131 lines
2.8 KiB
Groff
131 lines
2.8 KiB
Groff
.TH "QwtTransform" 3 "Sun Jul 18 2021" "Version 6.2.0" "Qwt User's Guide" \" -*- nroff -*-
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.ad l
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.nh
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.SH NAME
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QwtTransform \- A transformation between coordinate systems\&.
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.SH SYNOPSIS
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.br
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.PP
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.PP
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\fC#include <qwt_transform\&.h>\fP
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.PP
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Inherited by \fBQwtLogTransform\fP, \fBQwtNullTransform\fP, and \fBQwtPowerTransform\fP\&.
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.SS "Public Member Functions"
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.in +1c
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.ti -1c
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.RI "\fBQwtTransform\fP ()"
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.br
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.RI "Constructor\&. "
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.ti -1c
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.RI "virtual \fB~QwtTransform\fP ()"
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.br
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.RI "Destructor\&. "
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.ti -1c
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.RI "virtual double \fBbounded\fP (double value) const"
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.br
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.ti -1c
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.RI "virtual double \fBtransform\fP (double value) const =0"
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.br
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.ti -1c
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.RI "virtual double \fBinvTransform\fP (double value) const =0"
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.br
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.ti -1c
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.RI "virtual \fBQwtTransform\fP * \fBcopy\fP () const =0"
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.br
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.RI "Virtualized copy operation\&. "
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.in -1c
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.SH "Detailed Description"
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.PP
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A transformation between coordinate systems\&.
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\fBQwtTransform\fP manipulates values, when being mapped between the scale and the paint device coordinate system\&.
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.PP
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A transformation consists of 2 methods:
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.PP
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.IP "\(bu" 2
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transform
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.IP "\(bu" 2
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invTransform
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.PP
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.PP
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where one is is the inverse function of the other\&.
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.PP
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When p1, p2 are the boundaries of the paint device coordinates and s1, s2 the boundaries of the scale, \fBQwtScaleMap\fP uses the following calculations:
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.PP
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.IP "\(bu" 2
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p = p1 + ( p2 - p1 ) * ( T( s ) - T( s1 ) / ( T( s2 ) - T( s1 ) );
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.IP "\(bu" 2
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s = invT ( T( s1 ) + ( T( s2 ) - T( s1 ) ) * ( p - p1 ) / ( p2 - p1 ) );
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.PP
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.PP
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Definition at line 35 of file qwt_transform\&.h\&.
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.SH "Member Function Documentation"
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.PP
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.SS "double QwtTransform::bounded (double value) const\fC [virtual]\fP"
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Modify value to be a valid value for the transformation\&. The default implementation does nothing\&.
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.PP
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\fBParameters\fP
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.RS 4
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\fIvalue\fP Value to be bounded
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.RE
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.PP
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\fBReturns\fP
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.RS 4
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value unmodified
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.RE
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.PP
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.PP
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Reimplemented in \fBQwtLogTransform\fP\&.
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.PP
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Definition at line 33 of file qwt_transform\&.cpp\&.
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.SS "virtual double QwtTransform::invTransform (double value) const\fC [pure virtual]\fP"
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Inverse transformation function
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.PP
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\fBParameters\fP
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.RS 4
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\fIvalue\fP Value
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.RE
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.PP
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\fBReturns\fP
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.RS 4
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Modified value
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.RE
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.PP
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\fBSee also\fP
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.RS 4
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\fBtransform()\fP
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.RE
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.PP
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.PP
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Implemented in \fBQwtPowerTransform\fP, \fBQwtLogTransform\fP, and \fBQwtNullTransform\fP\&.
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.SS "virtual double QwtTransform::transform (double value) const\fC [pure virtual]\fP"
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Transformation function
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.PP
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\fBParameters\fP
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.RS 4
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\fIvalue\fP Value
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.RE
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.PP
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\fBReturns\fP
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.RS 4
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Modified value
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.RE
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.PP
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\fBSee also\fP
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.RS 4
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\fBinvTransform()\fP
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.RE
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.PP
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.PP
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Implemented in \fBQwtPowerTransform\fP, \fBQwtLogTransform\fP, and \fBQwtNullTransform\fP\&.
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.SH "Author"
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.PP
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Generated automatically by Doxygen for Qwt User's Guide from the source code\&.
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