.TH "QwtAbstractScaleDraw" 3 "Mon Dec 28 2020" "Version 6.1.6" "Qwt User's Guide" \" -*- nroff -*-
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.SH NAME
QwtAbstractScaleDraw \- A abstract base class for drawing scales\&.  

.SH SYNOPSIS
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.PP
.PP
\fC#include <qwt_abstract_scale_draw\&.h>\fP
.PP
Inherited by \fBQwtRoundScaleDraw\fP, and \fBQwtScaleDraw\fP\&.
.SS "Public Types"

.in +1c
.ti -1c
.RI "enum \fBScaleComponent\fP { \fBBackbone\fP = 0x01, \fBTicks\fP = 0x02, \fBLabels\fP = 0x04 }"
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.RI "typedef QFlags< \fBScaleComponent\fP > \fBScaleComponents\fP"
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.RI "Scale components\&. "
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.SS "Public Member Functions"

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.RI "\fBQwtAbstractScaleDraw\fP ()"
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.RI "Constructor\&. "
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.RI "virtual \fB~QwtAbstractScaleDraw\fP ()"
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.RI "Destructor\&. "
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.RI "void \fBsetScaleDiv\fP (const \fBQwtScaleDiv\fP &)"
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.RI "const \fBQwtScaleDiv\fP & \fBscaleDiv\fP () const"
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.RI "void \fBsetTransformation\fP (\fBQwtTransform\fP *)"
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.RI "const \fBQwtScaleMap\fP & \fBscaleMap\fP () const"
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.RI "\fBQwtScaleMap\fP & \fBscaleMap\fP ()"
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.RI "void \fBenableComponent\fP (\fBScaleComponent\fP, bool enable=true)"
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.RI "bool \fBhasComponent\fP (\fBScaleComponent\fP) const"
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.RI "void \fBsetTickLength\fP (\fBQwtScaleDiv::TickType\fP, double length)"
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.RI "double \fBtickLength\fP (\fBQwtScaleDiv::TickType\fP) const"
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.RI "double \fBmaxTickLength\fP () const"
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.RI "void \fBsetSpacing\fP (double)"
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.RI "Set the spacing between tick and labels\&. "
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.RI "double \fBspacing\fP () const"
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.RI "Get the spacing\&. "
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.RI "void \fBsetPenWidth\fP (int width)"
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.RI "Specify the width of the scale pen\&. "
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.RI "int \fBpenWidth\fP () const"
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.RI "virtual void \fBdraw\fP (QPainter *, const QPalette &) const"
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.RI "Draw the scale\&. "
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.RI "virtual \fBQwtText\fP \fBlabel\fP (double) const"
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.RI "Convert a value into its representing label\&. "
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.RI "virtual double \fBextent\fP (const QFont &font) const =0"
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.RI "void \fBsetMinimumExtent\fP (double)"
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.RI "Set a minimum for the extent\&. "
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.RI "double \fBminimumExtent\fP () const"
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.SS "Protected Member Functions"

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.RI "virtual void \fBdrawTick\fP (QPainter *painter, double value, double len) const =0"
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.RI "virtual void \fBdrawBackbone\fP (QPainter *painter) const =0"
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.RI "virtual void \fBdrawLabel\fP (QPainter *painter, double value) const =0"
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.RI "void \fBinvalidateCache\fP ()"
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.RI "const \fBQwtText\fP & \fBtickLabel\fP (const QFont &, double value) const"
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.RI "Convert a value into its representing label and cache it\&. "
.in -1c
.SH "Detailed Description"
.PP 
A abstract base class for drawing scales\&. 

\fBQwtAbstractScaleDraw\fP can be used to draw linear or logarithmic scales\&.
.PP
After a scale division has been specified as a \fBQwtScaleDiv\fP object using \fBsetScaleDiv()\fP, the scale can be drawn with the \fBdraw()\fP member\&. 
.SH "Member Enumeration Documentation"
.PP 
.SS "enum \fBQwtAbstractScaleDraw::ScaleComponent\fP"
Components of a scale 
.PP
\fBSee also\fP
.RS 4
\fBenableComponent()\fP, \fBhasComponent\fP 
.RE
.PP

.PP
\fBEnumerator\fP
.in +1c
.TP
\fB\fIBackbone \fP\fP
Backbone = the line where the ticks are located\&. 
.TP
\fB\fITicks \fP\fP
Ticks\&. 
.TP
\fB\fILabels \fP\fP
Labels\&. 
.SH "Constructor & Destructor Documentation"
.PP 
.SS "QwtAbstractScaleDraw::QwtAbstractScaleDraw ()"

.PP
Constructor\&. The range of the scale is initialized to [0, 100], The spacing (distance between ticks and labels) is set to 4, the tick lengths are set to 4,6 and 8 pixels 
.SH "Member Function Documentation"
.PP 
.SS "void QwtAbstractScaleDraw::draw (QPainter * painter, const QPalette & palette) const\fC [virtual]\fP"

.PP
Draw the scale\&. 
.PP
\fBParameters\fP
.RS 4
\fIpainter\fP The painter
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\fIpalette\fP Palette, text color is used for the labels, foreground color for ticks and backbone 
.RE
.PP

.SS "virtual void QwtAbstractScaleDraw::drawBackbone (QPainter * painter) const\fC [protected]\fP, \fC [pure virtual]\fP"
Draws the baseline of the scale 
.PP
\fBParameters\fP
.RS 4
\fIpainter\fP Painter
.RE
.PP
\fBSee also\fP
.RS 4
\fBdrawTick()\fP, \fBdrawLabel()\fP 
.RE
.PP

.PP
Implemented in \fBQwtScaleDraw\fP, and \fBQwtRoundScaleDraw\fP\&.
.SS "virtual void QwtAbstractScaleDraw::drawLabel (QPainter * painter, double value) const\fC [protected]\fP, \fC [pure virtual]\fP"
Draws the label for a major scale tick
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\fBParameters\fP
.RS 4
\fIpainter\fP Painter 
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\fIvalue\fP Value
.RE
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\fBSee also\fP
.RS 4
\fBdrawTick()\fP, \fBdrawBackbone()\fP 
.RE
.PP

.PP
Implemented in \fBQwtScaleDraw\fP, and \fBQwtRoundScaleDraw\fP\&.
.SS "virtual void QwtAbstractScaleDraw::drawTick (QPainter * painter, double value, double len) const\fC [protected]\fP, \fC [pure virtual]\fP"
Draw a tick
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\fBParameters\fP
.RS 4
\fIpainter\fP Painter 
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\fIvalue\fP Value of the tick 
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\fIlen\fP Length of the tick
.RE
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\fBSee also\fP
.RS 4
\fBdrawBackbone()\fP, \fBdrawLabel()\fP 
.RE
.PP

.PP
Implemented in \fBQwtScaleDraw\fP, and \fBQwtRoundScaleDraw\fP\&.
.SS "void QwtAbstractScaleDraw::enableComponent (\fBScaleComponent\fP component, bool enable = \fCtrue\fP)"
En/Disable a component of the scale
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\fBParameters\fP
.RS 4
\fIcomponent\fP Scale component 
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\fIenable\fP On/Off
.RE
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\fBSee also\fP
.RS 4
\fBhasComponent()\fP 
.RE
.PP

.SS "virtual double QwtAbstractScaleDraw::extent (const QFont & font) const\fC [pure virtual]\fP"
Calculate the extent
.PP
The extent is the distance from the baseline to the outermost pixel of the scale draw in opposite to its orientation\&. It is at least \fBminimumExtent()\fP pixels\&.
.PP
\fBParameters\fP
.RS 4
\fIfont\fP Font used for drawing the tick labels 
.RE
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\fBReturns\fP
.RS 4
Number of pixels
.RE
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\fBSee also\fP
.RS 4
\fBsetMinimumExtent()\fP, \fBminimumExtent()\fP 
.RE
.PP

.PP
Implemented in \fBQwtScaleDraw\fP, and \fBQwtRoundScaleDraw\fP\&.
.SS "bool QwtAbstractScaleDraw::hasComponent (\fBScaleComponent\fP component) const"
Check if a component is enabled
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\fBParameters\fP
.RS 4
\fIcomponent\fP Component type 
.RE
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\fBReturns\fP
.RS 4
true, when component is enabled 
.RE
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\fBSee also\fP
.RS 4
\fBenableComponent()\fP 
.RE
.PP

.SS "void QwtAbstractScaleDraw::invalidateCache ()\fC [protected]\fP"
Invalidate the cache used by \fBtickLabel()\fP
.PP
The cache is invalidated, when a new \fBQwtScaleDiv\fP is set\&. If the labels need to be changed\&. while the same \fBQwtScaleDiv\fP is set, \fBinvalidateCache()\fP needs to be called manually\&. 
.SS "\fBQwtText\fP QwtAbstractScaleDraw::label (double value) const\fC [virtual]\fP"

.PP
Convert a value into its representing label\&. The value is converted to a plain text using QLocale()\&.toString(value)\&. This method is often overloaded by applications to have individual labels\&.
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\fBParameters\fP
.RS 4
\fIvalue\fP Value 
.RE
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\fBReturns\fP
.RS 4
Label string\&. 
.RE
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.PP
Reimplemented in \fBQwtDateScaleDraw\fP, and \fBQwtCompassScaleDraw\fP\&.
.SS "double QwtAbstractScaleDraw::maxTickLength () const"

.PP
\fBReturns\fP
.RS 4
Length of the longest tick
.RE
.PP
Useful for layout calculations 
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\fBSee also\fP
.RS 4
\fBtickLength()\fP, \fBsetTickLength()\fP 
.RE
.PP

.SS "double QwtAbstractScaleDraw::minimumExtent () const"
Get the minimum extent 
.PP
\fBReturns\fP
.RS 4
Minimum extent 
.RE
.PP
\fBSee also\fP
.RS 4
\fBextent()\fP, \fBsetMinimumExtent()\fP 
.RE
.PP

.SS "int QwtAbstractScaleDraw::penWidth () const"

.PP
\fBReturns\fP
.RS 4
Scale pen width 
.RE
.PP
\fBSee also\fP
.RS 4
\fBsetPenWidth()\fP 
.RE
.PP

.SS "const \fBQwtScaleDiv\fP & QwtAbstractScaleDraw::scaleDiv () const"

.PP
\fBReturns\fP
.RS 4
scale division 
.RE
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.SS "\fBQwtScaleMap\fP & QwtAbstractScaleDraw::scaleMap ()"

.PP
\fBReturns\fP
.RS 4
Map how to translate between scale and pixel values 
.RE
.PP

.SS "const \fBQwtScaleMap\fP & QwtAbstractScaleDraw::scaleMap () const"

.PP
\fBReturns\fP
.RS 4
Map how to translate between scale and pixel values 
.RE
.PP

.SS "void QwtAbstractScaleDraw::setMinimumExtent (double minExtent)"

.PP
Set a minimum for the extent\&. The extent is calculated from the components of the scale draw\&. In situations, where the labels are changing and the layout depends on the extent (f\&.e scrolling a scale), setting an upper limit as minimum extent will avoid jumps of the layout\&.
.PP
\fBParameters\fP
.RS 4
\fIminExtent\fP Minimum extent
.RE
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\fBSee also\fP
.RS 4
\fBextent()\fP, \fBminimumExtent()\fP 
.RE
.PP

.SS "void QwtAbstractScaleDraw::setPenWidth (int width)"

.PP
Specify the width of the scale pen\&. 
.PP
\fBParameters\fP
.RS 4
\fIwidth\fP Pen width 
.RE
.PP
\fBSee also\fP
.RS 4
\fBpenWidth()\fP 
.RE
.PP

.SS "void QwtAbstractScaleDraw::setScaleDiv (const \fBQwtScaleDiv\fP & scaleDiv)"
Change the scale division 
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\fBParameters\fP
.RS 4
\fIscaleDiv\fP New scale division 
.RE
.PP

.SS "void QwtAbstractScaleDraw::setSpacing (double spacing)"

.PP
Set the spacing between tick and labels\&. The spacing is the distance between ticks and labels\&. The default spacing is 4 pixels\&.
.PP
\fBParameters\fP
.RS 4
\fIspacing\fP Spacing
.RE
.PP
\fBSee also\fP
.RS 4
\fBspacing()\fP 
.RE
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.SS "void QwtAbstractScaleDraw::setTickLength (\fBQwtScaleDiv::TickType\fP tickType, double length)"
Set the length of the ticks
.PP
\fBParameters\fP
.RS 4
\fItickType\fP Tick type 
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\fIlength\fP New length
.RE
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\fBWarning\fP
.RS 4
the length is limited to [0\&.\&.1000] 
.RE
.PP

.SS "void QwtAbstractScaleDraw::setTransformation (\fBQwtTransform\fP * transformation)"
Change the transformation of the scale 
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\fBParameters\fP
.RS 4
\fItransformation\fP New scale transformation 
.RE
.PP

.SS "double QwtAbstractScaleDraw::spacing () const"

.PP
Get the spacing\&. The spacing is the distance between ticks and labels\&. The default spacing is 4 pixels\&.
.PP
\fBReturns\fP
.RS 4
Spacing 
.RE
.PP
\fBSee also\fP
.RS 4
\fBsetSpacing()\fP 
.RE
.PP

.SS "const \fBQwtText\fP & QwtAbstractScaleDraw::tickLabel (const QFont & font, double value) const\fC [protected]\fP"

.PP
Convert a value into its representing label and cache it\&. The conversion between value and label is called very often in the layout and painting code\&. Unfortunately the calculation of the label sizes might be slow (really slow for rich text in Qt4), so it's necessary to cache the labels\&.
.PP
\fBParameters\fP
.RS 4
\fIfont\fP Font 
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\fIvalue\fP Value
.RE
.PP
\fBReturns\fP
.RS 4
Tick label 
.RE
.PP

.SS "double QwtAbstractScaleDraw::tickLength (\fBQwtScaleDiv::TickType\fP tickType) const"

.PP
\fBReturns\fP
.RS 4
Length of the ticks 
.RE
.PP
\fBSee also\fP
.RS 4
\fBsetTickLength()\fP, \fBmaxTickLength()\fP 
.RE
.PP


.SH "Author"
.PP 
Generated automatically by Doxygen for Qwt User's Guide from the source code\&.