note
	description: "A font that can be use to draw text with a {TEXT_IMAGE}."
	author: "Louis Marchand"
	date: "Mon, 30 Mar 2015 01:06:37 +0000"
	revision: "2.0"

class interface
	TEXT_FONT

create 
	make (a_filename: READABLE_STRING_GENERAL; a_size: INTEGER_32)
			-- Initialization for Current.
		require
			is_text_enable: Text_library.is_text_enable
			filename_not_empty: not a_filename.is_empty
			size_stricly_positive: a_size > 1

	make_with_index (a_filename: READABLE_STRING_GENERAL; a_size: INTEGER_32; a_index: INTEGER_32)
			-- Initialization for Current.
			-- The index is use if there is more than one font in a ttf file.
		require
			is_text_enable: Text_library.is_text_enable
			filename_not_empty: not a_filename.is_empty
			size_stricly_positive: a_size > 1
			index_positive: a_index >= 0

feature -- Access

	ascent: INTEGER_32
			-- distance from the top of the drawing area to the baseline in pixel.
		require
				exists

	descent: INTEGER_32
			-- distance from the baseline to the bottom of the drawing area in pixel.
		require
				exists

	disable_bold
			-- remove a bold style modifier to Current
		require
				exists
		ensure
			is_disabled: not is_bold

	disable_hinting
			-- Disable the draw hinting of Current
		require
				exists

	disable_italic
			-- remove an italic style modifier to Current
		require
				exists
		ensure
			is_disabled: not is_italic

	disable_kerning
			-- Does not allow the library to use kerning when drawing a text with Current
		require
				exists
		ensure
			is_disabled: not is_kerning_enabled

	disable_outline
			-- Disable the outline size in Current
		require
				exists
		ensure
			is_disabled: not has_outline

	disable_strike_through
			-- remove a strike through style modifier to Current
		require
				exists
		ensure
			is_disabled: not is_strike_through

	disable_style_modifier
			-- Disable all style modifier (underline, bold, italic and strike through)
		require
				exists

	disable_underline
			-- remove an underline style modifier to Current
		require
				exists
		ensure
			is_disabled: not is_underline

	enable_bold
			-- Add a bold style modifier to Current
		require
				exists
		ensure
			is_enabled: is_bold

	enable_italic
			-- Add an italic style modifier to Current
		require
				exists
		ensure
			is_enabled: is_italic

	enable_kerning
			-- Allow the library to use kerning when drawing a text with Current
		require
				exists
		ensure
			is_enabled: is_kerning_enabled

	enable_light_hinting
			-- Use the light hinting to draw Current
		require
				exists
		ensure
			is_enable: has_light_hinting

	enable_monochrome_hinting
			-- Use the monochrome hinting to draw Current.
			-- Must only be use with monochrome display
		require
				exists
		ensure
			is_enable: has_monochrome_hinting

	enable_normal_hinting
			-- Use the normal hinting to draw Current
		require
				exists
		ensure
			is_enable: has_normal_hinting

	enable_strike_through
			-- Add a strike through style modifier to Current
		require
				exists
		ensure
			is_enabled: is_strike_through

	enable_underline
			-- Add an underline style modifier to Current
		require
				exists
		ensure
			is_enabled: is_underline

	exists: BOOLEAN
			-- Is allocated memory still allocated?

	face_family_name: READABLE_STRING_GENERAL
			-- The name of the face family of Curent
		require
				exists

	face_style_name: READABLE_STRING_GENERAL
			-- The name of the face style of Curent
		require
				exists

	generating_type: TYPE [detachable TEXT_FONT]
			-- Type of current object
			-- (type of which it is a direct instance)
			-- (from ANY)
		ensure -- from ANY
			generating_type_not_void: Result /= Void

	generator: STRING_8
			-- Name of current object's generating class
			-- (base class of the type of which it is a direct instance)
			-- (from ANY)
		ensure -- from ANY
			generator_not_void: Result /= Void
			generator_not_empty: not Result.is_empty

	glyph_metrics (a_character: CHARACTER_32): TUPLE [minimal_x: INTEGER_32; maximal_x: INTEGER_32; minimal_y: INTEGER_32; maximal_y: INTEGER_32; advance: INTEGER_32]
			-- The informations about the glyph representing a_character generated with Current.
			-- Set has_error on error.
		require
				exists
			is_character_valid: is_glyph_provided (a_character)

	has_error: BOOLEAN
			-- Is the library has generate an error
			-- (from GAME_ERROR_MANAGER)

	has_ressource_error: BOOLEAN
			-- Has an error occured while opening Current
			-- (from GAME_RESSOURCE)

	has_hinting: BOOLEAN
			-- Has the library a hint about how to draw Current
		require
				exists

	has_light_hinting: BOOLEAN
			-- The library has the light hinting to draw Current
		require
				exists

	has_monochrome_hinting: BOOLEAN
			-- The library has the monochrome hinting to draw Current.
		require
				exists

	has_normal_hinting: BOOLEAN
			-- The library has the normal hinting to draw `Current
		require
				exists

	has_outline: BOOLEAN
			-- Is Current has an outline size.
		require
				exists

	has_style_modifier: BOOLEAN
			-- Is Current has a style modifier (underline, bold, italic or strike through)
		require
				exists

	index: INTEGER_32
			-- The index of the font in the file.

	is_bold: BOOLEAN assign set_is_bold
			-- Is Current has a bold style modifier
		require
				exists

	is_glyph_provided (a_character: CHARACTER_32): BOOLEAN
			-- Is Current can draw a glyph representing a_character
		require
				exists

	is_italic: BOOLEAN assign set_is_italic
			-- Is Current has an italic style modifier
		require
				exists

	is_kerning_enabled: BOOLEAN assign set_is_kerning_enabled
			-- If True, the library can use kerning when drawing a text with Current
		require
				exists

	is_monospace: BOOLEAN
			-- True if every character that exists in Current is the same width
		require
				exists

	is_open: BOOLEAN
			-- Is Current has been properly opened
			-- (from GAME_RESSOURCE)

	is_openable: BOOLEAN
			-- Can Current be open

	is_strike_through: BOOLEAN assign set_is_strike_through
			-- Is Current has a strike through style modifier
		require
				exists

	is_underline: BOOLEAN assign set_is_underline
			-- Is Current has an underline style modifier
		require
				exists

	last_error: READABLE_STRING_GENERAL
			-- The last error generate by the library
			-- (from GAME_SDL_ANY)

	line_skip_height: INTEGER_32
			-- the recommended pixel height of a rendered line of text using Current
		require
				exists

	maximum_height: INTEGER_32
			-- The maximum height that a gliph can take in pixel using Current
		require
				exists

	open
			-- Open Current
		require -- from GAME_RESSOURCE
			ressource_is_openable: is_openable
			ressource_is_not_open: not is_open and not has_ressource_error
		ensure -- from GAME_RESSOURCE
			ressource_is_open: is_open or has_ressource_error
		ensure then
			exists: not has_error implies exists
			is_open: not has_error implies is_open

	outline_size: INTEGER_32 assign set_outline_size
			-- The ouline width of Current (0 for disabled)
		require
				exists

	set_is_bold (a_value: BOOLEAN)
			-- Assign to is_bold the value of a_value
		ensure
			is_assign: is_bold ~ a_value

	set_is_italic (a_value: BOOLEAN)
			-- Assign to is_italic the value of a_value
		ensure
			is_assign: is_italic ~ a_value

	set_is_kerning_enabled (a_value: BOOLEAN)
			-- Assign to is_kerning_enabled the value of a_value
		ensure
			is_assign: is_kerning_enabled ~ a_value

	set_is_strike_through (a_value: BOOLEAN)
			-- Assign to is_strike_through the value of a_value
		ensure
			is_assign: is_strike_through ~ a_value

	set_is_underline (a_value: BOOLEAN)
			-- Assign to is_underline the value of a_value
		ensure
			is_assign: is_underline ~ a_value

	set_outline_size (a_outline_size: INTEGER_32)
			-- Assign outline_size with the value of outline_size
		require
			exists: exists
			outline_size_valid: a_outline_size >= 0
		ensure
			is_assign: outline_size = a_outline_size

	size: INTEGER_32
			-- The font height.

	text_dimension (a_text: READABLE_STRING_GENERAL): TUPLE [width: INTEGER_32; height: INTEGER_32]
			-- The dimension of the a_text drawed with Current
		require
				exists

	Text_library: TEXT_CONTROLLER
			-- The main manager of the text library
			-- (from TEXT_LIBRARY_SHARED)
	
feature -- Comparison

	frozen deep_equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void
			-- or attached to isomorphic object structures?
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			shallow_implies_deep: standard_equal (a, b) implies Result
			both_or_none_void: (a = Void) implies (Result = (b = Void))
			same_type: (Result and (a /= Void)) implies (b /= Void and then a.same_type (b))
			symmetric: Result implies deep_equal (b, a)

	frozen equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void or attached
			-- to objects considered equal?
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.is_equal (b))

	frozen is_deep_equal alias "≡≡≡" (other: TEXT_FONT): BOOLEAN
			-- Are Current and other attached to isomorphic object structures?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			shallow_implies_deep: standard_is_equal (other) implies Result
			same_type: Result implies same_type (other)
			symmetric: Result implies other.is_deep_equal (Current)

	is_equal (other: TEXT_FONT): BOOLEAN
			-- Is other attached to an object considered
			-- equal to current object?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			symmetric: Result implies other ~ Current
			consistent: standard_is_equal (other) implies Result

	frozen standard_equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void or attached to
			-- field-by-field identical objects of the same type?
			-- Always uses default object comparison criterion.
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.standard_is_equal (b))

	frozen standard_is_equal alias "" (other: TEXT_FONT): BOOLEAN
			-- Is other attached to an object of the same type
			-- as current object, and field-by-field identical to it?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			same_type: Result implies same_type (other)
			symmetric: Result implies other.standard_is_equal (Current)
	
feature -- Status report

	conforms_to (other: ANY): BOOLEAN
			-- Does type of current object conform to type
			-- of other (as per Eiffel: The Language, chapter 13)?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void

	same_type (other: ANY): BOOLEAN
			-- Is type of current object identical to type of other?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			definition: Result = (conforms_to (other) and other.conforms_to (Current))
	
feature -- Duplication

	copy (other: TEXT_FONT)
			-- Update current object using fields of object attached
			-- to other, so as to yield equal objects.
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		ensure -- from ANY
			is_equal: Current ~ other

	frozen deep_copy (other: TEXT_FONT)
			-- Effect equivalent to that of:
			--		copy (other . deep_twin)
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			deep_equal: deep_equal (Current, other)

	frozen deep_twin: TEXT_FONT
			-- New object structure recursively duplicated from Current.
			-- (from ANY)
		ensure -- from ANY
			deep_twin_not_void: Result /= Void
			deep_equal: deep_equal (Current, Result)

	frozen standard_copy (other: TEXT_FONT)
			-- Copy every field of other onto corresponding field
			-- of current object.
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		ensure -- from ANY
			is_standard_equal: standard_is_equal (other)

	frozen standard_twin: TEXT_FONT
			-- New object field-by-field identical to other.
			-- Always uses default copying semantics.
			-- (from ANY)
		ensure -- from ANY
			standard_twin_not_void: Result /= Void
			equal: standard_equal (Result, Current)

	frozen twin: TEXT_FONT
			-- New object equal to Current
			-- twin calls copy; to change copying/twinning semantics, redefine copy.
			-- (from ANY)
		ensure -- from ANY
			twin_not_void: Result /= Void
			is_equal: Result ~ Current
	
feature -- Basic operations

	frozen default: detachable TEXT_FONT
			-- Default value of object's type
			-- (from ANY)

	frozen default_pointer: POINTER
			-- Default value of type POINTER
			-- (Avoid the need to write p.default for
			-- some p of type POINTER.)
			-- (from ANY)
		ensure -- from ANY
			instance_free: class

	default_rescue
			-- Process exception for routines with no Rescue clause.
			-- (Default: do nothing.)
			-- (from ANY)

	frozen do_nothing
			-- Execute a null action.
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
	
feature -- Implementation

	dispose
			-- Action to be executed just before garbage collection
			-- reclaims an object.
			-- Effect it in descendants to perform specific dispose
			-- actions. Those actions should only take care of freeing
			-- external resources; they should not perform remote calls
			-- on other objects since these may also be dead and reclaimed.
	
feature -- Output

	Io: STD_FILES
			-- Handle to standard file setup
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			io_not_void: Result /= Void

	out: STRING_8
			-- New string containing terse printable representation
			-- of current object
			-- (from ANY)
		ensure -- from ANY
			out_not_void: Result /= Void

	print (o: detachable ANY)
			-- Write terse external representation of o
			-- on standard output.
			-- (from ANY)
		ensure -- from ANY
			instance_free: class

	frozen tagged_out: STRING_8
			-- New string containing terse printable representation
			-- of current object
			-- (from ANY)
		ensure -- from ANY
			tagged_out_not_void: Result /= Void
	
feature -- Platform

	Operating_environment: OPERATING_ENVIRONMENT
			-- Objects available from the operating system
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			operating_environment_not_void: Result /= Void
	
invariant
	is_open_exists: is_open implies exists

		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)

end -- class TEXT_FONT

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