1 files changed, 67 insertions, 0 deletions
diff --git a/src/live_effects/lpe-tangent_to_curve.h b/src/live_effects/lpe-tangent_to_curve.h
new file mode 100644
index 0000000..32cacd1
--- /dev/null
+++ b/src/live_effects/lpe-tangent_to_curve.h
@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#ifndef INKSCAPE_LPE_TANGENT_TO_CURVE_H
+#define INKSCAPE_LPE_TANGENT_TO_CURVE_H
+
+/** \file
+ * LPE <tangent_to_curve> implementation, see lpe-tangent_to_curve.cpp.
+ */
+
+/*
+ * Authors:
+ *   Johan Engelen
+ *   Maximilian Albert
+ *
+ * Copyright (C) Johan Engelen 2007 <j.b.c.engelen@utwente.nl>
+ * Copyright (C) Maximilian Albert 2008 <maximilian.albert@gmail.com>
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include "live_effects/effect.h"
+#include "live_effects/parameter/parameter.h"
+#include "live_effects/parameter/point.h"
+
+namespace Inkscape {
+namespace LivePathEffect {
+
+namespace TtC {
+  // we need a separate namespace to avoid clashes with LPEPerpBisector
+  class KnotHolderEntityLeftEnd;
+  class KnotHolderEntityRightEnd;
+  class KnotHolderEntityAttachPt;
+}
+
+class LPETangentToCurve : public Effect {
+public:
+    LPETangentToCurve(LivePathEffectObject *lpeobject);
+    ~LPETangentToCurve() override;
+    Geom::Piecewise<Geom::D2<Geom::SBasis> >
+      doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > const & pwd2_in) override;
+
+    /* the knotholder entity classes must be declared friends */
+    friend class TtC::KnotHolderEntityLeftEnd;
+    friend class TtC::KnotHolderEntityRightEnd;
+    friend class TtC::KnotHolderEntityAttachPt;
+    void addKnotHolderEntities(KnotHolder * knotholder, SPItem * item) override;
+
+private:
+    ScalarParam angle;
+
+    ScalarParam t_attach;
+    ScalarParam length_left;
+    ScalarParam length_right;
+
+    Geom::Point ptA; // point of attachment to the curve
+    Geom::Point derivA;
+
+    Geom::Point C; // left end of tangent
+    Geom::Point D; // right end of tangent
+
+    LPETangentToCurve(const LPETangentToCurve&) = delete;
+    LPETangentToCurve& operator=(const LPETangentToCurve&) = delete;
+};
+
+} //namespace LivePathEffect
+} //namespace Inkscape
+
+#endif