Qwt User's Guide
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QwtPicker provides selections on a widget. More...
#include <qwt_picker.h>
Public Types | |
enum | RubberBand { NoRubberBand = 0, HLineRubberBand, VLineRubberBand, CrossRubberBand, RectRubberBand, EllipseRubberBand, PolygonRubberBand, UserRubberBand = 100 } |
enum | DisplayMode { AlwaysOff, AlwaysOn, ActiveOnly } |
Display mode. More... | |
enum | ResizeMode { Stretch, KeepSize } |
Public Slots | |
void | setEnabled (bool) |
En/disable the picker. | |
Signals | |
void | activated (bool on) |
void | selected (const QPolygon &polygon) |
void | appended (const QPoint &pos) |
void | moved (const QPoint &pos) |
void | removed (const QPoint &pos) |
void | changed (const QPolygon &selection) |
Public Member Functions | |
QwtPicker (QWidget *parent) | |
QwtPicker (RubberBand rubberBand, DisplayMode trackerMode, QWidget *) | |
virtual | ~QwtPicker () |
Destructor. | |
void | setStateMachine (QwtPickerMachine *) |
const QwtPickerMachine * | stateMachine () const |
QwtPickerMachine * | stateMachine () |
void | setRubberBand (RubberBand) |
RubberBand | rubberBand () const |
void | setTrackerMode (DisplayMode) |
Set the display mode of the tracker. | |
DisplayMode | trackerMode () const |
void | setResizeMode (ResizeMode) |
Set the resize mode. | |
ResizeMode | resizeMode () const |
void | setRubberBandPen (const QPen &) |
QPen | rubberBandPen () const |
void | setTrackerPen (const QPen &) |
QPen | trackerPen () const |
void | setTrackerFont (const QFont &) |
QFont | trackerFont () const |
bool | isEnabled () const |
bool | isActive () const |
virtual bool | eventFilter (QObject *, QEvent *) |
Event filter. | |
QWidget * | parentWidget () |
Return the parent widget, where the selection happens. | |
const QWidget * | parentWidget () const |
Return the parent widget, where the selection happens. | |
virtual QPainterPath | pickArea () const |
virtual void | drawRubberBand (QPainter *) const |
virtual void | drawTracker (QPainter *) const |
virtual QRegion | rubberBandMask () const |
virtual QwtText | trackerText (const QPoint &pos) const |
Return the label for a position. | |
QPoint | trackerPosition () const |
virtual QRect | trackerRect (const QFont &) const |
QPolygon | selection () const |
Protected Member Functions | |
virtual QPolygon | adjustedPoints (const QPolygon &) const |
Map the pickedPoints() into a selection() | |
virtual void | transition (const QEvent *) |
virtual void | begin () |
virtual void | append (const QPoint &) |
virtual void | move (const QPoint &) |
virtual void | remove () |
virtual bool | end (bool ok=true) |
Close a selection setting the state to inactive. | |
virtual bool | accept (QPolygon &) const |
Validate and fix up the selection. | |
virtual void | reset () |
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 | widgetEnterEvent (QEvent *) |
virtual void | widgetLeaveEvent (QEvent *) |
virtual void | stretchSelection (const QSize &oldSize, const QSize &newSize) |
virtual void | updateDisplay () |
Update the state of rubber band and tracker label. | |
const QwtWidgetOverlay * | rubberBandOverlay () const |
const QwtWidgetOverlay * | trackerOverlay () const |
const QPolygon & | pickedPoints () const |
QwtPicker provides selections on a widget.
QwtPicker filters all enter, leave, mouse and keyboard events of a widget and translates them into an array of selected points.
The way how the points are collected depends on type of state machine that is connected to the picker. Qwt offers a couple of predefined state machines for selecting:
While these state machines cover the most common ways to collect points it is also possible to implement individual machines as well.
QwtPicker translates the picked points into a selection using the adjustedPoints() method. adjustedPoints() is intended to be reimplemented to fix up the selection according to application specific requirements. (F.e. when an application accepts rectangles of a fixed aspect ratio only.)
Optionally QwtPicker support the process of collecting points by a rubber band and tracker displaying a text for the current mouse position.
#include <qwt_picker.h> #include <qwt_picker_machine.h> QwtPicker *picker = new QwtPicker(widget); picker->setStateMachine(new QwtPickerDragRectMachine); picker->setTrackerMode(QwtPicker::ActiveOnly); picker->setRubberBand(QwtPicker::RectRubberBand);
The state machine triggers the following commands:
The picker is active (isActive()), between begin() and end(). In active state the rubber band is displayed, and the tracker is visible in case of trackerMode is ActiveOnly or AlwaysOn.
The cursor can be moved using the arrow keys. All selections can be aborted using the abort key. (QwtEventPattern::KeyPatternCode)
Display mode.
Controls what to do with the selected points of an active selection when the observed widget is resized.
The default value is QwtPicker::Stretch.
Rubber band style
The default value is QwtPicker::NoRubberBand.
NoRubberBand |
No rubberband. |
HLineRubberBand |
A horizontal line ( only for QwtPickerMachine::PointSelection ) |
VLineRubberBand |
A vertical line ( only for QwtPickerMachine::PointSelection ) |
CrossRubberBand |
A crosshair ( only for QwtPickerMachine::PointSelection ) |
RectRubberBand |
A rectangle ( only for QwtPickerMachine::RectSelection ) |
EllipseRubberBand |
An ellipse ( only for QwtPickerMachine::RectSelection ) |
PolygonRubberBand |
A polygon ( only for QwtPickerMachine::PolygonSelection ) |
UserRubberBand |
Values >= UserRubberBand can be used to define additional rubber bands. |
QwtPicker::QwtPicker | ( | QWidget * | parent | ) | [explicit] |
Constructor
Creates an picker that is enabled, but without a state machine. rubber band and tracker are disabled.
parent | Parent widget, that will be observed |
QwtPicker::QwtPicker | ( | RubberBand | rubberBand, |
DisplayMode | trackerMode, | ||
QWidget * | parent | ||
) | [explicit] |
Constructor
rubberBand | Rubber band style |
trackerMode | Tracker mode |
parent | Parent widget, that will be observed |
bool QwtPicker::accept | ( | QPolygon & | selection | ) | const [protected, virtual] |
Validate and fix up the selection.
Accepts all selections unmodified
selection | Selection to validate and fix up |
Reimplemented in QwtPlotZoomer.
void QwtPicker::activated | ( | bool | on | ) | [signal] |
A signal indicating, when the picker has been activated. Together with setEnabled() it can be used to implement selections with more than one picker.
on | True, when the picker has been activated |
QPolygon QwtPicker::adjustedPoints | ( | const QPolygon & | points | ) | const [protected, virtual] |
Map the pickedPoints() into a selection()
adjustedPoints() maps the points, that have been collected on the parentWidget() into a selection(). The default implementation simply returns the points unmodified.
The reason, why a selection() differs from the picked points depends on the application requirements. F.e. :
The example below is for a rectangular selection, where the first point is the center of the selected rectangle.
QPolygon MyPicker::adjustedPoints(const QPolygon &points) const { QPolygon adjusted; if ( points.size() == 2 ) { const int width = qAbs(points[1].x() - points[0].x()); const int height = qAbs(points[1].y() - points[0].y()); QRect rect(0, 0, 2 * width, 2 * height); rect.moveCenter(points[0]); adjusted += rect.topLeft(); adjusted += rect.bottomRight(); } return adjusted; }
points | Selected points |
void QwtPicker::append | ( | const QPoint & | pos | ) | [protected, virtual] |
Append a point to the selection and update rubber band and tracker. The appended() signal is emitted.
pos | Additional point |
Reimplemented in QwtPlotPicker.
void QwtPicker::appended | ( | const QPoint & | pos | ) | [signal] |
void QwtPicker::begin | ( | ) | [protected, virtual] |
Open a selection setting the state to active
Reimplemented in QwtPlotZoomer.
void QwtPicker::changed | ( | const QPolygon & | selection | ) | [signal] |
A signal emitted when the active selection has been changed. This might happen when the observed widget is resized.
selection | Changed selection |
void QwtPicker::drawRubberBand | ( | QPainter * | painter | ) | const [virtual] |
Draw a rubber band, depending on rubberBand()
painter | Painter, initialized with a clip region |
void QwtPicker::drawTracker | ( | QPainter * | painter | ) | const [virtual] |
bool QwtPicker::end | ( | bool | ok = true | ) | [protected, virtual] |
Close a selection setting the state to inactive.
The selection is validated and maybe fixed by accept().
ok | If true, complete the selection and emit a selected signal otherwise discard the selection. |
Reimplemented in QwtPlotZoomer, and QwtPlotPicker.
bool QwtPicker::eventFilter | ( | QObject * | object, |
QEvent * | event | ||
) | [virtual] |
Event filter.
When isEnabled() is 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 rubber band and tracker up to date.
object | Object to be filtered |
event | Event |
bool QwtPicker::isActive | ( | ) | const |
bool QwtPicker::isEnabled | ( | ) | const |
void QwtPicker::move | ( | const QPoint & | pos | ) | [protected, virtual] |
Move the last point of the selection The moved() signal is emitted.
pos | New position |
Reimplemented in QwtPlotPicker.
void QwtPicker::moved | ( | const QPoint & | pos | ) | [signal] |
A signal emitted whenever the last appended point of the selection has been moved.
pos | Position of the moved last point of the selection. |
QPainterPath QwtPicker::pickArea | ( | ) | const [virtual] |
Find the area of the observed widget, where selection might happen.
const QPolygon & QwtPicker::pickedPoints | ( | ) | const [protected] |
Return the points, that have been collected so far. The selection() is calculated from the pickedPoints() in adjustedPoints().
void QwtPicker::remove | ( | ) | [protected, virtual] |
void QwtPicker::removed | ( | const QPoint & | pos | ) | [signal] |
A signal emitted whenever the last appended point of the selection has been removed.
pos | Position of the point, that has been removed |
void QwtPicker::reset | ( | ) | [protected, virtual] |
Reset the state machine and terminate ( end(false) ) the selection
QwtPicker::ResizeMode QwtPicker::resizeMode | ( | ) | const |
QwtPicker::RubberBand QwtPicker::rubberBand | ( | ) | const |
QRegion QwtPicker::rubberBandMask | ( | ) | const [virtual] |
Calculate the mask for the rubber band overlay
const QwtWidgetOverlay * QwtPicker::rubberBandOverlay | ( | ) | const [protected] |
QPen QwtPicker::rubberBandPen | ( | ) | const |
void QwtPicker::selected | ( | const QPolygon & | polygon | ) | [signal] |
A signal emitting the selected points, at the end of a selection.
polygon | Selected points |
QPolygon QwtPicker::selection | ( | ) | const |
void QwtPicker::setEnabled | ( | bool | enabled | ) | [slot] |
En/disable the picker.
When enabled is true an event filter is installed for the observed widget, otherwise the event filter is removed.
enabled | true or false |
void QwtPicker::setResizeMode | ( | ResizeMode | mode | ) |
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.
mode | Resize mode |
void QwtPicker::setRubberBand | ( | RubberBand | rubberBand | ) |
Set the rubber band style
rubberBand | Rubber band style The default value is NoRubberBand. |
void QwtPicker::setRubberBandPen | ( | const QPen & | pen | ) |
Set the pen for the rubberband
pen | Rubber band pen |
void QwtPicker::setStateMachine | ( | QwtPickerMachine * | stateMachine | ) |
Set a state machine and delete the previous one
stateMachine | State machine |
void QwtPicker::setTrackerFont | ( | const QFont & | font | ) |
Set the font for the tracker
font | Tracker font |
void QwtPicker::setTrackerMode | ( | DisplayMode | mode | ) |
Set the display mode of the tracker.
A tracker displays information about current position of the cursor as a string. The display mode controls if the tracker has to be displayed whenever the observed widget has focus and cursor (AlwaysOn), never (AlwaysOff), or only when the selection is active (ActiveOnly).
mode | Tracker display mode |
void QwtPicker::setTrackerPen | ( | const QPen & | pen | ) |
Set the pen for the tracker
pen | Tracker pen |
const QwtPickerMachine * QwtPicker::stateMachine | ( | ) | const |
void QwtPicker::stretchSelection | ( | const QSize & | oldSize, |
const QSize & | newSize | ||
) | [protected, virtual] |
Scale the selection by the ratios of oldSize and newSize The changed() signal is emitted.
oldSize | Previous size |
newSize | Current size |
QFont QwtPicker::trackerFont | ( | ) | const |
QwtPicker::DisplayMode QwtPicker::trackerMode | ( | ) | const |
const QwtWidgetOverlay * QwtPicker::trackerOverlay | ( | ) | const [protected] |
QPen QwtPicker::trackerPen | ( | ) | const |
QPoint QwtPicker::trackerPosition | ( | ) | const |
QRect QwtPicker::trackerRect | ( | const QFont & | font | ) | const [virtual] |
Calculate the bounding rectangle for the tracker text from the current position of the tracker
font | Font of the tracker text |
QwtText QwtPicker::trackerText | ( | const QPoint & | pos | ) | const [virtual] |
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 ',' .
The format for the string conversion is "%d".
pos | Position |
Reimplemented in QwtPlotPicker.
void QwtPicker::transition | ( | const QEvent * | event | ) | [protected, virtual] |
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() ).
event | Event |
void QwtPicker::widgetEnterEvent | ( | QEvent * | event | ) | [protected, virtual] |
Handle a enter event for the observed widget.
event | Qt event |
void QwtPicker::widgetKeyPressEvent | ( | QKeyEvent * | keyEvent | ) | [protected, virtual] |
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.
keyEvent | Key event |
Reimplemented in QwtPlotZoomer.
void QwtPicker::widgetKeyReleaseEvent | ( | QKeyEvent * | keyEvent | ) | [protected, virtual] |
Handle a key release event for the observed widget.
Passes the event to the state machine.
keyEvent | Key event |
void QwtPicker::widgetLeaveEvent | ( | QEvent * | event | ) | [protected, virtual] |
Handle a leave event for the observed widget.
event | Qt event |
void QwtPicker::widgetMouseDoubleClickEvent | ( | QMouseEvent * | mouseEvent | ) | [protected, virtual] |
Handle mouse double click event for the observed widget.
mouseEvent | Mouse event |
void QwtPicker::widgetMouseMoveEvent | ( | QMouseEvent * | mouseEvent | ) | [protected, virtual] |
Handle a mouse move event for the observed widget.
mouseEvent | Mouse event |
void QwtPicker::widgetMousePressEvent | ( | QMouseEvent * | mouseEvent | ) | [protected, virtual] |
Handle a mouse press event for the observed widget.
mouseEvent | Mouse event |
void QwtPicker::widgetMouseReleaseEvent | ( | QMouseEvent * | mouseEvent | ) | [protected, virtual] |
Handle a mouse release event for the observed widget.
mouseEvent | Mouse event |
Reimplemented in QwtPlotZoomer.
void QwtPicker::widgetWheelEvent | ( | QWheelEvent * | wheelEvent | ) | [protected, virtual] |
Handle a wheel event for the observed widget.
Move the last point of the selection in case of isActive() == true
wheelEvent | Wheel event |