Class QAccelPlot::Colormap¶

ClassList > QAccelPlot > Colormap

Maps data values to colors: a color ramp plus the rule that places a value on it. More...

#include <Colormap.hpp>

Inherits the following classes: QObject, QQmlParserStatus

Inheritance diagram¶

flowchart TB
  classQAccelPlot_1_1Colormap["QAccelPlot::Colormap"]

  external_base_classQAccelPlot_1_1Colormap_1["QObject"]
  external_base_classQAccelPlot_1_1Colormap_1 --> classQAccelPlot_1_1Colormap
  external_base_classQAccelPlot_1_1Colormap_2["QQmlParserStatus"]
  external_base_classQAccelPlot_1_1Colormap_2 --> classQAccelPlot_1_1Colormap

Public Types¶

Type	Name
enum	Preset Built-in color ramps.

Public Properties¶

Type	Name
property bool	logScale Whether values are placed on the ramp in log10 instead of linearly. Default: `false` .
property qreal	max Value at ramp position 1. Unset (NaN) resolves it from the data. Default: unset.
property qreal	min Value at ramp position 0. Unset (NaN) resolves it from the data. Default: unset.
property Preset	preset Built-in color ramp. Ignored when `stops` is non-empty. Default:`Viridis` .
property bool	reversed Whether the ramp runs from its last color to its first. Applies to `preset` and`stops` alike. Default:`false` .
property QQmlListProperty< QObject >	stops Custom ramp as a list of objects with `position` and`color` , such as`GradientStop` . Overrides`preset` when non-empty. Stops are read again once the component is complete. The ramp follows changes to a stop that notifies them, to a`GradientStop` inside a`Gradient` , and to a`GradientStop` declared in this list.

Public Signals¶

Type	Name
signal void	colormapChanged Emitted when the ramp, its bounds, or `logScale` changes.

Public Functions¶

Type	Name
	Colormap (QObject * parent=nullptr) Constructs a Colormap with the given__parent .
bool	logScale () const Returns `true` when values are placed on the ramp in log10.
qreal	max () const Returns the fixed upper bound, or NaN when it is resolved from the data.
qreal	min () const Returns the fixed lower bound, or NaN when it is resolved from the data.
Preset	preset () const Returns the built-in ramp.
const std::vector< GradientStopData > &	resolvedStops () const Returns the resolved ramp stops, in position order and covering [0, 1].
bool	reversed () const Returns whether the ramp is reversed.
void	setLogScale (bool on) Sets log-scale placement to on .
void	setMax (qreal value) Sets the fixed upper bound to value . NaN resolves it from the data.
void	setMin (qreal value) Sets the fixed lower bound to value . NaN resolves it from the data.
void	setPreset (Preset preset) Sets the built-in ramp to preset .
Q_INVOKABLE void	setRange (qreal min, qreal max) Sets both bounds to min and__max with a single`colormapChanged()` . NaN unsets a bound.
void	setReversed (bool reversed) Sets whether the ramp is reversed to reversed .
QQmlListProperty< QObject >	stops () Returns the custom ramp stops, empty when the preset supplies the ramp.

Protected Functions¶

Type	Name
void	classBegin () override Does nothing; part of `QQmlParserStatus` .
void	componentComplete () override Reads the stops again after their bindings are evaluated.

Detailed Description¶

A colormap has no geometry. It is a one-dimensional ramp addressed by a normalized coordinate in [0, 1], and logScale decides how a value reaches that coordinate. Series that color by value, such as PointCloud and HeatmapSeries, index the ramp with each value. Effects that paint a ramp across the plot, such as GradientFill and GradientStroke, supply the coordinate from a position instead and own that geometry themselves, so they use only the ramp.

The ramp comes from preset, or from stops when a custom ramp is given. min and max bound the value range; leaving either unset resolves it from the data, so one colormap can be shared between series that resolve different ranges. Each series reports what it resolved through ColormappedSeries::dataValueMin() and ColormappedSeries::dataValueMax().

Public Types Documentation¶

enum Preset¶

Built-in color ramps.

enum QAccelPlot::Colormap::Preset {
    Viridis,
    Plasma,
    Inferno,
    Magma,
    Grayscale,
    Rainbow
};

The perceptually uniform ramps are sampled from the matplotlib originals. Prefer them over Rainbow, whose uneven lightness invents boundaries that are not in the data.

Public Properties Documentation¶

property logScale¶

Whether values are placed on the ramp in log10 instead of linearly. Default: false .

bool QAccelPlot::Colormap::logScale;

Values at or below zero are unmapped. A ColorBar showing the colormap gets decade ticks.

property max¶

Value at ramp position 1. Unset (NaN) resolves it from the data. Default: unset.

qreal QAccelPlot::Colormap::max;

property min¶

Value at ramp position 0. Unset (NaN) resolves it from the data. Default: unset.

qreal QAccelPlot::Colormap::min;

property preset¶

Built-in color ramp. Ignored when stops is non-empty. Default:Viridis .

Preset QAccelPlot::Colormap::preset;

property reversed¶

Whether the ramp runs from its last color to its first. Applies to preset andstops alike. Default:false .

bool QAccelPlot::Colormap::reversed;

property stops¶

Custom ramp as a list of objects with position andcolor , such asGradientStop . Overridespreset when non-empty. Stops are read again once the component is complete. The ramp follows changes to a stop that notifies them, to aGradientStop inside aGradient , and to aGradientStop declared in this list.

QQmlListProperty<QObject> QAccelPlot::Colormap::stops;

Public Signals Documentation¶

signal colormapChanged¶

Emitted when the ramp, its bounds, or logScale changes.

void QAccelPlot::Colormap::colormapChanged;

Public Functions Documentation¶

function Colormap¶

Constructs a Colormap with the given__parent .

explicit QAccelPlot::Colormap::Colormap (
    QObject * parent=nullptr
)

function logScale¶

Returns true when values are placed on the ramp in log10.

bool QAccelPlot::Colormap::logScale () const

function max¶

Returns the fixed upper bound, or NaN when it is resolved from the data.

qreal QAccelPlot::Colormap::max () const

function min¶

Returns the fixed lower bound, or NaN when it is resolved from the data.

qreal QAccelPlot::Colormap::min () const

function preset¶

Returns the built-in ramp.

Preset QAccelPlot::Colormap::preset () const

function resolvedStops¶

Returns the resolved ramp stops, in position order and covering [0, 1].

const std::vector< GradientStopData > & QAccelPlot::Colormap::resolvedStops () const

Custom stops when set, otherwise the preset ramp, flipped when reversed is set.

function reversed¶

Returns whether the ramp is reversed.

bool QAccelPlot::Colormap::reversed () const

function setLogScale¶

Sets log-scale placement to on .

void QAccelPlot::Colormap::setLogScale (
    bool on
)

function setMax¶

Sets the fixed upper bound to value . NaN resolves it from the data.

void QAccelPlot::Colormap::setMax (
    qreal value
)

function setMin¶

Sets the fixed lower bound to value . NaN resolves it from the data.

void QAccelPlot::Colormap::setMin (
    qreal value
)

function setPreset¶

Sets the built-in ramp to preset .

void QAccelPlot::Colormap::setPreset (
    Preset preset
)

function setRange¶

Sets both bounds to min and__max with a singlecolormapChanged() . NaN unsets a bound.

Q_INVOKABLE void QAccelPlot::Colormap::setRange (
    qreal min,
    qreal max
)

function setReversed¶

Sets whether the ramp is reversed to reversed .

void QAccelPlot::Colormap::setReversed (
    bool reversed
)

function stops¶

Returns the custom ramp stops, empty when the preset supplies the ramp.

QQmlListProperty< QObject > QAccelPlot::Colormap::stops ()

Protected Functions Documentation¶

function classBegin¶

Does nothing; part of QQmlParserStatus .

void QAccelPlot::Colormap::classBegin () override

function componentComplete¶

Reads the stops again after their bindings are evaluated.

void QAccelPlot::Colormap::componentComplete () override

The documentation for this class was generated from the following file QAccelPlot/src/QAccelPlot/effects/Colormap.hpp