QwtAbstractScaleDraw(3)

📦

version 6.3.0 · 6 versions

🌸 `QwtAbstractScaleDraw(3)` 🌸

Hey bestie 💖 this page is from the Library Functions Manual, and it's all about QwtAbstractScaleDraw — the abstract-base-class blueprint for drawing scales. It's giving “I define the vibe, subclasses do the actual drawing.” ✨

🌟 NAME 🌟

QwtAbstractScaleDraw — a abstract base class for drawing scales.

✨ SYNOPSIS ✨

#include <qwt_abstract_scale_draw.h>

Inherited by QwtRoundScaleDraw, and QwtScaleDraw.

💅 Public Types

enum ScaleComponent { Backbone = 0x01, Ticks = 0x02, Labels = 0x04 }
typedef QFlags< ScaleComponent > ScaleComponents

🫶 Public Member Functions

QwtAbstractScaleDraw () — Constructor.
virtual ~QwtAbstractScaleDraw () — Destructor.
void setScaleDiv (const QwtScaleDiv &)
const QwtScaleDiv & scaleDiv () const
void setTransformation (QwtTransform *)
const QwtScaleMap & scaleMap () const
QwtScaleMap & scaleMap ()
void enableComponent (ScaleComponent, bool enable=true)
bool hasComponent (ScaleComponent) const
void setTickLength (QwtScaleDiv::TickType, double length)
double tickLength (QwtScaleDiv::TickType) const
double maxTickLength () const
void setSpacing (double) — Set the spacing between tick and labels.
double spacing () const — Get the spacing.
void setPenWidthF (qreal width) — Specify the width of the scale pen.
qreal penWidthF () const
virtual void draw (QPainter *, const QPalette &) const — Draw the scale.
virtual QwtText label (double) const — Convert a value into its representing label.
virtual double extent (const QFont &font) const =0
void setMinimumExtent (double) — Set a minimum for the extent.
double minimumExtent () const
void invalidateCache ()

🛡️ Protected Member Functions

virtual void drawTick (QPainter *painter, double value, double len) const =0
virtual void drawBackbone (QPainter *painter) const =0
virtual void drawLabel (QPainter *painter, double value) const =0
const QwtText & tickLabel (const QFont &, double value) const — Convert a value into its representing label and cache it.

🦋 Detailed Description 🦋

A abstract base class for drawing scales.

QwtAbstractScaleDraw can be used to draw linear or logarithmic scales.

After a scale division has been specified as a QwtScaleDiv object using setScaleDiv(), the scale can be drawn with the draw() member.

Definition at line 31 of file qwt_abstract_scale_draw.h.

🎀 Member Typedef Documentation 🎀

`typedef QFlags<ScaleComponent > QwtAbstractScaleDraw::ScaleComponents`

An ORed combination of ScaleComponent values.

Definition at line 51 of file qwt_abstract_scale_draw.h.

🌈 Member Enumeration Documentation 🌈

`enum QwtAbstractScaleDraw::ScaleComponent`

Components of a scale

See also: enableComponent(), hasComponent

Enumerator

Backbone — Backbone = the line where the ticks are located.
Ticks — Ticks.
Labels — Labels.

Definition at line 39 of file qwt_abstract_scale_draw.h.

💖 Constructor & Destructor Documentation 💖

`QwtAbstractScaleDraw::QwtAbstractScaleDraw ()`

Constructor. The range of the scale is initialized to [0, 100], The spacing (distance between ticks and labels) is set to 4, the tick lengths are set to 4,6 and 8 pixels

Definition at line 60 of file qwt_abstract_scale_draw.cpp.

`QwtAbstractScaleDraw::~QwtAbstractScaleDraw () [virtual]`

Destructor.

Definition at line 66 of file qwt_abstract_scale_draw.cpp.

🔥 Member Function Documentation 🔥

`void QwtAbstractScaleDraw::draw (QPainter * painter, const QPalette & palette) const [virtual]`

Draw the scale.

Parameters

painter — The painter
palette — Palette, text color is used for the labels, foreground color for ticks and backbone

Definition at line 169 of file qwt_abstract_scale_draw.cpp.

`virtual void QwtAbstractScaleDraw::drawBackbone (QPainter * painter) const [protected], [pure virtual]`

Draws the baseline of the scale

Parameters

painter — Painter

See also: drawTick(), drawLabel()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

`virtual void QwtAbstractScaleDraw::drawLabel (QPainter * painter, double value) const [protected], [pure virtual]`

Draws the label for a major scale tick

Parameters

painter — Painter
value — Value

See also: drawTick(), drawBackbone()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

`virtual void QwtAbstractScaleDraw::drawTick (QPainter * painter, double value, double len) const [protected], [pure virtual]`

Draw a tick

Parameters

painter — Painter
value — Value of the tick
len — Length of the tick

See also: drawBackbone(), drawLabel()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

`void QwtAbstractScaleDraw::enableComponent (ScaleComponent component, bool enable = true)`

En/Disable a component of the scale

Parameters

component — Scale component
enable — On/Off

See also: hasComponent()

Definition at line 79 of file qwt_abstract_scale_draw.cpp.

`virtual double QwtAbstractScaleDraw::extent (const QFont & font) const [pure virtual]`

Calculate the extent

The extent is the distance from the baseline to the outermost pixel of the scale draw in opposite to its orientation. It is at least minimumExtent() pixels.

Parameters

font — Font used for drawing the tick labels

Returns

Number of pixels

See also: setMinimumExtent(), minimumExtent()

Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

`bool QwtAbstractScaleDraw::hasComponent (ScaleComponent component) const`

Check if a component is enabled

Parameters

component — Component type

Returns

true, when component is enabled

See also: enableComponent()

Definition at line 95 of file qwt_abstract_scale_draw.cpp.

`void QwtAbstractScaleDraw::invalidateCache ()`

Invalidate the cache used by tickLabel()

The cache is invalidated, when a new QwtScaleDiv is set. If the labels need to be changed. while the same QwtScaleDiv is set, invalidateCache() needs to be called manually.

Definition at line 417 of file qwt_abstract_scale_draw.cpp.

`QwtText QwtAbstractScaleDraw::label (double value) const [virtual]`

Convert a value into its representing label. The value is converted to a plain text using QLocale().toString(value). This method is often overloaded by applications to have individual labels.

Parameters

value — Value

Returns

Label string.

Reimplemented in QwtCompassScaleDraw, and QwtDateScaleDraw.

Definition at line 375 of file qwt_abstract_scale_draw.cpp.

`double QwtAbstractScaleDraw::maxTickLength () const`

Returns

Length of the longest tick

Useful for layout calculations

See also: tickLength(), setTickLength()

Definition at line 355 of file qwt_abstract_scale_draw.cpp.

`double QwtAbstractScaleDraw::minimumExtent () const`

Get the minimum extent

Returns

Minimum extent

See also: extent(), setMinimumExtent()

Definition at line 302 of file qwt_abstract_scale_draw.cpp.

`qreal QwtAbstractScaleDraw::penWidthF () const`

Returns

Scale pen width

See also: setPenWidth()

Definition at line 156 of file qwt_abstract_scale_draw.cpp.

`const QwtScaleDiv & QwtAbstractScaleDraw::scaleDiv () const`

Returns

scale division

Definition at line 133 of file qwt_abstract_scale_draw.cpp.

`QwtScaleMap & QwtAbstractScaleDraw::scaleMap ()`

Returns

Map how to translate between scale and pixel values

Definition at line 127 of file qwt_abstract_scale_draw.cpp.

`const QwtScaleMap & QwtAbstractScaleDraw::scaleMap () const`

Returns

Map how to translate between scale and pixel values

Definition at line 121 of file qwt_abstract_scale_draw.cpp.

`void QwtAbstractScaleDraw::setMinimumExtent (double minExtent)`

Set a minimum for the extent. The extent is calculated from the components of the scale draw. In situations, where the labels are changing and the layout depends on the extent (f.e scrolling a scale), setting an upper limit as minimum extent will avoid jumps of the layout.

Parameters

minExtent — Minimum extent

See also: extent(), minimumExtent()

Definition at line 289 of file qwt_abstract_scale_draw.cpp.

`void QwtAbstractScaleDraw::setPenWidthF (qreal width)`

Specify the width of the scale pen.

Parameters

width — Pen width

See also: penWidth()

Definition at line 144 of file qwt_abstract_scale_draw.cpp.

`void QwtAbstractScaleDraw::setScaleDiv (const QwtScaleDiv & scaleDiv)`

Change the scale division

Parameters

scaleDiv — New scale division

Definition at line 104 of file qwt_abstract_scale_draw.cpp.

`void QwtAbstractScaleDraw::setSpacing (double spacing)`

Set the spacing between tick and labels. The spacing is the distance between ticks and labels. The default spacing is 4 pixels.

Parameters

spacing — Spacing

See also: spacing()

Definition at line 254 of file qwt_abstract_scale_draw.cpp.

`void QwtAbstractScaleDraw::setTickLength (QwtScaleDiv::TickType tickType, double length)`

Set the length of the ticks

Parameters

tickType — Tick type
length — New length

Warning: the length is limited to [0..1000]

Definition at line 315 of file qwt_abstract_scale_draw.cpp.

`void QwtAbstractScaleDraw::setTransformation (QwtTransform * transformation)`

Change the transformation of the scale

Parameters

transformation — New scale transformation

Definition at line 115 of file qwt_abstract_scale_draw.cpp.

`double QwtAbstractScaleDraw::spacing () const`

Get the spacing. The spacing is the distance between ticks and labels. The default spacing is 4 pixels.

Returns

Spacing

See also: setSpacing()

Definition at line 271 of file qwt_abstract_scale_draw.cpp.

`const QwtText & QwtAbstractScaleDraw::tickLabel (const QFont & font, double value) const [protected]`

Convert a value into its representing label and cache it. The conversion between value and label is called very often in the layout and painting code. Unfortunately the calculation of the label sizes might be slow (really slow for rich text in Qt4), so it's necessary to cache the labels.

Parameters

font — Font
value — Value

Returns

Tick label

Definition at line 393 of file qwt_abstract_scale_draw.cpp.

`double QwtAbstractScaleDraw::tickLength (QwtScaleDiv::TickType tickType) const`

Returns

Length of the ticks

See also: setTickLength(), maxTickLength()

Definition at line 338 of file qwt_abstract_scale_draw.cpp.

🌟 Author 🌟

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QwtAbstractScaleDraw(3)