indexing

	description: "[

		Zoom Tool

	]"
	date: "$Date$"
	revision: "$Revision$"

class ZOOM_TOOL

inherit

	TOOL

create

	make

feature -- Access

	cursor: MOUSE_CURSOR is
			-- appropriate cursor
		do
			if scene.focus_on_scene then
				Result := zoom_cursor
			else
				Result := arrow_cursor
			end
		end

feature -- Event Handling

	handle_mouse_button_down_event (event: EM_MOUSEBUTTON_EVENT) is
			-- Handle mouse button down event.
		local
			vec: EM_VECTOR_2D
			new_scaling_factor: DOUBLE
		do
			if event.is_left_button and scene.scale < max_scale and scene.focus_on_scene then
				vec := transform_position (event.x, event.y)
				scene.set_center (vec.x.rounded, vec.y.rounded)
				scene.set_scale (scene.scale * scaling_factor)
				new_scaling_factor := scene.scale
			elseif event.is_right_button and scene.scale > min_scale and scene.focus_on_scene then
				vec := transform_position (event.x, event.y)
				scene.set_center (vec.x.rounded, vec.y.rounded)
				scene.set_scale (scene.scale / scaling_factor)
				new_scaling_factor := scene.scale
			end

			if new_scaling_factor > 0 then
				-- a new scaling factor was set, update image_scaled
				from scene.image_panes.start
				until scene.image_panes.off
				loop
					scene.image_panes.item_for_iteration.generate_image_scaled (new_scaling_factor)
					scene.image_panes.forth
				end
			end
		end

	handle_mouse_button_up_event (event: EM_MOUSEBUTTON_EVENT) is
			-- Handle mouse button up event.
		do
		end

	handle_mouse_motion_event (event: EM_MOUSEMOTION_EVENT) is
			-- Handle mouse motion event.
		do
		end

	handle_key_down_event (event: EM_KEYBOARD_EVENT) is
			-- Handle key down event.
		do
		end

	handle_key_up_event (event: EM_KEYBOARD_EVENT) is
			-- Handle key up event.
		do
		end

feature {NONE} -- Implementation

	scaling_factor: DOUBLE is 1.5
			-- factor by which the scene is scaled for each click

	min_scale: DOUBLE is 0.01
			-- minimal scale factor

	max_scale: DOUBLE is 10.0
			-- maximal scale factor

end