QwtScaleDraw - Man Page
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 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.
Protected Member Functions
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
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.
Definition at line 35 of file qwt_scale_draw.h.
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.
Definition at line 42 of file qwt_scale_draw.h.
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.
Definition at line 292 of file qwt_scale_draw.cpp.
Member Function Documentation
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.
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()
Definition at line 798 of file qwt_scale_draw.cpp.
void QwtScaleDraw::drawBackbone (QPainter * painter) const [override], [protected], [virtual]
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.
void QwtScaleDraw::drawLabel (QPainter * painter, double value) const [override], [protected], [virtual]
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.
void QwtScaleDraw::drawTick (QPainter * painter, double value, double len) const [override], [protected], [virtual]
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.
double QwtScaleDraw::extent (const QFont & font) const [override], [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.
Definition at line 523 of file qwt_scale_draw.cpp.
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
Definition at line 361 of file qwt_scale_draw.cpp.
Qt::Alignment QwtScaleDraw::labelAlignment () const
- Returns
the label flags
- See also
setLabelAlignment(), labelRotation()
Definition at line 982 of file qwt_scale_draw.cpp.
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
Definition at line 596 of file qwt_scale_draw.cpp.
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
Definition at line 891 of file qwt_scale_draw.cpp.
double QwtScaleDraw::labelRotation () const
- Returns
the label rotation
- See also
setLabelRotation(), labelAlignment()
Definition at line 943 of file qwt_scale_draw.cpp.
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
Definition at line 916 of file qwt_scale_draw.cpp.
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()
Definition at line 821 of file qwt_scale_draw.cpp.
double QwtScaleDraw::length () const
- Returns
the length of the backbone
- See also
setLength(), pos()
Definition at line 753 of file qwt_scale_draw.cpp.
int QwtScaleDraw::maxLabelHeight (const QFont & font) const
- Parameters
font Font
- Returns
the maximum height of a label
Definition at line 1014 of file qwt_scale_draw.cpp.
int QwtScaleDraw::maxLabelWidth (const QFont & font) const
- Parameters
font Font
- Returns
the maximum width of a label
Definition at line 991 of file qwt_scale_draw.cpp.
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()
Definition at line 436 of file qwt_scale_draw.cpp.
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()
Definition at line 560 of file qwt_scale_draw.cpp.
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()
Definition at line 707 of file qwt_scale_draw.cpp.
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 &)
Definition at line 118 of file qwt_scale_draw.h.
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()
Definition at line 337 of file qwt_scale_draw.cpp.
QPointF QwtScaleDraw::pos () const
- Returns
Origin of the scale
- See also
move(), length()
Definition at line 717 of file qwt_scale_draw.cpp.
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()
Definition at line 322 of file qwt_scale_draw.cpp.
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().
Definition at line 973 of file qwt_scale_draw.cpp.
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().
Definition at line 934 of file qwt_scale_draw.cpp.
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()
Definition at line 732 of file qwt_scale_draw.cpp.
Author
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