Class TRgb

class TRgb;

Description

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

Members

Defined in TRgb:
Alpha(), Blue(), Color16(), Color16(), Color16M(), Color16M(), Color16MA(), Color16MA(), Color16MAP(), Color16MAP(), Color16MU(), Color16MU(), Color256(), Color256(), Color4K(), Color4K(), Color64K(), Color64K(), Difference(), ExternalizeL(), Gray16(), Gray16(), Gray2(), Gray2(), Gray256(), Gray256(), Gray4(), Gray4(), Green(), Internal(), InternalizeL(), Red(), SetAlpha(), SetBlue(), SetGreen(), SetInternal(), SetRed(), TRgb(), TRgb(), TRgb(), TRgb(), TRgb(), Value(), _Color16M(), _Color16M(), _Color16MA(), _Color16MA(), _Color16MAP(), _Color16MAP(), _Color16MU(), _Color16MU(), _Color4K(), _Color4K(), _Color64K(), _Color64K(), _Gray16(), _Gray16(), _Gray2(), _Gray2(), _Gray256(), _Gray256(), _Gray4(), _Gray4(), operator &(), operator &=(), operator!=(), operator==(), operator^(), operator^=(), operator|(), operator|=(), operator~()

See also:

• TDisplayMode
• DynamicPalette

inline TRgb();

Description

Constructs a TRgb initialised to KRgbWhite.

inline TRgb(TUint32 aValue);

Description

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

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

For example, TRgb(2,4,8) using the 3 colour constructor is equal to TRgb(0x00080402) using this constructor.

The constructor is deprecated. Use others constructor or SetInternal() instead.

Parameters

TUint32 aValue Integer representing colour value. Takes form 0x00bbggrr.

inline TRgb(TUint32 aInternalValue, TInt aAlpha);

Description

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 of 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 constructor is equal to TRgb(0x00020408, 255) using this constructor.

The constructor is a replacement for TRgb(TUint32 aValue).

Parameters

TUint32 aInternalValue Integer representing a colour value, which takes the form 0x00rrggbb. TInt aAlpha Alpha component of the colour (0 - 255).

inline TRgb(TInt aRed, TInt aGreen, TInt aBlue);

Description

Constructs a TRgb from its three component colours.

Each colour has a value between 0 and 255.

Parameters

TInt aRed Red component of the colour (0 - 255). TInt aGreen Green component of the colour (0 - 255). TInt aBlue Blue component of the colour (0 - 255).

inline TRgb(TInt aRed, TInt aGreen, TInt aBlue, TInt aAlpha);

Description

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).

Parameters

TInt aRed Red component of the colour (0 - 255). TInt aGreen Green component of the colour (0 - 255). TInt aBlue Blue component of the colour (0 - 255). TInt aAlpha Alpha component of the colour (0 - 255).

inline TInt Red() const;

Description

Gets the red component.

Return value

TInt The red component (0 - 255).

inline TInt Green() const;

Description

Gets the green component.

Return value

TInt The green component (0 - 255).

inline TInt Blue() const;

Description

Gets the blue component.

Return value

TInt The blue component (0 - 255).

inline TInt Alpha() const;

Description

Gets the alpha component.

Return value

TInt The alpha component (0 - 255).

IMPORT_C void SetRed(TInt aRed);

Description

Sets the red component.

Parameters

TInt aRed Red component (0 - 255).

IMPORT_C void SetGreen(TInt aGreen);

Description

Sets the green component.

Parameters

TInt aGreen Green component (0 - 255).

IMPORT_C void SetBlue(TInt aBlue);

Description

Sets the blue component.

Parameters

TInt aBlue Blue component (0 - 255).

IMPORT_C void SetAlpha(TInt aAlpha);

Description

Sets the alpha component.

Parameters

TInt aAlpha Alpha component (0 - 255).

static IMPORT_C TRgb Gray2(TInt aGray2);

Description

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.

Parameters

TInt aGray2 Grayscale value to be converted.

Return value

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

static IMPORT_C TRgb Gray4(TInt aGray4);

Description

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.

Parameters

TInt aGray4 Grayscale value to be converted.

Return value

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

static IMPORT_C TRgb Gray16(TInt aGray16);

Description

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.

Parameters

TInt aGray16 Grayscale value to be converted.

Return value

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

static IMPORT_C TRgb Gray256(TInt aGray256);

Description

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.

Parameters

TInt aGray256 Grayscale value to be converted.

Return value

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

static IMPORT_C TRgb Color16(TInt aColor16);

Description

Gets TRgb from 4 bit colour index.

The function takes a 4 bit index into a colour palette and returns a TRgb whose red, green and blue values are set to an appropriate level.

Parameters

TInt aColor16 4 bit index into a colour palette

Return value

TRgb Equivalent 24 bit colour.

static IMPORT_C TRgb Color256(TInt aColor256);

Description

Gets TRgb from 8 bit colour index.

The function takes an 8 bit index into a colour palette and returns a TRgb whose red, green and blue values are set to an appropriate level.

Parameters

TInt aColor256 8 bit index into a colour palette.

Return value

TRgb Equivalent 24 bit colour.

static IMPORT_C TRgb Color4K(TInt aColor4K);

Description

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.

Parameters

TInt aColor4K 12 bit index into a colour palette

Return value

TRgb Equivalent 24 bit colour.

static IMPORT_C TRgb Color64K(TInt aColor64K);

Description

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.

Parameters

TInt aColor64K 16 bit index into a colour palette

Return value

TRgb Equivalent 24 bit colour.

static IMPORT_C TRgb Color16M(TInt aColor16M);

Description

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.

Parameters

TInt aColor16M 24 bit index into a colour palette

Return value

TRgb The TRgb which represents the index exactly.

IMPORT_C TInt Gray2() const;

Description

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

Return value

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

IMPORT_C TInt Gray4() const;

Description

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

Return value

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

IMPORT_C TInt Gray16() const;

Description

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

Return value

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

IMPORT_C TInt Gray256() const;

Description

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

Return value

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

IMPORT_C TInt Color16() const;

Description

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

Return value

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

IMPORT_C TInt Color256() const;

Description

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

Return value

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

IMPORT_C TInt Color4K() const;

Description

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

Return value

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

IMPORT_C TInt Color64K() const;

Description

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

Return value

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

IMPORT_C TInt Color16M() const;

Description

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

Return value

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

inline TBool operator==(const TRgb &aColor) const;

Description

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.

Parameters

const TRgb &aColor Colour to be compared.

Return value

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

inline TBool operator!=(const TRgb &aColor) const;

Description

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.

Parameters

const TRgb &aColor Colour to be compared.

Return value

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

inline TRgb operator~() const;

Description

Bitwise logical inversion operator.

Return value

TRgb Contains results of logical inversion.

inline TRgb operator &(const TRgb &aColor);

Description

Bitwise logical AND operator.

Parameters

const TRgb &aColor Colour to be compared.

Return value

TRgb Contains results of logical AND.

inline TRgb operator|(const TRgb &aColor);

Description

Bitwise logical OR operator.

Parameters

const TRgb &aColor Colour to be compared.

Return value

TRgb Contains results of logical OR.

inline TRgb operator^(const TRgb &aColor);

Description

Bitwise EXCLUSIVE OR operator

Parameters

const TRgb &aColor Colour to be compared.

Return value

TRgb Contains results of logical EXCLUSIVE OR.

inline TRgb &operator &=(const TRgb &aColor);

Description

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.

Parameters

const TRgb &aColor Colour to be compared.

Return value

TRgb & First operand-contains result of logical AND.

inline TRgb &operator|=(const TRgb &aColor);

Description

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.

Parameters

const TRgb &aColor Colour to be compared.

Return value

TRgb & First operand- contains result of logical OR.

inline TRgb &operator^=(const TRgb &aColor);

Description

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.

Parameters

const TRgb &aColor Colour to be compared.

Return value

TRgb & First operand contains result of logical Exclusive OR.

inline TUint32 Value() const;

Description

Gets the 32-bit value of the TRgb as an integer. This function is deprecated. Use Internal() instead.

Return value

TUint32 The 32 bit value of the TRgb. Has the form 0xaabbggrr, where bb is the hex number of blue, gg is the hex number for green, rr is the hex number for red and aa is the hex number of alpha (0 means opaque, 255 means transparent).

inline TUint32 Internal() const;

Description

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

Return value

TUint32 The 32 bit value of the TRgb. Has the form 0xaarrggbb.

inline void SetInternal(TUint32 aInternal);

Description

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

Parameters

TUint32 aInternal Colour internal representation. Has the form 0xaarrggbb.

IMPORT_C TInt Difference(const TRgb &aColor) const;

Description

Gets the difference between two TRgbs.

This difference is defined as the sum of the absolute values of the difference in the red, green and blue components.

Parameters

const TRgb &aColor The TRgb to be compared.

Return value

TInt The sum of the absolute value of the differences between the red, green and blue components.

IMPORT_C void InternalizeL(RReadStream &aStream);

Description

Internalises a TRgb object from a stream.

The presence of this function means that the standard templated stream operator>>() is available to internalise objects of this class.

Parameters

RReadStream &aStream Stream from which the object is internalised.

See also:

• operator>>()

IMPORT_C void ExternalizeL(RWriteStream &aStream) const;

Description

Externalises a TRgb object to a stream.

The presence of this function means that the standard templated stream operator<<() is available to externalise objects of this class.

Parameters

RWriteStream &aStream Stream to which the object is externalised.

static IMPORT_C TRgb Color16MU(TInt a0RGB);

Description

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.

Parameters

TInt a0RGB The color - 0, R, G, B bytes. / BGR0 - little endian format /

Return value

TRgb The TRgb which represents the index exactly.

IMPORT_C TInt Color16MU() const;

Description

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

Return value

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

static IMPORT_C TRgb Color16MA(TUint aARGB);

Description

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.

Parameters

TUint aARGB The color - A, R, G, B bytes. / BGRA - little endian format /

Return value

TRgb The TRgb which represents the index exactly.

IMPORT_C TUint Color16MA() const;

Description

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

Return value

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

static IMPORT_C TRgb Color16MAP(TUint aARGB);

Description

Gets TRgb from 16MAP 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, and blue vales are divided by the alpha value.

Parameters

TUint aARGB The pre-multiplied (EColor16MAP) color value.

Return value

TRgb The TRgb which represents the color channel and alpha information.

IMPORT_C TUint Color16MAP() const;

Description

Gets the index of the closest TRgb value to this, based on the matching display mode. pre-multiplies the alpha channels with the color channel.

Return value

TUint The pre-multiplied color value

IMPORT_C TUint _Color16MAP() const;

Description

Converts the TRgb to EColor16MAP (with color channels pre-multiplied with the alpha channel.

Return value

TUint The index which represents the TRgb values after multiplication with Alpha value.

static IMPORT_C TRgb _Color16MAP(TUint aARGB);

Description

Gets TRgb from 16MAP 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, and blue vales are divided by the alpha value.

Parameters

TUint aARGB The pre-multiplied (EColor16MAP) color value.

Return value

TRgb The TRgb which represents the color channel and alpha information.

inline TInt _Gray2() const;

Description

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

Return value

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

inline TInt _Gray4() const;

Description

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

Return value

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

inline TInt _Gray16() const;

Description

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

Return value

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

inline TInt _Gray256() const;

Description

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

Return value

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

inline TInt _Color4K() const;

Description

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

Return value

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

inline TInt _Color64K() const;

Description

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

Return value

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

inline TInt _Color16M() const;

Description

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

Return value

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

inline TInt _Color16MU() const;

Description

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

Return value

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

inline TUint _Color16MA() const;

Description

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

Return value

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

static inline TRgb _Gray2(TInt aGray2);

Description

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.

Parameters

TInt aGray2 Grayscale value to be converted.

Return value

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

static inline TRgb _Gray4(TInt aGray4);

Description

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.

Parameters

TInt aGray4 Grayscale value to be converted.

Return value

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

static inline TRgb _Gray16(TInt aGray16);

Description

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.

Parameters

TInt aGray16 Grayscale value to be converted.

Return value

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

static inline TRgb _Gray256(TInt aGray256);

Description

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.

Parameters

TInt aGray256 Grayscale value to be converted.

Return value

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

static inline TRgb _Color4K(TInt aColor4K);

Description

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.

Parameters

TInt aColor4K 12 bit index into a colour palette

Return value

TRgb Equivalent 24 bit colour.

static inline TRgb _Color64K(TInt aColor64K);

Description

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.

Parameters

TInt aColor64K 16 bit index into a colour palette

Return value

TRgb Equivalent 24 bit colour.

static inline TRgb _Color16M(TInt aColor16M);

Description

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.

Parameters

TInt aColor16M 24 bit index into a colour palette

Return value

TRgb The TRgb which represents the index exactly.

static inline TRgb _Color16MU(TInt a0RGB);

Description

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.

Parameters

TInt a0RGB The color - 0, R, G, B bytes. / BGR0 - little endian format /

Return value

TRgb The TRgb which represents the index exactly.

static inline TRgb _Color16MA(TUint aARGB);

Description

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.

Parameters

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

Return value

TRgb The TRgb which represents the index exactly.