A transformation between coordinate systems. More...
#include <qwt_transform.h>
Public Member Functions | |
| virtual double | bounded (double value) const |
| virtual QwtTransform * | copy () const =0 |
| Virtualized copy operation. | |
| virtual double | invTransform (double value) const =0 |
| QwtTransform () | |
| Constructor. | |
| virtual double | transform (double value) const =0 |
| virtual | ~QwtTransform () |
| Destructor. | |
Detailed Description
A transformation between coordinate systems.
QwtTransform manipulates values, when being mapped between the scale and the paint device coordinate system.
A transformation consists of 2 methods:
- transform
- invTransform
where one is is the inverse function of the other.
When p1, p2 are the boundaries of the paint device coordinates and s1, s2 the boundaries of the scale, QwtScaleMap uses the following calculations:
- p = p1 + ( p2 - p1 ) * ( T( s ) - T( s1 ) / ( T( s2 ) - T( s1 ) );
- s = invT ( T( s1 ) + ( T( s2 ) - T( s1 ) ) * ( p - p1 ) / ( p2 - p1 ) );
Definition at line 35 of file qwt_transform.h.
Constructor & Destructor Documentation
Constructor.
Definition at line 24 of file qwt_transform.cpp.
| QwtTransform::~QwtTransform | ( | ) | [virtual] |
Destructor.
Definition at line 29 of file qwt_transform.cpp.
Member Function Documentation
| double QwtTransform::bounded | ( | double | value | ) | const [virtual] |
Modify value to be a valid value for the transformation. The default implementation does nothing.
- Parameters:
-
value Value to be bounded
- Returns:
- value unmodified
Reimplemented in QwtLogTransform.
Definition at line 37 of file qwt_transform.cpp.
| virtual QwtTransform* QwtTransform::copy | ( | ) | const [pure virtual] |
Virtualized copy operation.
Implemented in QwtPowerTransform, QwtLogTransform, and QwtNullTransform.
| virtual double QwtTransform::invTransform | ( | double | value | ) | const [pure virtual] |
Inverse transformation function
- Parameters:
-
value Value
- Returns:
- Modified value
- See also:
- transform()
Implemented in QwtPowerTransform, QwtLogTransform, and QwtNullTransform.
| virtual double QwtTransform::transform | ( | double | value | ) | const [pure virtual] |
Transformation function
- Parameters:
-
value Value
- Returns:
- Modified value
- See also:
- invTransform()
Implemented in QwtPowerTransform, QwtLogTransform, and QwtNullTransform.
The documentation for this class was generated from the following files: