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Qwt User's Guide 6.0.0
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A class for drawing scales. More...
#include <qwt_scale_draw.h>

Public Types | |
| enum | Alignment { BottomScale, TopScale, LeftScale, RightScale } |
Public Member Functions | |
| QwtScaleDraw () | |
| virtual | ~QwtScaleDraw () |
| void | getBorderDistHint (const QFont &, int &start, int &end) const |
| int | minLabelDist (const QFont &) const |
| int | minLength (const QFont &) const |
| virtual double | extent (const QFont &) const |
| void | move (double x, double y) |
| void | move (const QPointF &) |
| void | setLength (double length) |
| Alignment | alignment () const |
| void | setAlignment (Alignment) |
| Qt::Orientation | orientation () const |
| QPointF | pos () const |
| double | length () const |
| void | setLabelAlignment (Qt::Alignment) |
| Qt::Alignment | labelAlignment () const |
| void | setLabelRotation (double rotation) |
| double | labelRotation () const |
| int | maxLabelHeight (const QFont &) const |
| int | maxLabelWidth (const QFont &) const |
| QPointF | labelPosition (double val) const |
| QRectF | labelRect (const QFont &, double val) const |
| QSizeF | labelSize (const QFont &, double val) const |
| QRect | boundingLabelRect (const QFont &, double val) const |
Protected Member Functions | |
| QTransform | labelTransformation (const QPointF &, const QSizeF &) const |
| virtual void | drawTick (QPainter *, double val, double len) const |
| virtual void | drawBackbone (QPainter *) const |
| virtual void | drawLabel (QPainter *, double val) const |
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.
Alignment of the scale draw
| QwtScaleDraw::QwtScaleDraw | ( | ) |
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.
| QwtScaleDraw::~QwtScaleDraw | ( | ) | [virtual] |
Destructor.
| QwtScaleDraw::Alignment QwtScaleDraw::alignment | ( | ) | const |
Return alignment of the scale
| QRect QwtScaleDraw::boundingLabelRect | ( | const QFont & | font, |
| double | value | ||
| ) | const |
Find the bounding rect for the label. The coordinates of the rect are absolute coordinates ( calculated from pos() ). in direction of the tick.
| font | Font used for painting |
| value | Value |
| void QwtScaleDraw::drawBackbone | ( | QPainter * | painter | ) | const [protected, virtual] |
Draws the baseline of the scale
| painter | Painter |
Implements QwtAbstractScaleDraw.
| void QwtScaleDraw::drawLabel | ( | QPainter * | painter, |
| double | value | ||
| ) | const [protected, virtual] |
Draws the label for a major scale tick
| painter | Painter |
| value | Value |
Implements QwtAbstractScaleDraw.
| void QwtScaleDraw::drawTick | ( | QPainter * | painter, |
| double | value, | ||
| double | len | ||
| ) | const [protected, virtual] |
Draw a tick
| painter | Painter |
| value | Value of the tick |
| len | Lenght of the tick |
Implements QwtAbstractScaleDraw.
| double QwtScaleDraw::extent | ( | const QFont & | font | ) | const [virtual] |
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.
| font | Font used for painting the labels |
Implements QwtAbstractScaleDraw.
| void QwtScaleDraw::getBorderDistHint | ( | const QFont & | font, |
| int & | start, | ||
| int & | end | ||
| ) | const |
Determine the minimum border distance.
This member function returns the minimum space needed to draw the mark labels at the scale's endpoints.
| font | Font |
| start | Start border distance |
| end | End border distance |
| Qt::Alignment QwtScaleDraw::labelAlignment | ( | ) | const |
| QPointF QwtScaleDraw::labelPosition | ( | double | value | ) | const |
Find the position, where to paint a label
The position has a distance of majTickLength() + spacing() + 1 from the backbone. The direction depends on the alignment()
| value | Value |
| QRectF QwtScaleDraw::labelRect | ( | const QFont & | font, |
| double | value | ||
| ) | const |
Find the bounding rect for the label. The coordinates of the rect are relative to spacing + ticklength from the backbone in direction of the tick.
| font | Font used for painting |
| value | Value |
| double QwtScaleDraw::labelRotation | ( | ) | const |
| QSizeF QwtScaleDraw::labelSize | ( | const QFont & | font, |
| double | value | ||
| ) | const |
Calculate the size that is needed to draw a label
| font | Label font |
| value | Value |
| QTransform QwtScaleDraw::labelTransformation | ( | const QPointF & | pos, |
| const QSizeF & | size | ||
| ) | const [protected] |
Calculate the transformation that is needed to paint a label depending on its alignment and rotation.
| pos | Position where to paint the label |
| size | Size of the label |
| double QwtScaleDraw::length | ( | ) | const |
| int QwtScaleDraw::maxLabelHeight | ( | const QFont & | font | ) | const |
| font | Font |
| int QwtScaleDraw::maxLabelWidth | ( | const QFont & | font | ) | const |
| font | Font |
| int QwtScaleDraw::minLabelDist | ( | const QFont & | font | ) | const |
Determine the minimum distance between two labels, that is necessary that the texts don't overlap.
| font | Font |
| int QwtScaleDraw::minLength | ( | const QFont & | font | ) | const |
Calculate the minimum length that is needed to draw the scale
| font | Font used for painting the labels |
| void QwtScaleDraw::move | ( | double | x, |
| double | y | ||
| ) | [inline] |
Move the position of the scale
| void QwtScaleDraw::move | ( | const QPointF & | pos | ) |
Move the position of the scale.
The meaning of the parameter pos depends on the alignment:
| pos | Origin of the scale |
| Qt::Orientation QwtScaleDraw::orientation | ( | ) | const |
Return the orientation
TopScale, BottomScale are horizontal (Qt::Horizontal) scales, LeftScale, RightScale are vertical (Qt::Vertical) scales.
| void QwtScaleDraw::setAlignment | ( | Alignment | align | ) |
Set the alignment of the scale
The default alignment is QwtScaleDraw::BottomScale
| void QwtScaleDraw::setLabelAlignment | ( | Qt::Alignment | alignment | ) |
Change the label flags.
Labels are aligned to the point ticklength + 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.
| alignment | Or'd Qt::AlignmentFlags <see qnamespace.h> |
| void QwtScaleDraw::setLabelRotation | ( | double | rotation | ) |
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.
| rotation | Angle in degrees. When changing the label rotation, the label flags often needs to be adjusted too. |
| void QwtScaleDraw::setLength | ( | double | length | ) |
Set the length of the backbone.
The length doesn't include the space needed for overlapping labels.
1.7.3