QwtScaleDraw(3) | Qwt User's Guide | QwtScaleDraw(3) |
NAME¶
QwtScaleDraw -A class for drawing scales.
SYNOPSIS¶
#include <qwt_scale_draw.h>
Inherits QwtAbstractScaleDraw.
Inherited by QwtDateScaleDraw.
Public Types¶
enum Alignment { BottomScale, TopScale, LeftScale, RightScale }
Public Member Functions¶
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
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 val) const
QRectF labelRect (const QFont &, double val) const
QSizeF labelSize (const QFont &, double val) const
QRect boundingLabelRect (const QFont &, double val) const
Find the bounding rectangle for the label.
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
Detailed Description¶
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.
Member Enumeration Documentation¶
enum QwtScaleDraw::Alignment¶
Alignment of the scale drawSee Also:
Enumerator
- BottomScale
- The scale is below.
- TopScale
- The scale is above.
- LeftScale
- The scale is left.
- RightScale
- The scale is right.
Constructor & Destructor Documentation¶
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.Member Function Documentation¶
QwtScaleDraw::Alignment QwtScaleDraw::alignment () const¶
Return alignment of the scaleSee Also:
Returns:
QRect QwtScaleDraw::boundingLabelRect (const QFont &font, doublevalue) const¶
Find the bounding rectangle for the label. The coordinates of the rectangle are absolute ( calculated from pos() ). in direction of the tick.Parameters:
value Value
Returns:
See Also:
void QwtScaleDraw::drawBackbone (QPainter *painter) const [protected], [virtual]¶
Draws the baseline of the scaleParameters:
See Also:
Implements QwtAbstractScaleDraw.
void QwtScaleDraw::drawLabel (QPainter *painter, doublevalue) const [protected], [virtual]¶
Draws the label for a major scale tickParameters:
value Value
See Also:
Implements QwtAbstractScaleDraw.
void QwtScaleDraw::drawTick (QPainter *painter, doublevalue, doublelen) const [protected], [virtual]¶
Draw a tickParameters:
value Value of the tick
len Length of the tick
See Also:
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.
Parameters:
Returns:
See Also:
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.Parameters:
start Start border distance
end End border distance
Qt::Alignment QwtScaleDraw::labelAlignment () const¶
Returns:See Also:
QPointF QwtScaleDraw::labelPosition (doublevalue) const¶
Find the position, where to paint a labelThe position has a distance that depends on the length of the ticks in direction of the alignment().
Parameters:
Returns:
QRectF QwtScaleDraw::labelRect (const QFont &font, doublevalue) const¶
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:
value Value
Returns:
double QwtScaleDraw::labelRotation () const¶
Returns:See Also:
QSizeF QwtScaleDraw::labelSize (const QFont &font, doublevalue) const¶
Calculate the size that is needed to draw a labelParameters:
value Value
Returns:
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.Parameters:
size Size of the label
Returns:
See Also:
double QwtScaleDraw::length () const¶
Returns:See Also:
int QwtScaleDraw::maxLabelHeight (const QFont &font) const¶
Parameters:Returns:
int QwtScaleDraw::maxLabelWidth (const QFont &font) const¶
Parameters:Returns:
int QwtScaleDraw::minLabelDist (const QFont &font) const¶
Determine the minimum distance between two labels, that is necessary that the texts don't overlap.Parameters:
Returns:
See Also:
int QwtScaleDraw::minLength (const QFont &font) const¶
Calculate the minimum length that is needed to draw the scaleParameters:
Returns:
See Also:
void QwtScaleDraw::move (doublex, doubley) [inline]¶
Move the position of the scaleParameters:
y Y coordinate
See Also:
void QwtScaleDraw::move (const QPointF &pos)¶
Move the position of the scale. The meaning of the parameter pos depends on the alignment:- QwtScaleDraw::LeftScale
- 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.
- QwtScaleDraw::RightScale
- 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.
- QwtScaleDraw::TopScale
- The origin is the leftmost point of the backbone. The backbone is a horizontal line. Scale marks and labels are drawn above the backbone.
- QwtScaleDraw::BottomScale
- 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:
See Also:
Qt::Orientation QwtScaleDraw::orientation () const¶
Return the orientationTopScale, BottomScale are horizontal (Qt::Horizontal) scales, LeftScale, RightScale are vertical (Qt::Vertical) scales.
Returns:
See Also:
QPointF QwtScaleDraw::pos () const¶
Returns:See Also:
void QwtScaleDraw::setAlignment (Alignmentalign)¶
Set the alignment of the scaleParameters:
The default alignment is QwtScaleDraw::BottomScale
See Also:
void QwtScaleDraw::setLabelAlignment (Qt::Alignmentalignment)¶
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:
See Also:
Warning:
void QwtScaleDraw::setLabelRotation (doublerotation)¶
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:
See Also:
void QwtScaleDraw::setLength (doublelength)¶
Set the length of the backbone.The length doesn't include the space needed for overlapping labels.
Parameters:
See Also:
Author¶
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