the location in the range [0 1]x[0 1] around which"
+			"to center the drawings. Example 0.5x0.5 (default).")
 		("section-ref", po::value<std::string>(&section_ref),
 			"Element at which vertical cross sections should be created")
 		("elevation-ref", po::value<std::string>(&elevation_ref),
@@ -526,8 +529,8 @@ int main(int argc, char** argv) {
         }
     }
 
-	boost::optional<double> bounding_width;
+	boost::optional<double> bounding_width, bounding_height, relative_center_x, relative_center_y;
-	boost::optional<double> bounding_height;
+
 	if (vmap.count("bounds") == 1) {
 		int w, h;
 		if (sscanf(bounds.c_str(), "%ux%u", &w, &h) == 2 && w > 0 && h > 0) {
@@ -540,6 +543,18 @@ int main(int argc, char** argv) {
 		}
 	}
 
+	if (vmap.count("center") == 1) {
+		double cx, cy;
+		if (sscanf(svg_center.c_str(), "%lfx%lf", &cx, &cy) == 2 && cx >= 0. && cy >= 0. && cx <= 1. && cy <= 1.) {
+			relative_center_x = cx;
+			relative_center_y = cy;
+		} else {
+			cerr_ << "[Error] Invalid use of --bounds" << std::endl;
+			print_options(serializer_options);
+			return EXIT_FAILURE;
+		}
+	}
+
 	const path_t input_filename = vmap["input-file"].as<path_t>();
     if (!file_exists(IfcUtil::path::to_utf8(input_filename))) {
         cerr_ << "[Error] Input file '" << input_filename << "' does not exist" << std::endl;
@@ -925,6 +940,9 @@ int main(int argc, char** argv) {
 		if (vmap.count("elevation-ref")) {
 			static_cast<SvgSerializer*>(serializer.get())->setElevationRef(elevation_ref);
 		}
+		if (relative_center_x && relative_center_y) {
+			static_cast<SvgSerializer*>(serializer.get())->setDrawingCenter(*relative_center_x, *relative_center_y);
+		}
 	}
 
     if (convert_back_units) {

src/serializers/SvgSerializer.cpp

@@ -863,8 +863,8 @@ void SvgSerializer::resize() {
 		double sc, cx, cy;
 		if (scale_) {
 			sc = (*scale_) * 1000;
-			cx = (xmax + xmin) / 2. * sc - width / 2.;
+			cx = (xmax + xmin) / 2. * sc - width * center_x_.get_value_or(0.5);
-			cy = (ymax + ymin) / 2. * sc - height / 2.;
+			cy = (ymax + ymin) / 2. * sc - height * center_y_.get_value_or(0.5);
 		} else {
 			if (calculated_scale_) {
 				sc = *calculated_scale_;

src/serializers/SvgSerializer.h

@@ -116,7 +116,7 @@ protected:
 	double xmin, ymin, xmax, ymax, width, height;
 	boost::optional<std::vector<section_data>> section_data_;
 	boost::optional<std::vector<section_data>> deferred_section_data_;
-	boost::optional<double> scale_, calculated_scale_;
+	boost::optional<double> scale_, calculated_scale_, center_x_, center_y_;
 
 	bool rescale, print_space_names_, print_space_areas_, draw_door_arcs_;
 	bool with_section_heights_from_storey_, buffer_elements_;
@@ -186,6 +186,9 @@ public:
 		buffer_elements_ = true;
 	}
 	void setScale(double s) { scale_ = s; }
+	void setDrawingCenter(double x, double y) {
+		center_x_ = x; center_y_ = y;
+	}
     std::string nameElement(const IfcUtil::IfcBaseEntity* storey, const IfcGeom::Element<real_t>* elem);
 	std::string nameElement(const IfcUtil::IfcBaseEntity* elem);
 	std::string idElement(const IfcUtil::IfcBaseEntity* elem);