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,
	make_with_index

feature -- Access

	size: INTEGER_32
			-- The font height.

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

	is_openable: BOOLEAN
			-- Can Current be open

	open
			-- Open Current
		ensure then
			exists: not has_error implies exists
			is_open: not has_error implies is_open

	exists: BOOLEAN
			-- Is allocated memory still allocated?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

	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

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

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

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

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

	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

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

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

	disable_hinting
			-- Disable the draw hinting of Current
		require
				exists

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

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

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

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

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

	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

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

	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

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

	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

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

	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

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

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

	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

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

	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)

	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
	
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.
	
invariant
	is_open_exists: is_open implies exists

end -- class TEXT_FONT

Generated by ISE EiffelStudio