---
name: "QwtGrid"
section: "3"
platform: "linux"
package: "libqwt-doc"
version: "4.2.0-6"
release: "Debian 6.0 (Squeeze)"
platforms: ["linux"]
url: "https://new.carta.tech/QwtGrid"
---

# QwtGrid(3)

## NAME

QwtGrid -

## SYNOPSIS

Inherited by **QwtPlotGrid**.

## Detailed Description

A class which draws a coordinate grid.

The QwtGrid class can be used to draw a coordinate grid. A coordinate grid consists of major and minor vertical and horizontal gridlines. The locations of the gridlines are determined by the X and Y scale divisions which can be assigned with **QwtGrid::setXDiv** and **QwtGrid::setYDiv()** The **draw()** member draws the grid within a bounding rectangle.

Definition at line 32 of file qwt\_grid.h.

### Public Member Functions

**QwtGrid** ()\
 virtual **~QwtGrid** ()\
 virtual void **draw** (QPainter \*p, const QRect &r, const **QwtDiMap** &mx, const **QwtDiMap** &my) const\
 void **enableX** (bool tf)\
 bool **xEnabled** () const\
 void **enableY** (bool tf)\
 bool **yEnabled** () const\
 void **enableXMin** (bool tf)\
 bool **xMinEnabled** () const\
 void **enableYMin** (bool tf)\
 bool **yMinEnabled** () const\
 void **setXDiv** (const **QwtScaleDiv** &sx)\
 const **QwtScaleDiv** & **xScaleDiv** () const\
 void **setYDiv** (const **QwtScaleDiv** &sy)\
 const **QwtScaleDiv** & **yScaleDiv** () const\
 void **setPen** (const QPen &p)\
 void **setMajPen** (const QPen &p)\
 const QPen & **majPen** () const\
 void **setMinPen** (const QPen &p)\
 const QPen & **minPen** () const\

### Protected Member Functions

virtual void **gridChanged** ()\

## Constructor & Destructor Documentation

### QwtGrid::QwtGrid ()

Enables major grid, disables minor grid.

Definition at line 15 of file qwt\_grid.cpp.

### QwtGrid::~QwtGrid ()` [virtual]`

dtor

Definition at line 24 of file qwt\_grid.cpp.

## Member Function Documentation

### void QwtGrid::draw (QPainter \* p, const QRect & r, const QwtDiMap & mx, const QwtDiMap & my) const` [virtual]`

Draw the grid.

The grid is drawn into the bounding rectangle such that gridlines begin and end at the rectangle's borders. The X and Y maps are used to map the scale divisions into the drawing region screen.

**Parameters:**

*p* Painter \
 *r* Bounding rectangle \
 *mx* X axis map \
 *my* Y axis

Definition at line 170 of file qwt\_grid.cpp.

References QwtPainter::drawLine(), QwtScaleDiv::majCnt(), QwtScaleDiv::majMark(), QwtScaleDiv::minCnt(), QwtScaleDiv::minMark(), and QwtDiMap::transform().

Referenced by QwtPlot::drawCanvasItems().

### void QwtGrid::enableX (bool tf)

Enable or disable vertical gridlines.

**Parameters:**

*tf* Enable (TRUE) or disable

**See also:**

Minor gridlines can be enabled or disabled with **QwtGrid::enableXMin()**

Definition at line 35 of file qwt\_grid.cpp.

References gridChanged().

Referenced by QwtPlot::enableGridX().

### void QwtGrid::enableXMin (bool tf)

Enable or disable minor vertical gridlines.

**Parameters:**

*tf* Enable (TRUE) or disable

**See also:**

**QwtGrid::enableX()**

Definition at line 63 of file qwt\_grid.cpp.

References gridChanged().

Referenced by QwtPlot::enableGridXMin().

### void QwtGrid::enableY (bool tf)

Enable or disable horizontal gridlines.

**Parameters:**

*tf* Enable (TRUE) or disable

**See also:**

Minor gridlines can be enabled or disabled with **QwtGrid::enableYMin()**

Definition at line 49 of file qwt\_grid.cpp.

References gridChanged().

Referenced by QwtPlot::enableGridY().

### void QwtGrid::enableYMin (bool tf)

Enable or disable minor horizontal gridlines.

**Parameters:**

*tf* Enable (TRUE) or disable

**See also:**

**QwtGrid::enableY()**

Definition at line 77 of file qwt\_grid.cpp.

References gridChanged().

Referenced by QwtPlot::enableGridYMin().

### void QwtGrid::gridChanged ()` [protected, virtual]`

Notify a change of attributes.

This virtual function is called when an attribute of the grid has changed. It can be redefined by derived classes. The default implementation does nothing.

Reimplemented in **QwtPlotGrid**.

Definition at line 304 of file qwt\_grid.cpp.

Referenced by enableX(), enableXMin(), enableY(), enableYMin(), setMajPen(), setMinPen(), setPen(), setXDiv(), and setYDiv().

### const QPen & QwtGrid::majPen () const

**Returns:**

the pen for the major gridlines

**See also:**

**QwtGrid::setMinPen**, **QwtGrid::setPen**

Definition at line 234 of file qwt\_grid.cpp.

Referenced by QwtPlotPrintFilter::apply(), QwtPlot::gridMajPen(), and QwtPlotPrintFilter::reset().

### const QPen & QwtGrid::minPen () const

**Returns:**

the pen for the minor gridlines

**See also:**

**QwtGrid::setMinPen**, **QwtGrid::setPen**

Definition at line 243 of file qwt\_grid.cpp.

Referenced by QwtPlotPrintFilter::apply(), QwtPlot::gridMinPen(), and QwtPlotPrintFilter::reset().

### void QwtGrid::setMajPen (const QPen & p)

Assign a pen for the major gridlines.

**Parameters:**

*p* Pen

Definition at line 136 of file qwt\_grid.cpp.

References gridChanged().

Referenced by QwtPlotPrintFilter::apply(), QwtPlotPrintFilter::reset(), and QwtPlot::setGridMajPen().

### void QwtGrid::setMinPen (const QPen & p)

Assign a pen for the minor gridlines.

**Parameters:**

*p* Pen

Definition at line 149 of file qwt\_grid.cpp.

References gridChanged().

Referenced by QwtPlotPrintFilter::apply(), QwtPlotPrintFilter::reset(), and QwtPlot::setGridMinPen().

### void QwtGrid::setPen (const QPen & p)

Assign a pen for both major and minor gridlines.

**Parameters:**

*p* Pen

Definition at line 122 of file qwt\_grid.cpp.

References gridChanged().

Referenced by QwtPlot::setGridPen().

### void QwtGrid::setXDiv (const QwtScaleDiv & sx)

Assign an x axis scale division.

**Parameters:**

*sx* Scale division

**Warning:**

QwtGrid uses implicit sharing (see Qt Manual) for the scale divisions.

**See also:**

**QwtScaleDiv**

Definition at line 93 of file qwt\_grid.cpp.

References gridChanged().

Referenced by QwtPlot::setGridXAxis(), and QwtPlot::updateAxes().

### void QwtGrid::setYDiv (const QwtScaleDiv & sy)

Assign a y axis division.

**Parameters:**

*sy* Scale division

**Warning:**

QwtGrid uses implicit sharing (see Qt Manual) for the scale divisions.

**See also:**

**QwtScaleDiv**

Definition at line 109 of file qwt\_grid.cpp.

References gridChanged().

Referenced by QwtPlot::setGridYAxis(), and QwtPlot::updateAxes().

### bool QwtGrid::xEnabled () const

**Returns:**

TRUE if vertical gridlines are enabled

**See also:**

**QwtGrid::enableX**

Definition at line 252 of file qwt\_grid.cpp.

Referenced by QwtPlot::gridXEnabled().

### bool QwtGrid::xMinEnabled () const

**Returns:**

TRUE if minor vertical gridlines are enabled

**See also:**

**QwtGrid::enableXMin**

Definition at line 261 of file qwt\_grid.cpp.

Referenced by QwtPlot::gridXMinEnabled().

### const QwtScaleDiv & QwtGrid::xScaleDiv () const

**Returns:**

the scale division of the x axis

Definition at line 286 of file qwt\_grid.cpp.

### bool QwtGrid::yEnabled () const

**Returns:**

TRUE if horizontal gridlines are enabled

**See also:**

**QwtGrid::enableY**

Definition at line 270 of file qwt\_grid.cpp.

Referenced by QwtPlot::gridYEnabled().

### bool QwtGrid::yMinEnabled () const

**Returns:**

TRUE if minor horizontal gridlines are enabled

**See also:**

**QwtGrid::enableYMin**

Definition at line 279 of file qwt\_grid.cpp.

Referenced by QwtPlot::gridYMinEnabled().

### const QwtScaleDiv & QwtGrid::yScaleDiv () const

**Returns:**

the scale division of the y axis

Definition at line 292 of file qwt\_grid.cpp.

## Author

Generated automatically by Doxygen for Qwt User's Guide from the source code.