diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 19f5d33..18cf02f 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -7,5 +7,12 @@ SET (LibExtraSources ${CMAKE_CURRENT_BINARY_DIR}/library_constructor.c)
 SET (LC_RELATIVE_PREFIX "..")
 CONFIGURE_FILE ( "${CMAKE_SOURCE_DIR}/cmake/backbone/templates/library_constructor.c.in" "${LibExtraSources}")
 INCLUDE_DIRECTORIES ("${CMAKE_SOURCE_DIR}/src")
-SET (LibCustomVapis ${CMAKE_SOURCE_DIR}/src/float128type.vapi)
+SET (LibCustomVapis ${CMAKE_SOURCE_DIR}/src/cairo-chart-float128type.vapi)
 INCLUDE (ValaLibCommonRules)
+INSTALL (FILES ${CMAKE_CURRENT_SOURCE_DIR}/cairo-chart-float128type.h DESTINATION include
+         RENAME cairo-chart-float128type-${MAJOR}.h)
+INSTALL (FILES ${CMAKE_CURRENT_SOURCE_DIR}/cairo-chart-float128type.vapi DESTINATION share/vala/vapi
+         RENAME cairo-chart-float128type-${MAJOR}.vapi)
+CONFIGURE_FILE (${CMAKE_CURRENT_SOURCE_DIR}/cairo-chart.deps.in
+                ${CMAKE_CURRENT_BINARY_DIR}/cairo-chart-${MAJOR}.deps)
+INSTALL (FILES ${CMAKE_CURRENT_BINARY_DIR}/cairo-chart-${MAJOR}.deps DESTINATION share/vala/vapi)
diff --git a/src/GtkChart.vala b/src/GtkChart.vala
index c7a77b9..8b00d7b 100644
--- a/src/GtkChart.vala
+++ b/src/GtkChart.vala
@@ -43,8 +43,8 @@ namespace Gtk.CairoChart {
 			bg_color = Color (1, 1, 1);
 		}
 
-		protected Double128 cur_x_min = 0.0;
-		protected Double128 cur_x_max = 0.0;
+		protected Float128 cur_x_min = 0.0;
+		protected Float128 cur_x_max = 0.0;
 		protected double cur_y_min = 0.0;
 		protected double cur_y_max = 0.0;
 
@@ -402,10 +402,10 @@ namespace Gtk.CairoChart {
 		protected virtual void calc_axis_rec_sizes (Series.Axis axis, out double max_rec_width, out double max_rec_height, bool is_horizontal = true) {
 			max_rec_width = max_rec_height = 0;
 			for (var i = 0; i < axis_rec_npoints; ++i) {
-				Double128 x = axis.min + (axis.max - axis.min) / axis_rec_npoints * i;
+				Float128 x = axis.min + (axis.max - axis.min) / axis_rec_npoints * i;
 				switch (axis.type) {
 				case Series.Axis.Type.NUMBERS:
-					var text = new Text (axis.format.printf(x) + (is_horizontal ? "_" : ""));
+					var text = new Text (axis.format.printf((LongDouble)x) + (is_horizontal ? "_" : ""));
 					text.style = axis.font_style;
 					max_rec_width = double.max (max_rec_width, text.get_width(context));
 					max_rec_height = double.max (max_rec_height, text.get_height(context));
@@ -435,8 +435,8 @@ namespace Gtk.CairoChart {
 			}
 		}
 
-		protected virtual Double128 calc_round_step (Double128 aver_step, bool date_time = false) {
-			Double128 step = 1.0;
+		protected virtual Float128 calc_round_step (Float128 aver_step, bool date_time = false) {
+			Float128 step = 1.0;
 
 			if (aver_step > 1.0) {
 				if (date_time) while (step < aver_step) step *= 60;
@@ -463,7 +463,7 @@ namespace Gtk.CairoChart {
 		bool common_x_axes = false;
 		bool common_y_axes = false;
 
-		bool are_intersect (Double128 a_min, Double128 a_max, Double128 b_min, Double128 b_max) {
+		bool are_intersect (Float128 a_min, Float128 a_max, Float128 b_min, Float128 b_max) {
 			if (   a_min < a_max <= b_min < b_max
 			    || b_min < b_max <= a_min < a_max)
 				return false;
@@ -594,8 +594,8 @@ namespace Gtk.CairoChart {
 			}
 		}
 
-		bool point_belong (Double128 p, Double128 a, Double128 b) {
-			if (a > b) { Double128 tmp = a; a = b; b = tmp; }
+		bool point_belong (Float128 p, Float128 a, Float128 b) {
+			if (a > b) { Float128 tmp = a; a = b; b = tmp; }
 			if (a <= p <= b) return true;
 			return false;
 		}
@@ -612,12 +612,12 @@ namespace Gtk.CairoChart {
 				long max_nrecs = (long) ((plot_area_x_max - plot_area_x_min) * (s.place.x_high - s.place.x_low) / max_rec_width);
 
 				// 3. Calculate grid step.
-				Double128 step = calc_round_step ((s.axis_x.max - s.axis_x.min) / max_nrecs, s.axis_x.type == Series.Axis.Type.DATE_TIME);
+				Float128 step = calc_round_step ((s.axis_x.max - s.axis_x.min) / max_nrecs, s.axis_x.type == Series.Axis.Type.DATE_TIME);
 				if (step > s.axis_x.max - s.axis_x.min)
 					step = s.axis_x.max - s.axis_x.min;
 
 				// 4. Calculate x_min (s.axis_x.min / step, round, multiply on step, add step if < s.axis_x.min).
-				Double128 x_min = 0.0;
+				Float128 x_min = 0.0;
 				if (step >= 1) {
 					int64 x_min_nsteps = (int64) (s.axis_x.min / step);
 					x_min = x_min_nsteps * step;
@@ -652,18 +652,19 @@ namespace Gtk.CairoChart {
 					}
 
 				// 5. Draw records, update cur_{x,y}_{min,max}.
-				for (Double128 x = x_min, x_max = s.axis_x.max; point_belong (x, x_min, x_max); x += step) {
+				for (Float128 x = x_min, x_max = s.axis_x.max; point_belong (x, x_min, x_max); x += step) {
 					if (common_x_axes) set_source_rgba(Color(0,0,0,1));
 					else set_source_rgba(s.axis_x.color);
 					string text = "", time_text = "";
 					switch (s.axis_x.type) {
 					case Series.Axis.Type.NUMBERS:
-						text = s.axis_x.format.printf(x);
+						text = s.axis_x.format.printf((LongDouble)x);
 						break;
 					case Series.Axis.Type.DATE_TIME:
 						var dt = new DateTime.from_unix_utc((int64)x);
 						text = dt.format(s.axis_x.date_format);
-						var dsec_str = ("%."+(s.axis_x.dsec_signs.to_string())+"Lf").printf((x - (int64)x)).offset(1);
+						var dsec_str =
+							("%."+(s.axis_x.dsec_signs.to_string())+"Lf").printf((LongDouble)(x - (int64)x)).offset(1);
 						time_text = dt.format(s.axis_x.time_format) + dsec_str;
 						break;
 					default:
@@ -799,12 +800,12 @@ namespace Gtk.CairoChart {
 				long max_nrecs = (long) ((plot_area_y_max - plot_area_y_min) * (s.place.y_high - s.place.y_low) / max_rec_height);
 
 				// 3. Calculate grid step.
-				Double128 step = calc_round_step ((s.axis_y.max - s.axis_y.min) / max_nrecs);
+				Float128 step = calc_round_step ((s.axis_y.max - s.axis_y.min) / max_nrecs);
 				if (step > s.axis_y.max - s.axis_y.min)
 					step = s.axis_y.max - s.axis_y.min;
 
 				// 4. Calculate y_min (s.axis_y.min / step, round, multiply on step, add step if < s.axis_y.min).
-				Double128 y_min = 0.0;
+				Float128 y_min = 0.0;
 				if (step >= 1) {
 					int64 y_min_nsteps = (int64) (s.axis_y.min / step);
 					y_min = y_min_nsteps * step;
@@ -839,10 +840,10 @@ namespace Gtk.CairoChart {
 					}
 
 				// 5. Draw records, update cur_{x,y}_{min,max}.
-				for (Double128 y = y_min, y_max = s.axis_y.max; point_belong (y, y_min, y_max); y += step) {
+				for (Float128 y = y_min, y_max = s.axis_y.max; point_belong (y, y_min, y_max); y += step) {
 					if (common_y_axes) set_source_rgba(Color(0,0,0,1));
 					else set_source_rgba(s.axis_y.color);
-					var text = s.axis_y.format.printf(y);
+					var text = s.axis_y.format.printf((LongDouble)y);
 					var scr_y = plot_area_y_max - (plot_area_y_max - plot_area_y_min)
 					            * (s.place.y_low + (s.place.y_high - s.place.y_low) / (s.axis_y.max - s.axis_y.min) * (y - s.axis_y.min));
 					var text_t = new Text(text, s.axis_y.font_style, s.axis_y.color);
@@ -936,12 +937,12 @@ namespace Gtk.CairoChart {
 			context.stroke ();
 		}
 
-		protected virtual double get_scr_x (Series s, Double128 x) {
+		protected virtual double get_scr_x (Series s, Float128 x) {
 				return plot_area_x_min + (plot_area_x_max - plot_area_x_min) * (s.place.x_low + (x - s.axis_x.min)
 				                         / (s.axis_x.max - s.axis_x.min) * (s.place.x_high - s.place.x_low));
 		}
 
-		protected virtual double get_scr_y (Series s, Double128 y) {
+		protected virtual double get_scr_y (Series s, Float128 y) {
 				return plot_area_y_max - (plot_area_y_max - plot_area_y_min) * (s.place.y_low + (y - s.axis_y.min)
 				                         / (s.axis_y.max - s.axis_y.min) * (s.place.y_high - s.place.y_low));
 		}
diff --git a/src/Series.vala b/src/Series.vala
index db74ffd..47d5b69 100644
--- a/src/Series.vala
+++ b/src/Series.vala
@@ -5,10 +5,10 @@ namespace Gtk.CairoChart {
 	public class Series {
 
 		public struct Point {
-			Double128 x;
-			Double128 y;
+			Float128 x;
+			Float128 y;
 
-			public Point (Double128 x, Double128 y) {
+			public Point (Float128 x, Float128 y) {
 				this.x = x; this.y = y;
 			}
 		}
@@ -25,8 +25,8 @@ namespace Gtk.CairoChart {
 		// then draw separate axis for each/all series
 		// or specify series name near the axis
 		public class Axis {
-			public Double128 min = 0;
-			public Double128 max = 1;
+			public Float128 min = 0;
+			public Float128 max = 1;
 			public Text title = new Text ("");
 			public enum Type {
 				NUMBERS = 0,
@@ -137,7 +137,7 @@ namespace Gtk.CairoChart {
 
 		public Grid grid = new Grid ();
 
-		public GLib.List<Double128?> cursors = new List<Double128?> ();
+		public GLib.List<Float128?> cursors = new List<Float128?> ();
 		public LineStyle line_style = new LineStyle ();
 
 		protected Color _color = Color (0.0, 0.0, 0.0, 1.0);
diff --git a/src/cairo-chart-float128type.h b/src/cairo-chart-float128type.h
new file mode 100644
index 0000000..9e68163
--- /dev/null
+++ b/src/cairo-chart-float128type.h
@@ -0,0 +1,2 @@
+typedef __float128 cairo_chart_float128;
+typedef long double cairo_chart_long_double;
diff --git a/src/cairo-chart-float128type.vapi b/src/cairo-chart-float128type.vapi
new file mode 100644
index 0000000..04aaa8c
--- /dev/null
+++ b/src/cairo-chart-float128type.vapi
@@ -0,0 +1,6 @@
+namespace Gtk.CairoChart {
+	[CCode (cname = "cairo_chart_float128", has_type_id = false, cheader_filename = "cairo-chart-float128type.h")]
+	public struct Float128 : double {}
+	[CCode (cname = "cairo_chart_long_double", has_type_id = false, cheader_filename = "cairo-chart-float128type.h")]
+	public struct LongDouble : double {}
+}
diff --git a/src/cairo-chart.deps.in b/src/cairo-chart.deps.in
new file mode 100644
index 0000000..c6ec5d0
--- /dev/null
+++ b/src/cairo-chart.deps.in
@@ -0,0 +1 @@
+cairo-chart-float128type-@MAJOR@
diff --git a/src/float128type.h b/src/float128type.h
deleted file mode 100644
index b230774..0000000
--- a/src/float128type.h
+++ /dev/null
@@ -1 +0,0 @@
-typedef long double double128;
diff --git a/src/float128type.vapi b/src/float128type.vapi
deleted file mode 100644
index 8b19687..0000000
--- a/src/float128type.vapi
+++ /dev/null
@@ -1,2 +0,0 @@
-[CCode (cname = "double128", has_type_id = false, cheader_filename = "float128type.h")]
-public struct Double128 : double {}
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 2067fb2..417fe08 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -1,7 +1,7 @@
 SET (BinName chart_test)
 FILE (GLOB_RECURSE BinSources RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} ChartTest.vala)
 SET (BinPackages gtk+-3.0)
-SET (BinCustomVapis ${CMAKE_BINARY_DIR}/src/${PROJECT_LOWERCASE_NAME}-${MAJOR}.vapi ${CMAKE_SOURCE_DIR}/src/float128type.vapi)
+SET (BinCustomVapis ${CMAKE_BINARY_DIR}/src/${PROJECT_LOWERCASE_NAME}-${MAJOR}.vapi ${CMAKE_SOURCE_DIR}/src/cairo-chart-float128type.vapi)
 SET (BinLinkLibs ${PROJECT_LOWERCASE_NAME})
 INCLUDE_DIRECTORIES ("${CMAKE_BINARY_DIR}/src;${CMAKE_SOURCE_DIR}/src")
 INCLUDE (ValaBinCommonRules)
diff --git a/test/ChartTest.vala b/test/ChartTest.vala
index 4bd3d70..7ed7019 100644
--- a/test/ChartTest.vala
+++ b/test/ChartTest.vala
@@ -379,7 +379,6 @@ int main (string[] args) {
 
 	window.show_all();
 
-Double128 d = 5.5;
 	Gtk.main();
 	return 0;
 }