diff options
Diffstat (limited to 'svg-flatten/src/svg_path.cpp')
| -rw-r--r-- | svg-flatten/src/svg_path.cpp | 39 |
1 files changed, 34 insertions, 5 deletions
diff --git a/svg-flatten/src/svg_path.cpp b/svg-flatten/src/svg_path.cpp index 537b5dd..e45a0c9 100644 --- a/svg-flatten/src/svg_path.cpp +++ b/svg-flatten/src/svg_path.cpp @@ -32,13 +32,14 @@ static void clipper_add_cairo_path(cairo_t *cr, ClipperLib::Clipper &c, bool clo c.AddPaths(in_poly, ClipperLib::ptSubject, closed); } -static void path_to_clipper_via_cairo(cairo_t *cr, ClipperLib::Clipper &c, const pugi::char_t *path_data) { +static bool path_to_clipper_via_cairo(cairo_t *cr, ClipperLib::Clipper &c, const pugi::char_t *path_data) { istringstream d(path_data); string cmd; double x, y, c1x, c1y, c2x, c2y; bool first = true; + bool has_closed = false; bool path_is_empty = true; while (!d.eof()) { d >> cmd; @@ -48,6 +49,7 @@ static void path_to_clipper_via_cairo(cairo_t *cr, ClipperLib::Clipper &c, const if (cmd == "Z") { /* Close path */ cairo_close_path(cr); clipper_add_cairo_path(cr, c, /* closed= */ true); + has_closed = true; cairo_new_path(cr); path_is_empty = true; @@ -61,8 +63,9 @@ static void path_to_clipper_via_cairo(cairo_t *cr, ClipperLib::Clipper &c, const */ cairo_user_to_device(cr, &x, &y); assert (!d.fail()); - if (!first) + if (!first) { clipper_add_cairo_path(cr, c, /* closed= */ false); + } cairo_new_path (cr); path_is_empty = true; cairo_move_to(cr, x, y); @@ -93,6 +96,8 @@ static void path_to_clipper_via_cairo(cairo_t *cr, ClipperLib::Clipper &c, const cairo_close_path(cr); clipper_add_cairo_path(cr, c, /* closed= */ false); } + + return has_closed; } void gerbolyze::load_svg_path(cairo_t *cr, const pugi::xml_node &node, ClipperLib::PolyTree &ptree) { @@ -107,9 +112,33 @@ void gerbolyze::load_svg_path(cairo_t *cr, const pugi::xml_node &node, ClipperLi ClipperLib::Clipper c; c.StrictlySimple(true); - path_to_clipper_via_cairo(cr, c, path_data); - /* We canont clip the polygon here since that would produce incorrect results for our stroke. */ - c.Execute(ClipperLib::ctUnion, ptree, fill_rule, ClipperLib::pftNonZero); + bool has_closed = path_to_clipper_via_cairo(cr, c, path_data); + + if (!has_closed) { + /* FIXME: Workaround! + * + * When we render silkscreen layers from gerbv's output, we get a lot of two-point paths (lines). Many of these are + * horizontal. Now, clipper seems to have a bug (probably related to its scan-line algorithm) that makes it + * misbehave here: + * + * It seems that when the input paths are all perfectly colinear and horizontal, so that the resulting bounding box + * has zero height, clipper doesn't output anything. At least for open input paths. + * + * Since there is no way to get paths out of a Clipper once they're Add'ed, we work around this by just doing an + * intersection with a maximum-size rectangle instead, that seems to work. + * + * TODO: Fix clipper instead. + */ + auto le_min = -ClipperLib::loRange; + auto le_max = ClipperLib::hiRange; + ClipperLib::Path p = {{le_min, le_min}, {le_max, le_min}, {le_max, le_max}, {le_min, le_max}}; + c.AddPath(p, ClipperLib::ptClip, /* closed= */ true); + c.Execute(ClipperLib::ctIntersection, ptree, fill_rule, ClipperLib::pftNonZero); + + } else { + /* We cannot clip the polygon here since that would produce incorrect results for our stroke. */ + c.Execute(ClipperLib::ctUnion, ptree, fill_rule, ClipperLib::pftNonZero); + } } void gerbolyze::parse_dasharray(const pugi::xml_node &node, vector<double> &out) { |