svg-flatten: add curve flattening tolerance command line param

svg-flatten/include/gerbolyze.hpp

@@ -139,6 +139,7 @@ namespace gerbolyze {
     class RenderSettings {
     public:
         double m_minimum_feature_size_mm = 0.1;
+        double curve_tolerance_mm;
         VectorizerSelectorizer &m_vec_sel;
     };
 
@@ -174,7 +175,7 @@ namespace gerbolyze {
             void export_svg_path(const RenderSettings &rset, const pugi::xml_node &node, ClipperLib::Paths &clip_path);
             void setup_debug_output(std::string filename="");
             void setup_viewport_clip();
-            void load_clips();
+            void load_clips(const RenderSettings &rset);
             void load_patterns();
 
             bool _valid;

svg-flatten/src/main.cpp

@@ -42,6 +42,9 @@ int main(int argc, char **argv) {
             {"min_feature_size", {"-d", "--trace-space"},
                 "Minimum feature size of elements in vectorized graphics (trace/space) in mm. Default: 0.1mm.",
                 1},
+            {"curve_tolerance", {"-c", "--curve-tolerance"},
+                "Tolerance for curve flattening in mm. Default: 0.1mm.",
+                1},
             {"no_header", {"--no-header"},
                 "Do not export output format header/footer, only export the primitives themselves",
                 0},
@@ -243,10 +246,8 @@ int main(int argc, char **argv) {
     }
     delete vec;
 
-    double min_feature_size = 0.1; /* mm */
-    if (args["min_feature_size"]) {
-        min_feature_size = args["min_feature_size"].as<double>();
-    }
+    double min_feature_size = args["min_feature_size"].as<double>(0.1); /* mm */
+    double curve_tolerance = args["curve_tolerance"].as<double>(0.1); /* mm */
 
     string ending = "";
     auto idx = in_f_name.rfind(".");
@@ -411,6 +412,7 @@ int main(int argc, char **argv) {
     VectorizerSelectorizer vec_sel(vectorizer, args["vectorizer_map"] ? args["vectorizer_map"].as<string>() : "");
     RenderSettings rset {
         min_feature_size,
+        curve_tolerance,
         vec_sel,
     };
 

svg-flatten/src/svg_doc.cpp

@@ -86,7 +86,6 @@ bool gerbolyze::SVGDocument::load(istream &in, string debug_out_filename) {
 
     setup_debug_output(debug_out_filename);
     setup_viewport_clip();
-    load_clips();
     load_patterns();
 
     _valid = true;
@@ -142,10 +141,14 @@ bool IDElementSelector::match(const pugi::xml_node &node, bool included, bool is
 
 /* Recursively export all SVG elements in the given group. */
 void gerbolyze::SVGDocument::export_svg_group(const RenderSettings &rset, const pugi::xml_node &group, Paths &parent_clip_path, const ElementSelector *sel, bool included, bool is_root) {
+
+    /* Load clip paths from defs given bezier flattening tolerance from rset */
+    load_clips(rset);
+    
     /* Enter the group's coordinate system */
     cairo_save(cr);
     apply_cairo_transform_from_svg(cr, group.attribute("transform").value());
-    
+
     /* Fetch clip path from global registry and transform it into document coordinates. */
     Paths clip_path;
     auto *lookup = lookup_clip_path(group);
@@ -237,7 +240,7 @@ void gerbolyze::SVGDocument::export_svg_path(const RenderSettings &rset, const p
     PolyTree ptree_stroke;
     PolyTree ptree_fill;
     PolyTree ptree;
-    load_svg_path(cr, node, ptree_stroke, ptree_fill);
+    load_svg_path(cr, node, ptree_stroke, ptree_fill, rset.curve_tolerance_mm);
 
     double _y = 0;
     cairo_user_to_device_distance(cr, &stroke_width, &_y);
@@ -462,7 +465,7 @@ void gerbolyze::SVGDocument::load_patterns() {
     }
 }
 
-void gerbolyze::SVGDocument::load_clips() {
+void gerbolyze::SVGDocument::load_clips(const RenderSettings &rset) {
     /* Set up document-wide clip path registry: Extract clip path definitions from <defs> element */
     for (const auto &node : defs_node.children("clipPath")) {
         cairo_save(cr);
@@ -481,7 +484,7 @@ void gerbolyze::SVGDocument::load_clips() {
             cairo_save(cr);
             /* TODO: we currently only support clipPathUnits="userSpaceOnUse", not "objectBoundingBox". */
             apply_cairo_transform_from_svg(cr, child.attribute("transform").value());
-            load_svg_path(cr, child, ptree_stroke, ptree_fill);
+            load_svg_path(cr, child, ptree_stroke, ptree_fill, rset.curve_tolerance_mm);
             cairo_restore (cr);
 
             Paths paths;

svg-flatten/src/svg_path.cpp

@@ -110,14 +110,14 @@ static pair<bool, bool> path_to_clipper_via_cairo(cairo_t *cr, ClipperLib::Clipp
     return {has_closed, num_subpaths > 1};
 }
 
-void gerbolyze::load_svg_path(cairo_t *cr, const pugi::xml_node &node, ClipperLib::PolyTree &ptree_stroke, ClipperLib::PolyTree &ptree_fill) {
+void gerbolyze::load_svg_path(cairo_t *cr, const pugi::xml_node &node, ClipperLib::PolyTree &ptree_stroke, ClipperLib::PolyTree &ptree_fill, double curve_tolerance) {
     auto *path_data = node.attribute("d").value();
     auto fill_rule = clipper_fill_rule(node);
 
     /* For open paths, clipper does not correctly remove self-intersections. Thus, we pass everything into
      * clipper twice: Once with all paths set to "closed" to compute fill areas, and once with correct
      * open/closed properties for stroke offsetting. */
-    cairo_set_tolerance (cr, 0.1); /* FIXME make configurable, scale properly for units */
+    cairo_set_tolerance (cr, curve_tolerance); /* FIXME make configurable, scale properly for units */
     cairo_set_fill_rule(cr, CAIRO_FILL_RULE_WINDING);
 
     ClipperLib::Clipper c_stroke;

svg-flatten/src/svg_path.h

@@ -23,7 +23,7 @@
 #include "svg_geom.h"
 
 namespace gerbolyze {
-void load_svg_path(cairo_t *cr, const pugi::xml_node &node, ClipperLib::PolyTree &ptree_stroke, ClipperLib::PolyTree &ptree_fill);
+void load_svg_path(cairo_t *cr, const pugi::xml_node &node, ClipperLib::PolyTree &ptree_stroke, ClipperLib::PolyTree &ptree_fill, double curve_tolerance);
 void parse_dasharray(const pugi::xml_node &node, std::vector<double> &out);
 void dash_path(const ClipperLib::Path &in, ClipperLib::Paths &out, const std::vector<double> dasharray, double dash_offset=0.0);
 }