- Qt 6.7
- Qt Graphs
- C++ Classes
- QtGraphs (Technical Preview)
- Q3DTheme
- Qt Graphs | Commercial or GPLv3

# Q3DTheme Class

Q3DTheme class provides a visual style for graphs. More...

Header: | #include <Q3DTheme>
CMake: | find_package(Qt6 REQUIRED COMPONENTS Graphs) target_link_libraries(mytarget PRIVATE Qt6::Graphs)
qmake: | QT += graphs
Instantiated By: | Theme3D
Inherits: | QObject and QQmlParserStatus
Status: | Technical Preview

- List of all members, including inherited members
- Q3DTheme is part of Qt Graphs C++ Classes for 3D.

## Public Types

enum class | ColorStyle { Uniform, ObjectGradient, RangeGradient }
enum class | Theme { Qt, PrimaryColors, StoneMoss, ArmyBlue, Retro, …, UserDefined }

## Properties

ambientLightStrength : float backgroundColor : QColor backgroundEnabled : bool baseColors : const QQmlListProperty<QQuickGraphsColor> baseGradients : const QQmlListProperty<QObject> colorStyle : Q3DTheme::ColorStyle font : QFont gridEnabled : bool gridLineColor : QColor labelBackgroundColor : QColor labelBackgroundEnabled : bool labelBorderEnabled : bool | labelTextColor : QColor labelsEnabled : bool lightColor : QColor lightStrength : float multiHighlightColor : QColor multiHighlightGradient : QJSValue shadowStrength : float singleHighlightColor : QColor singleHighlightGradient : QJSValue type : Q3DTheme::Theme windowColor : QColor

## Public Functions

| Q3DTheme(QObject *parent = nullptr)
| Q3DTheme(Q3DTheme::Theme themeType, QObject *parent = nullptr)
virtual | ~Q3DTheme() override
float | ambientLightStrength() const
QColor | backgroundColor() const
Q3DTheme::ColorStyle | colorStyle() const
QFont | font() const
QColor | gridLineColor() const
bool | isBackgroundEnabled() const
bool | isGridEnabled() const
bool | isLabelBackgroundEnabled() const
bool | isLabelBorderEnabled() const
bool | isLabelsEnabled() const
QColor | labelBackgroundColor() const
QColor | labelTextColor() const
QColor | lightColor() const
float | lightStrength() const
QColor | multiHighlightColor() const
void | setAmbientLightStrength(float strength)
void | setBackgroundColor(const QColor &color)
void | setBackgroundEnabled(bool enabled)
void | setColorStyle(Q3DTheme::ColorStyle style)
void | setFont(const QFont &font)
void | setGridEnabled(bool enabled)
void | setGridLineColor(const QColor &color)
void | setLabelBackgroundColor(const QColor &color)
void | setLabelBackgroundEnabled(bool enabled)
void | setLabelBorderEnabled(bool enabled)
void | setLabelTextColor(const QColor &color)
void | setLabelsEnabled(bool enabled)
void | setLightColor(const QColor &color)
void | setLightStrength(float strength)
void | setMultiHighlightColor(const QColor &color)
void | setMultiHighlightGradient(const QLinearGradient &gradient)
void | setShadowStrength(float strength)
void | setSingleHighlightColor(const QColor &color)
void | setSingleHighlightGradient(const QLinearGradient &gradient)
void | setType(Q3DTheme::Theme themeType)
void | setWindowColor(const QColor &color)
float | shadowStrength() const
QColor | singleHighlightColor() const
Q3DTheme::Theme | type() const
QColor | windowColor() const

## Signals

void | ambientLightStrengthChanged(float strength)
void | backgroundColorChanged(const QColor &color)
void | backgroundEnabledChanged(bool enabled)
void | colorStyleChanged(Q3DTheme::ColorStyle style)
void | fontChanged(const QFont &font)
void | gridEnabledChanged(bool enabled)
void | gridLineColorChanged(const QColor &color)
void | labelBackgroundColorChanged(const QColor &color)
void | labelBackgroundEnabledChanged(bool enabled)
void | labelBorderEnabledChanged(bool enabled)
void | labelTextColorChanged(const QColor &color)
void | labelsEnabledChanged(bool enabled)
void | lightColorChanged(const QColor &color)
void | lightStrengthChanged(float strength)
void | multiHighlightColorChanged(const QColor &color)
void | multiHighlightGradientChangedQML(QJSValue gradient)
void | shadowStrengthChanged(float strength)
void | singleHighlightColorChanged(const QColor &color)
void | singleHighlightGradientQMLChanged(QJSValue gradient)
void | typeChanged(Q3DTheme::Theme themeType)
void | windowColorChanged(const QColor &color)

## Detailed Description

Specifies visual properties that affect the whole graph. There are several built-in themes that can be used as is or modified freely.

The following properties can be overridden by using QAbstract3DSeries properties to set them explicitly in the series: baseColors, baseGradients, and colorStyle.

Themes can be created from scratch using the UserDefined enum value. Creating a theme using the default constructor produces a new user-defined theme.

### Default Theme

The following table lists the properties controlled by themes and the default values for UserDefined.

Property | Default Value
--- | ---
ambientLightStrength | 0.25
backgroundColor | Qt::black
backgroundEnabled | `true`
baseColors | Qt::black
baseGradients | QLinearGradient. Essentially fully black.
colorStyle | Uniform
font | QFont
gridEnabled | `true`
gridLineColor | Qt::white
labelBackgroundColor | Qt::gray
labelBackgroundEnabled | `true`
labelBorderEnabled | `true`
labelTextColor | Qt::white
labelsEnabled | `true`
lightColor | Qt::white
lightStrength | 5.0
multiHighlightColor | Qt::blue
multiHighlightGradient | QLinearGradient. Essentially fully black.
shadowStrength | 25.0
singleHighlightColor | Qt::red
singleHighlightGradient | QLinearGradient. Essentially fully black.
windowColor | Qt::black

### Usage Examples

Creating a built-in theme without any modifications:

     Q3DTheme *theme = new Q3DTheme(Q3DTheme::Theme::Qt);

Creating a built-in theme and modifying some properties:

     Q3DTheme *theme = new Q3DTheme(Q3DTheme::Theme::Qt);
     theme->setBackgroundEnabled(false);
     theme->setLabelBackgroundEnabled(false);

Creating a user-defined theme:

     Q3DTheme *theme = new Q3DTheme();
     theme->setAmbientLightStrength(0.3f);
     theme->setBackgroundColor(QColor(QRgb(0x99ca53)));
     theme->setBackgroundEnabled(true);
     QList<QColor> colors = { QColor(QRgb(0x209fdf)) };
     theme->setBaseColors(colors);
     theme->setColorStyle(Q3DTheme::ColorStyle::Uniform);
     theme->setFont(QFont(QStringLiteral("Impact"), 35));
     theme->setGridEnabled(true);
     theme->setGridLineColor(QColor(QRgb(0x99ca53)));
     theme->setLabelBackgroundColor(QColor(0xf6, 0xa6, 0x25, 0xa0));
     theme->setLabelBackgroundEnabled(true);
     theme->setLabelBorderEnabled(true);
     theme->setLabelTextColor(QColor(QRgb(0x404044)));
     theme->setLightColor(Qt::white);
     theme->setLightStrength(6.0f);
     theme->setMultiHighlightColor(QColor(QRgb(0x6d5fd5)));
     theme->setSingleHighlightColor(QColor(QRgb(0xf6a625)));
     theme->setWindowColor(QColor(QRgb(0xffffff)));

Creating a built-in theme and modifying some properties after it has been set:

     Q3DBars *graph = new Q3DBars();
     graph->activeTheme()->setType(Q3DTheme::Theme::PrimaryColors);
     QList<QColor> color = { QColor(Qt::red) };
     graph->activeTheme()->setBaseColors(color);
     graph->activeTheme()->setSingleHighlightColor(Qt::yellow);

## Member Type Documentation

### enum class Q3DTheme::ColorStyle

Color styles.

Constant | Value | Description
--- | --- | ---
`Q3DTheme::ColorStyle::Uniform` | `0` | Objects are rendered in a single color. The color used is specified in baseColors, singleHighlightColor and multiHighlightColor properties.
`Q3DTheme::ColorStyle::ObjectGradient` | `1` | Objects are colored using a full gradient for each object regardless of object height. The gradient used is specified in baseGradients, singleHighlightGradient and multiHighlightGradient properties.
`Q3DTheme::ColorStyle::RangeGradient` | `2` | Objects are colored using a portion of the full gradient determined by the object's height and its position on the Y-axis. The gradient used is specified in baseGradients, singleHighlightGradient and multiHighlightGradient properties.

### enum class Q3DTheme::Theme

Built-in themes.

Constant | Value | Description
--- | --- | ---
`Q3DTheme::Theme::Qt` | `0` | A light theme with green as the base color.
`Q3DTheme::Theme::PrimaryColors` | `1` | A light theme with yellow as the base color.
`Q3DTheme::Theme::StoneMoss` | `2` | A medium dark theme with yellow as the base color.
`Q3DTheme::Theme::ArmyBlue` | `3` | A medium light theme with blue as the base color.
`Q3DTheme::Theme::Retro` | `4` | A medium light theme with brown as the base color.
`Q3DTheme::Theme::Ebony` | `5` | A dark theme with white as the base color.
`Q3DTheme::Theme::Isabelle` | `6` | A dark theme with yellow as the base color.
`Q3DTheme::Theme::UserDefined` | `7` | A user-defined theme. For more information, see Default Theme.

## Property Documentation

### ambientLightStrength : float

This property holds the ambient light strength for the whole graph.

This value determines how evenly and brightly the colors are shown throughout the graph regardless of the light position.

The value must be between `0.0f` and `1.0f`.

Access functions:

float | ambientLightStrength() const
void | setAmbientLightStrength(float strength)

Notifier signal:

void | ambientLightStrengthChanged(float strength)

### backgroundColor : QColor

This property holds the color of the graph background.

Access functions:

QColor | backgroundColor() const
void | setBackgroundColor(const QColor &color)

Notifier signal:

void | backgroundColorChanged(const QColor &color)

### backgroundEnabled : bool

This property holds whether the background is visible.

The background is drawn by using the value of backgroundColor.

Access functions:

bool | isBackgroundEnabled() const
void | setBackgroundEnabled(bool enabled)

Notifier signal:

void | backgroundEnabledChanged(bool enabled)

### `[read-only]` baseColors : const QQmlListProperty<QQuickGraphsColor>

This property holds the list of base colors to be used for all the objects in the graph, series by series.

If there are more series than colors, the color list wraps and starts again with the first color in the list.

Has no immediate effect if colorStyle is not Uniform.

This value can be overridden by setting the baseColor explicitly in the series.

### `[read-only]` baseGradients : const QQmlListProperty<QObject>

This property holds the list of base gradients to be used for all the objects in the graph, series by series.

If there are more series than gradients, the gradient list wraps and starts again with the first gradient in the list

Has no immediate effect if colorStyle is Uniform.

This value can be overridden by setting the baseGradient explicitly in the series.

### colorStyle : Q3DTheme::ColorStyle

This property holds the style of the graph colors.

One of the ColorStyle enum values.

This value can be overridden by setting colorStyle explicitly in the series.

Access functions:

Q3DTheme::ColorStyle | colorStyle() const
void | setColorStyle(Q3DTheme::ColorStyle style)

Notifier signal:

void | colorStyleChanged(Q3DTheme::ColorStyle style)

### font : QFont

This property holds the font to be used for labels.

Access functions:

QFont | font() const
void | setFont(const QFont &font)

Notifier signal:

void | fontChanged(const QFont &font)

### gridEnabled : bool

This property holds whether the grid lines are drawn.

This value affects all grid lines.

Access functions:

bool | isGridEnabled() const
void | setGridEnabled(bool enabled)

Notifier signal:

void | gridEnabledChanged(bool enabled)

### gridLineColor : QColor

This property holds the color of the grid lines.

Access functions:

QColor | gridLineColor() const
void | setGridLineColor(const QColor &color)

Notifier signal:

void | gridLineColorChanged(const QColor &color)

### labelBackgroundColor : QColor

This property holds the color of the label backgrounds.

Has no effect if labelBackgroundEnabled is `false`.

Access functions:

QColor | labelBackgroundColor() const
void | setLabelBackgroundColor(const QColor &color)

Notifier signal:

void | labelBackgroundColorChanged(const QColor &color)

### labelBackgroundEnabled : bool

This property holds whether the label is drawn with a color background or with a fully transparent background.

The labelBackgroundColor value (including alpha) is used for drawing the background.

Labels with a background are drawn to equal sizes per axis based on the longest label, and the text is centered in them. Labels without a background are drawn as is and are left or right aligned based on their position in the graph.

Access functions:

bool | isLabelBackgroundEnabled() const
void | setLabelBackgroundEnabled(bool enabled)

Notifier signal:

void | labelBackgroundEnabledChanged(bool enabled)

### labelBorderEnabled : bool

This property holds whether label borders are drawn for labels that have a background.

Has no effect if labelBackgroundEnabled is `false`.

Access functions:

bool | isLabelBorderEnabled() const
void | setLabelBorderEnabled(bool enabled)

Notifier signal:

void | labelBorderEnabledChanged(bool enabled)

### labelTextColor : QColor

This property holds the color of the font used for labels.

Access functions:

QColor | labelTextColor() const
void | setLabelTextColor(const QColor &color)

Notifier signal:

void | labelTextColorChanged(const QColor &color)

### labelsEnabled : bool

This property holds whether labels are drawn at all.

If this is `false`, all other label properties have no effect.

Access functions:

bool | isLabelsEnabled() const
void | setLabelsEnabled(bool enabled)

Notifier signal:

void | labelsEnabledChanged(bool enabled)

### lightColor : QColor

This property holds the color for the ambient and specular light.

This value affects the light specified in Q3DScene.

Access functions:

QColor | lightColor() const
void | setLightColor(const QColor &color)

Notifier signal:

void | lightColorChanged(const QColor &color)

### lightStrength : float

This property holds the specular light strength for the whole graph.

The value must be between `0.0f` and `10.0f`.

This value affects the light specified in Q3DScene.

Access functions:

float | lightStrength() const
void | setLightStrength(float strength)

Notifier signal:

void | lightStrengthChanged(float strength)

### multiHighlightColor : QColor

This property holds the highlight color for selected objects.

Used if selectionMode has the `QAbstract3DGraph::SelectionRow` or `QAbstract3DGraph::SelectionColumn` flag set.

Access functions:

QColor | multiHighlightColor() const
void | setMultiHighlightColor(const QColor &color)

Notifier signal:

void | multiHighlightColorChanged(const QColor &color)

### multiHighlightGradient : QJSValue

This property holds the highlight gradient for selected objects.

Used if selectionMode has the `QAbstract3DGraph::SelectionRow` or `QAbstract3DGraph::SelectionColumn` flag set.

Access functions:

void | setMultiHighlightGradient(const QLinearGradient &gradient)

Notifier signal:

void | multiHighlightGradientChangedQML(QJSValue gradient)

### shadowStrength : float

This property holds the shadow strength for the whole graph.

The higher the number, the darker the shadows will be. The value must be between `0.0` and `100.0`.

This value affects the light specified in Q3DScene.

Access functions:

float | shadowStrength() const
void | setShadowStrength(float strength)

Notifier signal:

void | shadowStrengthChanged(float strength)

### singleHighlightColor : QColor

This property holds the highlight color for a selected object.

Used if selectionMode has the `QAbstract3DGraph::SelectionItem` flag set.

Access functions:

QColor | singleHighlightColor() const
void | setSingleHighlightColor(const QColor &color)

Notifier signal:

void | singleHighlightColorChanged(const QColor &color)

### singleHighlightGradient : QJSValue

This property holds the highlight gradient for a selected object.

Used if selectionMode has the `QAbstract3DGraph::SelectionItem` flag set.

Access functions:

void | setSingleHighlightGradient(const QLinearGradient &gradient)

Notifier signal:

void | singleHighlightGradientQMLChanged(QJSValue gradient)

### type : Q3DTheme::Theme

This property holds the type of the theme.

The type is automatically set when constructing a theme, but can also be changed later. Changing the theme type will change all other properties of the theme to what the predefined theme specifies. Changing the theme type of the active theme of the graph will also reset all attached series to use the new theme.

Access functions:

Q3DTheme::Theme | type() const
void | setType(Q3DTheme::Theme themeType)

Notifier signal:

void | typeChanged(Q3DTheme::Theme themeType)

### windowColor : QColor

This property holds the color of the application window the graph is drawn into.

Access functions:

QColor | windowColor() const
void | setWindowColor(const QColor &color)

Notifier signal:

void | windowColorChanged(const QColor &color)

## Member Function Documentation

### `[explicit]` Q3DTheme::Q3DTheme(QObject *parent = nullptr)

Constructs a new theme of type UserDefined. An optional parent parameter can be given and is then passed to QObject constructor.

### `[explicit]` Q3DTheme::Q3DTheme(Q3DTheme::Theme themeType, QObject *parent = nullptr)

Constructs a new theme with themeType, which can be one of the built-in themes from Theme. An optional parent parameter can be given and is then passed to QObject constructor.

### `[override virtual noexcept]` Q3DTheme::~Q3DTheme()

Destroys the theme.