note
	description: "Eiffel Vision gauge. Cocoa implementation."
	author: "Daniel Furrer"
	date: "$Date$"
	revision: "$Revision$"

deferred class
	EV_GAUGE_IMP

inherit
	EV_GAUGE_I
		redefine
			interface
		end

	EV_PRIMITIVE_IMP
		redefine
			interface,
			make
		end

	EV_GAUGE_ACTION_SEQUENCES_IMP

feature {NONE} -- Initialization

	make
		do
			initialize_gauge_imp
			Precursor {EV_PRIMITIVE_IMP}
		end

	initialize_gauge_imp
		do
			create value_range.make (0, 100)
			set_leap (10)
			set_step (1)
			value_range.change_actions.extend (agent set_range)
			set_range
		end

feature -- Access

	value: INTEGER
			-- Current value of the gauge.

	step: INTEGER
			-- Value by which `value' is increased after `step_forward'.

	leap: INTEGER
			-- Value by which `value' is increased after `leap_forward'.

feature -- Status setting

	step_forward
			-- Increment `value' by `step' if possible.
		do
			set_value (value_range.upper.min (value + step))
		end

	step_backward
			-- Decrement `value' by `step' if possible.
		do
			set_value (value_range.lower.max (value - step))
		end

	leap_forward
			-- Increment `value' by `leap' if possible.
		do
			set_value (value_range.upper.min (value + leap))
		end

	leap_backward
			-- Decrement `value' by `leap' if possible.
		do
			set_value (value_range.lower.max (value - leap))
		end

feature -- Element change

	set_value (a_value: INTEGER)
			-- Set `value' to `a_value'.
		do
			value := a_value
		ensure then
			step_same: step = old step
			leap_same: leap = old leap
			range_same: value_range.is_equal (old value_range)
		end

	set_step (a_step: INTEGER)
			-- Set `step' to `a_step'.
		do
			step := a_step
		ensure then
			value_same: value = old value
			leap_same: leap = old leap
			range_same: value_range.is_equal (old value_range)
		end

	set_leap (a_leap: INTEGER)
			-- Set `leap' to `a_leap'.
		do
			leap := a_leap
		end

	set_range
			-- Update widget range from `value_range'
		local
			temp_value: INTEGER
		do
			temp_value := value
			if temp_value > value_range.upper then
				temp_value := value_range.upper
			elseif temp_value < value_range.lower then
				temp_value := value_range.lower
			end
			set_value ( temp_value )
		end

feature {EV_ANY, EV_ANY_I} -- Implementation

	interface: detachable EV_GAUGE note option: stable attribute end

end -- class EV_GAUGE_I