smooth visual curve drawing

6 files changed, 31 insertions, 46 deletions

diff --git a/libs/canvas/canvas.cc b/libs/canvas/canvas.cc
index d5d8562361..ceaa366c35 100644
--- a/libs/canvas/canvas.cc
+++ b/libs/canvas/canvas.cc
@@ -193,14 +193,15 @@ Canvas::window_to_canvas (Duple const & d) const
 }
 
 Duple
-Canvas::canvas_to_window (Duple const & d) const
+Canvas::canvas_to_window (Duple const & d, bool rounded) const
 {
 	Duple wd = d.translate (Duple (-_scroll_offset_x, -_scroll_offset_y));
 
-	/* Note that this intentionally always returns integer coordinates */
-
-	wd.x = round (wd.x);
-	wd.y = round (wd.y);
+	/* Note that this intentionally almost always returns integer coordinates */
+	if (rounded) {
+		wd.x = round (wd.x);
+		wd.y = round (wd.y);
+	}
 
 	return wd;
 }	
@@ -212,16 +213,18 @@ Canvas::window_to_canvas (Rect const & r) const
 }
 
 Rect
-Canvas::canvas_to_window (Rect const & r) const
+Canvas::canvas_to_window (Rect const & r, bool rounded) const
 {
 	Rect wr = r.translate (Duple (-_scroll_offset_x, -_scroll_offset_y));
 
-	/* Note that this intentionally always returns integer coordinates */
+	/* Note that this intentionally almost always returns integer coordinates */
 
-	wr.x0 = round (wr.x0);
-	wr.x1 = round (wr.x1);
-	wr.y0 = round (wr.y0);
-	wr.y1 = round (wr.y1);
+	if (rounded) {
+		wr.x0 = round (wr.x0);
+		wr.x1 = round (wr.x1);
+		wr.y0 = round (wr.y0);
+		wr.y1 = round (wr.y1);
+	}
 
 	return wr;
 }	
diff --git a/libs/canvas/canvas/canvas.h b/libs/canvas/canvas/canvas.h
index 616336409d..b15c2f4d54 100644
--- a/libs/canvas/canvas/canvas.h
+++ b/libs/canvas/canvas/canvas.h
@@ -90,9 +90,9 @@ public:
 
         virtual Cairo::RefPtr<Cairo::Context> context () = 0;
 
-        Rect canvas_to_window (Rect const&) const;
+        Rect canvas_to_window (Rect const&, bool rounded = true) const;
         Rect window_to_canvas (Rect const&) const;
-        Duple canvas_to_window (Duple const&) const;
+        Duple canvas_to_window (Duple const&, bool rounded = true) const;
         Duple window_to_canvas (Duple const&) const;
 
         void canvas_to_window (Coord cx, Coord cy, Coord& wx, Coord& wy) {
diff --git a/libs/canvas/canvas/item.h b/libs/canvas/canvas/item.h
index da061f5bfc..d7d4ba7254 100644
--- a/libs/canvas/canvas/item.h
+++ b/libs/canvas/canvas/item.h
@@ -136,7 +136,7 @@ public:
 	Rect canvas_to_item (Rect const &) const;
         Duple item_to_canvas (Duple const &) const;
 
-        Duple item_to_window (Duple const&) const;
+        Duple item_to_window (Duple const&, bool rounded = true) const;
         Duple window_to_item (Duple const&) const;
         Rect item_to_window (Rect const&) const;
 
diff --git a/libs/canvas/curve.cc b/libs/canvas/curve.cc
index 827dee206d..ce479b28bb 100644
--- a/libs/canvas/curve.cc
+++ b/libs/canvas/curve.cc
@@ -188,18 +188,9 @@ Curve::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
 		/* draw line between samples */
 		window_space = item_to_window (Duple (samples[left].x, samples[left].y));
 		context->move_to (window_space.x, window_space.y);
-		Coord last_x = round(window_space.x);
-		Coord last_y = round(window_space.y);
 		for (uint32_t idx = left + 1; idx < right; ++idx) {
 			window_space = item_to_window (Duple (samples[idx].x, samples[idx].y));
-			if (last_x == round(window_space.x)) continue;
-			if (last_y == round(window_space.y)) continue;
-			last_x = round(window_space.x);
-			last_y = round(window_space.y);
-			context->line_to (last_x - .5 , last_y + .5);
-		}
-		if (last_x != round(window_space.x) || last_y != round(window_space.y)) {
-			context->line_to (window_space.x - .5 , window_space.y + .5);
+			context->line_to (window_space.x, window_space.y);
 		}
 
 		switch (curve_fill) {
diff --git a/libs/canvas/item.cc b/libs/canvas/item.cc
index e4e3c30546..674daa4275 100644
--- a/libs/canvas/item.cc
+++ b/libs/canvas/item.cc
@@ -160,9 +160,9 @@ Item::canvas_to_item (Coord& x, Coord& y) const
 }
 
 Duple
-Item::item_to_window (ArdourCanvas::Duple const & d) const
+Item::item_to_window (ArdourCanvas::Duple const & d, bool rounded) const
 {
-	return _canvas->canvas_to_window (item_to_canvas (d));
+	return _canvas->canvas_to_window (item_to_canvas (d), rounded);
 }
 
 Duple
diff --git a/libs/canvas/xfade_curve.cc b/libs/canvas/xfade_curve.cc
index ed5c45d57d..52be6c0095 100644
--- a/libs/canvas/xfade_curve.cc
+++ b/libs/canvas/xfade_curve.cc
@@ -139,9 +139,9 @@ XFadeCurve::get_path(Rect const & area, Cairo::RefPtr<Cairo::Context> context, C
 
 	if (c.points.size () == 2) {
 
-		window_space = item_to_window (c.points.front());
+		window_space = item_to_window (c.points.front(), false);
 		context->move_to (window_space.x, window_space.y);
-		window_space = item_to_window (c.points.back());
+		window_space = item_to_window (c.points.back(), false);
 		context->line_to (window_space.x, window_space.y);
 
 	} else {
@@ -152,30 +152,21 @@ XFadeCurve::get_path(Rect const & area, Cairo::RefPtr<Cairo::Context> context, C
 
 		for (Points::size_type idx = 0; idx < c.n_samples - 1; ++idx) {
 			left = idx;
-			window_space = item_to_window (Duple (c.samples[idx].x, 0.0));
+			window_space = item_to_window (Duple (c.samples[idx].x, 0.0), false);
 			if (window_space.x >= area.x0) break;
 		}
 		for (Points::size_type idx = c.n_samples; idx > left + 1; --idx) {
-			window_space = item_to_window (Duple (c.samples[idx].x, 0.0));
+			window_space = item_to_window (Duple (c.samples[idx].x, 0.0), false);
 			if (window_space.x <= area.x1) break;
 			right = idx;
 		}
 
 		/* draw line between samples */
-		window_space = item_to_window (Duple (c.samples[left].x, c.samples[left].y));
+		window_space = item_to_window (Duple (c.samples[left].x, c.samples[left].y), false);
 		context->move_to (window_space.x, window_space.y);
-		Coord last_x = round(window_space.x);
-		Coord last_y = round(window_space.y);
 		for (uint32_t idx = left + 1; idx < right; ++idx) {
-			window_space = item_to_window (Duple (c.samples[idx].x, c.samples[idx].y));
-			if (last_x == round(window_space.x)) continue;
-			if (last_y == round(window_space.y)) continue;
-			last_x = round(window_space.x);
-			last_y = round(window_space.y);
-			context->line_to (last_x - .5 , last_y + .5);
-		}
-		if (last_x != round(window_space.x) || last_y != round(window_space.y)) {
-			context->line_to (window_space.x - .5 , window_space.y + .5);
+			window_space = item_to_window (Duple (c.samples[idx].x, c.samples[idx].y), false);
+			context->line_to (window_space.x, window_space.y);
 		}
 	}
 	return context->copy_path ();
@@ -186,15 +177,15 @@ XFadeCurve::close_path(Rect const & area, Cairo::RefPtr<Cairo::Context> context,
 {
 	Duple window_space;
 	if (inside) {
-		window_space = item_to_window (Duple(c.points.back().x, area.height()));
+		window_space = item_to_window (Duple(c.points.back().x, area.height()), false);
 		context->line_to (window_space.x, window_space.y);
-		window_space = item_to_window (Duple(c.points.front().x, area.height()));
+		window_space = item_to_window (Duple(c.points.front().x, area.height()), false);
 		context->line_to (window_space.x, window_space.y);
 		context->close_path();
 	} else {
-		window_space = item_to_window (Duple(c.points.back().x, 0.0));
+		window_space = item_to_window (Duple(c.points.back().x, 0.0), false);
 		context->line_to (window_space.x, window_space.y);
-		window_space = item_to_window (Duple(c.points.front().x, 0.0));
+		window_space = item_to_window (Duple(c.points.front().x, 0.0), false);
 		context->line_to (window_space.x, window_space.y);
 		context->close_path();
 	}