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# QwtScaleDiv Class Reference

List of all members.

## Detailed Description

A class for building scale divisions.

The QwtScaleDiv class can build linear and logarithmic scale divisions for specified intervals. It uses an adjustable algorithm to generate the major and minor step widths automatically. A scale division has a minimum value, a maximum value, a vector of major marks, and a vector of minor marks.

Warning:
  QwtScaleDiv uses implicit sharing for the mark vectors.

Example
  To build a logarithmic scale division from 0.01 to 1000 and print out the major and minor marks.

      #include "../include/qwt_scldiv.h>
      #include <iostream.h>

      main()
      {
        int i,k;
        QwtScaleDiv sd;

        sd.rebuild(0.01, 100, 10, 10, TRUE, 0.0);

        k=0;
        for (i=0;i<sd.majCnt();i++)
        {
          while(k < sd.minCnt())
          {
            if (sd.minMark(k) < sd.majMark(i))
            {
              cout << " - " << sd.minMark(i) << "\n";
          k++;
            }
            else
              break;
          }
          cout << "-- " << sd.majMark(i) << "\n";
        }
        while(k < sd.minCnt())
        {
          cout << " - " << sd.minMark(i) << "\n";
          k++;
        }
      }

Definition at line 69 of file qwt_scldiv.h.

## Public Member Functions
| QwtScaleDiv ()
int | operator== (const QwtScaleDiv &s) const
int | operator!= (const QwtScaleDiv &s) const
double | lBound () const
double | hBound () const
uint | minCnt () const
uint | majCnt () const
bool | logScale () const
double | majMark (int i) const
double | minMark (int i) const
double | majStep () const
void | reset ()
bool | rebuild (double lBound, double hBound, int maxMaj, int maxMin, bool log, double step=0.0, bool ascend=TRUE)

## Constructor & Destructor Documentation

QwtScaleDiv::QwtScaleDiv | ( |  | ) |

| Construct a QwtScaleDiv instance. Definition at line 42 of file qwt_scldiv.cpp.

## Member Function Documentation

double QwtScaleDiv::hBound | ( |  | ) | const

| Returns: right bound See also: QwtScaleDiv::rebuild Definition at line 86 of file qwt_scldiv.h. Referenced by QwtPlot::canvasMap(), QwtPlot::print(), QwtPlotPicker::scaleRect(), QwtScaleDraw::setScale(), QwtScaleIf::setScaleMaxMajor(), and QwtScaleIf::setScaleMaxMinor().

double QwtScaleDiv::lBound | ( |  | ) | const

| Returns: left bound See also: QwtScaleDiv::rebuild Definition at line 81 of file qwt_scldiv.h. Referenced by QwtPlot::canvasMap(), QwtPlot::print(), QwtPlotPicker::scaleRect(), QwtScaleDraw::setScale(), QwtScaleIf::setScaleMaxMajor(), and QwtScaleIf::setScaleMaxMinor().

bool QwtScaleDiv::logScale | ( |  | ) | const

| Returns: TRUE id ths scale div is logarithmic See also: QwtScaleDiv::rebuild Definition at line 102 of file qwt_scldiv.h. Referenced by QwtPlot::canvasMap(), QwtScaleDraw::draw(), QwtScaleDraw::labelPlacement(), QwtScaleDraw::maxLabelHeight(), QwtScaleDraw::maxLabelWidth(), QwtPlot::print(), QwtScaleDraw::setScale(), QwtScaleIf::setScaleMaxMajor(), and QwtScaleIf::setScaleMaxMinor().

uint QwtScaleDiv::majCnt | ( |  | ) | const

| Returns: major mark count See also: QwtScaleDiv::rebuild Definition at line 96 of file qwt_scldiv.h. Referenced by QwtScaleDraw::draw(), QwtGrid::draw(), QwtScaleDraw::maxLabelHeight(), QwtScaleDraw::maxLabelWidth(), QwtScaleDraw::minBorderDist(), QwtScaleDraw::minHeight(), QwtScaleDraw::minLabelDist(), QwtScaleDraw::minWidth(), QwtScaleIf::setScale(), and QwtPlot::sizeHint().

double QwtScaleDiv::majMark | ( | int | i | ) | const

| Return major mark at position i. Definition at line 105 of file qwt_scldiv.h. Referenced by QwtScaleDraw::draw(), QwtGrid::draw(), QwtScaleDraw::maxLabelHeight(), QwtScaleDraw::maxLabelWidth(), QwtScaleDraw::minBorderDist(), and QwtScaleDraw::minLabelDist().

double QwtScaleDiv::majStep | ( |  | ) | const

| Returns: major step size See also: QwtScaleDiv::rebuild Definition at line 113 of file qwt_scldiv.h. Referenced by QwtScaleDraw::draw(), QwtScaleDraw::labelPlacement(), QwtScaleDraw::maxLabelHeight(), and QwtScaleDraw::maxLabelWidth().

uint QwtScaleDiv::minCnt | ( |  | ) | const

| Returns: minor mark count See also: QwtScaleDiv::rebuild Definition at line 91 of file qwt_scldiv.h. Referenced by QwtScaleDraw::draw(), QwtGrid::draw(), QwtScaleDraw::minHeight(), QwtScaleDraw::minWidth(), and QwtScaleIf::setScale().

double QwtScaleDiv::minMark | ( | int | i | ) | const

| Return minor mark at position i. Definition at line 107 of file qwt_scldiv.h. Referenced by QwtScaleDraw::draw(), and QwtGrid::draw().

int QwtScaleDiv::operator!= | ( | const QwtScaleDiv & | s | ) | const

| Inequality. Returns: TRUE if this instance is not equal to s Definition at line 439 of file qwt_scldiv.cpp.

int QwtScaleDiv::operator== | ( | const QwtScaleDiv & | s | ) | const

| Equality operator. Returns: TRUE if this instance is equal to s Definition at line 425 of file qwt_scldiv.cpp. References d_hBound, d_lBound, d_log, d_majMarks, d_majStep, and d_minMarks.

bool QwtScaleDiv::rebuild | ( | double | x1,
|  | double | x2,
|  | int | maxMajSteps,
|  | int | maxMinSteps,
|  | bool | log,
|  | double | step = `0.0`,
|  | bool | ascend = `TRUE`
| ) |

  | Build a scale width major and minor divisions If no fixed step width is specified or if it is set to 0, the major step width will be calculated automatically according to the the value of maxMajSteps. The maxMajSteps parameter has no effect if a fixed step size is specified. The minor step width is always calculated automatically. If the step width is to be calculated automatically, the algorithm tries to find reasonable values fitting into the scheme {1,2,5}*10^n with an integer number n for linear scales. For logarithmic scales, there are three different cases If the major step width is one decade, the minor marks will fit into one of the schemes {1,2,...9}, {2,4,6,8}, {2,5} or {5}, depending on the maxMinSteps parameter. If the major step size spans more than one decade, the minor step size will be {1,2,5}*10^n decades with a natural number n. If the whole range is less than one decade, a linear scale division will be built. Parameters:
  | x1 | first boundary value
  | x2 | second boundary value
  | maxMajSteps | max. number of major step intervals
  | maxMinSteps | max. number of minor step intervals
  | log | logarithmic division (TRUE/FALSE)
  | step | fixed major step width. Defaults to 0.0.
  | ascend | if TRUE, sort in ascending order from min(x1, x2) to max(x1, x2). If FALSE, sort in the direction from x1 to x2. Defaults to TRUE.
Returns: True if the arrays have been allocated successfully. Warning: For logarithmic scales, the step width is measured in decades. Definition at line 86 of file qwt_scldiv.cpp. Referenced by QwtAutoScale::build(), QwtAutoScale::buildLinScale(), QwtAutoScale::buildLogScale(), and QwtScaleDraw::setScale().

void QwtScaleDiv::reset | ( |  | ) |

| Detach the shared data and set everything to zero. Definition at line 445 of file qwt_scldiv.cpp. Referenced by QwtAutoScale::reset().