1 files changed, 106 insertions, 0 deletions
diff --git a/calibration.e b/calibration.e
new file mode 100644
index 0000000..e1b2d6a
--- /dev/null
+++ b/calibration.e
@@ -0,0 +1,106 @@
+class CALIBRATION
+-- This class is able to
+-- - build some calibration grid with user assistance,
+-- - save calibration grid,
+-- - reload calibration grid,
+-- - use calibration grid for coordinates conversion.
+
+create {ANY}
+	make
+
+feature {}
+	make is
+		do
+			create reference_points.make
+		end
+
+feature {ANY}
+	ready: BOOLEAN
+
+	build (display_width_, display_height_: INTEGER) is
+		local
+			uncalibrated: FAST_ARRAY[INTEGER]
+		do
+			display_width := display_width_
+			display_height := display_height_
+			from
+				uncalibrated := {FAST_ARRAY[INTEGER] <<0, 0, display_width, display_height>>}
+			until
+				uncalibrated.is_empty
+			loop
+				
+			end
+		ensure
+			ready
+		end
+
+	write_to (os: OUTPUT_STREAM) is
+		require
+			os.is_connected
+		do
+		ensure
+			os.is_connected
+		end
+
+	load_from (data: INPUT_STREAM) is
+		require
+			data.is_connected
+		do
+		end
+
+	set_offset(x_display, y_display: INTEGER) is
+		do
+			x_offset := x_display
+			y_offset := y_display
+		end
+	
+	convert (x_device, y_device: INTEGER) is
+			-- Result is available in last_x, last_y
+		require
+			x_device.in_range(0, device_width)
+			y_device.in_range(0, device_height)
+		local
+			i, j: INTEGER
+			x_rest, y_rest: INTEGER
+			
+		do
+			i := x_device // horizontal_step
+			j := y_device // vertical_step
+			x_rest := x_device - i * horizontal_step
+			y_rest := y_device - j * vertical_step
+			if y_rest * 2 < vertical_step then
+				last_x := ((x_table.item(i, j) * x_rest + x_table.item(i + 1, j) * (horizontal_step - x_rest)) / horizontal_step).force_to_integer_32
+			else
+				last_x := ((x_table.item(i, j + 1) * x_rest + x_table.item(i + 1, j + 1) * (horizontal_step - x_rest)) / horizontal_step).force_to_integer_32
+			end
+			if x_rest * 2 < horizontal_step then
+				last_y := ((y_table.item(i, j) * y_rest + y_table.item(i, j + 1) * (vertical_step - y_rest)) / vertical_step).force_to_integer_32
+			else
+				last_y := ((y_table.item(i + 1, j) * y_rest + y_table.item(i + 1, j + 1) * (vertical_step - y_rest)) / vertical_step).force_to_integer_32
+			end
+		ensure
+			last_x.in_range(x_offset, x_offset + display_width -1)
+			last_y.in_range(y_offset, y_offset + display_height - 1)
+		end
+
+	last_x, last_y: INTEGER
+			-- Last conversion result (in display coordinates)
+	
+feature {}
+	x_offset, y_offset, display_width, display_height: INTEGER
+			-- coordinates and size of the displayed area in pixels
+
+	x_table, y_table: FAST_ARRAY2[REAL]
+			-- Store display coordinates for device coordinate. Use 
+			-- `horizontal_step' and `vertical_step' for table indexes values.
+
+	horizontal_step, vertical_step: INTEGER
+			-- Indexes steps for tables
+
+	device_width, device_height: INTEGER
+			-- Digitizer size
+	
+	reference_points: REFERENCE_POINTS
+			-- 4 values per reference point x_device
+end
+