allow a user to pan the graph at all scales

[dirk-thomas]

From @jbohren on April 1, 2013 18:46

rqt_graph is frustrating to use with large graphs since it prevents the user from panning the graph when it fits in the frame. This means that in order to zoom in on a given part of the graph, the user must first zoom into the middle of the graph, and then pan repeatedly to get to some other region. Note that in rxgraph, you can pan to arbitrary locations at any scale.

_Copied from original issue: ros-visualization/rqt_commonplugins#65

[dirk-thomas]

Please use a more descriptive title for issues.

[dirk-thomas]

From @DorianScholz on April 7, 2013 18:7

[removed confused unrelated comment] ;-)

[dirk-thomas]

From @jbohren on April 7, 2013 18:19

I'm not taking about rqt_plot, I'm talking about rqt_graph, which displays the ROS network graph.

[dirk-thomas]

From @DorianScholz on April 7, 2013 18:44

Sorry about that, I must have been confused ;-)

[dirk-thomas]

Is this issue still valid for you @jbohren?

I tried to zoom in and rqt_graph zooms into the current mouse position. That should allow you to zoom to any arbitrary position of the graph without the need to pan afterwards.

[dirk-thomas]

From @jbohren on September 30, 2013 3:51

Yeah this is still a bug. If you pan out all the way, you cannot reposition the graph.

[dirk-thomas]

From @jbohren on September 30, 2013 3:53

Specifically, it will zoom into the center until the graph fills the window, and then it will continue to zoom on the location of the mouse.

[dirk-thomas]

Your use case is to scroll into an area which has no content? Am I getting this right (just trying to understand the scenario)?

[dirk-thomas]

From @jbohren on September 30, 2013 4:20

To be able to pan the graph when the size of the graph is smaller than the size of the visible window.

[dirk-thomas]

rxgraph supported unlimited panning. Qt only allows panning within the scene rectangle. This is automatically determined by the bounding box of all items in the scene.

It can be overwritten using QGraphicsView::setSceneRect() but to me it is unclear what values we could feed in there. Basically since zooming is not restricted the scene area would need to be unlimited in order to be able to pan in any zoom level (as far as I know Qt does not support unlimited scene sized). I also think that having the scrollbars limited to a small enough area that the graph is always visible is a plus so that the user does not get lost (as it was possible in rxgraph).

[dirk-thomas]

I will close this ticket for now since it seems to be requesting something not easily possible in Qt and no argument has been made why that feature is important. Please feel free to comment and the ticket can be reopened.