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-rw-r--r--svg-flatten/src/svg_doc.cpp196
1 files changed, 107 insertions, 89 deletions
diff --git a/svg-flatten/src/svg_doc.cpp b/svg-flatten/src/svg_doc.cpp
index 9eed1e6..019760b 100644
--- a/svg-flatten/src/svg_doc.cpp
+++ b/svg-flatten/src/svg_doc.cpp
@@ -350,10 +350,6 @@ void gerbolyze::SVGDocument::export_svg_path(RenderContext &ctx, const pugi::xml
stroke_clip.StrictlySimple(true);
stroke_clip.AddPaths(ctx.clip(), ptClip, /* closed */ true);
- ClipperOffset offx;
- offx.ArcTolerance = 0.01 * clipper_scale; /* 10µm; TODO: Make this configurable */
- offx.MiterLimit = stroke_miterlimit;
-
/* We forward strokes as regular gerber interpolations instead of tracing their outline using clipper when one
* of these is true:
*
@@ -362,107 +358,129 @@ void gerbolyze::SVGDocument::export_svg_path(RenderContext &ctx, const pugi::xml
*
* We have to ignore patterned strokes since then we recursively call down to the pattern renderer. The checks
* in (2) are to make sure that the semantics of our source SVG align with gerber's aperture semantics. Gerber
- * cannot express anything other than "round" joins and ends. If a clip is set, the clipped line ends would not
- * be round so we have to exclude that as well. A possible future optimization would be to check if we actually
- * did clip the stroke, but that is too expensive since then we'd have to outline it first to account for
- * stroke thickness and end caps.
+ * cannot express anything other than "round" joins and ends. If any part of the path is clipped, the clipped
+ * line ends would not be round so we have to exclude that as well. In case of outline mode, we accept this
+ * inaccuracies for usability (the only alternative would be to halt and catch fire).
*/
- bool local_outline_mode =
- stroke_color != GRB_PATTERN_FILL && (
- ctx.settings().outline_mode || (
- ctx.clip().empty() &&
- end_type == ClipperLib::etOpenRound &&
- join_type == ClipperLib::jtRound));
-
- /* For stroking we have to separately handle open and closed paths */
- for (auto &poly : stroke_closed) {
- if (poly.empty())
- continue;
-
- /* Special case: A closed path becomes a number of open paths when it is dashed. */
- if (dasharray.empty()) {
-
- if (local_outline_mode) {
- stroke_clip.AddPath(poly, ptSubject, /* closed */ true);
- } else {
- offx.AddPath(poly, join_type, etClosedLine);
+
+ /* Calculate out dashes: A closed path becomes a number of open paths when it is dashed. */
+ if (!dasharray.empty()) {
+ for (auto &poly : stroke_closed) {
+ if (poly.empty()) {
+ continue;
}
- } else {
- Path poly_copy(poly);
- poly_copy.push_back(poly[0]);
- Paths out;
- dash_path(poly_copy, out, dasharray, stroke_dashoffset);
-
- if (local_outline_mode) {
- stroke_clip.AddPaths(out, ptSubject, /* closed */ false);
- } else {
- offx.AddPaths(out, join_type, end_type);
- }
+ poly.push_back(poly[0]);
+ dash_path(poly, stroke_open, dasharray, stroke_dashoffset);
}
}
- for (const auto &poly : stroke_open) {
- Paths out;
- dash_path(poly, out, dasharray, stroke_dashoffset);
+ if (stroke_color != GRB_PATTERN_FILL) {
+ cerr << "Analyzing direct conversion of stroke" << endl;
+ cerr << " stroke_closed.size() = " << stroke_closed.size() << endl;
+ cerr << " stroke_open.size() = " << stroke_open.size() << endl;
+ ctx.sink() << (stroke_color == GRB_DARK ? GRB_POL_DARK : GRB_POL_CLEAR);
+
+ ClipperOffset offx;
+ offx.ArcTolerance = 0.01 * clipper_scale; /* see below. */
+ offx.MiterLimit = 10;
+ offx.AddPaths(ctx.clip(), jtRound, etClosedPolygon);
+ PolyTree clip_ptree;
+ offx.Execute(clip_ptree, -0.5 * stroke_width * clipper_scale);
+
+ Paths dilated_clip;
+ ClosedPathsFromPolyTree(clip_ptree, dilated_clip);
+
+ Clipper stroke_clip;
+ stroke_clip.StrictlySimple(true);
+ stroke_clip.AddPaths(dilated_clip, ptClip, /* closed */ true);
+ stroke_clip.AddPaths(stroke_closed, ptSubject, /* closed */ true);
+ stroke_clip.AddPaths(stroke_open, ptSubject, /* closed */ false);
+ stroke_clip.Execute(ctDifference, ptree, pftNonZero, pftNonZero);
+
+ /* Did any part of the path clip the clip path (which defaults to the document border)? */
+ bool nothing_clipped = ptree.Total() == 0;
+
+ /* Can all joins be mapped? True if either jtRound, or if there are no joins. */
+ bool joins_can_be_mapped = true;
+ if (join_type != ClipperLib::jtRound) {
+ for (auto &p : stroke_closed) {
+ if (p.size() > 2) {
+ joins_can_be_mapped = false;
+ }
+ }
+ }
- if (ctx.settings().outline_mode) {
- stroke_clip.AddPaths(out, ptSubject, /* closed */ false);
- } else {
- offx.AddPaths(out, join_type, end_type);
+ /* Can all ends be mapped? True if either etOpenRound or if there are no ends (we only have closed paths) */
+ 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 << " 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);
+ for (auto &path : stroke_closed) {
+ if (path.empty()) {
+ continue;
+ }
+ /* We have to manually close these here. */
+ path.push_back(path[0]);
+ ctx.sink() << path;
+ }
+ ctx.sink() << stroke_open;
+ return;
}
+ cerr << " -> NOT converting directly" << endl;
+ /* else fall through to normal processing */
}
- if (ctx.settings().outline_mode) {
- stroke_clip.Execute(ctIntersection, ptree, pftNonZero, pftNonZero);
- Paths outline_paths;
- ctx.sink() << ApertureToken(stroke_width);
-
- ClosedPathsFromPolyTree(ptree, outline_paths);
- for (auto &path : outline_paths) {
- /* we have to connect the last and first point here */
- if (path.empty())
- continue;
- path.push_back(path[0]);
- ctx.sink() << path;
- }
+ ClipperOffset offx;
+ offx.ArcTolerance = 0.01 * clipper_scale; /* 10µm; TODO: Make this configurable */
+ offx.MiterLimit = stroke_miterlimit;
- OpenPathsFromPolyTree(ptree, outline_paths);
- ctx.sink() << outline_paths;
+ /* 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);
+ offx.AddPaths(stroke_open, join_type, end_type);
+ /* Execute clipper offset operation to generate stroke outlines */
+ offx.Execute(ptree, 0.5 * stroke_width * clipper_scale);
- } else {
- /* Execute clipper offset operation to generate stroke outlines */
- offx.Execute(ptree, 0.5 * stroke_width * clipper_scale);
-
- /* 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()) {
- Paths outline_paths;
- PolyTreeToPaths(ptree, outline_paths);
- stroke_clip.AddPaths(outline_paths, ptSubject, /* closed */ true);
- /* fill rules are nonzero since both subject and clip have already been normalized by clipper. */
- stroke_clip.Execute(ctIntersection, ptree, pftNonZero, pftNonZero);
- }
+ /* 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()) {
+ Paths outline_paths;
+ PolyTreeToPaths(ptree, outline_paths);
+ Clipper stroke_clip;
+ stroke_clip.StrictlySimple(true);
+ stroke_clip.AddPaths(ctx.clip(), ptClip, /* closed */ true);
+ stroke_clip.AddPaths(outline_paths, ptSubject, /* closed */ true);
+ /* fill rules are nonzero since both subject and clip have already been normalized by clipper. */
+ stroke_clip.Execute(ctIntersection, ptree, pftNonZero, pftNonZero);
+ }
- /* Call out to pattern tiler for pattern strokes. The stroke's outline becomes the clip here. */
- if (stroke_color == GRB_PATTERN_FILL) {
- string stroke_pattern_id = usvg_id_url(node.attribute("stroke").value());
- Pattern *pattern = lookup_pattern(stroke_pattern_id);
- if (!pattern) {
- cerr << "Warning: Fill pattern with id \"" << stroke_pattern_id << "\" not found." << endl;
-
- } else {
- Paths clip;
- PolyTreeToPaths(ptree, clip);
- RenderContext local_ctx(ctx, xform2d(), clip, true);
- pattern->tile(local_ctx);
- }
+ /* Call out to pattern tiler for pattern strokes. The stroke's outline becomes the clip here. */
+ if (stroke_color == GRB_PATTERN_FILL) {
+ string stroke_pattern_id = usvg_id_url(node.attribute("stroke").value());
+ Pattern *pattern = lookup_pattern(stroke_pattern_id);
+ if (!pattern) {
+ cerr << "Warning: Fill pattern with id \"" << stroke_pattern_id << "\" not found." << endl;
} else {
- Paths s_polys;
- dehole_polytree(ptree, s_polys);
- ctx.sink() << (stroke_color == GRB_DARK ? GRB_POL_DARK : GRB_POL_CLEAR) << ApertureToken() << s_polys;
+ Paths clip;
+ PolyTreeToPaths(ptree, clip);
+ RenderContext local_ctx(ctx, xform2d(), clip, true);
+ pattern->tile(local_ctx);
}
+
+ } else {
+ Paths s_polys;
+ dehole_polytree(ptree, s_polys);
+ /* color has alredy been pushed above. */
+ ctx.sink() << ApertureToken() << s_polys;
}
}
}
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