TRgb Class Reference

class TRgb

24-bit RGB colour value with 8 bits each for red, green and blue.

All Graphics drawing functions are specified in terms of a 32-bit TRgb colour containing the three colour values plus 8 bits for alpha channel. For hardware which does not support 24-bit colour, a mapping from TRgb to display colours is performed.

Generally, the convention for the alpha blending fact is 0 = transparent, 255 = opaque, unless otherwise stated. The exception to this are the TRgb constructor taking a single value, where the top byte of the passed in parameter is used for alpha information and the function Value(), which returns alpha information in the top byte. In both these cases, 0 means opaque, 255 means transparent.

The supported display modes are enumerated in the TDisplayMode type. In each display mode a unique index can represent each physical colours supported, and which can be mapped onto a full RGB value. The mappings are as follows:

16-colour displays use the EGA colour set: black, white, and then both light and dark versions of grey, red, green, blue, cyan, magenta and yellow

256-colour displays support 216 colours made up of 6x6x6 RGB values, each containing all possible multiples of 51 for R,G,B values. Additionally, all remaining 10 shades of pure red, green, blue and grey are represented, by adding all remaining multiples of 17. This use of 256 colours is sometimes known as the Netscape colour cube.

4096-colour displays effectively support RGB values with 4 bits per primary colour

64k-colour displays effectively support RGB values with 5 bits allocated to red, 6 to green and 5 to blue

16 million-colour displays support true colour with 8 bits allocated to each primary colour

TDisplayMode

DynamicPalette

Public Member Functions
TRgb()
TRgb(TUint32)
TRgb(TUint32, TInt)
TRgb(TInt, TInt, TInt)
TRgb(TInt, TInt, TInt, TInt)
TInt Alpha()
TInt Blue()
IMPORT_C TRgbColor16(TInt)
IMPORT_C TIntColor16()
IMPORT_C TRgbColor16M(TInt)
IMPORT_C TIntColor16M()
IMPORT_C TRgbColor16MA(TUint)
IMPORT_C TUintColor16MA()
IMPORT_C TRgbColor16MAP(TUint)
IMPORT_C TUintColor16MAP()
IMPORT_C TRgbColor16MU(TInt)
IMPORT_C TIntColor16MU()
IMPORT_C TRgbColor256(TInt)
IMPORT_C TIntColor256()
IMPORT_C TRgbColor4K(TInt)
IMPORT_C TIntColor4K()
IMPORT_C TRgbColor64K(TInt)
IMPORT_C TIntColor64K()
IMPORT_C TIntDifference(const TRgb &)
IMPORT_C voidExternalizeL(RWriteStream &)
IMPORT_C TRgbGray16(TInt)
IMPORT_C TIntGray16()
IMPORT_C TRgbGray2(TInt)
IMPORT_C TIntGray2()
IMPORT_C TRgbGray256(TInt)
IMPORT_C TIntGray256()
IMPORT_C TRgbGray4(TInt)
IMPORT_C TIntGray4()
TInt Green()
TUint32 Internal()
IMPORT_C voidInternalizeL(RReadStream &)
TInt Red()
IMPORT_C voidSetAlpha(TInt)
IMPORT_C voidSetBlue(TInt)
IMPORT_C voidSetGreen(TInt)
voidSetInternal(TUint32)
IMPORT_C voidSetRed(TInt)
TUint32 Value()
TInt _Color16M()
TRgb _Color16M(TInt)
TUint _Color16MA()
TRgb _Color16MA(TUint)
IMPORT_C TUint_Color16MAP()
IMPORT_C TRgb_Color16MAP(TUint)
TInt _Color16MU()
TRgb _Color16MU(TInt)
TInt _Color4K()
TRgb _Color4K(TInt)
TInt _Color64K()
TRgb _Color64K(TInt)
TInt _Gray16()
TRgb _Gray16(TInt)
TInt _Gray2()
TRgb _Gray2(TInt)
TInt _Gray256()
TRgb _Gray256(TInt)
TInt _Gray4()
TRgb _Gray4(TInt)
TBool operator!=(const TRgb &)
TRgb operator&(const TRgb &)
TRgb &operator&=(const TRgb &)
TBool operator==(const TRgb &)
TRgb operator^(const TRgb &)
TRgb &operator^=(const TRgb &)
TRgb operator|(const TRgb &)
TRgb &operator|=(const TRgb &)
TRgb operator~()
Private Attributes
TUint32 iValue

Constructor & Destructor Documentation

TRgb()

TRgb()[inline]

Constructs a TRgb initialised to KRgbWhite.

TRgb(TUint32)

TRgb(TUint32aValue)[inline]

Constructs a TRgb directly from a single 32-bit integer.

The integer is of the form 0xaabbggrr, where bb is the hex number for blue, gg is the hex number for green, rr is the hex number for red, and aa is the hex number for "transparency" alpha (0 means opaque, 255 means transparent).

This constructor is deprecated. The byte order of Red ,Green and Blue does not match other constructors and methods in this class, and the meaning of alpha is reversed compared to current convention.

For example, TRgb(0x00080402) using this constructor can be replaced with the 3 colour constructor TRgb(2,4,8). The equivalent explicit alpha constructors are TRgb(0x020408,0xff) and TRgb(2,4,8,255). The equivalent call to SetInternal is SetInternal(0xff020408).

This constructor is deprecated. Use other constructors or SetInternal() instead.

Parameters

TUint32 aValueInteger representing colour value. Takes form 0x00bbggrr.

TRgb(TUint32, TInt)

TRgb(TUint32aInternalValue,
TIntaAlpha
)[inline]

Constructs a TRgb from a 32-bit integer (which corresponds to a colour) and from an alpha value.

The first parameter is of the form 0x00rrggbb, where rr is the hex number for red, gg is the hex number for green, and bb is the hex number for blue.

The second parameter corresponds to an alpha channel (0 means transparent, 255 means opaque).

For example, TRgb(2,4,8,255) using the 3 colour+alpha constructor is equal to TRgb(0x00020408, 255) using this constructor.

This constructor, which implements alpha in the conventional way, replaces TRgb( TUint32 aValue ) which is deprecated.

Parameters

TUint32 aInternalValueInteger representing a colour value, which takes the form 0x00rrggbb.
TInt aAlphaAlpha component of the colour (0 - 255).

TRgb(TInt, TInt, TInt)

TRgb(TIntaRed,
TIntaGreen,
TIntaBlue
)[inline]

Constructs a TRgb from its three component colours.

Each colour has a value between 0 and 255. The alpha component is always set to opaque (255)

Parameters

TInt aRedRed component of the colour (0 - 255).
TInt aGreenGreen component of the colour (0 - 255).
TInt aBlueBlue component of the colour (0 - 255).

TRgb(TInt, TInt, TInt, TInt)

TRgb(TIntaRed,
TIntaGreen,
TIntaBlue,
TIntaAlpha
)[inline]

Constructs a TRgb from its three colour components and alpha component.

Each component has a value between 0 and 255. The fourth parameter corresponds to an alpha channel (0 means transparent, 255 means opaque).

This constructor, which implements alpha in the conventional way, replaces TRgb( TUint32 aValue ) which is deprecated.

Parameters

TInt aRedRed component of the colour (0 - 255).
TInt aGreenGreen component of the colour (0 - 255).
TInt aBlueBlue component of the colour (0 - 255).
TInt aAlphaAlpha component of the colour (0 - 255).

Member Functions Documentation

Alpha()

TInt Alpha()const [inline]

Gets the alpha component. The alpha component (0 - 255).

Blue()

TInt Blue()const [inline]

Gets the blue component.

The blue component (0 - 255).

Color16(TInt)

IMPORT_C TRgbColor16(TIntaColor16)[static]

Parameters

TInt aColor16

Color16()

IMPORT_C TIntColor16()const

Color16M(TInt)

IMPORT_C TRgbColor16M(TIntaColor16M)[static]

Parameters

TInt aColor16M

Color16M()

IMPORT_C TIntColor16M()const

Color16MA(TUint)

IMPORT_C TRgbColor16MA(TUintaARGB)[static]

Parameters

TUint aARGB

Color16MA()

IMPORT_C TUintColor16MA()const

Color16MAP(TUint)

IMPORT_C TRgbColor16MAP(TUintaARGB)[static]

Parameters

TUint aARGB

Color16MAP()

IMPORT_C TUintColor16MAP()const

Color16MU(TInt)

IMPORT_C TRgbColor16MU(TInta0RGB)[static]

Parameters

TInt a0RGB

Color16MU()

IMPORT_C TIntColor16MU()const

Color256(TInt)

IMPORT_C TRgbColor256(TIntaColor256)[static]

Parameters

TInt aColor256

Color256()

IMPORT_C TIntColor256()const

Color4K(TInt)

IMPORT_C TRgbColor4K(TIntaColor4K)[static]

Parameters

TInt aColor4K

Color4K()

IMPORT_C TIntColor4K()const

Color64K(TInt)

IMPORT_C TRgbColor64K(TIntaColor64K)[static]

Parameters

TInt aColor64K

Color64K()

IMPORT_C TIntColor64K()const

Difference(const TRgb &)

IMPORT_C TIntDifference(const TRgb &aColor)const

Parameters

const TRgb & aColor

ExternalizeL(RWriteStream &)

IMPORT_C voidExternalizeL(RWriteStream &aStream)const

Parameters

RWriteStream & aStream

Gray16(TInt)

IMPORT_C TRgbGray16(TIntaGray16)[static]

Parameters

TInt aGray16

Gray16()

IMPORT_C TIntGray16()const

Gray2(TInt)

IMPORT_C TRgbGray2(TIntaGray2)[static]

Parameters

TInt aGray2

Gray2()

IMPORT_C TIntGray2()const

Gray256(TInt)

IMPORT_C TRgbGray256(TIntaGray256)[static]

Parameters

TInt aGray256

Gray256()

IMPORT_C TIntGray256()const

Gray4(TInt)

IMPORT_C TRgbGray4(TIntaGray4)[static]

Parameters

TInt aGray4

Gray4()

IMPORT_C TIntGray4()const

Green()

TInt Green()const [inline]

Gets the green component.

The green component (0 - 255).

Internal()

TUint32 Internal()const [inline]

Gets the 32-bit value of the TRgb as an integer.

The 32 bit value of the TRgb. Has the form 0xaarrggbb.

InternalizeL(RReadStream &)

IMPORT_C voidInternalizeL(RReadStream &aStream)

Parameters

RReadStream & aStream

Red()

TInt Red()const [inline]

Gets the red component.

The red component (0 - 255).

SetAlpha(TInt)

IMPORT_C voidSetAlpha(TIntaAlpha)

Parameters

TInt aAlpha

SetBlue(TInt)

IMPORT_C voidSetBlue(TIntaBlue)

Parameters

TInt aBlue

SetGreen(TInt)

IMPORT_C voidSetGreen(TIntaGreen)

Parameters

TInt aGreen

SetInternal(TUint32)

voidSetInternal(TUint32aInternal)[inline]

Sets the 32-bit value of the TRgb as a 32-bit integer.

Parameters

TUint32 aInternalColour internal representation. Has the form 0xaarrggbb.

SetRed(TInt)

IMPORT_C voidSetRed(TIntaRed)

Parameters

TInt aRed

Value()

TUint32 Value()const [inline]

Gets the 32-bit value of the TRgb as an integer. This function is deprecated. Use Internal() instead. Note: the order of Red, Green and Blue components returned by this method is reversed compared to all other methods. The alpha value is also reversed in meaning compared to current convention, such that 0 represents opaque and 0xff represents transparent.

The 32 bit value of the TRgb. Has the form 0xaabbggrr, where bb is the hex number for blue, gg is the hex number for green, rr is the hex number for red, and aa is the hex number for "transparency" alpha (0 means opaque, 255 means transparent).

_Color16M()

TInt _Color16M()const [inline]

Gets the index of the closest TRgb value to this, based on the matching display mode.

The index (0 - 16777215) representing the nearest TRgb.

_Color16M(TInt)

TRgb _Color16M(TIntaColor16M)[static, inline]

Gets TRgb from 16M colour index.

The function takes a 24 bit index into a colour palette and returns the TRgb whose red, green and blue values represent it exactly.

The TRgb which represents the index exactly.

Parameters

TInt aColor16M24 bit index into a colour palette

_Color16MA()

TUint _Color16MA()const [inline]

Gets the index of the closest TRgb value to this, based on the matching display mode. The index (0 - 16777215) representing the nearest TRgb.

_Color16MA(TUint)

TRgb _Color16MA(TUintaARGB)[static, inline]

Gets TRgb from 16MA colour index. The function takes a 32 bit colour value with eight bits for each component, blue in the low byte, and returns the TRgb whose red, green, blue and alpha values represent it exactly. The TRgb which represents the index exactly.

Parameters

TUint aARGBThe color - A, R, G, B bytes. / BGR0 - little endian format /

_Color16MAP()

IMPORT_C TUint_Color16MAP()const

_Color16MAP(TUint)

IMPORT_C TRgb_Color16MAP(TUintaARGB)[static]

Parameters

TUint aARGB

_Color16MU()

TInt _Color16MU()const [inline]

Gets the index of the closest TRgb value to this, based on the matching display mode. The index (0 - 16777215) representing the nearest TRgb.

_Color16MU(TInt)

TRgb _Color16MU(TInta0RGB)[static, inline]

Gets TRgb from 16MU colour index. The function takes a 24 bit colour value with eight bits for each component, blue in the low byte, and returns the TRgb whose red, green and blue values represent it exactly. The TRgb which represents the index exactly.

Parameters

TInt a0RGBThe color - 0, R, G, B bytes. / BGR0 - little endian format /

_Color4K()

TInt _Color4K()const [inline]

Gets the index of the closest TRgb value to this, based on the matching display mode.

The index (0 - 4095) representing the nearest TRgb.

_Color4K(TInt)

TRgb _Color4K(TIntaColor4K)[static, inline]

Gets TRgb from 4K colour index.

The function takes a 12 bit index into a colour palette and returns a TRgb whose red, green and blue values are set to an appropriate level.

Equivalent 24 bit colour.

Parameters

TInt aColor4K12 bit index into a colour palette

_Color64K()

TInt _Color64K()const [inline]

Gets the index of the closest TRgb value to this, based on the matching display mode.

The index (0 - 65535) representing the nearest TRgb.

_Color64K(TInt)

TRgb _Color64K(TIntaColor64K)[static, inline]

Gets TRgb from 64K colour index.

The function takes a 16 bit index into a colour palette and returns a TRgb whose red, green and blue values are set to an appropriate level.

Equivalent 24 bit colour.

Parameters

TInt aColor64K16 bit index into a colour palette

_Gray16()

TInt _Gray16()const [inline]

Gets the index of the closest TRgb value to this, based on the matching display mode.

The index (0 - 15) representing the nearest TRgb.

_Gray16(TInt)

TRgb _Gray16(TIntaGray16)[static, inline]

Gets TRgb from 16 level grayscale.

The function takes a grayscale argument and return a TRgb whose red, green and blue values are set to an appropriate level.

Equivalent 24 bit colour. Gray16 has 16 levels - the function returns r=g=b=17*c, where c=0, 1, ... 15.

Parameters

TInt aGray16Grayscale value to be converted.

_Gray2()

TInt _Gray2()const [inline]

Gets the index of the closest TRgb value to this, based on the matching display mode.

The index (0 - 1) representing the nearest TRgb.

_Gray2(TInt)

TRgb _Gray2(TIntaGray2)[static, inline]

Gets TRgb from 2 level grayscale.

The function takes a grayscale argument and return a TRgb whose red, green and blue values are set to an appropriate level.

Equivalent 24 bit colour. Gray2 has only 2 levels (black and white), the function returns r=g=b=0 or r=g=b=255.

Parameters

TInt aGray2Grayscale value to be converted.

_Gray256()

TInt _Gray256()const [inline]

Gets the index of the closest TRgb value to this, based on the matching display mode.

The index (0 - 255) representing the nearest TRgb.

_Gray256(TInt)

TRgb _Gray256(TIntaGray256)[static, inline]

Gets TRgb from 256 level grayscale.

The function takes a grayscale argument and return a TRgb whose red, green and blue values are set to an appropriate level.

Equivalent 24 bit colour. Gray256 has 256 levels- the function returns r=g=b=c, where c=0, 1, ... 255.

Parameters

TInt aGray256Grayscale value to be converted.

_Gray4()

TInt _Gray4()const [inline]

Gets the index of the closest TRgb value to this, based on the matching display mode.

The index (0 - 3) representing the nearest TRgb.

_Gray4(TInt)

TRgb _Gray4(TIntaGray4)[static, inline]

Gets TRgb from 4 level grayscale.

The function takes a grayscale argument and return a TRgb whose red, green and blue values are set to an appropriate level.

Equivalent 24 bit colour. Gray4 has 4 levels- the function returns r=g=b=85*c, where c=0,1,2, or 3.

Parameters

TInt aGray4Grayscale value to be converted.

operator!=(const TRgb &)

TBool operator!=(const TRgb &aColor)const [inline]

Compares this colour with the specified colour for inequality.

Two colours are unequal if one at least one of their red, green and blue components are unequal.

ETrue, if the colours are not equal; EFalse, otherwise.

Parameters

const TRgb & aColorColour to be compared.

operator&(const TRgb &)

TRgb operator&(const TRgb &aColor)[inline]

Bitwise logical AND operator.

Contains results of logical AND.

Parameters

const TRgb & aColorColour to be compared.

operator&=(const TRgb &)

TRgb &operator&=(const TRgb &aColor)[inline]

Logical AND assignment operator.

The operator ANDs the first operand with the second and then assigns the result back to the first operand.

Note:

This operates in the TRgb domain. Graphics defines logical operations for drawing primitives which operate in the device colour domain.

First operand-contains result of logical AND.

Parameters

const TRgb & aColorColour to be compared.

operator==(const TRgb &)

TBool operator==(const TRgb &aColor)const [inline]

Compares this colour with the specified colour for equality.

For two colours to be equal, their red, green and blue components must all be equal.

ETrue. if the colours are equal; EFalse, otherwise.

Parameters

const TRgb & aColorColour to be compared.

operator^(const TRgb &)

TRgb operator^(const TRgb &aColor)[inline]

Bitwise EXCLUSIVE OR operator

Contains results of logical EXCLUSIVE OR.

Parameters

const TRgb & aColorColour to be compared.

operator^=(const TRgb &)

TRgb &operator^=(const TRgb &aColor)[inline]

Logical EXCLUSIVE OR assignment operator.

The operator Exclusive ORs the first operand with the second and then assigns the result back to the first operand.

Note:

This operates in the TRgb domain. Graphics defines logical operations for drawing primitives which operate in the device colour domain.

First operand contains result of logical Exclusive OR.

Parameters

const TRgb & aColorColour to be compared.

operator|(const TRgb &)

TRgb operator|(const TRgb &aColor)[inline]

Bitwise logical OR operator.

Contains results of logical OR.

Parameters

const TRgb & aColorColour to be compared.

operator|=(const TRgb &)

TRgb &operator|=(const TRgb &aColor)[inline]

Logical OR assignment operator.

The operator ORs the first operand with the second and then assigns the result back to the first operand.

Note:

This operates in the TRgb domain. Graphics defines logical operations for drawing primitives which operate in the device colour domain.

First operand- contains result of logical OR.

Parameters

const TRgb & aColorColour to be compared.

operator~()

TRgb operator~()const [inline]

Bitwise logical inversion operator.

Contains results of logical inversion.

Member Data Documentation

TUint32 iValue

TUint32 iValue[private]