QwtPlotZoomer(3) Qwt User's Guide QwtPlotZoomer(3) NAME QwtPlotZoomer - QwtPlotZoomer provides stacked zooming for a plot widget. SYNOPSIS #include Inherits QwtPlotPicker. 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 QwtPlotZoomer (QWidget *, bool doReplot=true) Create a zoomer for a plot canvas. QwtPlotZoomer (QwtAxisId xAxis, QwtAxisId yAxis, QWidget *, bool doReplot=true) Create a zoomer for a plot canvas. virtual void setZoomBase (bool doReplot=true) virtual void setZoomBase (const QRectF &) Set the initial size of the zoomer. QRectF zoomBase () const QRectF zoomRect () const virtual void setAxes (QwtAxisId xAxis, QwtAxisId yAxis) override void setMaxStackDepth (int) Limit the number of recursive zoom operations to depth. int maxStackDepth () const const QStack< QRectF > & zoomStack () const void setZoomStack (const QStack< QRectF > &, int zoomRectIndex=-1) Assign a zoom stack. uint zoomRectIndex () const Protected Member Functions virtual void rescale () virtual QSizeF minZoomSize () const Limit zooming by a minimum rectangle. virtual void widgetMouseReleaseEvent (QMouseEvent *) override virtual void widgetKeyPressEvent (QKeyEvent *) override virtual void begin () override virtual bool end (bool ok=true) override virtual bool accept (QPolygon &) const override Check and correct a selected rectangle. Additional Inherited Members 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: o 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. o QwtEventPattern::KeySelect1 The first key press selects the first, the second key press selects the second point. o QwtEventPattern::KeyAbort Discard the selection in the state, where the first point is selected. To traverse the zoom stack the following bindings are used: o QwtEventPattern::MouseSelect3, QwtEventPattern::KeyUndo Zoom out one position on the zoom stack o QwtEventPattern::MouseSelect6, QwtEventPattern::KeyRedo Zoom in one position on the zoom stack o 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 QwtAxis::XBottom. If both or no y-axis are enabled, it is set to QwtAxis::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 (QwtAxisId xAxisId, QwtAxisId yAxisId, 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 xAxisId X axis of the zoomer yAxisId 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. 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. 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. 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 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::setAxes (QwtAxisId xAxisId, QwtAxisId yAxisId) [override], [virtual] Reinitialize the axes, and set the zoom base to their scales. Parameters xAxisId X axis yAxisId 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. 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. 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. Author Generated automatically by Doxygen for Qwt User's Guide from the source code. Version 6.2.0 Sun Jul 18 2021 QwtPlotZoomer(3)