Simple class holding red, green, blue, and alpha values. Each should be a value in [0,1].
More...
#include <creativity/data/graph/style.hpp>
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| constexpr | RGBA (const double &r, const double &g, const double &b, const double &a=1.0) |
| | Creates a RGBA colour object with a red, green, blue, and (optional) alpha value. More...
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| constexpr | RGBA (const double &i, const double &a=1.0) |
| | Creates a RGBA object with a gray value and optional alpha value. More...
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RGBA & | operator= (const RGBA ©) |
| | Copy assignment operator.
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constexpr bool | operator== (const RGBA &other) const |
| | Compares two RGBA objects: they are considered equal if all components are equal.
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constexpr bool | operator!= (const RGBA &other) const |
| | Negation of ==.
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| constexpr bool | equalsRGB (const RGBA &other) const |
| | Returns true if the red, green, and blue channels are equal. More...
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| constexpr bool | opaque () const |
| | Returns true if the object is opaque, that is, has alpha = 1. More...
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| constexpr bool | transparent () const |
| | Returns true if the object is completely transparent, that is, has alpha = 0. More...
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| constexpr | operator bool () const |
| | Using an RGBA object as a bool returns true unless the object is fully transparent. More...
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| RGBA | operator* (const RGBA &other) const |
| | "Multiplies" two RGBA objects together via alpha compositing "over" filter. More...
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| RGBA & | operator*= (const RGBA &other) |
| | Multiplies this colour by another colour. More...
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void | applyTo (Cairo::RefPtr< Cairo::Context > ctx) const |
| | Applies this colour to the given Cairo::Context as the source colour.
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| template<class T , typename = typename std::enable_if< std::is_same<double, decltype(T::get_red())>::value and std::is_same<double, decltype(T::get_green())>::value and std::is_same<double, decltype(T::get_blue())>::value and std::is_same<double, decltype(T::get_alpha())>::value>::type> |
| | RGBA (const T &rgba) |
| | Creates the struct from an object with get_red(), get_green(), get_blue(), and get_alpha() methods. More...
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const double | red |
| | The red channel value.
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const double | green |
| | The green channel value.
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const double | blue |
| | The blue channel value.
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const double | alpha |
| | The alpha channel value (1 == opaque, 0 == transparent)
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std::ostream & | operator<< (std::ostream &os, const RGBA &colour) |
| | Sents this RGBA to an output stream in the form "RGBA(r,g,b,a)" where r, g, b, and a are replaced with their [0,1] values.
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Simple class holding red, green, blue, and alpha values. Each should be a value in [0,1].
§ RGBA() [1/3]
| constexpr creativity::data::graph::RGBA::RGBA |
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const double & |
r, |
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const double & |
g, |
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const double & |
b, |
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const double & |
a = 1.0 |
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inline |
Creates a RGBA colour object with a red, green, blue, and (optional) alpha value.
- Parameters
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| r | the red channel value, from 0 to 1. 0 is off, 1 is full intensity. |
| g | the red channel value, from 0 to 1. 0 is off, 1 is full intensity. |
| b | the red channel value, from 0 to 1. 0 is off, 1 is full intensity. |
| a | the alpha channel value, from 0 to 1. 0 is completely transparent, 1 is completely opaque. If omitted, defaults to 1 (fully opaque). |
- Exceptions
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| std::out_of_range | if any of the given values are outside the [0,1] range. |
§ RGBA() [2/3]
| constexpr creativity::data::graph::RGBA::RGBA |
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const double & |
i, |
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const double & |
a = 1.0 |
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inlineexplicit |
Creates a RGBA object with a gray value and optional alpha value.
The gray intensity is used for the three red, green, and blue values.
- Exceptions
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| std::out_of_range | if any of the given values are outside the [0,1] range. |
§ RGBA() [3/3]
template<class T , typename = typename std::enable_if< std::is_same<double, decltype(T::get_red())>::value and std::is_same<double, decltype(T::get_green())>::value and std::is_same<double, decltype(T::get_blue())>::value and std::is_same<double, decltype(T::get_alpha())>::value>::type>
| creativity::data::graph::RGBA::RGBA |
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const T & |
rgba | ) |
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Creates the struct from an object with get_red(), get_green(), get_blue(), and get_alpha() methods.
In particular, this is designed to be usable with Gdk::RGBA (without actually having to add a dependency on gdkmm).
§ equalsRGB()
| constexpr bool creativity::data::graph::RGBA::equalsRGB |
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const RGBA & |
other | ) |
const |
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Returns true if the red, green, and blue channels are equal.
The alpha values do not have to match.
§ opaque()
| constexpr bool creativity::data::graph::RGBA::opaque |
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const |
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Returns true if the object is opaque, that is, has alpha = 1.
§ operator bool()
| constexpr creativity::data::graph::RGBA::operator bool |
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const |
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Using an RGBA object as a bool returns true unless the object is fully transparent.
In other words, if (color) is equivalent to if (not color.transparent()).
§ operator*()
| RGBA creativity::data::graph::RGBA::operator* |
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const RGBA & |
other | ) |
const |
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inline |
"Multiplies" two RGBA objects together via alpha compositing "over" filter.
The result is the colour that would result if the left hand side argument was painted, then the right-hand-side argument was painted over top. If the RHS argument is opaque or LHS is transparent, the result is simply a copy of the RHS object; if RHS transparent, the result is a copy of the LHS object; otherwise the result is a new, combined color. The final opacity of the object will be between the larger opacity value of the two objects and 1 (i.e. overlaying results in increasing opacity).
§ operator*=()
| RGBA& creativity::data::graph::RGBA::operator*= |
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const RGBA & |
other | ) |
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§ transparent()
| constexpr bool creativity::data::graph::RGBA::transparent |
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const |
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Returns true if the object is completely transparent, that is, has alpha = 0.
The documentation for this class was generated from the following file:
