QwtScaleDraw(3)

NAME
QwtScaleDraw - A class for drawing scales.

SYNOPSIS

#include <qwt_scldraw.h>

Inherits QwtDiMap.

  Public Types
enum Orientation { Bottom, Top, Left, Right, Round }

  Public Methods
QwtScaleDraw ()
void setScale (const QwtScaleDiv &s)
void setScale (double vmin, double vmax, int maxMajIntv, int maxMinIntv, double step=0.0, int logarithmic=0)
void setGeometry (int xorigin, int yorigin, int length, Orientation o)
void setAngleRange (double angle1, double angle2)
void setLabelFormat (char f, int prec)
const QwtScaleDiv & scaleDiv () const
Orientation orientation () const
QRect maxBoundingRect (QPainter *p) const
int maxWidth (QPainter *p, bool worst=TRUE) const
int maxHeight (QPainter *p) const
int maxLabelWidth (QPainter *p, int worst=TRUE) const
void labelFormat (char &f, int &prec) const
void draw (QPainter *p) const

DETAILED DESCRIPTION

A class for drawing scales.

 QwtScaleDraw can be used to draw linear or logarithmic scales. A scale has an origin, an orientation and a length, which all can be specified with setGeometry().

After a scale division has been specified as a QwtScaleDiv object using setScale(const QwtScaleDiv &s), or determined internally using setScale(double vmin, double vmax, int maxMajIntv, int maxMinIntv, double step = 0.0, int logarithmic = 0), the scale can be drawn with the QwtScaleDiv::draw() member.

CONSTRUCTOR & DESTRUCTOR DOCUMENTATION

  QwtScaleDraw::QwtScaleDraw ()

Constructor.

 The range of the scale is initialized to [0, 100], the angle range is set to [-135, 135], the geometry is initialized such that the origin is at (0,0), the length is 100, and the orientation is QwtScaleDraw::Bottom.

MEMBER FUNCTION DOCUMENTATION

  void QwtScaleDraw::draw (QPainter * p) const

Draw the scale.

Parameters:

p   the painter

  void QwtScaleDraw::labelFormat (char & f, int & prec) const

Format character and precision have the same meaning as for the QString class.

Return values:

f   format character

prec
    Returns:
    the number format for the major scale labels

See also:
QString::setNum in the Qt manual

  QRect QwtScaleDraw::maxBoundingRect (QPainter * p) const

The bounding rectangle is not very exact for round scales with strange angle ranges.

Parameters:

p   painter

Returns:
the maximum bounding rectangle of the scale for a specified painter

  int QwtScaleDraw::maxHeight (QPainter * p) const

Parameters:

p   painter

Returns:
the maximum height of the scale for the specified painter

  int QwtScaleDraw::maxLabelWidth (QPainter * p, int worst = TRUE) const

Parameters:

p   painter

worst
    If TRUE, take the worst case. If FALSE, take the actual width of the largest label.

Returns:
the maximum width of a label

  int QwtScaleDraw::maxWidth (QPainter * p, bool worst = TRUE) const

Parameters:

p   painter

worst
    if TRUE, assume the worst possible case. If FALSE, calculate the real maximum width, which is more CPU intensive.

Returns:
the maximum width of the scale for a specified QPainter

  Orientation QwtScaleDraw::orientation () const

Returns:
scale orientation

  const QwtScaleDiv& QwtScaleDraw::scaleDiv () const

Returns:
scale division

  void QwtScaleDraw::setAngleRange (double angle1, double angle2)

Adjust the baseline circle segment for round scales.

 The baseline will be drawn from min(angle1,angle2) to max(angle1, angle2). The settings have no effect if the scale orientation is not set to QwtScaleDraw::Round. The default setting is [ -135, 135 ]. An angle of 0 degrees corresponds to the 12 o'clock position, and positive angles count in a clockwise direction.

Parameters:

angle1

angle2
    boundaries of the angle interval in degrees.

Warning:

The angle range is limited to [-360, 360] degrees. Angles exceeding this range will be clipped.

For angles more than 359 degrees above or below min(angle1, angle2), scale marks will not be drawn.

If you need a counterclockwise scale, use QwtScaleDiv::setRange

  void QwtScaleDraw::setGeometry (int xorigin, int yorigin, int length, Orientation o)

Specify the geometry of the scale.

 The parameters xorigin, yorigin and length have different meanings, dependent on the orientation:

QwtScaleDraw::Left
    The origin is the topmost point of the baseline. The baseline is a vertical line with the specified length. Scale marks and labels are drawn at the left of the baseline.

QwtScaleDraw::Right
    The origin is the topmost point of the baseline. The baseline is a vertical line with the specified length. Scale marks and labels are drawn at the right of the baseline.

QwtScaleDraw::Top
    The origin is the leftmost point of the baseline. The baseline is a horizontal line with the specified length. Scale marks and labels are drawn above the baseline.

QwtScaleDraw::Bottom
    The origin is the leftmost point of the baseline. The baseline is a horizontal line with the specified length. Scale marks and labels are drawn below the baseline.

QwtScaleDraw::Round
    The origin is the top left corner of the bounding rectangle of the baseline circle. The baseline is the segment of a circle with a diameter of the specified length. Scale marks and labels are drawn outside the baseline circle.

Parameters:

xorigin
    x coordinate of the origin

yorigin
    y coordinate of the origin

length
    length or diameter of the scale

o   The orientation

  void QwtScaleDraw::setLabelFormat (char f, int prec)

Set the number format for the major scale labels.

 Format character and precision have the same meaning as for the QString class.

Parameters:

f   format character

prec
    precision

See also:
QString::setNum in the Qt manual

  void QwtScaleDraw::setScale (double x1, double x2, int maxMajIntv, int maxMinIntv, double step = 0.0, int logscale = 0)

Adjust the range of the scale.

 If step == 0.0, the step width is calculated automatically dependent on the maximal number of scale ticks.

Parameters:

x1  value at the left/low endpoint of the scale

x2  value at the right/high endpoint of the scale

step
    step size (default : 0.0)

logscale
    logarithmic scale (default : 0)

  void QwtScaleDraw::setScale (const QwtScaleDiv & s)

Change the scale division.

Parameters:

sd  new scale division

AUTHOR

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