QwtScaleDraw(3) Qwt User's Guide QwtScaleDraw(3)

QwtScaleDraw - A class for drawing scales.

#include <qwt_scale_draw.h>

Inherits QwtAbstractScaleDraw.

Inherited by QwtDateScaleDraw.


enum Alignment { BottomScale, TopScale, LeftScale, RightScale }


QwtScaleDraw ()
Constructor. virtual ~QwtScaleDraw ()
Destructor. void getBorderDistHint (const QFont &, int &start, int &end) const
Determine the minimum border distance. int minLabelDist (const QFont &) const
int minLength (const QFont &) const
virtual double extent (const QFont &) const override
void move (double x, double y)
void move (const QPointF &)
Move the position of the scale. void setLength (double length)
Alignment alignment () const
void setAlignment (Alignment)
Qt::Orientation orientation () const
QPointF pos () const
double length () const
void setLabelAlignment (Qt::Alignment)
Change the label flags. Qt::Alignment labelAlignment () const
void setLabelRotation (double rotation)
double labelRotation () const
int maxLabelHeight (const QFont &) const
int maxLabelWidth (const QFont &) const
QPointF labelPosition (double value) const
QRectF labelRect (const QFont &, double value) const
QSizeF labelSize (const QFont &, double value) const
QRect boundingLabelRect (const QFont &, double value) const
Find the bounding rectangle for the label.


QTransform labelTransformation (const QPointF &, const QSizeF &) const
virtual void drawTick (QPainter *, double value, double len) const override
virtual void drawBackbone (QPainter *) const override
virtual void drawLabel (QPainter *, double value) const override

A class for drawing scales.

QwtScaleDraw can be used to draw linear or logarithmic scales. A scale has a position, an alignment and a length, which can be specified . The labels can be rotated and aligned to the ticks using setLabelRotation() and setLabelAlignment().

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

Definition at line 35 of file qwt_scale_draw.h.

Alignment of the scale draw

See also

setAlignment(), alignment()

Enumerator

The scale is below.
The scale is above.
The scale is left.
The scale is right.

Definition at line 42 of file qwt_scale_draw.h.

Constructor. The range of the scale is initialized to [0, 100], The position is at (0, 0) with a length of 100. The orientation is QwtAbstractScaleDraw::Bottom.

Definition at line 292 of file qwt_scale_draw.cpp.

QwtScaleDraw::Alignment QwtScaleDraw::alignment () const

Return alignment of the scale

See also

setAlignment()

Returns

Alignment of the scale

Definition at line 309 of file qwt_scale_draw.cpp.

Find the bounding rectangle for the label. The coordinates of the rectangle are absolute ( calculated from pos() ). in direction of the tick.

Parameters

font Font used for painting
value Value

Returns

Bounding rectangle

See also

labelRect()

Definition at line 798 of file qwt_scale_draw.cpp.

Draws the baseline of the scale

Parameters

painter Painter

See also

drawTick(), drawLabel()

Implements QwtAbstractScaleDraw.

Definition at line 668 of file qwt_scale_draw.cpp.

Draws the label for a major scale tick

Parameters

painter Painter
value Value

See also

drawTick(), drawBackbone(), boundingLabelRect()

Implements QwtAbstractScaleDraw.

Definition at line 766 of file qwt_scale_draw.cpp.

Draw a tick

Parameters

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

See also

drawBackbone(), drawLabel()

Implements QwtAbstractScaleDraw.

Definition at line 649 of file qwt_scale_draw.cpp.

Calculate the width/height that is needed for a vertical/horizontal scale.

The extent is calculated from the pen width of the backbone, the major tick length, the spacing and the maximum width/height of the labels.

Parameters

font Font used for painting the labels

Returns

Extent

See also

minLength()

Implements QwtAbstractScaleDraw.

Definition at line 523 of file qwt_scale_draw.cpp.

Determine the minimum border distance. This member function returns the minimum space needed to draw the mark labels at the scale's endpoints.

Parameters

font Font
start Start border distance
end End border distance

Definition at line 361 of file qwt_scale_draw.cpp.

Returns

the label flags

See also

setLabelAlignment(), labelRotation()

Definition at line 982 of file qwt_scale_draw.cpp.

Find the position, where to paint a label

The position has a distance that depends on the length of the ticks in direction of the alignment().

Parameters

value Value

Returns

Position, where to paint a label

Definition at line 596 of file qwt_scale_draw.cpp.

Find the bounding rectangle for the label. The coordinates of the rectangle are relative to spacing + tick length from the backbone in direction of the tick.

Parameters

font Font used for painting
value Value

Returns

Bounding rectangle that is needed to draw a label

Definition at line 891 of file qwt_scale_draw.cpp.

Returns

the label rotation

See also

setLabelRotation(), labelAlignment()

Definition at line 943 of file qwt_scale_draw.cpp.

Calculate the size that is needed to draw a label

Parameters

font Label font
value Value

Returns

Size that is needed to draw a label

Definition at line 916 of file qwt_scale_draw.cpp.

Calculate the transformation that is needed to paint a label depending on its alignment and rotation.

Parameters

pos Position where to paint the label
size Size of the label

Returns

Transformation matrix

See also

setLabelAlignment(), setLabelRotation()

Definition at line 821 of file qwt_scale_draw.cpp.

Returns

the length of the backbone

See also

setLength(), pos()

Definition at line 753 of file qwt_scale_draw.cpp.

Parameters

font Font

Returns

the maximum height of a label

Definition at line 1014 of file qwt_scale_draw.cpp.

Parameters

font Font

Returns

the maximum width of a label

Definition at line 991 of file qwt_scale_draw.cpp.

Determine the minimum distance between two labels, that is necessary that the texts don't overlap.

Parameters

font Font

Returns

The maximum width of a label

See also

getBorderDistHint()

Definition at line 436 of file qwt_scale_draw.cpp.

Calculate the minimum length that is needed to draw the scale

Parameters

font Font used for painting the labels

Returns

Minimum length that is needed to draw the scale

See also

extent()

Definition at line 560 of file qwt_scale_draw.cpp.

Move the position of the scale. The meaning of the parameter pos depends on the alignment:

The origin is the topmost point of the backbone. The backbone is a vertical line. Scale marks and labels are drawn at the left of the backbone.
The origin is the topmost point of the backbone. The backbone is a vertical line. Scale marks and labels are drawn at the right of the backbone.
The origin is the leftmost point of the backbone. The backbone is a horizontal line. Scale marks and labels are drawn above the backbone.
The origin is the leftmost point of the backbone. The backbone is a horizontal line Scale marks and labels are drawn below the backbone.

Parameters

pos Origin of the scale

See also

pos(), setLength()

Definition at line 707 of file qwt_scale_draw.cpp.

Move the position of the scale

Parameters

x X coordinate
y Y coordinate

See also

move(const QPointF &)

Definition at line 118 of file qwt_scale_draw.h.

Return the orientation

TopScale, BottomScale are horizontal (Qt::Horizontal) scales, LeftScale, RightScale are vertical (Qt::Vertical) scales.

Returns

Orientation of the scale

See also

alignment()

Definition at line 337 of file qwt_scale_draw.cpp.

Returns

Origin of the scale

See also

move(), length()

Definition at line 717 of file qwt_scale_draw.cpp.

Set the alignment of the scale

Parameters

align Alignment of the scale

The default alignment is QwtScaleDraw::BottomScale

See also

alignment()

Definition at line 322 of file qwt_scale_draw.cpp.

Change the label flags. Labels are aligned to the point tick length + spacing away from the backbone.

The alignment is relative to the orientation of the label text. In case of an flags of 0 the label will be aligned depending on the orientation of the scale:

QwtScaleDraw::TopScale: Qt::AlignHCenter | Qt::AlignTop
QwtScaleDraw::BottomScale: Qt::AlignHCenter | Qt::AlignBottom
QwtScaleDraw::LeftScale: Qt::AlignLeft | Qt::AlignVCenter
QwtScaleDraw::RightScale: Qt::AlignRight | Qt::AlignVCenter
Changing the alignment is often necessary for rotated labels.

Parameters

alignment Or'd Qt::AlignmentFlags see <qnamespace.h>

See also

setLabelRotation(), labelRotation(), labelAlignment()

Warning

The various alignments might be confusing. The alignment of the label is not the alignment of the scale and is not the alignment of the flags ( QwtText::flags() ) returned from QwtAbstractScaleDraw::label().

Definition at line 973 of file qwt_scale_draw.cpp.

Rotate all labels.

When changing the rotation, it might be necessary to adjust the label flags too. Finding a useful combination is often the result of try and error.

Parameters

rotation Angle in degrees. When changing the label rotation, the label flags often needs to be adjusted too.

See also

setLabelAlignment(), labelRotation(), labelAlignment().

Definition at line 934 of file qwt_scale_draw.cpp.

Set the length of the backbone.

The length doesn't include the space needed for overlapping labels.

Parameters

length Length of the backbone

See also

move(), minLabelDist()

Definition at line 732 of file qwt_scale_draw.cpp.

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