QwtPainter(3) Qwt User's Guide QwtPainter(3)

QwtPainter - A collection of QPainter workarounds.

#include <qwt_painter.h>


static void setPolylineSplitting (bool)
En/Disable line splitting for the raster paint engine. static bool polylineSplitting ()
static void setRoundingAlignment (bool)
static bool roundingAlignment ()
static bool roundingAlignment (const QPainter *)
static void drawText (QPainter *, qreal x, qreal y, const QString &)
Wrapper for QPainter::drawText() static void drawText (QPainter *, const QPointF &, const QString &)
Wrapper for QPainter::drawText() static void drawText (QPainter *, qreal x, qreal y, qreal w, qreal h, int flags, const QString &)
Wrapper for QPainter::drawText() static void drawText (QPainter *, const QRectF &, int flags, const QString &)
Wrapper for QPainter::drawText() static void drawSimpleRichText (QPainter *, const QRectF &, int flags, const QTextDocument &)
static void drawRect (QPainter *, qreal x, qreal y, qreal w, qreal h)
Wrapper for QPainter::drawRect() static void drawRect (QPainter *, const QRectF &rect)
Wrapper for QPainter::drawRect() static void fillRect (QPainter *, const QRectF &, const QBrush &)
Wrapper for QPainter::fillRect() static void drawEllipse (QPainter *, const QRectF &)
Wrapper for QPainter::drawEllipse() static void drawPie (QPainter *, const QRectF &r, int a, int alen)
Wrapper for QPainter::drawPie() static void drawLine (QPainter *, qreal x1, qreal y1, qreal x2, qreal y2)
Wrapper for QPainter::drawLine() static void drawLine (QPainter *, const QPointF &p1, const QPointF &p2)
Wrapper for QPainter::drawLine() static void drawLine (QPainter *, const QLineF &)
Wrapper for QPainter::drawLine() static void drawPolygon (QPainter *, const QPolygonF &)
Wrapper for QPainter::drawPolygon() static void drawPolyline (QPainter *, const QPolygonF &)
Wrapper for QPainter::drawPolyline() static void drawPolyline (QPainter *, const QPointF *, int pointCount)
Wrapper for QPainter::drawPolyline() static void drawPolygon (QPainter *, const QPolygon &)
Wrapper for QPainter::drawPolygon() static void drawPolyline (QPainter *, const QPolygon &)
Wrapper for QPainter::drawPolyline() static void drawPolyline (QPainter *, const QPoint *, int pointCount)
Wrapper for QPainter::drawPolyline() static void drawPoint (QPainter *, const QPoint &)
Wrapper for QPainter::drawPoint() static void drawPoints (QPainter *, const QPolygon &)
Wrapper for QPainter::drawPoints() static void drawPoints (QPainter *, const QPoint *, int pointCount)
Wrapper for QPainter::drawPoints() static void drawPoint (QPainter *, qreal x, qreal y)
Wrapper for QPainter::drawPoint() static void drawPoint (QPainter *, const QPointF &)
Wrapper for QPainter::drawPoint() static void drawPoints (QPainter *, const QPolygonF &)
Wrapper for QPainter::drawPoints() static void drawPoints (QPainter *, const QPointF *, int pointCount)
Wrapper for QPainter::drawPoints() static void drawPath (QPainter *, const QPainterPath &)
Wrapper for QPainter::drawPath() static void drawImage (QPainter *, const QRectF &, const QImage &)
Wrapper for QPainter::drawImage() static void drawPixmap (QPainter *, const QRectF &, const QPixmap &)
Wrapper for QPainter::drawPixmap() static void drawRoundFrame (QPainter *, const QRectF &, const QPalette &, int lineWidth, int frameStyle)
static void drawRoundedFrame (QPainter *, const QRectF &, qreal xRadius, qreal yRadius, const QPalette &, int lineWidth, int frameStyle)
static void drawFrame (QPainter *, const QRectF &rect, const QPalette &palette, QPalette::ColorRole foregroundRole, int lineWidth, int midLineWidth, int frameStyle)
static void drawFocusRect (QPainter *, const QWidget *)
Draw a focus rectangle on a widget using its style. static void drawFocusRect (QPainter *, const QWidget *, const QRect &)
Draw a focus rectangle on a widget using its style. static void drawColorBar (QPainter *, const QwtColorMap &, const QwtInterval &, const QwtScaleMap &, Qt::Orientation, const QRectF &)
static bool isAligning (const QPainter *)
static bool isX11GraphicsSystem ()
static void fillPixmap (const QWidget *, QPixmap &, const QPoint &offset=QPoint())
static void drawBackgound (QPainter *, const QRectF &, const QWidget *)
static QPixmap backingStore (QWidget *, const QSize &)
static qreal devicePixelRatio (const QPaintDevice *)
static qreal effectivePenWidth (const QPen &)
static int horizontalAdvance (const QFontMetrics &, const QString &)
static qreal horizontalAdvance (const QFontMetricsF &, const QString &)
static int horizontalAdvance (const QFontMetrics &, QChar)
static qreal horizontalAdvance (const QFontMetricsF &, QChar)
static QFont scaledFont (const QFont &, const QPaintDevice *=nullptr)

A collection of QPainter workarounds.

Definition at line 36 of file qwt_painter.h.

Returns

A pixmap that can be used as backing store

Parameters

widget Widget, for which the backingstore is intended
size Size of the pixmap

Definition at line 1525 of file qwt_painter.cpp.

Returns

Pixel ratio for a paint device

Parameters

paintDevice Paint device

Definition at line 1491 of file qwt_painter.cpp.

Fill rect with the background of a widget

Parameters

painter Painter
rect Rectangle to be filled
widget Widget

See also

QStyle::PE_Widget, QWidget::backgroundRole()

Definition at line 1351 of file qwt_painter.cpp.

Draw a color bar into a rectangle

Parameters

painter Painter
colorMap Color map
interval Value range
scaleMap Scale map
orientation Orientation
rect Target rectangle

Definition at line 1205 of file qwt_painter.cpp.

Draw a rectangular frame

Parameters

painter Painter
rect Frame rectangle
palette Palette
foregroundRole Foreground role used for QFrame::Plain
frameWidth Frame width
midLineWidth Used for QFrame::Box
frameStyle bitwise OR´ed value of QFrame::Shape and QFrame::Shadow

Definition at line 911 of file qwt_painter.cpp.

Draw a rectangular frame with rounded borders

Parameters

painter Painter
rect Frame rectangle
xRadius x-radius of the ellipses defining the corners
yRadius y-radius of the ellipses defining the corners
palette QPalette::WindowText is used for plain borders QPalette::Dark and QPalette::Light for raised or sunken borders
lineWidth Line width
frameStyle bitwise OR´ed value of QFrame::Shape and QFrame::Shadow

Definition at line 1065 of file qwt_painter.cpp.

Draw a round frame

Parameters

painter Painter
rect Frame rectangle
palette QPalette::WindowText is used for plain borders QPalette::Dark and QPalette::Light for raised or sunken borders
lineWidth Line width
frameStyle bitwise OR´ed value of QFrame::Shape and QFrame::Shadow

Definition at line 845 of file qwt_painter.cpp.

Draw a text document into a rectangle

Parameters

painter Painter
rect Target rectangle
flags Alignments/Text flags, see QPainter::drawText()
text Text document

Definition at line 489 of file qwt_painter.cpp.

Returns

pen.widthF() expanded to at least 1.0

Parameters

pen Pen

Definition at line 201 of file qwt_painter.h.

Fill a pixmap with the content of a widget

In Qt >= 5.0 QPixmap::fill() is a nop, in Qt 4.x it is buggy for backgrounds with gradients. Thus fillPixmap() offers an alternative implementation.

Parameters

widget Widget
pixmap Pixmap to be filled
offset Offset

See also

QPixmap::fill()

Definition at line 1311 of file qwt_painter.cpp.

Distance appropriate for drawing a subsequent character after text.

Parameters

fontMetrics Font metrics
text Text

Returns

horizontal advance in pixels

Definition at line 1379 of file qwt_painter.cpp.

Distance appropriate for drawing a subsequent character after ch.

Parameters

fontMetrics Font metrics
ch Character

Returns

horizontal advance in pixels

Definition at line 1414 of file qwt_painter.cpp.

Distance appropriate for drawing a subsequent character after text.

Parameters

fontMetrics Font metrics
text Text

Returns

horizontal advance in pixels

Definition at line 1397 of file qwt_painter.cpp.

Distance appropriate for drawing a subsequent character after ch.

Parameters

fontMetrics Font metrics
ch Character

Returns

horizontal advance in pixels

Definition at line 1431 of file qwt_painter.cpp.

Check if the painter is using a paint engine, that aligns coordinates to integers. Today these are all paint engines beside QPaintEngine::Pdf and QPaintEngine::SVG.

If we have an integer based paint engine it is also checked if the painter has a transformation matrix, that rotates or scales.

Parameters

painter Painter

Returns

true, when the painter is aligning

See also

setRoundingAlignment()

Definition at line 267 of file qwt_painter.cpp.

Check is the application is running with the X11 graphics system that has some special capabilities that can be used for incremental painting to a widget.

Returns

True, when the graphics system is X11

Definition at line 233 of file qwt_painter.cpp.

Returns

True, when line splitting for the raster paint engine is enabled.

See also

setPolylineSplitting()

Definition at line 170 of file qwt_painter.h.

Check whether coordinates should be rounded, before they are painted to a paint engine that rounds to integer values. For other paint engines ( PDF, SVG ), this flag has no effect.

Returns

True, when rounding is enabled

See also

setRoundingAlignment(), isAligning()

Definition at line 183 of file qwt_painter.h.

Returns

roundingAlignment() && isAligning(painter);

Parameters

painter Painter

Definition at line 192 of file qwt_painter.h.

Adjust the DPI value of font according to the DPI value of the paint device

Parameters

font Unscaled font
paintDevice Paint device providing a DPI value. If paintDevice == null the DPI value of the primary screen will be used

Returns

Font being adjusted to the DPI value of the paint device

Definition at line 1450 of file qwt_painter.cpp.

En/Disable line splitting for the raster paint engine. In some Qt versions the raster paint engine paints polylines of many points much faster when they are split in smaller chunks: f.e all supported Qt versions >= Qt 5.0 when drawing an antialiased polyline with a pen width >=2.

Also the raster paint engine has a nasty bug in many versions ( Qt 4.8 - ... ) for short lines ( https://codereview.qt-project.org/#/c/99456 ), that is worked around in this mode.

The default setting is true.

See also

polylineSplitting()

Definition at line 335 of file qwt_painter.cpp.

Enable whether coordinates should be rounded, before they are painted to a paint engine that floors to integer values. For other paint engines ( PDF, SVG ) this flag has no effect. QwtPainter stores this flag only, the rounding itself is done in the painting code ( f.e the plot items ).

The default setting is true.

See also

roundingAlignment(), isAligning()

Definition at line 315 of file qwt_painter.cpp.

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Sun Jul 18 2021 Version 6.2.0