QIDISlicer1.0.0

src/libslic3r/NSVGUtils.cpp

@@ -0,0 +1,85 @@
+#include "NSVGUtils.hpp"
+#include "ClipperUtils.hpp"
+
+using namespace Slic3r;
+
+// inspired by nanosvgrast.h function nsvgRasterize -> nsvg__flattenShape -> nsvg__flattenCubicBez
+// https://github.com/memononen/nanosvg/blob/f0a3e1034dd22e2e87e5db22401e44998383124e/src/nanosvgrast.h#L335
+void NSVGUtils::flatten_cubic_bez(Polygon &polygon,
+                                  float    tessTol,
+                                  Vec2f    p1,
+                                  Vec2f    p2,
+                                  Vec2f    p3,
+                                  Vec2f    p4,
+                                  int      level)
+{
+    Vec2f p12  = (p1 + p2) * 0.5f;
+    Vec2f p23  = (p2 + p3) * 0.5f;
+    Vec2f p34  = (p3 + p4) * 0.5f;
+    Vec2f p123 = (p12 + p23) * 0.5f;
+
+    Vec2f pd  = p4 - p1;
+    Vec2f pd2 = p2 - p4;
+    float d2  = std::abs(pd2.x() * pd.y() - pd2.y() * pd.x());
+    Vec2f pd3 = p3 - p4;
+    float d3  = std::abs(pd3.x() * pd.y() - pd3.y() * pd.x());
+    float d23 = d2 + d3;
+
+    if ((d23 * d23) < tessTol * (pd.x() * pd.x() + pd.y() * pd.y())) {
+        polygon.points.emplace_back(p4.x(), p4.y());
+        return;
+    }
+
+    --level;
+    if (level == 0) return;
+    Vec2f p234  = (p23 + p34) * 0.5f;
+    Vec2f p1234 = (p123 + p234) * 0.5f;
+    flatten_cubic_bez(polygon, tessTol, p1, p12, p123, p1234, level);
+    flatten_cubic_bez(polygon, tessTol, p1234, p234, p34, p4, level);
+}
+
+Polygons NSVGUtils::to_polygons(NSVGimage *image, float tessTol, int max_level)
+{
+    Polygons polygons;
+    for (NSVGshape *shape = image->shapes; shape != NULL;
+         shape            = shape->next) {
+        if (!(shape->flags & NSVG_FLAGS_VISIBLE)) continue;
+        Slic3r::Polygon polygon;
+        if (shape->fill.type != NSVG_PAINT_NONE) {
+            for (NSVGpath *path = shape->paths; path != NULL;
+                 path           = path->next) {
+                // Flatten path
+                polygon.points.emplace_back(path->pts[0], path->pts[1]);
+                size_t path_size = (path->npts > 1) ?
+                    static_cast<size_t>(path->npts - 1) : 0;
+                for (size_t i = 0; i < path_size; i += 3) {
+                    float *p = &path->pts[i * 2];
+                    Vec2f  p1(p[0], p[1]), p2(p[2], p[3]), p3(p[4], p[5]),
+                        p4(p[6], p[7]);
+                    flatten_cubic_bez(polygon, tessTol, p1, p2, p3, p4,
+                                      max_level);
+                }
+                if (path->closed && !polygon.empty()) {
+                    polygons.push_back(polygon);
+                    polygon = Slic3r::Polygon();
+                }
+            }
+        }
+        if (!polygon.empty())
+            polygons.push_back(polygon);
+    }
+    return polygons;
+}
+
+ExPolygons NSVGUtils::to_ExPolygons(NSVGimage *image,
+                                    float      tessTol,
+                                    int        max_level)
+{
+    Polygons polygons = to_polygons(image, tessTol, max_level);
+
+    // Fix Y axis
+    for (Polygon &polygon : polygons)
+        for (Point &p : polygon.points) p.y() *= -1;
+
+    return Slic3r::union_ex(polygons);
+}