Files
allwpilib/wpilibc/wpilibC++Devices/include/AnalogPotentiometer.h
James Kuszmaul f65e697107 Revert changes preventing old user code from compiling.
I'm not 100% sure whether we want these, but they are a quick
find and replace to do.

Basically, there are two primary things that we have done
this summer that break existing user code:
-Changing GetInstance() calls to return references instead
 of pointers. This forces users to change from doing something
 like LiveWindow::GetInstance()->AddSensor() to LiveWindow::GetInstance().AddSensor().
-Making PIDGet() and related calls const, forcing users to change
 the function signatures wherever they override them.

The GetInstance() calls don't really matter to me either way,
especially since there are no real ownership issues going on there,
unlike the rest of the smart pointer-related changes.

For the const stuff, it is certainly more correct to mandate that
user PIDGet() functions be const and the such, but at the same time,
I'm not sure that there is any strong need for it, and the errors
generated are not the most helpful. While this wouldn't necessarily
be an issue for more experienced teams or completely new teams (who
don't have any old code to be reusing), it may cause issues for more
average teams who aren't familiar with the intricacies of C++ anything.

Change-Id: I6e7007982069292ea70e6d0fc8ca40203340df1b
2015-09-16 19:10:01 -04:00

92 lines
3.0 KiB
C++

#include "AnalogInput.h"
#include "interfaces/Potentiometer.h"
#include "LiveWindow/LiveWindowSendable.h"
#include <memory>
/**
* Class for reading analog potentiometers. Analog potentiometers read
* in an analog voltage that corresponds to a position. The position is
* in whichever units you choose, by way of the scaling and offset
* constants passed to the constructor.
*
* @author Alex Henning
* @author Colby Skeggs (rail voltage)
*/
class AnalogPotentiometer : public Potentiometer, public LiveWindowSendable {
public:
/**
* AnalogPotentiometer constructor.
*
* Use the fullRange and offset values so that the output produces
* meaningful values. I.E: you have a 270 degree potentiometer and
* you want the output to be degrees with the halfway point as 0
* degrees. The fullRange value is 270.0(degrees) and the offset is
* -135.0 since the halfway point after scaling is 135 degrees.
*
* This will calculate the result from the fullRange times the
* fraction of the supply voltage, plus the offset.
*
* @param channel The analog channel this potentiometer is plugged into.
* @param fullRange The scaling to multiply the voltage by to get a meaningful
* unit.
* @param offset The offset to add to the scaled value for controlling the
* zero value
*/
explicit AnalogPotentiometer(int channel, double fullRange = 1.0,
double offset = 0.0);
[[deprecated(
"Raw pointers are deprecated; if you just want to construct an "
"AnalogPotentiometer with its own AnalogInput, then call the "
"AnalogPotentiometer(int channel). If you want to keep your own copy of "
"the AnalogInput, use std::shared_ptr.")]]
explicit AnalogPotentiometer(AnalogInput *input, double fullRange = 1.0,
double offset = 0.0);
explicit AnalogPotentiometer(std::shared_ptr<AnalogInput> input,
double fullRange = 1.0, double offset = 0.0);
virtual ~AnalogPotentiometer() = default;
/**
* Get the current reading of the potentiomer.
*
* @return The current position of the potentiometer.
*/
virtual double Get() const override;
/**
* Implement the PIDSource interface.
*
* @return The current reading.
*/
virtual double PIDGet() override;
/*
* Live Window code, only does anything if live window is activated.
*/
virtual std::string GetSmartDashboardType() const override;
virtual void InitTable(std::shared_ptr<ITable> subtable) override;
virtual void UpdateTable() override;
virtual std::shared_ptr<ITable> GetTable() const override;
/**
* AnalogPotentiometers don't have to do anything special when entering the
* LiveWindow.
*/
virtual void StartLiveWindowMode() override {}
/**
* AnalogPotentiometers don't have to do anything special when exiting the
* LiveWindow.
*/
virtual void StopLiveWindowMode() override {}
private:
std::shared_ptr<AnalogInput> m_analog_input;
double m_fullRange, m_offset;
std::shared_ptr<ITable> m_table;
bool m_init_analog_input;
};