color_element_type, color_element_reference_type, color_element_const_reference_type, get_color, contains_color

get_color: Named channel accessors More...

Classes
struct	contains_color< ColorBase, Color >
	A predicate metafunction determining whether a given color base contains a given color. More...
struct	color_element_type< ColorBase, Color >
	Specifies the type of the element associated with a given color tag. More...
struct	color_element_reference_type< ColorBase, Color >
	Specifies the return type of the mutable element accessor by color name, get_color(color_base, Color());. More...
struct	color_element_const_reference_type< ColorBase, Color >
	Specifies the return type of the constant element accessor by color name, get_color(color_base, Color());. More...

Functions
template<typename ColorBase , typename Color >
auto	get_color (ColorBase &cb, Color=Color()) -> typename color_element_reference_type< ColorBase, Color >::type
	Mutable accessor to the element associated with a given color name.
template<typename ColorBase , typename Color >
auto	get_color (const ColorBase &cb, Color=Color()) -> typename color_element_const_reference_type< ColorBase, Color >::type
	Constant accessor to the element associated with a given color name.

Detailed Description

get_color: Named channel accessors

Support for accessing the elements of a color base by color name

Example: A function that takes a generic pixel containing a red channel and sets it to 100%:

template <typename Pixel>
void set_red_to_max(Pixel& pixel) {
    boost::function_requires<MutablePixelConcept<Pixel> >();
    static_assert(contains_color<Pixel, red_t>::value, "");
 
    using red_channel_t = typename color_element_type<Pixel, red_t>::type;
    get_color(pixel, red_t()) = channel_traits<red_channel_t>::max_value();
}