Allow merging a path into another

Author: floppyhammer

pathfinder/core/path2d.cpp

@@ -159,6 +159,20 @@ void Path2d::add_circle(const Vec2F &center, float radius) {
     close_path();
 }
 
+void Path2d::add_path(const Path2d &other, const Transform2 &transform) {
+    flush_current_contour();
+
+    // We need to get the outline from the other path.
+    // Since into_outline() might be destructive/mutating, we'll use a const_cast
+    // or better, just access the internal outline if we are a member.
+    Outline other_outline = const_cast<Path2d&>(other).into_outline();
+    other_outline.transform(transform);
+
+    for (const auto &contour : other_outline.contours) {
+        outline.push_contour(contour);
+    }
+}
+
 Outline Path2d::into_outline() {
     flush_current_contour();
     return outline;

pathfinder/core/path2d.h

@@ -31,6 +31,8 @@ class Path2d {
     void add_rect_with_corners(const RectF &rect, const RectF &corner_radius);
 
     void add_circle(const Vec2F &center, float radius);
+
+    void add_path(const Path2d &other, const Transform2 &transform = Transform2::from_scale({1.0f, 1.0f}));
     // -----------------------------------------------
 
     /// Returns the outline.