Joint::GetAngle returns Angle, which is confusing for non-angular joints

[osrf-migration]

Original report (archived issue) by John Hsu (Bitbucket: hsu, GitHub: hsu).

---

Typical usage right now expects user to do:

   double sliderPosition = myJoint->GetAngle().Radian()

even for prismatic joints, or joints with non-angular positions. This is potentially confusing.

[osrf-migration]

Original comment by Nate Koenig (Bitbucket: Nathan Koenig).

---

• changed state from "new" to "on hold"

Until after June, 2013.

[osrf-migration]

Original comment by Ian Chen (Bitbucket: Ian Chen, GitHub: iche033).

---

• changed state from "on hold" to "open"

[osrf-migration]

Original comment by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

---

related question

Maybe we could deprecate math::Angle Joint::GetAngle in favor of double Joint::GetPosition and create GetAngle functions in the relevant joint specific headers (like RevoluteJoint.hh, UniversalJoint.hh, etc)?

[osrf-migration]

Original comment by Nate Koenig (Bitbucket: Nathan Koenig).

---

Sounds good.

[osrf-migration]

Original comment by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

---

It'll take a bit more work than I thought because we also use math::Angle as the argument for joint limits.

[osrf-migration]

Original comment by Louise Poubel (Bitbucket: chapulina, GitHub: chapulina).

---

Related issue #1086

[osrf-migration]

Original comment by Nate Koenig (Bitbucket: Nathan Koenig).

---

• set version to "all"

[osrf-migration]

Original comment by Nate Koenig (Bitbucket: Nathan Koenig).

---

• changed state from "open" to "new"

[osrf-migration]

Original comment by Louise Poubel (Bitbucket: chapulina, GitHub: chapulina).

---

@nkoenig , something to consider while migrating to ignition math

[osrf-migration]

Original comment by Louise Poubel (Bitbucket: chapulina, GitHub: chapulina).

---

• set assignee_account_id to "557058:6ff86fcb-b7ab-44a5-b8a6-f6d9cae8b6e8"
• set assignee to "chapulina (Bitbucket: chapulina, GitHub: chapulina)"

[osrf-migration]

Original comment by Louise Poubel (Bitbucket: chapulina, GitHub: chapulina).

---

I'm planning on tackling this while migrating to ignition math. The plan:

1. Deprecate everything which mentions "angle" from the base joint class:

   • bool SetHighStop(unsigned int _index, const math::Angle &_angle)

   • void SetUpperLimit(unsigned int _index, math::Angle _limit)

   • bool SetLowStop(unsigned int _index, const math::Angle &_angle)

   • void SetLowerLimit(unsigned int _index, math::Angle _limit)

   • math::Angle GetHighStop(unsigned int _index)

   • math::Angle GetUpperLimit(unsigned int _index) const

   • math::Angle GetLowStop(unsigned int _index)

   • math::Angle GetLowerLimit(unsigned int _index) const

   • math::Angle GetAngle(unsigned int _index) const

   • virtual unsigned int GetAngleCount() const

2. Substitute with equivalents that return/take double. Also make the return axis 0 by default. Note that the "*Stop" will disappear completely.

   • void SetUpperLimit(const unsigned int _index, const double _limit)

   • void SetLowerLimit(const unsigned int _index, const double _limit)

   • double UpperLimit(const unsigned int _index = 0) const

   • double LowerLimit(const unsigned int _index = 0) const

   • double Position(const unsigned int _index = 0) const

   • unsigned int DOF() const

3. Add functions that return angles for each rotational joint.

[osrf-migration]

Original comment by Louise Poubel (Bitbucket: chapulina, GitHub: chapulina).

---

Implemented numbers 1 and 2 in pull request #2568.

I believe we can add number 3 later without breaking ABI/API.

[osrf-migration]

Original comment by Nate Koenig (Bitbucket: Nathan Koenig).

---

• changed state from "new" to "resolved"

Resolved in pull request #2568

[osrf-migration]

Original comment by Nate Koenig (Bitbucket: Nathan Koenig).

---

• changed state from "resolved" to "closed"