[GUI] Rapid stepping puts play/pause button in bad state

[osrf-migration]

Original report (archived issue) by Nate Koenig (Bitbucket: Nathan Koenig).

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Rapidly clicking the step button can cause the play/pause button to get into the opposite state. For example, the pause icon will show but the simulation is already paused.

[osrf-migration]

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

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There is a timing issue related to this problem. The GUI changes button state when a WorldStats message is received and when the step-button is pressed. The service call to step/play/pause simulation returns when the message is received, not when the state actually changes. Finally, the WorldStats message is published at 5Hz. So, if the GUI button is clicked rapidly, then the WorldStats message could skip state transitions and get out of sync with the GUI.

We may need an additional topic that publishes all state transitions. Or, we modify the service call to return only when the state actually changes.

[osrf-migration]

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

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• set component to "gui"