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# QGridView Class Reference

The QGridView class provides an abstract base for fixed-size grids. More...

    #include <QGridView>

This class is part of the Qt 3 compatibility library. It is provided to keep old source code working. We strongly advise against using it in new code.

Inherits QScrollView.

- List of all members, including inherited members

### Writable Properties

- cellHeight : int
- cellWidth : int
- numCols : int
- numRows : int

- 4 writable properties inherited from QScrollView
- 5 writable properties inherited from QFrame
- 33 writable properties inherited from QWidget
- 1 writable property inherited from QObject

### Read-Only Properties

- 6 read-only properties inherited from QScrollView
- 1 read-only property inherited from QFrame
- 24 read-only properties inherited from QWidget

### Public Functions

- QGridView ( QWidget * parent = 0, const char * name = 0, Qt::WFlags f = 0 )
- ~QGridView ()
- QRect cellGeometry ( int row, int column )
- QRect cellRect () const
- int columnAt ( int x ) const
- void ensureCellVisible ( int row, int column )
- QSize gridSize () const
- void repaintCell ( int row, int column, bool erase = true )
- int rowAt ( int y ) const
- void updateCell ( int row, int column )

- 32 public functions inherited from QScrollView
- 2 public functions inherited from QFrame
- 83 public functions inherited from QWidget
- 24 public functions inherited from QObject
- 2 public functions inherited from QPaintDevice

### Public Slots

- 8 public slots inherited from QScrollView
- 16 public slots inherited from QWidget
- 1 public slot inherited from QObject

### Signals

- 5 signals inherited from QScrollView
- 1 signal inherited from QObject

### Static Public Members

- 4 static public members inherited from QWidget
- 4 static public members inherited from QObject

### Protected Functions

- virtual void dimensionChange ( int oldNumRows, int oldNumCols )
- virtual void paintCell ( QPainter * p, int row, int col ) = 0
- virtual void paintEmptyArea ( QPainter * p, int cx, int cy, int cw, int ch )

- 22 protected functions inherited from QScrollView
- 44 protected functions inherited from QWidget
- 9 protected functions inherited from QObject

## Detailed Description

The QGridView class provides an abstract base for fixed-size grids.

A grid view consists of a number of abstract cells organized in rows and columns. The cells have a fixed size and are identified with a row index and a column index. The top-left cell is in row 0, column 0. The bottom-right cell is in row numRows()-1, column numCols()-1.

You can define numRows, numCols, cellWidth and cellHeight. Reimplement the pure virtual function paintCell() to draw the contents of a cell.

With ensureCellVisible(), you can ensure a certain cell is visible. With rowAt() and columnAt() you can find a cell based on the given x- and y-coordinates.

If you need to monitor changes to the grid's dimensions (i.e. when numRows or numCols is changed), reimplement the dimensionChange() change handler.

Note: the row and column indexes are always given in the order, row (vertical offset) then column (horizontal offset). This order is the opposite of all pixel operations, which are given in the order x (horizontal offset), y (vertical offset).

QGridView is a very simple abstract class based on QScrollView. It is designed to simplify the task of drawing many cells of the same size in a potentially scrollable canvas. If you need rows and columns with different sizes, use a QTable instead. If you need a simple list of items, use a QListBox. If you need to present hierachical data use a QListView, and if you need random objects at random positions, consider using either a QIconView or a QCanvas.

## Property Documentation

### cellHeight : int

This property holds the height of a grid row.

All rows in a grid view have the same height.

Access functions:

- int cellHeight () const
- virtual void setCellHeight ( int )

See also cellWidth.

### cellWidth : int

This property holds the width of a grid column.

All columns in a grid view have the same width.

Access functions:

- int cellWidth () const
- virtual void setCellWidth ( int )

See also cellHeight.

### numCols : int

This property holds the number of columns in the grid.

Access functions:

- int numCols () const
- virtual void setNumCols ( int )

See also numRows.

### numRows : int

This property holds the number of rows in the grid.

Access functions:

- int numRows () const
- virtual void setNumRows ( int )

See also numCols.

## Member Function Documentation

### QGridView::QGridView ( QWidget * parent = 0, const char * name = 0, Qt::WFlags f = 0 )

Constructs a grid view.

The parent, name and widget flag, f, arguments are passed to the QScrollView constructor.

### QGridView::~QGridView ()

Destroys the grid view.

### QRect QGridView::cellGeometry ( int row, int column )

Returns the geometry of cell (row, column) in the content coordinate system.

See also cellRect().

### QRect QGridView::cellRect () const

Returns the geometry of a cell in a cell's coordinate system. This is a convenience function useful in paintCell(). It is equivalent to QRect(0, 0, cellWidth(), cellHeight()).

See also cellGeometry().

### int QGridView::columnAt ( int x ) const

Returns the number of the column at position x. x must be given in content coordinates.

See also rowAt().

### void QGridView::dimensionChange ( int oldNumRows, int oldNumCols ) `[virtual protected]`

This change handler is called whenever any of the grid's dimensions change. oldNumRows and oldNumCols contain the old dimensions, numRows() and numCols() contain the new dimensions.

### void QGridView::ensureCellVisible ( int row, int column )

Ensures cell (row, column) is visible, scrolling the grid view if necessary.

### QSize QGridView::gridSize () const

Returns the size of the grid in pixels.

### void QGridView::paintCell ( QPainter * p, int row, int col ) `[pure virtual protected]`

This pure virtual function is called to paint the single cell at (row, col) using painter p. The painter must be open when paintCell() is called and must remain open.

The coordinate system is translated so that the origin is at the top-left corner of the cell to be painted, i.e. cell coordinates. Do not scale or shear the coordinate system (or if you do, restore the transformation matrix before you return).

The painter is not clipped by default in order to get maximum efficiency. If you want clipping, use

        p->setClipRect(cellRect(), QPainter::CoordPainter);
        //... your drawing code
        p->setClipping(false);

### void QGridView::paintEmptyArea ( QPainter * p, int cx, int cy, int cw, int ch ) `[virtual protected]`

This function fills the cw pixels wide and ch pixels high rectangle starting at position (cx, cy) with the background color using the painter p.

paintEmptyArea() is invoked by drawContents() to erase or fill unused areas.

### void QGridView::repaintCell ( int row, int column, bool erase = true )

Repaints cell (row, column).

If erase is true, Qt erases the area of the cell before the paintCell() call; otherwise no erasing takes place.

See also QWidget::repaint().

### int QGridView::rowAt ( int y ) const

Returns the number of the row at position y. y must be given in content coordinates.

See also columnAt().

### void QGridView::updateCell ( int row, int column )

Updates cell (row, column).

See also QWidget::update().