QwtMetricsMap - Man Page

Name

QwtMetricsMap —

A Map to translate between layout, screen and paint device metrics.

QPoint deviceToLayout (const QPoint &, const QPainter *=NULL) const
QSize deviceToLayout (const QSize &) const
QRect deviceToLayout (const QRect &, const QPainter *=NULL) const
QwtPolygon deviceToLayout (const QwtPolygon &, const QPainter *=NULL) const
int deviceToLayoutX (int x) const
int deviceToLayoutY (int y) const
bool isIdentity () const
QSize layoutToDevice (const QSize &) const
QwtPolygon layoutToDevice (const QwtPolygon &, const QPainter *=NULL) const
QRect layoutToDevice (const QRect &, const QPainter *=NULL) const
QPoint layoutToDevice (const QPoint &, const QPainter *=NULL) const
int layoutToDeviceX (int x) const
int layoutToDeviceY (int y) const
QSize layoutToScreen (const QSize &) const
QRect layoutToScreen (const QRect &) const
QPoint layoutToScreen (const QPoint &point) const
int layoutToScreenX (int x) const
int layoutToScreenY (int y) const
QPoint screenToLayout (const QPoint &) const
QRect screenToLayout (const QRect &) const
QSize screenToLayout (const QSize &) const
int screenToLayoutX (int x) const
int screenToLayoutY (int y) const
void setMetrics (const QPaintDevice *layoutMetrics, const QPaintDevice *deviceMetrics)

Static Public Member Functions

static QwtPolygon translate (const QMatrix &, const QwtPolygon &)
static QRect translate (const QMatrix &, const QRect &)

Detailed Description

A Map to translate between layout, screen and paint device metrics.

Qt3 supports painting in integer coordinates only. Therefore it is not possible to scale the layout in screen coordinates to layouts in higher resolutions ( f.e printing ) without losing the higher precision. QwtMetricsMap is used to incorporate the various widget attributes ( always in screen resolution ) into the layout/printing code of QwtPlot.

Qt4 is able to paint floating point based coordinates, what makes it possible always to render in screen coordinates ( with a common scale factor ). QwtMetricsMap will be obsolete as soon as Qt3 support has been dropped ( Qwt 6.x ).