Inheritance diagram for QwtPicker:
QwtPicker filters all mouse and keyboard events of a widget and translates them into an array of selected points. Depending on the QwtPicker::SelectionType the selection might be a single point, a rectangle or a polygon. The selection process is supported by optional rubberbands (rubberband selection) and position labels.
QwtPicker is useful for widgets where the event handlers canīt be overloaded, like for components of composite widgets. It offers alternative handlers for mouse and key events.
#include <qwt_picker.h> QwtPicker *picker = new QwtPicker(widget); picker->setCursorLabelMode(QwtPicker::ActiveOnly); connect(picker, SIGNAL(selected(const QPointArray &)), ...); // emit the position of clicks on widget picker->setSelectionFlags(QwtPicker::PointSelection | QwtPicker::ClickSelection); ... // now select rectangles picker->setSelectionFlags(QwtPicker::RectSelection | QwtPicker::DragSelection); picker->setRubberBand(QwtPicker::RectRubberBand);
The commands are initiated from a small state machine (QwtPickerMachine) that translates mouse and key events. There are a couple of predefined state machines for point, rect and polygon selections. The selectionFlags() control which one should be used. It is possible to use other machines by overloading stateMachine().
The picker is active (isActive()), between begin() and end(). In active state the rubberband is displayed, and the cursor label is visible in case of cursorLabelMode is ActiveOnly or AlwaysOn.
The cursor can be moved using the arrow keys. All selections can be aborted using the abort key. (QwtEventPattern::KeyPatternCode)
Public Types | |
enum | SelectionType { NoSelection = 0, PointSelection = 1, RectSelection = 2, PolygonSelection = 4 } |
enum | RectSelectionType { CornerToCorner = 64, CenterToCorner = 128, CenterToRadius = 256 } |
enum | SelectionMode { ClickSelection = 1024, DragSelection = 2048 } |
enum | RubberBand { NoRubberBand = 0, HLineRubberBand, VLineRubberBand, CrossRubberBand, RectRubberBand, EllipseRubberBand, PolygonRubberBand, UserRubberBand = 100 } |
enum | DisplayMode { AlwaysOff, AlwaysOn, ActiveOnly } |
enum | ResizeMode { Stretch, KeepSize } |
Public Member Functions | |
QwtPicker (QWidget *, const char *name=0) | |
QwtPicker (int selectionFlags, RubberBand rubberBand, DisplayMode cursorLabelMode, QWidget *, const char *name=0) | |
virtual | ~QwtPicker () |
virtual void | setSelectionFlags (int) |
int | selectionFlags () const |
virtual void | setRubberBand (RubberBand) |
RubberBand | rubberBand () const |
virtual void | setCursorLabelMode (DisplayMode) |
DisplayMode | cursorLabelMode () const |
virtual void | setResizeMode (ResizeMode) |
ResizeMode | resizeMode () const |
virtual void | setRubberBandPen (const QPen &) |
QPen | rubberBandPen () const |
virtual void | setCursorLabelPen (const QPen &) |
QPen | cursorLabelPen () const |
virtual void | setCursorLabelFont (const QFont &) |
QFont | cursorLabelFont () const |
bool | isEnabled () const |
virtual void | setEnabled (bool) |
bool | isActive () const |
virtual bool | event (QEvent *) |
virtual bool | eventFilter (QObject *, QEvent *) |
QWidget * | parentWidget () |
const QWidget * | parentWidget () const |
virtual QRect | pickRect () const |
const QPointArray & | selection () const |
Protected Member Functions | |
void | selected (const QPointArray &pa) |
void | appended (const QPoint &pos) |
void | moved (const QPoint &pos) |
void | changed (const QPointArray &pa) |
virtual bool | accept (QPointArray &selection) const |
virtual void | transition (const QEvent *) |
virtual void | begin () |
virtual void | append (const QPoint &) |
virtual void | move (const QPoint &) |
virtual bool | end (bool ok=TRUE) |
virtual void | widgetMousePressEvent (QMouseEvent *) |
virtual void | widgetMouseReleaseEvent (QMouseEvent *) |
virtual void | widgetMouseDoubleClickEvent (QMouseEvent *) |
virtual void | widgetMouseMoveEvent (QMouseEvent *) |
virtual void | widgetWheelEvent (QWheelEvent *) |
virtual void | widgetKeyPressEvent (QKeyEvent *) |
virtual void | widgetKeyReleaseEvent (QKeyEvent *) |
virtual void | drawRubberBand (const QRect &clipRect=QRect()) const |
virtual void | drawRubberBand (QPainter *, const QRect &rect, const QPointArray &) const |
virtual void | drawCursorLabel (const QRect &clipRect=QRect()) const |
virtual void | drawCursorLabel (QPainter *, const QRect &rect, const QPoint &, const QPointArray &) const |
virtual void | stretchSelection (const QSize &oldSize, const QSize &newSize) |
virtual QString | cursorLabel (const QPoint &pos) const |
virtual QwtPickerMachine * | stateMachine (int) const |
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Selection subtype for RectSelection This enum type describes the type of rectangle selections. It can be orīd with QwtPicker::RectSelectionType and QwtPicker::SelectionMode and passed to QwtPicker::setSelectionFlags().
The default value is CornerToCorner. |
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Controls what to do with the selected points of an active selection when the observed widget is resized.
The default value is Stretch.
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Rubberband style
The default value is NoRubberBand. |
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Values of this enum type orīd together with a SelectionType value identifies which state machine should be used for the selection. The default value is ClickSelection.
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This enum type describes the type of a selection. It can be orīd with QwtPicker::RectSelectionType and QwtPicker::SelectionMode and passed to QwtPicker::setSelectionFlags()
The default value is NoSelection. |
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Constructor Creates an picker that is enabled, but where selection flags s set to NoSelection, rubberband and cursor label are disabled.
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Constructor
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Destructor.
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Validate and fixup the selection. Accepts all selections unmodified
Reimplemented in QwtPlotZoomer. |
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Append a point to the selection and update rubberband and cursor label. The appended() signal is emitted.
Reimplemented in QwtPlotPicker. |
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A signal emitted when a point has been appended to the selection
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Open a selection setting the state to active
Reimplemented in QwtPlotZoomer. |
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A signal emitted when the active selection has been changed. This might happen when the observed widget is resized.
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Return the label for a position. In case of HLineRubberBand the label is the value of the y position, in case of VLineRubberBand the value of the x position. Otherwise the label contains x and y position separated by a ī, ī. The format for the string conversion is "%d".
Reimplemented in QwtPlotPicker. |
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Draw a cursor label. The default position of the label is top-right of the cursor. In case of a rubberband the label is placed not to conflict with the rubberband.
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Draw the cursor label. The cursor label is painted in Qt::XorROP mode, what means the first call paints the second erases the painted rubberband.
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Draw a rubberband , depending on rubberBand() and selectionFlags()
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Draw the rubberband. The rubberband is painted in Qt::XorROP mode, what means the first call paints the second erases the painted rubberband.
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Close a selection setting the state to inactive. The selection is validated and maybe fixed by QwtPicker::accept().
Reimplemented in QwtPlotPicker, and QwtPlotZoomer. |
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Event Handler. Paint events for the observed widgets require to repaint rubberband an cursor label too. To delay them until the widget is repainted the event filter sends a QEvent::Paint to the picker, that is handled here.
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Event filter. When isEnabled() == TRUE all events of the observed widget are filtered. Mouse and keyboard events are translated into widgetMouse- and widgetKey- and widgetWheel-events. Paint and resize events are handled to keep rubberband and cursor label up to date.
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A picker is active between begin() and end().
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Move the last point of the selection The moved() signal is emitted.
Reimplemented in QwtPlotPicker. |
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A signal emitted whenever the last appended point of the selection has been moved.
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Return the parent widget, where the selection happens.
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Return the parent widget, where the selection happens.
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Find the area of the observed widget, where selection might happen.
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A signal emitting the selected points, at the end of a selection.
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Return Selected points.
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Set the font for the cursor label
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Set the display mode of the cursor label. A cursor label dispays the current position of the cursor as a string. The display mode controls if the label has to be displayed whenever the observed widget has focus and cursor (AlwaysOn), never (AlwaysOff), or only when the selection is active (ActiveOnly).
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Set the pen for the cursor label
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En/disable the picker. When enabled is TRUE an event filter is installed for the observed widget, otherwise the event filter is removed.
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Set the resize mode. The resize mode controls what to do with the selected points of an active selection when the observed widget is resized. Stretch means the points are scaled according to the new size, KeepSize means the points remain unchanged. The default mode is Stretch.
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Set the rubberband style
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Set the pen for the rubberband
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Set the selection flags
Reimplemented in QwtPlotZoomer. |
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Create a state machine depending on the selection flags.
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Scale the selection by the ratios of oldSize and newSize The changed() signal is emitted.
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Passes an event to the state machine and executes the resulting commands. Append and Move commands use the current position of the cursor (QCursor::pos()).
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Handle a key press event for the observed widget. Selections can be completely done by the keyboard. The arrow keys move the cursor, the abort key aborts a selection. All other keys are handled by the current state machine.
Reimplemented in QwtPlotZoomer. |
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Handle a key release event for the observed widget. Passes the event to the state machine.
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Handle mouse double click event for the observed widget. Empty implementation, does nothing.
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Handle a mouse move event for the observed widget. Move the last point of the selection in case of isActive() == TRUE
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Handle a mouse press event for the observed widget. Begin and/or end a selection depending on the selection flags.
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Handle a mouse relase event for the observed widget. End a selection depending on the selection flags.
Reimplemented in QwtPlotZoomer. |
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Handle a wheel event for the observed widget. Move the last point of the selection in case of isActive() == TRUE
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