add fill-area feature to poly-line

3 files changed, 55 insertions, 4 deletions

diff --git a/libs/canvas/canvas/poly_item.h b/libs/canvas/canvas/poly_item.h
index bdb7c20b1a..311ca80933 100644
--- a/libs/canvas/canvas/poly_item.h
+++ b/libs/canvas/canvas/poly_item.h
@@ -32,7 +32,7 @@ public:
 	PolyItem (Canvas*);
 	PolyItem (Item*);
 
-	void compute_bounding_box () const;
+	virtual void compute_bounding_box () const;
 
 	virtual void set (Points const &);
 	Points const & get () const;
diff --git a/libs/canvas/canvas/poly_line.h b/libs/canvas/canvas/poly_line.h
index fce013dfd6..7c6894719c 100644
--- a/libs/canvas/canvas/poly_line.h
+++ b/libs/canvas/canvas/poly_line.h
@@ -28,15 +28,16 @@ namespace ArdourCanvas {
 
 class LIBCANVAS_API PolyLine : public PolyItem
 {
-  public:
+public:
 	PolyLine (Canvas*);
 	PolyLine (Item*);
 
 	void render (Rect const & area, Cairo::RefPtr<Cairo::Context>) const;
 
 	virtual void set_steps (Points const &, bool stepped);
+	virtual void compute_bounding_box () const;
 
-        bool covers (Duple const &) const;
+	bool covers (Duple const &) const;
 	/**
 	 * Set the distance at which a point will be considered to be covered
 	 * by the line. For the definition of "distance" see
@@ -44,8 +45,11 @@ class LIBCANVAS_API PolyLine : public PolyItem
 	 */
 	void set_covers_threshold (double);
 
-  private:
+	void set_fill_y1 (double);
+
+private:
 	double _threshold;
+	double _y1;
 };
 
 }
diff --git a/libs/canvas/poly_line.cc b/libs/canvas/poly_line.cc
index 5d6abb9814..5086df76a3 100644
--- a/libs/canvas/poly_line.cc
+++ b/libs/canvas/poly_line.cc
@@ -28,6 +28,7 @@ using namespace ArdourCanvas;
 PolyLine::PolyLine (Canvas* c)
 	: PolyItem (c)
 	, _threshold (1.0)
+	, _y1 (0)
 {
 }
 
@@ -38,8 +39,54 @@ PolyLine::PolyLine (Item* parent)
 }
 
 void
+PolyLine::compute_bounding_box () const
+{
+	PolyItem::compute_bounding_box ();
+	if (_y1 > 0 && _bounding_box) {
+		_bounding_box.get().x0 = 0;
+		_bounding_box.get().x1 = COORD_MAX;
+		if (_y1 > _bounding_box.get().y1) {
+			_bounding_box.get().y1 = _y1;
+		}
+	}
+}
+
+void
+PolyLine::set_fill_y1 (double y1) {
+	begin_change ();
+	_bounding_box_dirty = true;
+	_y1 = y1;
+	end_change ();
+}
+
+void
 PolyLine::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
 {
+	if (_fill && _y1 > 0 && _points.size() > 0) {
+		const ArdourCanvas::Rect& vp (_canvas->visible_area());
+		setup_fill_context (context);
+
+		Duple y (0, _y1);
+		float y1 = item_to_window (y).y;
+		render_path (area, context);
+		Duple c0 (item_to_window (_points.back()));
+		Duple c1 (item_to_window (_points.front()));
+		if (c0.x < vp.x1) {
+			context->line_to (vp.x1, c0.y);
+			context->line_to (vp.x1, y1);
+		} else {
+			context->line_to (vp.x1, y1);
+		}
+		if (c1.x > vp.x0) {
+			context->line_to (vp.x0, y1);
+			context->line_to (vp.x0, c1.y);
+		} else {
+			context->line_to (vp.x0, y1);
+		}
+		context->close_path ();
+		context->fill ();
+	}
+
 	if (_outline) {
 		setup_outline_context (context);
 		render_path (area, context);