svg_doc: Fix gerber mapping of strokes with skewed or non-uniform transforms

4 files changed, 108 insertions, 30 deletions

diff --git a/svg-flatten/include/geom2d.hpp b/svg-flatten/include/geom2d.hpp
index 9650575..128da0f 100644
--- a/svg-flatten/include/geom2d.hpp
+++ b/svg-flatten/include/geom2d.hpp
@@ -99,6 +99,7 @@ namespace gerbolyze {
                 yy = n_yy;
                 x0 = n_x0;
                 y0 = n_y0;
+                decomposed = false;
 
                 return *this;
             };
@@ -111,48 +112,90 @@ namespace gerbolyze {
                 return dist_doc / sqrt(xx*xx + xy*xy);
             }
 
-            double doc2phys_skew(double dist_doc) {
+            void decompose() {
+                /* FIXME unit tests, especially for degenerate cases! */
+                if (decomposed) {
+                    return;
+                }
+
                 /* https://math.stackexchange.com/a/3521141 */
                 /* https://stackoverflow.com/a/70381885 */
                 /* xx yx x0
                  * xy yy y0 */
-                double s_x = sqrt(xx*xx + xy*xy);
+                s_x = sqrt(xx*xx + xy*xy);
 
                 if (xx == 0 && xy == 0) {
-                    return std::numeric_limits<double>::infinity;
+                    theta = 0;
+                } else {
+                    theta = atan2(xy, xx);
                 }
 
-                double theta = atan2(xy, xx);
                 double f = (xx*yy - xy*yx);
 
                 if (f == 0) {
-                    return std::numeric_limits<double>::infinity;
+                    m = 0;
+                } else {
+                    m = (xx*yx + yy*xy) / f;
                 }
 
-                double m = (xx*yx + yy*xy) / f;
-
-                double f = xx + m*xy;
-                double s_y = 0;
-
+                f = xx + m*xy;
                 if (f == 0) {
                     f = m*xx - xy;
                     if (f == 0) {
-                        return std::numeric_limits<double>::infinity;
+                        s_y = 0;
                     }
                     s_y = yx*s_x / f;
                 } else {
                     s_y = yy*s_x / f;
                 }
 
-                return s_x - s_y > 
+                double b = sqrt(s_y*s_y + m*m);
+                f_min = fmin(s_x, b);
+                f_max = fmax(s_x, b);
+
+                decomposed = true;
+            }
+
+            bool doc2phys_skew_ok(double dist_doc, double rel_tol, double abs_tol) {
+                decompose();
+
+                if (f_min == 0) {
+                    return false;
+                }
+
+                double imbalance = f_max / f_min - 1.0;
+                //cerr << "  * skew check: " << dbg_str();
+                //cerr << "    imbalance=" << imbalance << endl;
+                //cerr << "    rel=" << (imbalance < rel_tol) << " abs=" << (imbalance*fabs(dist_doc) < abs_tol) << endl;
+                return imbalance < rel_tol && imbalance*fabs(dist_doc) < abs_tol;
             }
 
             double doc2phys_min(double dist_doc) {
-                return dist_doc * fmin(sqrt(xx*xx + xy*xy), sqrt(yy*yy + yx*yx));
+                decompose();
+                return dist_doc * f_min;
             }
 
             double doc2phys_max(double dist_doc) {
-                return dist_doc * fmax(sqrt(xx*xx + xy*xy), sqrt(yy*yy + yx*yx));
+                decompose();
+                return dist_doc * f_max;
+            }
+
+            double phys2doc_min(double dist_doc) {
+                decompose();
+
+                if (f_min == 0)
+                    return std::nan("9");
+
+                return dist_doc / f_min;
+            }
+
+            double phys2doc_max(double dist_doc) {
+                decompose();
+
+                if (f_max == 0)
+                    return std::nan("9");
+
+                return dist_doc / f_max;
             }
 
             d2p doc2phys(const d2p p) {
@@ -181,6 +224,7 @@ namespace gerbolyze {
 
                 if (success_out)
                     *success_out = true;
+
                 return *this;
             }
 
@@ -210,9 +254,17 @@ namespace gerbolyze {
             }
 
             void phys2doc_clipper(ClipperLib::Path &path) {
+                xform2d copy(*this);
+                bool inverted = false;
+                copy.invert(&inverted);
+                if (!inverted) {
+                    path.clear();
+                    return;
+                }
+
                 std::transform(path.begin(), path.end(), path.begin(),
-                        [this](ClipperLib::IntPoint p) -> ClipperLib::IntPoint {
-                            d2p out(this->doc2phys(d2p{p.X / clipper_scale, p.Y / clipper_scale}));
+                        [this, &copy](ClipperLib::IntPoint p) -> ClipperLib::IntPoint {
+                            d2p out(copy.doc2phys(d2p{p.X / clipper_scale, p.Y / clipper_scale}));
                             return {
                                 (ClipperLib::cInt)round(out[0] * clipper_scale),
                                 (ClipperLib::cInt)round(out[1] * clipper_scale)
@@ -231,7 +283,9 @@ namespace gerbolyze {
                 ostringstream os;
                 os << "xform2d< " << setw(5);
                 os << xx << ", " << xy << ", " << x0 << " / ";
-                os << yy << ", " << yx << ", " << y0;
+                os << yy << ", " << yx << ", " << y0 << " / ";
+                os << "θ=" << theta << ", m=" << m << " s=(" << s_x << ", " << s_y << " | ";
+                os << "f_min=" << f_min << ", f_max=" << f_max;
                 os << " >";
                 return os.str();
             }
@@ -240,5 +294,8 @@ namespace gerbolyze {
             double xx, yx,
                    xy, yy,
                    x0, y0;
+            double theta, m, s_x, s_y;
+            double f_min, f_max;
+            bool decomposed = false;
     };
 }
diff --git a/svg-flatten/include/gerbolyze.hpp b/svg-flatten/include/gerbolyze.hpp
index f90b9bf..7c54337 100644
--- a/svg-flatten/include/gerbolyze.hpp
+++ b/svg-flatten/include/gerbolyze.hpp
@@ -218,6 +218,7 @@ namespace gerbolyze {
         bool flip_color_interpretation = false;
         bool pattern_complete_tiles_only = false;
         bool use_apertures_for_patterns = false;
+        bool do_gerber_interpolation = true;
     };
 
     class RenderContext {
diff --git a/svg-flatten/src/main.cpp b/svg-flatten/src/main.cpp
index 6ba32a9..122b75b 100644
--- a/svg-flatten/src/main.cpp
+++ b/svg-flatten/src/main.cpp
@@ -88,6 +88,9 @@ int main(int argc, char **argv) {
             {"stroke_width_cutoff", {"--min-stroke-width"},
                 "Don't render strokes thinner than the given width in mm. Default: 0.01mm.",
                 1},
+            {"no_stroke_interpolation", {"--no-stroke-interpolation"},
+                "Always outline SVG strokes as regions instead of rendering them using Geber interpolation commands where possible.",
+                0},
             {"drill_test_polsby_popper_tolerance", {"--drill-test-tolerance"},
                 "Tolerance for identifying circles as drills in outline mode",
                 1},
@@ -316,7 +319,7 @@ int main(int argc, char **argv) {
     delete vec;
 
     double min_feature_size = args["min_feature_size"].as<double>(0.1); /* mm */
-    double geometric_tolerance = args["geometric_tolerance"].as<double>(0.1); /* mm */
+    double geometric_tolerance = args["geometric_tolerance"].as<double>(0.01); /* mm */
     double stroke_width_cutoff = args["stroke_width_cutoff"].as<double>(0.01); /* mm */
     double drill_test_polsby_popper_tolerance = args["drill_test_polsby_popper_tolerance"].as<double>(0.1);
     double aperture_rect_test_tolerance = args["aperture_rect_test_tolerance"].as<double>(0.1);
@@ -451,6 +454,7 @@ int main(int argc, char **argv) {
     bool flip_svg_colors = args["flip_svg_color_interpretation"];
     bool pattern_complete_tiles_only = args["pattern_complete_tiles_only"];
     bool use_apertures_for_patterns = args["use_apertures_for_patterns"];
+    bool do_gerber_interpolation = !args["no_stroke_interpolation"];
 
     RenderSettings rset {
         min_feature_size,
@@ -464,6 +468,7 @@ int main(int argc, char **argv) {
         flip_svg_colors,
         pattern_complete_tiles_only,
         use_apertures_for_patterns,
+        do_gerber_interpolation,
     };
 
     SVGDocument doc;
diff --git a/svg-flatten/src/svg_doc.cpp b/svg-flatten/src/svg_doc.cpp
index df6e67a..6cb6138 100644
--- a/svg-flatten/src/svg_doc.cpp
+++ b/svg-flatten/src/svg_doc.cpp
@@ -253,7 +253,7 @@ void gerbolyze::SVGDocument::export_svg_path(RenderContext &ctx, const pugi::xml
     Paths stroke_open, stroke_closed;
     PolyTree ptree_fill;
     PolyTree ptree;
-    double geometric_tolerance_px = ctx.mat().doc2phys_min(ctx.settings().geometric_tolerance_mm);
+    double geometric_tolerance_px = ctx.mat().phys2doc_min(ctx.settings().geometric_tolerance_mm);
     load_svg_path(node, stroke_open, stroke_closed, ptree_fill, geometric_tolerance_px);
 
     Paths fill_paths;
@@ -267,6 +267,7 @@ void gerbolyze::SVGDocument::export_svg_path(RenderContext &ctx, const pugi::xml
     bool has_stroke = stroke_color && ctx.mat().doc2phys_min(stroke_width) > ctx.settings().stroke_width_cutoff;
 
     cerr << "processing svg path" << endl;
+    cerr << "  * " << (has_stroke ? "has stroke" : "no stroke") << " / " << (has_fill ? "has fill" : "no fill") << endl;
     cerr << "  * " << fill_paths.size() << " fill paths" << endl;
     cerr << "  * " << stroke_closed.size() << " closed strokes" << endl;
     cerr << "  * " << stroke_open.size() << " open strokes" << endl;
@@ -298,7 +299,8 @@ void gerbolyze::SVGDocument::export_svg_path(RenderContext &ctx, const pugi::xml
                 centroid[0] /= clipper_scale;
                 centroid[1] /= clipper_scale;
                 double diameter = sqrt(4*fabs(area)/M_PI) / clipper_scale;
-                diameter = round(diameter * 1000.0) / 1000.0; /* Round to micrometer precsion; FIXME: make configurable */
+                double tolerance = ctx.settings().geometric_tolerance_mm / 2;
+                diameter = round(diameter/tolerance) * tolerance;
                 ctx.sink() << ApertureToken(diameter) << FlashToken(centroid);
             }
         }
@@ -315,10 +317,10 @@ void gerbolyze::SVGDocument::export_svg_path(RenderContext &ctx, const pugi::xml
             c.AddPaths(ctx.clip(), ptClip, /* closed */ true);
             c.StrictlySimple(true);
 
-            cerr << "clipping " << fill_paths.size() << " paths, got polytree with " << ptree_fill.ChildCount() << " top-level children" << endl;
+            //cerr << "clipping " << fill_paths.size() << " paths, got polytree with " << ptree_fill.ChildCount() << " top-level children" << endl;
             /* fill rules are nonzero since both subject and clip have already been normalized by clipper. */ 
             c.Execute(ctIntersection, ptree_fill, pftNonZero, pftNonZero);
-            cerr << "  > " << ptree_fill.ChildCount() << " clipped fill ptree top-level children" << endl;
+            //cerr << "  > " << ptree_fill.ChildCount() << " clipped fill ptree top-level children" << endl;
         }
 
         /* Call out to pattern tiler for pattern fills. The path becomes the clip here. */
@@ -399,8 +401,9 @@ void gerbolyze::SVGDocument::export_svg_path(RenderContext &ctx, const pugi::xml
 
         if (stroke_color != GRB_PATTERN_FILL
                 && ctx.sink().can_do_apertures()
+                && ctx.settings().do_gerber_interpolation
                 /* check if we have an uniform transform */
-                && ctx.mat().doc2phys_skew(stroke_width) < ctx.settings().geometric_tolerance_mm) {
+                && ctx.mat().doc2phys_skew_ok(stroke_width, 0.05, ctx.settings().geometric_tolerance_mm)) {
             // cerr << "Analyzing direct conversion of stroke" << endl;
             // cerr << "  stroke_closed.size() = " << stroke_closed.size() << endl;
             // cerr << "  stroke_open.size() = " << stroke_open.size() << endl;
@@ -411,7 +414,7 @@ void gerbolyze::SVGDocument::export_svg_path(RenderContext &ctx, const pugi::xml
             offx.MiterLimit = 10;
             offx.AddPaths(ctx.clip(), jtRound, etClosedPolygon);
             PolyTree clip_ptree;
-            offx.Execute(clip_ptree, -0.5 * stroke_width * clipper_scale);
+            offx.Execute(clip_ptree, -0.5 * ctx.mat().doc2phys_dist(stroke_width) * clipper_scale);
 
             Paths dilated_clip;
             ClosedPathsFromPolyTree(clip_ptree, dilated_clip);
@@ -426,7 +429,7 @@ void gerbolyze::SVGDocument::export_svg_path(RenderContext &ctx, const pugi::xml
             stroke_clip.AddPaths(stroke_closed_phys, ptSubject, /* closed */ true);
             stroke_clip.AddPaths(stroke_open_phys, ptSubject, /* closed */ false);
             stroke_clip.Execute(ctDifference, ptree, pftNonZero, pftNonZero);
-            cerr << "  > " << ptree.ChildCount() << " clipped stroke ptree top-level children" << endl;
+            // cerr << "  > " << ptree.ChildCount() << " clipped stroke ptree top-level children" << endl;
             
             /* Did any part of the path clip the clip path (which defaults to the document border)? */
             bool nothing_clipped = ptree.Total() == 0;
@@ -445,14 +448,18 @@ void gerbolyze::SVGDocument::export_svg_path(RenderContext &ctx, const pugi::xml
             bool ends_can_be_mapped = (end_type == ClipperLib::etOpenRound) || (stroke_open.size() == 0);
             /* Can gerber losslessly express this path? */
             bool gerber_lossless = nothing_clipped && ends_can_be_mapped && joins_can_be_mapped;
+            //cerr << "  ends_can_be_mapped=" << ends_can_be_mapped << ", nothing_clipped=" << nothing_clipped << ", joins_can_be_mapped=" << joins_can_be_mapped << endl;
             
             // cerr << "  nothing_clipped = " << nothing_clipped << endl;
             // cerr << "  ends_can_be_mapped = " << ends_can_be_mapped << endl;
             // cerr << "  joins_can_be_mapped = " << joins_can_be_mapped << endl;
             /* Accept loss of precision in outline mode. */
             if (ctx.settings().outline_mode || gerber_lossless) {
-                // cerr << "  -> converting directly" << endl;
-                ctx.sink() << ApertureToken(stroke_width);
+                //cerr << "  -> converting directly" << endl;
+                ctx.mat().doc2phys_clipper(stroke_closed);
+                ctx.mat().doc2phys_clipper(stroke_open);
+
+                ctx.sink() << ApertureToken(ctx.mat().doc2phys_dist(stroke_width));
                 for (auto &path : stroke_closed) {
                     if (path.empty()) {
                         continue;
@@ -464,7 +471,7 @@ void gerbolyze::SVGDocument::export_svg_path(RenderContext &ctx, const pugi::xml
                 ctx.sink() << stroke_open;
                 return;
             }
-            // cerr << "  -> NOT converting directly" << endl;
+            //cerr << "  -> NOT converting directly" << endl;
             /* else fall through to normal processing */
         }
 
@@ -472,7 +479,12 @@ void gerbolyze::SVGDocument::export_svg_path(RenderContext &ctx, const pugi::xml
         offx.ArcTolerance = ctx.mat().phys2doc_min(ctx.settings().geometric_tolerance_mm) * clipper_scale;
         offx.MiterLimit = stroke_miterlimit;
 
-        //cerr << "offsetting " << stroke_closed.size() << " closed and " << stroke_open.size() << " open paths" << endl;
+        //cerr << "  offsetting " << stroke_closed.size() << " closed and " << stroke_open.size() << " open paths" << endl;
+        //cerr << "  geometric tolerance = " << ctx.settings().geometric_tolerance_mm << " mm" << endl;
+        //cerr << "  arc tolerance = " << offx.ArcTolerance/clipper_scale << " px" << endl;
+        //cerr << "  stroke_width=" << stroke_width << "px" << endl;
+        //cerr << "  offset = " << (0.5 * stroke_width * clipper_scale) << endl;
+
         /* For stroking we have to separately handle open and closed paths since coincident start and end points may
          * render differently than joined start and end points. */
         offx.AddPaths(stroke_closed, join_type, etClosedLine);
@@ -483,6 +495,7 @@ void gerbolyze::SVGDocument::export_svg_path(RenderContext &ctx, const pugi::xml
         /* Clip. Note that (outside of outline mode) after the clipper outline operation, all we have is closed paths as
          * any open path's stroke outline is itself a closed path. */
         if (!ctx.clip().empty()) {
+            //cerr << "  Clipping polytree" << endl;
             Paths outline_paths;
             PolyTreeToPaths(ptree, outline_paths);
 
@@ -518,6 +531,7 @@ void gerbolyze::SVGDocument::export_svg_path(RenderContext &ctx, const pugi::xml
             dehole_polytree(ptree, s_polys);
             ctx.mat().doc2phys_clipper(s_polys);
             /* color has alredy been pushed above. */
+            //cerr << "  sinking " << s_polys.size() << " paths" << endl;
             ctx.sink() << ApertureToken() << s_polys;
         }
     }
@@ -590,10 +604,11 @@ void gerbolyze::SVGDocument::load_clips(const RenderSettings &rset) {
             xform2d child_xf(local_xf);
             child_xf.transform(xform2d(child.attribute("transform").value()));
 
-            load_svg_path(child_xf, child, _stroke_open, _stroke_closed, ptree_fill, rset.geometric_tolerance_mm);
+            load_svg_path(child, _stroke_open, _stroke_closed, ptree_fill, rset.geometric_tolerance_mm);
 
             Paths paths;
             PolyTreeToPaths(ptree_fill, paths);
+            child_xf.doc2phys_clipper(paths);
             c.AddPaths(paths, ptSubject, /* closed */ false);
         }