QColorSpace Class
The QColorSpace class provides a color space abstraction. More...
| Header: | #include <QColorSpace> |
| CMake: | find_package(Qt6 REQUIRED COMPONENTS Gui)target_link_libraries(mytarget PRIVATE Qt6::Gui) |
| qmake: | QT += gui |
- List of all members, including inherited members
- QColorSpace is part of Painting Classes.
Public Types
(since 6.8) enum class | ColorModel { Undefined, Rgb, Gray, Cmyk } |
| enum | NamedColorSpace { SRgb, SRgbLinear, AdobeRgb, DisplayP3, ProPhotoRgb, …, Bt2100Hlg } |
| enum class | Primaries { Custom, SRgb, AdobeRgb, DciP3D65, ProPhotoRgb, Bt2020 } |
| enum class | TransferFunction { Custom, Linear, Gamma, SRgb, ProPhotoRgb, …, Hlg } |
(since 6.8) enum class | TransformModel { ThreeComponentMatrix, ElementListProcessing } |
Public Functions
| QColorSpace() | |
| QColorSpace(QColorSpace::NamedColorSpace namedColorSpace) | |
(since 6.1) | QColorSpace(QColorSpace::Primaries gamut, const QList<uint16_t> &transferFunctionTable) |
| QColorSpace(QColorSpace::Primaries primaries, float gamma) | |
(since 6.8) | QColorSpace(QPointF whitePoint, const QList<uint16_t> &transferFunctionTable) |
| QColorSpace(QColorSpace::Primaries primaries, QColorSpace::TransferFunction transferFunction, float gamma = 0.0f) | |
(since 6.8) | QColorSpace(QPointF whitePoint, QColorSpace::TransferFunction transferFunction, float gamma = 0.0f) |
(since 6.1) | QColorSpace(const QPointF &whitePoint, const QPointF &redPoint, const QPointF &greenPoint, const QPointF &bluePoint, const QList<uint16_t> &transferFunctionTable) |
| QColorSpace(const QPointF &whitePoint, const QPointF &redPoint, const QPointF &greenPoint, const QPointF &bluePoint, QColorSpace::TransferFunction transferFunction, float gamma = 0.0f) | |
(since 6.1) | QColorSpace(const QPointF &whitePoint, const QPointF &redPoint, const QPointF &greenPoint, const QPointF &bluePoint, const QList<uint16_t> &redTransferFunctionTable, const QList<uint16_t> &greenTransferFunctionTable, const QList<uint16_t> &blueTransferFunctionTable) |
(since 6.8) QColorSpace::ColorModel | colorModel() const |
(since 6.2) QString | description() const |
| float | gamma() const |
| QByteArray | iccProfile() const |
| bool | isValid() const |
(since 6.8) bool | isValidTarget() const |
| QColorSpace::Primaries | primaries() const |
(since 6.2) void | setDescription(const QString &description) |
| void | setPrimaries(QColorSpace::Primaries primariesId) |
| void | setPrimaries(const QPointF &whitePoint, const QPointF &redPoint, const QPointF &greenPoint, const QPointF &bluePoint) |
(since 6.1) void | setTransferFunction(const QList<uint16_t> &transferFunctionTable) |
| void | setTransferFunction(QColorSpace::TransferFunction transferFunction, float gamma = 0.0f) |
(since 6.1) void | setTransferFunctions(const QList<uint16_t> &redTransferFunctionTable, const QList<uint16_t> &greenTransferFunctionTable, const QList<uint16_t> &blueTransferFunctionTable) |
(since 6.8) void | setWhitePoint(QPointF whitePoint) |
| void | swap(QColorSpace &other) |
| QColorSpace::TransferFunction | transferFunction() const |
(since 6.8) QColorSpace::TransformModel | transformModel() const |
| QColorTransform | transformationToColorSpace(const QColorSpace &colorspace) const |
(since 6.8) QPointF | whitePoint() const |
(since 6.1) QColorSpace | withTransferFunction(const QList<uint16_t> &transferFunctionTable) const |
| QColorSpace | withTransferFunction(QColorSpace::TransferFunction transferFunction, float gamma = 0.0f) const |
(since 6.1) QColorSpace | withTransferFunctions(const QList<uint16_t> &redTransferFunctionTable, const QList<uint16_t> &greenTransferFunctionTable, const QList<uint16_t> &blueTransferFunctionTable) const |
| QVariant | operator QVariant() const |
Static Public Members
| QColorSpace | fromIccProfile(const QByteArray &iccProfile) |
Related Non-Members
| bool | operator!=(const QColorSpace &colorSpace1, const QColorSpace &colorSpace2) |
| QDataStream & | operator<<(QDataStream &stream, const QColorSpace &colorSpace) |
| bool | operator==(const QColorSpace &colorSpace1, const QColorSpace &colorSpace2) |
| QDataStream & | operator>>(QDataStream &stream, QColorSpace &colorSpace) |
Detailed Description
Color values can be interpreted in different ways, and based on the interpretation can live in different spaces. We call this color spaces.
QColorSpace provides access to creating several predefined color spaces and can generate QColorTransforms for converting colors from one color space to another.
QColorSpace can also represent color spaces defined by ICC profiles or embedded in images, that do not otherwise fit the predefined color spaces.
A color space can generally speaking be conceived as a combination of set of primary colors and a transfer function. The primaries defines the axes of the color space, and the transfer function how values are mapped on the axes. The primaries are for ColorModel::Rgb color spaces defined by three primary colors that represent exactly how red, green, and blue look in this particular color space, and a white color that represents where and how bright pure white is. For grayscale color spaces, only a single white primary is needed. The range of colors expressible by the primary colors is called the gamut, and a color space that can represent a wider range of colors is also known as a wide-gamut color space.
The transfer function or gamma curve determines how each component in the color space is encoded. These are used because human perception does not operate linearly, and the transfer functions try to ensure that colors will seem evenly spaced to human eyes.
Member Type Documentation
[since 6.8] enum class QColorSpace::ColorModel
Defines the color model used by the color space data.
| Constant | Value | Description |
|---|---|---|
QColorSpace::ColorModel::Undefined | 0 | No color model |
QColorSpace::ColorModel::Rgb | 1 | An RGB color model with red, green, and blue colors. Can apply to RGB and grayscale data. |
QColorSpace::ColorModel::Gray | 2 | A gray scale color model. Can only apply to grayscale data. |
QColorSpace::ColorModel::Cmyk | 3 | Can only represent color data defined with cyan, magenta, yellow, and black colors. In effect only QImage::Format_CMYK32. Note Cmyk color spaces will be TransformModel::ElementListProcessing. |
This enum was introduced in Qt 6.8.
enum QColorSpace::NamedColorSpace
Predefined color spaces.
| Constant | Value | Description |
|---|---|---|
QColorSpace::SRgb | 1 | The sRGB color space, which Qt operates in by default. It is a close approximation of how most classic monitors operate, and a mode most software and hardware support. ICC registration of sRGB. |
QColorSpace::SRgbLinear | 2 | The sRGB color space with linear gamma. Useful for gamma-corrected blending. |
QColorSpace::AdobeRgb | 3 | The Adobe RGB color space is a classic wide-gamut color space, using a gamma of 2.2. ICC registration of Adobe RGB (1998) |
QColorSpace::DisplayP3 | 4 | A color-space using the primaries of DCI-P3, but with the whitepoint and transfer function of sRGB. Common in modern wide-gamut screens. ICC registration of DCI-P3 |
QColorSpace::ProPhotoRgb | 5 | The Pro Photo RGB color space, also known as ROMM RGB is a very wide gamut color space. ICC registration of ROMM RGB |
QColorSpace::Bt2020 (since Qt 6.8) | 6 | BT.2020, also known as Rec.2020 is a basic colorspace of HDR TVs. ICC registration of BT.2020 |
QColorSpace::Bt2100Pq (since Qt 6.8) | 7 | BT.2100(PQ), also known as Rec.2100 or HDR10 is an HDR encoding with the same primaries as Bt2020 but using the Perceptual Quantizer transfer function. ICC registration of BT.2100 |
QColorSpace::Bt2100Hlg (since Qt 6.8) | 8 | BT.2100 (HLG) is an HDR encoding with the same primaries as Bt2020 but using the Hybrid Log-Gamma transfer function. |
enum class QColorSpace::Primaries
Predefined sets of primary colors.
| Constant | Value | Description |
|---|---|---|
QColorSpace::Primaries::Custom | 0 | The primaries are undefined or does not match any predefined sets. |
QColorSpace::Primaries::SRgb | 1 | The sRGB primaries |
QColorSpace::Primaries::AdobeRgb | 2 | The Adobe RGB primaries |
QColorSpace::Primaries::DciP3D65 | 3 | The DCI-P3 primaries with the D65 whitepoint |
QColorSpace::Primaries::ProPhotoRgb | 4 | The ProPhoto RGB primaries with the D50 whitepoint |
QColorSpace::Primaries::Bt2020 (since Qt 6.8) | 5 | The BT.2020 primaries with a D65 whitepoint |
enum class QColorSpace::TransferFunction
Predefined transfer functions or gamma curves.
| Constant | Value | Description |
|---|---|---|
QColorSpace::TransferFunction::Custom | 0 | The custom or null transfer function |
QColorSpace::TransferFunction::Linear | 1 | The linear transfer functions |
QColorSpace::TransferFunction::Gamma | 2 | A transfer function that is a real gamma curve based on the value of gamma() |
QColorSpace::TransferFunction::SRgb | 3 | The sRGB transfer function, composed of linear and gamma parts |
QColorSpace::TransferFunction::ProPhotoRgb | 4 | The ProPhoto RGB transfer function, composed of linear and gamma parts |
QColorSpace::TransferFunction::Bt2020 (since Qt 6.8) | 5 | The BT.2020 transfer function, composited of linear and gamma parts |
QColorSpace::TransferFunction::St2084 (since Qt 6.8) | 6 | The SMPTE ST 2084 transfer function, also known Perceptual Quantizer(PQ). |
QColorSpace::TransferFunction::Hlg (since Qt 6.8) | 7 | The Hybrid log-gamma transfer function. |
[since 6.8] enum class QColorSpace::TransformModel
Defines the processing model used for color space transforms.
| Constant | Value | Description |
|---|---|---|
QColorSpace::TransformModel::ThreeComponentMatrix | 0 | The transform consist of a matrix calculated from primaries and set of transfer functions for each color channel. This is very fast and used by all predefined color spaces. Any color space on this form is reversible and always both valid sources and targets. |
QColorSpace::TransformModel::ElementListProcessing | 1 | The transforms are one or two lists of processing elements that can do many things, each list only process either to the connection color space or from it. This is very flexible, but rather slow, and can only be set by reading ICC profiles (See fromIccProfile()). Since the two lists are separate a color space on this form can be a valid source, but not necessarily also a valid target. When changing either primaries or transfer function on a color space on this type it will reset to an empty ThreeComponentMatrix form. |
This enum was introduced in Qt 6.8.
Member Function Documentation
[noexcept] QColorSpace::QColorSpace()
Creates a new colorspace object that represents an undefined and invalid colorspace.
QColorSpace::QColorSpace(QColorSpace::NamedColorSpace namedColorSpace)
Creates a new colorspace object that represents a namedColorSpace.
[since 6.1] QColorSpace::QColorSpace(QColorSpace::Primaries gamut, const QList<uint16_t> &transferFunctionTable)
Creates a custom color space with the primaries gamut, using a custom transfer function described by transferFunctionTable.
The table should contain at least 2 values, and contain an monotonically increasing list of values from 0 to 65535.
This function was introduced in Qt 6.1.
QColorSpace::QColorSpace(QColorSpace::Primaries primaries, float gamma)
Creates a custom color space with the primaries primaries, using a gamma transfer function of gamma.
[explicit, since 6.8] QColorSpace::QColorSpace(QPointF whitePoint, const QList<uint16_t> &transferFunctionTable)
Creates a custom grayscale color space with white point whitePoint, and using the custom transfer function described by transferFunctionTable.
This function was introduced in Qt 6.8.
QColorSpace::QColorSpace(QColorSpace::Primaries primaries, QColorSpace::TransferFunction transferFunction, float gamma = 0.0f)
Creates a custom color space with the primaries primaries, using the transfer function transferFunction and optionally gamma.
[explicit, since 6.8] QColorSpace::QColorSpace(QPointF whitePoint, QColorSpace::TransferFunction transferFunction, float gamma = 0.0f)
Creates a custom grayscale color space with the white point whitePoint, using the transfer function transferFunction and optionally gamma.
This function was introduced in Qt 6.8.
[since 6.1] QColorSpace::QColorSpace(const QPointF &whitePoint, const QPointF &redPoint, const QPointF &greenPoint, const QPointF &bluePoint, const QList<uint16_t> &transferFunctionTable)
Creates a custom color space with primaries based on the chromaticities of the primary colors whitePoint, redPoint, greenPoint and bluePoint, and using the custom transfer function described by transferFunctionTable.
This function was introduced in Qt 6.1.
QColorSpace::QColorSpace(const QPointF &whitePoint, const QPointF &redPoint, const QPointF &greenPoint, const QPointF &bluePoint, QColorSpace::TransferFunction transferFunction, float gamma = 0.0f)
Creates a custom colorspace with a primaries based on the chromaticities of the primary colors whitePoint, redPoint, greenPoint and bluePoint, and using the transfer function transferFunction and optionally gamma.
[since 6.1] QColorSpace::QColorSpace(const QPointF &whitePoint, const QPointF &redPoint, const QPointF &greenPoint, const QPointF &bluePoint, const QList<uint16_t> &redTransferFunctionTable, const QList<uint16_t> &greenTransferFunctionTable, const QList<uint16_t> &blueTransferFunctionTable)
Creates a custom color space with primaries based on the chromaticities of the primary colors whitePoint, redPoint, greenPoint and bluePoint, and using the custom transfer functions described by redTransferFunctionTable, greenTransferFunctionTable, and blueTransferFunctionTable.
This function was introduced in Qt 6.1.
[noexcept, since 6.8] QColorSpace::ColorModel QColorSpace::colorModel() const
Returns the color model this color space can represent
This function was introduced in Qt 6.8.
[noexcept, since 6.2] QString QColorSpace::description() const
Returns the name or short description. If a description hasn't been given in setDescription(), the original name of the profile is returned if the profile is unmodified, a guessed name is returned if the profile has been recognized as a known color space, otherwise an empty string is returned.
This function was introduced in Qt 6.2.
See also setDescription().
[static] QColorSpace QColorSpace::fromIccProfile(const QByteArray &iccProfile)
Creates a QColorSpace from ICC profile iccProfile.
Note: Not all ICC profiles are supported. QColorSpace only supports RGB or Gray ICC profiles.
If the ICC profile is not supported an invalid QColorSpace is returned where you can still read the original ICC profile using iccProfile().
See also iccProfile().
[noexcept] float QColorSpace::gamma() const
Returns the gamma value of color spaces with TransferFunction::Gamma, an approximate gamma value for other predefined color spaces, or 0.0 if no approximate gamma is known.
See also transferFunction().
QByteArray QColorSpace::iccProfile() const
Returns an ICC profile representing the color space.
If the color space was generated from an ICC profile, that profile is returned, otherwise one is generated.
Note: Even invalid color spaces may return the ICC profile if they were generated from one, to allow applications to implement wider support themselves.
See also fromIccProfile().
[noexcept] bool QColorSpace::isValid() const
Returns true if the color space is valid. For a color space with TransformModel::ThreeComponentMatrix that means both primaries and transfer functions set, and implies isValidTarget(). For a color space with TransformModel::ElementListProcessing it means it has a valid source transform, to check if it also a valid target color space use isValidTarget().
See also isValidTarget().
[noexcept, since 6.8] bool QColorSpace::isValidTarget() const
Returns true if the color space is a valid target color space.
This function was introduced in Qt 6.8.
[noexcept] QColorSpace::Primaries QColorSpace::primaries() const
Returns the predefined primaries of the color space or primaries::Custom if it doesn't match any of them.
See also setPrimaries().
[since 6.2] void QColorSpace::setDescription(const QString &description)
Sets the name or short description of the color space to description.
If set to empty description() will return original or guessed descriptions instead.
This function was introduced in Qt 6.2.
See also description().
void QColorSpace::setPrimaries(QColorSpace::Primaries primariesId)
Sets the primaries to those of the primariesId set.
See also primaries().
void QColorSpace::setPrimaries(const QPointF &whitePoint, const QPointF &redPoint, const QPointF &greenPoint, const QPointF &bluePoint)
Set primaries to the chromaticities of whitePoint, redPoint, greenPoint and bluePoint.
See also primaries().
[since 6.1] void QColorSpace::setTransferFunction(const QList<uint16_t> &transferFunctionTable)
Sets the transfer function to transferFunctionTable.
This function was introduced in Qt 6.1.
See also transferFunction() and withTransferFunction().
void QColorSpace::setTransferFunction(QColorSpace::TransferFunction transferFunction, float gamma = 0.0f)
Sets the transfer function to transferFunction and gamma.
See also transferFunction(), gamma(), and withTransferFunction().
[since 6.1] void QColorSpace::setTransferFunctions(const QList<uint16_t> &redTransferFunctionTable, const QList<uint16_t> &greenTransferFunctionTable, const QList<uint16_t> &blueTransferFunctionTable)
Sets the transfer functions to redTransferFunctionTable, greenTransferFunctionTable and blueTransferFunctionTable.
This function was introduced in Qt 6.1.
See also withTransferFunctions().
[since 6.8] void QColorSpace::setWhitePoint(QPointF whitePoint)
Sets the white point to used for this color space to whitePoint.
This function was introduced in Qt 6.8.
See also whitePoint().
[noexcept] void QColorSpace::swap(QColorSpace &other)
Swaps color space other with this color space. This operation is very fast and never fails.
[noexcept] QColorSpace::TransferFunction QColorSpace::transferFunction() const
Returns the predefined transfer function of the color space or TransferFunction::Custom if it doesn't match any of them.
See also gamma(), setTransferFunction(), and withTransferFunction().
[noexcept, since 6.8] QColorSpace::TransformModel QColorSpace::transformModel() const
Returns the transfrom processing model used for this color space.
This function was introduced in Qt 6.8.
QColorTransform QColorSpace::transformationToColorSpace(const QColorSpace &colorspace) const
Generates and returns a color space transformation from this color space to colorspace.
[since 6.8] QPointF QColorSpace::whitePoint() const
Returns the white point used for this color space. Returns a null QPointF if not defined.
This function was introduced in Qt 6.8.
See also setWhitePoint().
[since 6.1] QColorSpace QColorSpace::withTransferFunction(const QList<uint16_t> &transferFunctionTable) const
Returns a copy of this color space, except using the transfer function described by transferFunctionTable.
This function was introduced in Qt 6.1.
See also transferFunction() and setTransferFunction().
QColorSpace QColorSpace::withTransferFunction(QColorSpace::TransferFunction transferFunction, float gamma = 0.0f) const
Returns a copy of this color space, except using the transfer function transferFunction and gamma.
See also transferFunction(), gamma(), and setTransferFunction().
[since 6.1] QColorSpace QColorSpace::withTransferFunctions(const QList<uint16_t> &redTransferFunctionTable, const QList<uint16_t> &greenTransferFunctionTable, const QList<uint16_t> &blueTransferFunctionTable) const
Returns a copy of this color space, except using the transfer functions described by redTransferFunctionTable, greenTransferFunctionTable and blueTransferFunctionTable.
This function was introduced in Qt 6.1.
See also setTransferFunctions().
QVariant QColorSpace::operator QVariant() const
Returns the color space as a QVariant.
Related Non-Members
bool operator!=(const QColorSpace &colorSpace1, const QColorSpace &colorSpace2)
Returns true if colorspace colorSpace1 is not equal to colorspace colorSpace2; otherwise returns false
QDataStream &operator<<(QDataStream &stream, const QColorSpace &colorSpace)
Writes the given colorSpace to the given stream as an ICC profile.
See also QColorSpace::iccProfile() and Serializing Qt Data Types.
bool operator==(const QColorSpace &colorSpace1, const QColorSpace &colorSpace2)
Returns true if colorspace colorSpace1 is equal to colorspace colorSpace2; otherwise returns false
QDataStream &operator>>(QDataStream &stream, QColorSpace &colorSpace)
Reads a color space from the given stream and stores it in the given colorSpace.
See also QColorSpace::fromIccProfile() and Serializing Qt Data Types.
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