---
name: "QwtPlotGLCanvas"
section: "3"
platform: "linux"
package: "libqwt-doc"
version: "6.1.4-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/QwtPlotGLCanvas"
---

# QwtPlotGLCanvas(3)

An alternative canvas for a QwtPlot derived from QGLWidget.

## NAME

QwtPlotGLCanvas - An alternative canvas for a **QwtPlot** derived from QGLWidget.

## SYNOPSIS

`#include <qwt_plot_glcanvas.h>`

Inherits QGLWidget.

### Public Types

enum **Shadow** { **Plain** = QFrame::Plain, **Raised** = QFrame::Raised, **Sunken** = QFrame::Sunken }\
 Frame shadow.  enum **Shape** { **NoFrame** = QFrame::NoFrame, **Box** = QFrame::Box, **Panel** = QFrame::Panel }\
 Frame shape.

### Public Slots

void **replot** ()\
 Calls repaint()

### Public Member Functions

**QwtPlotGLCanvas** (**QwtPlot** \*=NULL)\
 Constructor.  virtual **~QwtPlotGLCanvas** ()\
 Destructor.  void **setFrameStyle** (int style)\
 int **frameStyle** () const\
 void **setFrameShadow** (**Shadow**)\
 **Shadow** **frameShadow** () const\
 void **setFrameShape** (**Shape**)\
 **Shape** **frameShape** () const\
 void **setLineWidth** (int)\
 int **lineWidth** () const\
 void **setMidLineWidth** (int)\
 int **midLineWidth** () const\
 int **frameWidth** () const\
 QRect **frameRect** () const\
 Q\_INVOKABLE QPainterPath **borderPath** (const QRect &) const\
 virtual bool **event** (QEvent \*)\

### Protected Member Functions

virtual void **paintEvent** (QPaintEvent \*)\
 virtual void **drawBackground** (QPainter \*)\
 virtual void **drawBorder** (QPainter \*)\
 virtual void **drawItems** (QPainter \*)\

## Detailed Description

An alternative canvas for a **QwtPlot** derived from QGLWidget.

**QwtPlotGLCanvas** implements the very basics to act as canvas inside of a **QwtPlot** widget. It might be extended to a full featured alternative to **QwtPlotCanvas** in a future version of Qwt.

Even if **QwtPlotGLCanvas** is not derived from QFrame it imitates its API. When using style sheets it supports the box model - beside backgrounds with rounded borders.

**See also:**

**QwtPlot::setCanvas()**, **QwtPlotCanvas**

**Note:**

With Qt4 you might want to use the QPaintEngine::OpenGL paint engine ( see QGL::setPreferredPaintEngine() ). On a Linux test system QPaintEngine::OpenGL2 shows very basic problems like translated geometries.

## Member Enumeration Documentation

### enum QwtPlotGLCanvas::Shadow

Frame shadow. Unfortunately it is not possible to use QFrame::Shadow as a property of a widget that is not derived from QFrame. The following enum is made for the designer only. It is safe to use QFrame::Shadow instead.

**Enumerator**

- *Plain*

  *QFrame::Plain.*

- *Raised*

  *QFrame::Raised.*

- *Sunken*

  *QFrame::Sunken.*

### enum QwtPlotGLCanvas::Shape

*Frame shape. Unfortunately it is not possible to use QFrame::Shape as a property of a widget that is not derived from QFrame. The following enum is made for the designer only. It is safe to use QFrame::Shadow instead.*

**Note:**

*QFrame::StyledPanel and QFrame::WinPanel are unsupported and will be displayed as QFrame::Panel.*

## Constructor & Destructor Documentation

### QwtPlotGLCanvas::QwtPlotGLCanvas (QwtPlot \* plot = `NULL`)` [explicit]`

*Constructor.*

**Parameters:**

*plot Parent plot widget*

**See also:**

**QwtPlot::setCanvas()**

## Member Function Documentation

### QPainterPath QwtPlotGLCanvas::borderPath (const QRect & rect) const

**Returns:**

*Empty path*

### void QwtPlotGLCanvas::drawBackground (QPainter \* painter)` [protected]`, ` [virtual]`

*Draw the background of the canvas*

**Parameters:**

*painter Painter*

### void QwtPlotGLCanvas::drawBorder (QPainter \* painter)` [protected]`, ` [virtual]`

*Draw the border of the canvas*

**Parameters:**

*painter Painter*

### void QwtPlotGLCanvas::drawItems (QPainter \* painter)` [protected]`, ` [virtual]`

*Draw the plot items*

**Parameters:**

*painter Painter*

**See also:**

**QwtPlot::drawCanvas()**

### bool QwtPlotGLCanvas::event (QEvent \* event)` [virtual]`

*Qt event handler for QEvent::PolishRequest and QEvent::StyleChange*

**Parameters:**

*event Qt Event*

**Returns:**

*See QGLWidget::event()*

### QRect QwtPlotGLCanvas::frameRect () const

**Returns:**

*The rectangle where the frame is drawn in.*

### QwtPlotGLCanvas::Shadow QwtPlotGLCanvas::frameShadow () const

**Returns:**

*Frame shadow*

**See also:**

**setFrameShadow()***, QFrame::setFrameShadow()*

### QwtPlotGLCanvas::Shape QwtPlotGLCanvas::frameShape () const

**Returns:**

*Frame shape*

**See also:**

**setFrameShape()***, QFrame::frameShape()*

### int QwtPlotGLCanvas::frameStyle () const

**Returns:**

*The bitwise OR between a* **frameShape()** *and a* **frameShadow()**

**See also:**

**setFrameStyle()***, QFrame::frameStyle()*

### int QwtPlotGLCanvas::frameWidth () const

**Returns:**

*Frame width depending on the style, line width and midline width.*

### int QwtPlotGLCanvas::lineWidth () const

**Returns:**

*Line width of the frame*

**See also:**

**setLineWidth()***,* **midLineWidth()**

### int QwtPlotGLCanvas::midLineWidth () const

**Returns:**

*Midline width of the frame*

**See also:**

**setMidLineWidth()***,* **lineWidth()**

### void QwtPlotGLCanvas::paintEvent (QPaintEvent \* event)` [protected]`, ` [virtual]`

*Paint event*

**Parameters:**

*event Paint event*

**See also:**

**QwtPlot::drawCanvas()**

### void QwtPlotGLCanvas::setFrameShadow (Shadow shadow)

*Set the frame shadow*

**Parameters:**

*shadow Frame shadow*

**See also:**

**frameShadow()***,* **setFrameShape()***, QFrame::setFrameShadow()*

### void QwtPlotGLCanvas::setFrameShape (Shape shape)

*Set the frame shape*

**Parameters:**

*shape Frame shape*

**See also:**

**frameShape()***,* **setFrameShadow()***, QFrame::frameShape()*

### void QwtPlotGLCanvas::setFrameStyle (int style)

*Set the frame style*

**Parameters:**

*style The bitwise OR between a shape and a shadow.*

**See also:**

**frameStyle()***, QFrame::setFrameStyle(),* **setFrameShadow()***,* **setFrameShape()**

### void QwtPlotGLCanvas::setLineWidth (int width)

*Set the frame line width*

*The default line width is 2 pixels.*

**Parameters:**

*width Line width of the frame*

**See also:**

**lineWidth()***,* **setMidLineWidth()**

### void QwtPlotGLCanvas::setMidLineWidth (int width)

*Set the frame mid line width*

*The default midline width is 0 pixels.*

**Parameters:**

*width Midline width of the frame*

**See also:**

**midLineWidth()***,* **setLineWidth()**

## Author

*Generated automatically by Doxygen for Qwt User's Guide from the source code.*