This class provides static methods for dealing with colors. More...

#include "gcolor.h"

Public Types
enum	{ BLACK = 0x000000, BLUE = 0x0000FF, BROWN = 0x926239, CYAN = 0x00FFFF, DARKGRAY = 0x595959, GRAY = 0x999999, GREEN = 0x00FF00, LIGHTGRAY = 0xBFBFBF, MAGENTA = 0xFF00FF, ORANGE = 0xFFC800, PINK = 0xFFAFAF, PURPLE = 0xFF00FF, RED = 0xFF0000, WHITE = 0xFFFFFF, YELLOW = 0xFFFF00 }
	Constants representing common system color names. More...

Static Public Member Functions
static int	convertARGBToARGB(int a, int r, int g, int b)
	Converts four integer RGB values from 0-255 into an ARGB integer of the form `0xaarrggbb`. More...

static string	convertARGBToColor(int a, int r, int g, int b)
	Converts four integer RGB values from 0-255 into a color name in the form `"#aarrggbb"`. More...

static string	convertARGBToColor(int argb)
	Converts the given ARGB integer into a color name in the form `"#aarrggbb"`. More...

static int	convertColorToARGB(string colorName)
	Converts a color name into an ARGB integer that encodes the alpha (opacity), red, green, and blue components of the color. More...

static int	convertColorToRGB(string colorName)
	Converts a color name into an integer that encodes the red, green, and blue components of the color. More...

static string	convertQColorToColor(const QColor &color)
	Converts a Qt RGB color object into a color string. More...

static int	convertQColorToRGB(const QColor &color)
	Converts a Qt color object into an RGB integer. More...

static string	convertRGBToColor(int rgb)
	Converts an RGB integer value into a color name in the form `"#rrggbb"`. More...

static string	convertRGBToColor(int r, int g, int b)
	Converts three integer RGB values from 0-255 into a color name in the form `"#rrggbb"`. More...

static int	convertRGBToRGB(int r, int g, int b)
	Converts three integer RGB values from 0-255 into a single RGB integer. More...

static int	fixAlpha(int argb)
	Sets the 'alpha' (high order bits) of the given integer to ff. More...

static double	getLuminance(int rgb)
	Returns the photometric luminance of the given RGB integer, which is a measure of how bright the color is. More...

static double	getLuminance(string color)
	Returns the photometric luminance of the given color, which is a measure of how bright the color is. More...

static bool	hasAlpha(string color)
	Returns true if the given color string is of the 8-hex-character form that contains an alpha channel in the highest order two characters, preceded by a hash sign, such as "#aaff0033". More...

static void	splitARGB(int argb, int &a, int &r, int &g, int &b)
	Splits the given ARGB integer into four integer RGB values from 0-255. More...

static void	splitRGB(int rgb, int &r, int &g, int &b)
	Splits the given RGB integer into three integer RGB values from 0-255. More...

static QColor	toQColor(string color)
	Converts a color string into a Qt color object. More...

static QColor	toQColorARGB(int argb)
	Converts an ARGB integer into a Qt color object. More...

Public Attributes
enum sgl::GColor:: { ... }	Color
	Constants representing common system color names. More...

Detailed Description

This class provides static methods for dealing with colors.

Many graphical interactors and objects accept colors specified as strings or as RGB integers. An RGB integer is an integer with red, green, and blue values from 0-255 packed into its bits as follows:

00000000 00000000 00000000 00000000
   ^        ^        ^        ^
   |        |        |        |
 alpha     red     green     blue

A color can also be specified as a string. A color string can be one of the predefined color names:

BLACK, BLUE, CYAN, DARK_GRAY, GRAY, GREEN, LIGHT_GRAY, MAGENTA, ORANGE, PINK, RED, WHITE, and YELLOW.

The case of the individual letters in the color name is ignored, as are spaces and underscores, so that the color DARK_GRAY can be written as "Dark Gray".

Lastly, the color can also be specified as a string in the form "#rrggbb" where rr, gg, and bb are pairs of hexadecimal digits indicating the red, green, and blue components of the color, respectively. You can also include an alpha (opacity) channel by writing the hex string in ARGB form as "#aarrggbb".

Member Enumeration Documentation

◆ anonymous enum

anonymous enum

Constants representing common system color names.

Enumerator
BLACK
BLUE
BROWN
CYAN
DARKGRAY
GRAY
GREEN
LIGHTGRAY
MAGENTA
ORANGE
PINK
PURPLE
RED
WHITE
YELLOW

Member Function Documentation

◆ convertARGBToARGB()

int convertARGBToARGB	(	int	a,
		int	r,
		int	g,
		int	b
	)

static

Converts four integer RGB values from 0-255 into an ARGB integer of the form 0xaarrggbb.

Each of the aa, rr, gg, and bb values are two-digit hexadecimal numbers indicating the intensity of that component. If any of a, r, g, or b is outside the range of 0-255, throws an error.

◆ convertARGBToColor() [1/2]

string convertARGBToColor	(	int	a,
		int	r,
		int	g,
		int	b
	)

static

Converts four integer RGB values from 0-255 into a color name in the form "#aarrggbb".

Each of the aa, rr, gg, and bb values are two-digit hexadecimal numbers indicating the intensity of that component. If any of a, r, g, or b is outside the range of 0-255, throws an error.

◆ convertARGBToColor() [2/2]

string convertARGBToColor ( int argb )

static

Converts the given ARGB integer into a color name in the form "#aarrggbb".

◆ convertColorToARGB()

int convertColorToARGB ( string colorName )

static

Converts a color name into an ARGB integer that encodes the alpha (opacity), red, green, and blue components of the color.

◆ convertColorToRGB()

int convertColorToRGB ( string colorName )

static

Converts a color name into an integer that encodes the red, green, and blue components of the color.

This function is also compatible with ARGB colors.

◆ convertQColorToColor()

string convertQColorToColor ( const QColor & color )

static

Converts a Qt RGB color object into a color string.

Does not preserve alpha transparency.

◆ convertQColorToRGB()

int convertQColorToRGB ( const QColor & color )

static

Converts a Qt color object into an RGB integer.

Does not preserve alpha transparency.

◆ convertRGBToColor() [1/2]

string convertRGBToColor ( int rgb )

static

Converts an RGB integer value into a color name in the form "#rrggbb".

Does not preserve alpha transparency.

◆ convertRGBToColor() [2/2]

string convertRGBToColor	(	int	r,
		int	g,
		int	b
	)

static

Converts three integer RGB values from 0-255 into a color name in the form "#rrggbb".

Each of the rr, gg, and bb values are two-digit hexadecimal numbers indicating the intensity of that component. If any of r, g, or b is outside the range of 0-255, throws an error.

◆ convertRGBToRGB()

int convertRGBToRGB	(	int	r,
		int	g,
		int	b
	)

static

Converts three integer RGB values from 0-255 into a single RGB integer.

Each of the rr, gg, and bb values are two-digit hexadecimal numbers indicating the intensity of that component. If any of r, g, or b is outside the range of 0-255, throws an error.

◆ fixAlpha()

int fixAlpha ( int argb )

static

Sets the 'alpha' (high order bits) of the given integer to ff.

If RGB is not completely black, but alpha is 0, assumes that the client meant to use an opaque color and add ff as alpha channel.

◆ getLuminance() [1/2]

double getLuminance ( int rgb )

static

Returns the photometric luminance of the given RGB integer, which is a measure of how bright the color is.

This is calculated using the following formula: https://en.wikipedia.org/wiki/Relative_luminance

◆ getLuminance() [2/2]

double getLuminance ( string color )

static

Returns the photometric luminance of the given color, which is a measure of how bright the color is.

This is calculated using the following formula: https://en.wikipedia.org/wiki/Relative_luminance

◆ hasAlpha()

bool hasAlpha ( string color )

static

Returns true if the given color string is of the 8-hex-character form that contains an alpha channel in the highest order two characters, preceded by a hash sign, such as "#aaff0033".

◆ splitARGB()

void splitARGB	(	int	argb,
		int &	a,
		int &	r,
		int &	g,
		int &	b
	)

static

Splits the given ARGB integer into four integer RGB values from 0-255.

Each of the aa, rr, gg, and bb values are two-digit hexadecimal numbers indicating the intensity of that component.

◆ splitRGB()

void splitRGB	(	int	rgb,
		int &	r,
		int &	g,
		int &	b
	)

static

Splits the given RGB integer into three integer RGB values from 0-255.

Each of the rr, gg, and bb values are two-digit hexadecimal numbers indicating the intensity of that component. Ignores alpha transparency.

◆ toQColor()

QColor toQColor ( string color )

static

Converts a color string into a Qt color object.

Preserves alpha transparency if the color string contains an alpha component.

◆ toQColorARGB()

QColor toQColorARGB ( int argb )

static

Converts an ARGB integer into a Qt color object.

Preserves alpha transparency in the QColor object.

Member Data Documentation

◆ Color

enum { ... } Color

Constants representing common system color names.

Public Types

Static Public Member Functions

Public Attributes

Detailed Description

Member Enumeration Documentation

◆ anonymous enum

Member Function Documentation

◆ convertARGBToARGB()

◆ convertARGBToColor() [1/2]

◆ convertARGBToColor() [2/2]

◆ convertColorToARGB()

◆ convertColorToRGB()

◆ convertQColorToColor()

◆ convertQColorToRGB()

◆ convertRGBToColor() [1/2]

◆ convertRGBToColor() [2/2]

◆ convertRGBToRGB()

◆ fixAlpha()

◆ getLuminance() [1/2]

◆ getLuminance() [2/2]

◆ hasAlpha()

◆ splitARGB()

◆ splitRGB()

◆ toQColor()

◆ toQColorARGB()

Member Data Documentation

◆ Color