Provided by: libqwt-doc_6.1.4-2_all 
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 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.
Protected Member Functions
QTransform labelTransformation (const QPointF &, const QSizeF &) const
virtual void drawTick (QPainter *, double value, double len) const
virtual void drawBackbone (QPainter *) const
virtual void drawLabel (QPainter *, double value) 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 draw
See also:
setAlignment(), alignment()
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 scale
See also:
setAlignment()
Returns:
Alignment of the scale
QRect QwtScaleDraw::boundingLabelRect (const QFont & font, double value) const
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()
void QwtScaleDraw::drawBackbone (QPainter * painter) const [protected], [virtual]
Draws the baseline of the scale
Parameters:
painter Painter
See also:
drawTick(), drawLabel()
Implements QwtAbstractScaleDraw.
void QwtScaleDraw::drawLabel (QPainter * painter, double value) const [protected], [virtual]
Draws the label for a major scale tick
Parameters:
painter Painter
value Value
See also:
drawTick(), drawBackbone(), boundingLabelRect()
Implements QwtAbstractScaleDraw.
void QwtScaleDraw::drawTick (QPainter * painter, double value, double len) const [protected],
[virtual]
Draw a tick
Parameters:
painter Painter
value Value of the tick
len Length of the tick
See also:
drawBackbone(), drawLabel()
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:
font Font used for painting the labels
Returns:
Extent
See also:
minLength()
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:
font Font
start Start border distance
end End border distance
Qt::Alignment QwtScaleDraw::labelAlignment () const
Returns:
the label flags
See also:
setLabelAlignment(), labelRotation()
QPointF QwtScaleDraw::labelPosition (double value) const
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
QRectF QwtScaleDraw::labelRect (const QFont & font, double value) 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:
font Font used for painting
value Value
Returns:
Bounding rectangle that is needed to draw a label
double QwtScaleDraw::labelRotation () const
Returns:
the label rotation
See also:
setLabelRotation(), labelAlignment()
QSizeF QwtScaleDraw::labelSize (const QFont & font, double value) const
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
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:
pos Position where to paint the label
size Size of the label
Returns:
Transformation matrix
See also:
setLabelAlignment(), setLabelRotation()
double QwtScaleDraw::length () const
Returns:
the length of the backbone
See also:
setLength(), pos()
int QwtScaleDraw::maxLabelHeight (const QFont & font) const
Parameters:
font Font
Returns:
the maximum height of a label
int QwtScaleDraw::maxLabelWidth (const QFont & font) const
Parameters:
font Font
Returns:
the maximum width of a label
int QwtScaleDraw::minLabelDist (const QFont & font) const
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()
int QwtScaleDraw::minLength (const QFont & font) const
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()
void QwtScaleDraw::move (double x, double y) [inline]
Move the position of the scale
Parameters:
x X coordinate
y Y coordinate
See also:
move(const QPointF &)
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:
pos Origin of the scale
See also:
pos(), setLength()
Qt::Orientation QwtScaleDraw::orientation () const
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()
QPointF QwtScaleDraw::pos () const
Returns:
Origin of the scale
See also:
move(), length()
void QwtScaleDraw::setAlignment (Alignment align)
Set the alignment of the scale
Parameters:
align Alignment of the scale
The default alignment is QwtScaleDraw::BottomScale
See also:
alignment()
void QwtScaleDraw::setLabelAlignment (Qt::Alignment alignment)
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().
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.
Parameters:
rotation Angle in degrees. When changing the label rotation, the label flags often
needs to be adjusted too.
See also:
setLabelAlignment(), labelRotation(), labelAlignment().
void QwtScaleDraw::setLength (double length)
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()
Author
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