OK. In progress...

src/Chart.vala

@@ -368,40 +368,6 @@ namespace CairoChart {
 			}
 		}
 
-		public virtual void set_active_cursor (Point p, bool remove = false) {
-			cursors.active_cursor = scr2rel_point(p);
-			cursors.is_cursor_active = ! remove;
-		}
-		public virtual void add_active_cursor () {
-			cursors.list.append (cursors.active_cursor);
-			cursors.is_cursor_active = false;
-		}
-		public virtual void remove_active_cursor () {
-			if (cursors.list.length() == 0) return;
-			var distance = width * width;
-			uint rm_indx = 0;
-			uint i = 0;
-			foreach (var c in cursors.list) {
-				double d = distance;
-				switch (cursors.cursor_style.orientation) {
-				case Cursors.Orientation.VERTICAL:
-					d = (rel2scr_x(c.x) - rel2scr_x(cursors.active_cursor.x)).abs();
-					break;
-				case Cursors.Orientation.HORIZONTAL:
-					d = (rel2scr_y(c.y) - rel2scr_y(cursors.active_cursor.y)).abs();
-					break;
-				}
-				if (d < distance) {
-					distance = d;
-					rm_indx = i;
-				}
-				++i;
-			}
-			if (distance < cursors.cursor_style.select_distance)
-				cursors.list.delete_link(cursors.list.nth(rm_indx));
-			cursors.is_cursor_active = false;
-		}
-
 		protected virtual bool x_in_plot_area (double x) {
 			if (math.x_in_range(x, plot_x_min, plot_x_max))
 				return true;
@@ -418,13 +384,13 @@ namespace CairoChart {
 			return false;
 		}
 
-		protected virtual Float128 scr2rel_x (Float128 x) {
+		public virtual Float128 scr2rel_x (Float128 x) {
 			return rz_x_min + (x - plot_x_min) / (plot_x_max - plot_x_min) * (rz_x_max - rz_x_min);
 		}
-		protected virtual Float128 scr2rel_y (Float128 y) {
+		public virtual Float128 scr2rel_y (Float128 y) {
 			return rz_y_max - (plot_y_max - y) / (plot_y_max - plot_y_min) * (rz_y_max - rz_y_min);
 		}
-		protected virtual Point scr2rel_point (Point p) {
+		public virtual Point scr2rel_point (Point p) {
 			return Point (scr2rel_x(p.x), scr2rel_y(p.y));
 		}
 		public virtual Float128 rel2scr_x(Float128 x) {

src/Cursor.vala

@@ -55,6 +55,42 @@ namespace CairoChart {
 			CursorCross[] crossings;
 		}
 
+		public virtual void set_active_cursor (Chart chart, Point p, bool remove = false) {
+			active_cursor = chart.scr2rel_point(p);
+			is_cursor_active = ! remove;
+		}
+
+		public virtual void add_active_cursor () {
+			list.append (active_cursor);
+			is_cursor_active = false;
+		}
+
+		public virtual void remove_active_cursor (Chart chart) {
+			if (list.length() == 0) return;
+			var distance = 1024.0 * 1024.0;//width * width;
+			uint rm_indx = 0;
+			uint i = 0;
+			foreach (var c in list) {
+				double d = distance;
+				switch (cursor_style.orientation) {
+				case Cursors.Orientation.VERTICAL:
+					d = (chart.rel2scr_x(c.x) - chart.rel2scr_x(active_cursor.x)).abs();
+					break;
+				case Cursors.Orientation.HORIZONTAL:
+					d = (chart.rel2scr_y(c.y) - chart.rel2scr_y(active_cursor.y)).abs();
+					break;
+				}
+				if (d < distance) {
+					distance = d;
+					rm_indx = i;
+				}
+				++i;
+			}
+			if (distance < cursor_style.select_distance)
+				list.delete_link(list.nth(rm_indx));
+			is_cursor_active = false;
+		}
+
 		protected List<Point?> get_all_cursors (Chart chart) {
 			var all_cursors = list.copy_deep ((src) => { return src; });
 			if (is_cursor_active)

test/ChartTest.vala

@@ -454,11 +454,11 @@ int main (string[] args) {
 		switch (event.button) {
 		case 1:  // start cursor position selection
 			if ((event.state & Gdk.ModifierType.SHIFT_MASK) != 0) { // remove cursor
-				chart.set_active_cursor (Point(event.x, event.y), true);
+				chart.cursors.set_active_cursor (chart, Point(event.x, event.y), true);
-				chart.remove_active_cursor();
+				chart.cursors.remove_active_cursor(chart);
 				mouse_state = MouseState.FREE;
 			} else { // add cursor
-				chart.set_active_cursor (Point(event.x, event.y));
+				chart.cursors.set_active_cursor (chart, Point(event.x, event.y));
 				mouse_state = MouseState.CURSOR_SELECTION;
 			}
 			da.queue_draw_area(0, 0, da.get_allocated_width(), da.get_allocated_height());
@@ -490,7 +490,7 @@ int main (string[] args) {
 				//da.queue_draw_area(0, 0, da.get_allocated_width(), da.get_allocated_height());
 				//mouse_state = MouseState.FREE;
 			} else { // add cursor
-				chart.add_active_cursor ();
+				chart.cursors.add_active_cursor ();
 				mouse_state = MouseState.FREE;
 			}
 			break;
@@ -532,7 +532,7 @@ int main (string[] args) {
 			break;
 
 		case MouseState.CURSOR_SELECTION:
-			chart.set_active_cursor (Point(event.x, event.y));
+			chart.cursors.set_active_cursor (chart, Point(event.x, event.y));
 			da.queue_draw_area(0, 0, da.get_allocated_width(), da.get_allocated_height());
 			break;
 		}