QwtPlotZoomer provides stacked zooming for a plot widget. More...

#include <qwt_plot_zoomer.h>

Inheritance diagram for QwtPlotZoomer:

Classes
class	PrivateData
Public Slots
void	moveBy (double dx, double dy)
virtual void	moveTo (const QPointF &)
virtual void	zoom (const QRectF &)
	Zoom in.
virtual void	zoom (int offset)
	Zoom in or out.
Signals
void	zoomed (const QRectF &rect)
Public Member Functions
int	maxStackDepth () const
	QwtPlotZoomer (QWidget *, bool doReplot=true)
	Create a zoomer for a plot canvas.
	QwtPlotZoomer (int xAxis, int yAxis, QWidget *, bool doReplot=true)
	Create a zoomer for a plot canvas.
virtual void	setAxis (int xAxis, int yAxis) override
void	setMaxStackDepth (int)
	Limit the number of recursive zoom operations to depth.
virtual void	setZoomBase (bool doReplot=true)
virtual void	setZoomBase (const QRectF &)
	Set the initial size of the zoomer.
void	setZoomStack (const QStack< QRectF > &, int zoomRectIndex=-1)
	Assign a zoom stack.
QRectF	zoomBase () const
QRectF	zoomRect () const
uint	zoomRectIndex () const
const QStack< QRectF > &	zoomStack () const
virtual	~QwtPlotZoomer ()
Protected Member Functions
virtual bool	accept (QPolygon &) const override
	Check and correct a selected rectangle.
virtual void	begin () override
virtual bool	end (bool ok=true) override
virtual QSizeF	minZoomSize () const
	Limit zooming by a minimum rectangle.
virtual void	rescale ()
virtual void	widgetKeyPressEvent (QKeyEvent *) override
virtual void	widgetMouseReleaseEvent (QMouseEvent *) override
Private Member Functions
void	init (bool doReplot)
	Init the zoomer, used by the constructors.
Private Attributes
PrivateData *	d_data

Detailed Description

QwtPlotZoomer provides stacked zooming for a plot widget.

QwtPlotZoomer selects rectangles from user inputs ( mouse or keyboard ) translates them into plot coordinates and adjusts the axes to them. The selection is supported by a rubber band and optionally by displaying the coordinates of the current mouse position.

Zooming can be repeated as often as possible, limited only by maxStackDepth() or minZoomSize(). Each rectangle is pushed on a stack.

The default setting how to select rectangles is a QwtPickerDragRectMachine with the following bindings:

QwtEventPattern::MouseSelect1
The first point of the zoom rectangle is selected by a mouse press, the second point from the position, where the mouse is released.

QwtEventPattern::KeySelect1
The first key press selects the first, the second key press selects the second point.

QwtEventPattern::KeyAbort
Discard the selection in the state, where the first point is selected.

To traverse the zoom stack the following bindings are used:

QwtEventPattern::MouseSelect3, QwtEventPattern::KeyUndo
Zoom out one position on the zoom stack

QwtEventPattern::MouseSelect6, QwtEventPattern::KeyRedo
Zoom in one position on the zoom stack

QwtEventPattern::MouseSelect2, QwtEventPattern::KeyHome
Zoom to the zoom base

The setKeyPattern() and setMousePattern() functions can be used to configure the zoomer actions. The following example shows, how to configure the 'I' and 'O' keys for zooming in and out one position on the zoom stack. The "Home" key is used to "unzoom" the plot.

   zoomer = new QwtPlotZoomer( plot );
   zoomer->setKeyPattern( QwtEventPattern::KeyRedo, Qt::Key_I, Qt::ShiftModifier );
   zoomer->setKeyPattern( QwtEventPattern::KeyUndo, Qt::Key_O, Qt::ShiftModifier );
   zoomer->setKeyPattern( QwtEventPattern::KeyHome, Qt::Key_Home );

QwtPlotZoomer is tailored for plots with one x and y axis, but it is allowed to attach a second QwtPlotZoomer ( without rubber band and tracker ) for the other axes.

Note:: The realtime example includes an derived zoomer class that adds scrollbars to the plot canvas.

See also:: QwtPlotPanner, QwtPlotMagnifier

Definition at line 79 of file qwt_plot_zoomer.h.

Constructor & Destructor Documentation

QwtPlotZoomer::QwtPlotZoomer	(	QWidget *	canvas,
		bool	doReplot = `true`
	)		`[explicit]`

Create a zoomer for a plot canvas.

The zoomer is set to those x- and y-axis of the parent plot of the canvas that are enabled. If both or no x-axis are enabled, the picker is set to QwtPlot::xBottom. If both or no y-axis are enabled, it is set to QwtPlot::yLeft.

The zoomer is initialized with a QwtPickerDragRectMachine, the tracker mode is set to QwtPicker::ActiveOnly and the rubber band is set to QwtPicker::RectRubberBand

Parameters:

canvas	Plot canvas to observe, also the parent object
doReplot	Call QwtPlot::replot() for the attached plot before initializing the zoomer with its scales. This might be necessary, when the plot is in a state with pending scale changes.

See also:: QwtPlot::autoReplot(), QwtPlot::replot(), setZoomBase()

Definition at line 109 of file qwt_plot_zoomer.cpp.

QwtPlotZoomer::QwtPlotZoomer	(	int	xAxis,
		int	yAxis,
		QWidget *	canvas,
		bool	doReplot = `true`
	)		`[explicit]`

Create a zoomer for a plot canvas.

The zoomer is initialized with a QwtPickerDragRectMachine, the tracker mode is set to QwtPicker::ActiveOnly and the rubber band is set to QwtPicker;;RectRubberBand

Parameters:

xAxis	X axis of the zoomer
yAxis	Y axis of the zoomer
canvas	Plot canvas to observe, also the parent object
doReplot	Call QwtPlot::replot() for the attached plot before initializing the zoomer with its scales. This might be necessary, when the plot is in a state with pending scale changes.

See also:: QwtPlot::autoReplot(), QwtPlot::replot(), setZoomBase()

Definition at line 133 of file qwt_plot_zoomer.cpp.

QwtPlotZoomer::~QwtPlotZoomer ( ) [virtual]

Definition at line 158 of file qwt_plot_zoomer.cpp.

Member Function Documentation

bool QwtPlotZoomer::accept ( QPolygon & pa ) const [override, protected, virtual]

Check and correct a selected rectangle.

Reject rectangles with a height or width < 2, otherwise expand the selected rectangle to a minimum size of 11x11 and accept it.

Returns:: true If the rectangle is accepted, or has been changed to an accepted one.

Reimplemented from QwtPicker.

Reimplemented in PlotZoomer.

Definition at line 567 of file qwt_plot_zoomer.cpp.

void QwtPlotZoomer::begin ( ) [override, protected, virtual]

Rejects selections, when the stack depth is too deep, or the zoomed rectangle is minZoomSize().

See also:: minZoomSize(), maxStackDepth()

Reimplemented from QwtPicker.

Definition at line 609 of file qwt_plot_zoomer.cpp.

bool QwtPlotZoomer::end ( bool ok = true ) [override, protected, virtual]

Expand the selected rectangle to minZoomSize() and zoom in if accepted.

Parameters:

ok	If true, complete the selection and emit selected signals otherwise discard the selection.

See also:: accept(), minZoomSize()

Returns:: True if the selection has been accepted, false otherwise

Reimplemented from QwtPlotPicker.

Definition at line 643 of file qwt_plot_zoomer.cpp.

void QwtPlotZoomer::init ( bool doReplot ) [private]

Init the zoomer, used by the constructors.

Definition at line 142 of file qwt_plot_zoomer.cpp.

int QwtPlotZoomer::maxStackDepth ( ) const

Returns:: Maximal depth of the zoom stack.

See also:: setMaxStackDepth()

Definition at line 201 of file qwt_plot_zoomer.cpp.

QSizeF QwtPlotZoomer::minZoomSize ( ) const [protected, virtual]

Limit zooming by a minimum rectangle.

Returns:: zoomBase().width() / 10e4, zoomBase().height() / 10e4

Reimplemented in PlotZoomer.

Definition at line 597 of file qwt_plot_zoomer.cpp.

void QwtPlotZoomer::moveBy	(	double	dx,
		double	dy
	)		`[slot]`

Move the current zoom rectangle.

Parameters:

dx	X offset
dy	Y offset

Note:: The changed rectangle is limited by the zoom base

Definition at line 520 of file qwt_plot_zoomer.cpp.

void QwtPlotZoomer::moveTo ( const QPointF & pos ) [virtual, slot]

Move the the current zoom rectangle.

Parameters:

pos	New position

See also:: QRectF::moveTo()

Note:: The changed rectangle is limited by the zoom base

Definition at line 534 of file qwt_plot_zoomer.cpp.

void QwtPlotZoomer::rescale ( ) [protected, virtual]

Adjust the observed plot to zoomRect()

Note:: Initiates QwtPlot::replot()

Definition at line 416 of file qwt_plot_zoomer.cpp.

void QwtPlotZoomer::setAxis	(	int	xAxis,
		int	yAxis
	)		`[override, virtual]`

Reinitialize the axes, and set the zoom base to their scales.

Parameters:

xAxis	X axis
yAxis	Y axis

Reimplemented from QwtPlotPicker.

Definition at line 455 of file qwt_plot_zoomer.cpp.

void QwtPlotZoomer::setMaxStackDepth ( int depth )

Limit the number of recursive zoom operations to depth.

A value of -1 set the depth to unlimited, 0 disables zooming. If the current zoom rectangle is below depth, the plot is unzoomed.

Parameters:

depth Maximum for the stack depth

See also:: maxStackDepth()

Note:: depth doesn't include the zoom base, so zoomStack().count() might be maxStackDepth() + 1.

Definition at line 174 of file qwt_plot_zoomer.cpp.

void QwtPlotZoomer::setZoomBase ( bool doReplot = true ) [virtual]

Reinitialized the zoom stack with scaleRect() as base.

Parameters:

doReplot Call QwtPlot::replot() for the attached plot before initializing the zoomer with its scales. This might be necessary, when the plot is in a state with pending scale changes.

See also:: zoomBase(), scaleRect() QwtPlot::autoReplot(), QwtPlot::replot().

Definition at line 235 of file qwt_plot_zoomer.cpp.

void QwtPlotZoomer::setZoomBase ( const QRectF & base ) [virtual]

Set the initial size of the zoomer.

base is united with the current scaleRect() and the zoom stack is reinitialized with it as zoom base. plot is zoomed to scaleRect().

Parameters:

base Zoom base

See also:: zoomBase(), scaleRect()

Definition at line 261 of file qwt_plot_zoomer.cpp.

void QwtPlotZoomer::setZoomStack	(	const QStack< QRectF > &	zoomStack,
		int	zoomRectIndex = `-1`
	)

Assign a zoom stack.

In combination with other types of navigation it might be useful to modify to manipulate the complete zoom stack.

Parameters:

zoomStack	New zoom stack
zoomRectIndex	Index of the current position of zoom stack. In case of -1 the current position is at the top of the stack.

Note:: The zoomed signal might be emitted.

See also:: zoomStack(), zoomRectIndex()

Definition at line 383 of file qwt_plot_zoomer.cpp.

void QwtPlotZoomer::widgetKeyPressEvent ( QKeyEvent * ke ) [override, protected, virtual]

Qt::Key_Plus zooms in, Qt::Key_Minus zooms out one position on the zoom stack, Qt::Key_Escape zooms out to the zoom base.

Changes the current position on the stack, but doesn't pop any rectangle.

Note:: The keys codes can be changed, using QwtEventPattern::setKeyPattern: 3, 4, 5

Reimplemented from QwtPicker.

Definition at line 497 of file qwt_plot_zoomer.cpp.

void QwtPlotZoomer::widgetMouseReleaseEvent ( QMouseEvent * me ) [override, protected, virtual]

Qt::MidButton zooms out one position on the zoom stack, Qt::RightButton to the zoom base.

Changes the current position on the stack, but doesn't pop any rectangle.

Note:: The mouse events can be changed, using QwtEventPattern::setMousePattern: 2, 1

Reimplemented from QwtPicker.

Reimplemented in PlotZoomer.

Definition at line 474 of file qwt_plot_zoomer.cpp.

void QwtPlotZoomer::zoom ( const QRectF & rect ) [virtual, slot]

Zoom in.

Clears all rectangles above the current position of the zoom stack and pushes the normalized rectangle on it.

Note:: If the maximal stack depth is reached, zoom is ignored.; The zoomed signal is emitted.

Reimplemented in PlotZoomer.

Definition at line 310 of file qwt_plot_zoomer.cpp.

void QwtPlotZoomer::zoom ( int offset ) [virtual, slot]

Zoom in or out.

Activate a rectangle on the zoom stack with an offset relative to the current position. Negative values of offset will zoom out, positive zoom in. A value of 0 zooms out to the zoom base.

Parameters:

offset Offset relative to the current position of the zoom stack.

Note:: The zoomed signal is emitted.

See also:: zoomRectIndex()

Definition at line 347 of file qwt_plot_zoomer.cpp.

QRectF QwtPlotZoomer::zoomBase ( ) const

Returns:: Initial rectangle of the zoomer

See also:: setZoomBase(), zoomRect()

Definition at line 221 of file qwt_plot_zoomer.cpp.

void QwtPlotZoomer::zoomed ( const QRectF & rect ) [signal]

A signal emitting the zoomRect(), when the plot has been zoomed in or out.

Parameters:

rect	Current zoom rectangle.

QRectF QwtPlotZoomer::zoomRect ( ) const

Returns:: Rectangle at the current position on the zoom stack.

See also:: zoomRectIndex(), scaleRect().

Definition at line 287 of file qwt_plot_zoomer.cpp.

uint QwtPlotZoomer::zoomRectIndex ( ) const

Returns:: Index of current position of zoom stack.

Definition at line 295 of file qwt_plot_zoomer.cpp.

const QStack< QRectF > & QwtPlotZoomer::zoomStack ( ) const

Returns:: The zoom stack. zoomStack()[0] is the zoom base, zoomStack()[1] the first zoomed rectangle.

See also:: setZoomStack(), zoomRectIndex()

Definition at line 212 of file qwt_plot_zoomer.cpp.

Member Data Documentation

PrivateData* QwtPlotZoomer::d_data [private]

Reimplemented from QwtPicker.

Definition at line 138 of file qwt_plot_zoomer.h.

The documentation for this class was generated from the following files:

Classes

Public Slots

Signals

Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation