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# QwtPlotCanvas Class Reference

List of all members.

## Detailed Description

Canvas of a QwtPlot.

See also:
  QwtPlot

Definition at line 29 of file qwt_plot_canvas.h.

## Public Types
enum | FocusIndicator { NoFocusIndicator, CanvasFocusIndicator, ItemFocusIndicator }
## Signals
void | mousePressed (const QMouseEvent &e)
void | mouseReleased (const QMouseEvent &e)
void | mouseMoved (const QMouseEvent &e)
## Public Member Functions
void | setFocusIndicator (FocusIndicator)
FocusIndicator | focusIndicator () const
void | setCacheMode (bool on)
bool | cacheMode () const
const QPixmap * | cache () const
void | invalidateCache ()
void | enableOutline (bool tf)
bool | outlineEnabled () const
void | setOutlinePen (const QPen &p)
const QPen & | outlinePen () const
void | setOutlineStyle (Qwt::Shape os)
Qwt::Shape | outlineStyle () const
## Protected Member Functions
| QwtPlotCanvas (QwtPlot *)
virtual | ~QwtPlotCanvas ()
QPixmap * | cache ()
virtual void | frameChanged ()
virtual void | drawContents (QPainter *)
virtual void | drawFocusIndicator (QPainter *, const QRect &)
void | drawCanvas (QPainter *painter=NULL)
virtual void | mousePressEvent (QMouseEvent *)
virtual void | mouseReleaseEvent (QMouseEvent *)
virtual void | mouseMoveEvent (QMouseEvent *)

## Member Enumeration Documentation

enum QwtPlotCanvas::FocusIndicator

| Focus indicator. NoFocusIndicator Donīt paint a focus indicator CanvasFocusIndicator The focus is related to the complete canvas. Paint the focus indicator using paintFocus() ItemFocusIndicator The focus is related to an item (curve, point, ...) on the canvas. It is up to the application to display a focus indication using f.e. highlighting. See also: setFocusIndicator(), focusIndicator(), paintFocus() Definition at line 51 of file qwt_plot_canvas.h. Referenced by focusIndicator().

## Constructor & Destructor Documentation

QwtPlotCanvas::QwtPlotCanvas | ( | QwtPlot * |  | ) | `[protected]`

| Sets a cross cursor, and an invisible red outline. Definition at line 25 of file qwt_plot_canvas.cpp.

QwtPlotCanvas::~QwtPlotCanvas | ( |  | ) | `[protected, virtual]`

| Destructor. Definition at line 42 of file qwt_plot_canvas.cpp.

## Member Function Documentation

QPixmap * QwtPlotCanvas::cache | ( |  | ) | `[protected]`

| Return the paint cache, might be null. Definition at line 89 of file qwt_plot_canvas.cpp.

const QPixmap * QwtPlotCanvas::cache | ( |  | ) | const

| Return the paint cache, might be null. Definition at line 95 of file qwt_plot_canvas.cpp. Referenced by QwtPlot::drawCurve().

bool QwtPlotCanvas::cacheMode | ( |  | ) | const

| Returns: Cache mode See also: setCacheMode Definition at line 83 of file qwt_plot_canvas.cpp. Referenced by drawCanvas(), drawContents(), and QwtPlot::drawCurve().

void QwtPlotCanvas::drawCanvas | ( | QPainter * | painter = `NULL` | ) | `[protected]`

| Draw the the canvas Paints all plot items to the contentsRect(), using QwtPlot::drawCanvas and updates the cache. See also: QwtPlot::drawCanvas, setCacheMode(), cacheMode() Definition at line 174 of file qwt_plot_canvas.cpp. References QwtPaintBuffer::buffer(), cacheMode(), QwtPaintBuffer::isEnabled(), and QwtPaintBuffer::painter(). Referenced by drawContents().

void QwtPlotCanvas::drawContents | ( | QPainter * |  | ) | `[protected, virtual]`

| Redraw the canvas, and focus rect. Definition at line 139 of file qwt_plot_canvas.cpp. References cacheMode(), drawCanvas(), drawFocusIndicator(), and focusIndicator().

void QwtPlotCanvas::drawFocusIndicator | ( | QPainter * | ,
|  | const QRect & |
| ) | `[protected, virtual]`

| Draw the focus indication. Definition at line 221 of file qwt_plot_canvas.cpp. Referenced by drawContents().

void QwtPlotCanvas::enableOutline | ( | bool | tf | ) |

  | Enables or disables outline drawing. Warning: Outlining functionality is obsolete: use QwtPlotPicker or QwtPlotZoomer. When the outline feature is enabled, a shape will be drawn in the plotting region when the user presses or drags the mouse. It can be used to implement crosshairs, mark a selected region, etc. Parameters:
  | tf | `TRUE` (enabled) or `FALSE` (disabled)
Warning: An outline style has to be specified. See also: QwtPlotCanvas::setOutlineStyle() Definition at line 315 of file qwt_plot_canvas.cpp. Referenced by QwtPlot::enableOutline().

QwtPlotCanvas::FocusIndicator QwtPlotCanvas::focusIndicator | ( |  | ) | const

| Returns: Focus indicator See also: FocusIndicator, setFocusIndicator Definition at line 122 of file qwt_plot_canvas.cpp. References FocusIndicator. Referenced by drawContents().

void QwtPlotCanvas::frameChanged | ( |  | ) | `[protected, virtual]`

| Requires layout updates of the parent plot. Definition at line 128 of file qwt_plot_canvas.cpp.

void QwtPlotCanvas::invalidateCache | ( |  | ) |

| Invalidate the internal paint cache. Definition at line 101 of file qwt_plot_canvas.cpp. Referenced by QwtPlot::replot().

void QwtPlotCanvas::mouseMoved | ( | const QMouseEvent & | e | ) | `[signal]`

  | A signal which is emitted when the mouse is moved in the canvas. Warning: Outlining functionality is obsolete: use QwtPlotPicker or QwtPlotZoomer. Parameters:
  | e | Mouse event object
Referenced by mouseMoveEvent().

void QwtPlotCanvas::mouseMoveEvent | ( | QMouseEvent * |  | ) | `[protected, virtual]`

| Mouse event handler. Definition at line 284 of file qwt_plot_canvas.cpp. References mouseMoved().

void QwtPlotCanvas::mousePressed | ( | const QMouseEvent & | e | ) | `[signal]`

  | A signal which is emitted when the mouse is pressed in the canvas. Warning: Outlining functionality is obsolete: use QwtPlotPicker or QwtPlotZoomer. Parameters:
  | e | Mouse event object
Referenced by mousePressEvent().

void QwtPlotCanvas::mousePressEvent | ( | QMouseEvent * |  | ) | `[protected, virtual]`

| Mouse event handler. Definition at line 234 of file qwt_plot_canvas.cpp. References mousePressed().

void QwtPlotCanvas::mouseReleased | ( | const QMouseEvent & | e | ) | `[signal]`

  | A signal which is emitted when a mouse button has been released in the canvas. Warning: Outlining functionality is obsolete: use QwtPlotPicker or QwtPlotZoomer. Parameters:
  | e | Mouse event object
Referenced by mouseReleaseEvent().

void QwtPlotCanvas::mouseReleaseEvent | ( | QMouseEvent * |  | ) | `[protected, virtual]`

| Mouse event handler. Definition at line 266 of file qwt_plot_canvas.cpp. References mouseReleased().

bool QwtPlotCanvas::outlineEnabled | ( |  | ) | const

| Returns: `TRUE` if the outline feature is enabled Warning: Outlining functionality is obsolete: use QwtPlotPicker or QwtPlotZoomer. See also: QwtPlotCanvas::enableOutline Definition at line 340 of file qwt_plot_canvas.cpp. Referenced by QwtPlot::outlineEnabled().

const QPen & QwtPlotCanvas::outlinePen | ( |  | ) | const

| Returns: the pen used to draw outlines Warning: Outlining functionality is obsolete: use QwtPlotPicker or QwtPlotZoomer. See also: QwtPlotCanvas::setOutlinePen Definition at line 433 of file qwt_plot_canvas.cpp. Referenced by QwtPlot::outlinePen().

Qwt::Shape QwtPlotCanvas::outlineStyle | ( |  | ) | const

| Returns: the outline style Warning: Outlining functionality is obsolete: use QwtPlotPicker or QwtPlotZoomer. See also: QwtPlotCanvas::setOutlineStyle() Definition at line 404 of file qwt_plot_canvas.cpp. Referenced by QwtPlot::outlineStyle().

void QwtPlotCanvas::setCacheMode | ( | bool | on | ) |

  | En/Disable caching. When cache mode is enabled the canvas contents are copied to a pixmap that is used for trivial repaints. Such repaints happen when a plot gets unhidden, deiconified or changes the focus. The win of caching depends on the costs of QwtPlot::drawCanvas. In case of plots with huge data it might be significant. The price of caching is wasting memory for the cache, what is a pixmap in size of contentsRect(). In case of QwtPaintBuffer::isEnabled() updating the cache produces no performance overhead as it reuses the temporary paintbuffer of the double buffering. Otherwise canvas updates have to painted twice to widget and cache. Parameters:
  | on | Enable caching, when TRUE
See also: cacheMode(), drawCanvas(), drawContents(), cache() Definition at line 66 of file qwt_plot_canvas.cpp.

void QwtPlotCanvas::setFocusIndicator | ( | FocusIndicator | focusIndicator | ) |

| Set the focus indicator See also: FocusIndicator, focusIndicator Definition at line 112 of file qwt_plot_canvas.cpp.

void QwtPlotCanvas::setOutlinePen | ( | const QPen & | pen | ) |

  | Specify a pen for the outline. Warning: Outlining functionality is obsolete: use QwtPlotPicker or QwtPlotZoomer. Parameters:
  | pen | new pen
See also: QwtPlotCanvas::outlinePen Definition at line 419 of file qwt_plot_canvas.cpp. Referenced by QwtPlot::setOutlinePen().

void QwtPlotCanvas::setOutlineStyle | ( | Qwt::Shape | os | ) |

  | Specify the style of the outline. Warning: Outlining functionality is obsolete: use QwtPlotPicker or QwtPlotZoomer. The outline style determines which kind of shape is drawn in the plotting region when the user presses a mouse button or drags the mouse. Valid Styles are: Parameters:
  | os | Outline Style. Valid values are: `Qwt::HLine`, `Qwt::VLine`, `Qwt::Cross`, `Qwt::Rect`, `Qwt::Ellipse` Qwt::Cros Cross hairs are drawn across the plotting area when the user presses a mouse button. The lines intersect at the point where the mouse was pressed and move with the mouse pointer. Qwt::HLine, Qwt::VLine A horizontal or vertical line appears when the user presses a mouse button. This is useful for moving line markers. Qwt::Rect A rectangle is displayed when the user drags the mouse. One corner is fixed at the point where the mouse was pressed, and the opposite corner moves with the mouse pointer. This can be used for selecting regions. Qwt::Ellipse Similar to Qwt::Rect, but with an ellipse inside a bounding rectangle.
See also: QwtPlotCanvas::enableOutline(), QwtPlotCanvas::outlineStyle() Definition at line 379 of file qwt_plot_canvas.cpp. Referenced by QwtPlot::setOutlineStyle().