donner::css::Color Struct Reference

Represents a CSS color value, like a RGBA color from a #rrggbb or #rgb hex value, or the currentcolor keyword. More...

#include "donner/css/Color.h"

Classes
struct	CurrentColor
	Represents the currentColor keyword. More...

Public Types
using	Type = std::variant<RGBA, CurrentColor, HSLA>
	A variant for supported color types.

Public Member Functions
constexpr	Color (Type value)
	Construct a new color object from a supported color type.
bool	operator== (const Color &other) const
	Equality operator.
bool	isCurrentColor () const
	Returns true if the color is currentcolor.
bool	hasRGBA () const
	Returns true if the color is an RGBA color.
RGBA	rgba () const
	Returns the RGBA color value, if this object stores an RGBA color.
bool	hasHSLA () const
	Returns true if the color is an HSLA color.
HSLA	hsla () const
	Returns the HSLA color value, if this object stores an HSLA color.
RGBA	asRGBA () const
	Returns the color as RGBA.
RGBA	resolve (RGBA currentColor, float opacity) const
	Resolves the current value of this color to RGBA, by using the current rendering state, such as the currentColor and opacity.

Static Public Member Functions
static std::optional< Color >	ByName (std::string_view name)
	Parse a named color, such as red or steelblue.

Public Attributes
Type	value
	The color value.

Friends
std::ostream &	operator<< (std::ostream &os, const Color &color)
	Ostream output operator.

Detailed Description

Represents a CSS color value, like a RGBA color from a #rrggbb or #rgb hex value, or the currentcolor keyword.

Colors are parsed using donner::css::parser::ColorParser.

Note that non-RGB colors, such as HSL are not yet supported, see bug https://github.com/jwmcglynn/donner/issues/6.

Constructor & Destructor Documentation

Color()

constexpr donner::css::Color::Color ( Type value )

inlineconstexpr

Construct a new color object from a supported color type.

For example:

Color(RGBA::RGB(0xFF, 0x00, 0x00));

Parameters

value

The color value.

Member Function Documentation

asRGBA()

RGBA donner::css::Color::asRGBA

(

)

const

Returns the color as RGBA.

Note that isCurrentColor() colors cannot be converted to RGBA and will assert if called.

ByName()

std::optional< Color > donner::css::Color::ByName ( std::string_view name )

static

Parse a named color, such as red or steelblue.

All colors on the CSS named color list are supported, https://www.w3.org/TR/css-color-4/#named-colors, plus two special colors, transparent and currentcolor.

Parameters

name	The color name, such as red or steelblue.

Returns

The parsed color, or std::nullopt if the color could not be parsed.

hsla()

HSLA donner::css::Color::hsla ( ) const

inline

Returns the HSLA color value, if this object stores an HSLA color.

Precondition

hasHSLA() returns true.

resolve()

RGBA donner::css::Color::resolve	(	RGBA	currentColor,
		float	opacity ) const

Resolves the current value of this color to RGBA, by using the current rendering state, such as the currentColor and opacity.

Parameters

currentColor	The current color, used if this color is currentcolor.
opacity	The current opacity, used to multiply the alpha channel.

rgba()

RGBA donner::css::Color::rgba ( ) const

inline

Returns the RGBA color value, if this object stores an RGBA color.

Precondition

hasRGBA() returns true.

Friends And Related Symbol Documentation

operator<<

std::ostream & operator<< ( std::ostream & os, const Color & color )

friend

Ostream output operator.

Example output:

Color(currentColor)

or

Color(rgba(0, 255, 128, 255))

Parameters

os	The output stream.
color	The color to output.

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The documentation for this struct was generated from the following files:

• donner/css/Color.h
• donner/css/Color.cc