API for user interactions

[dimateos]

First of all, this lib is looking lit! congrats and thanks a lot for sharing :)

I was thinking about my potential users and how they usually prefer context-menus/buttons over complex hotkeys/mouse-interactions.

So I guess I would love some additional API for simulating user interaction programmatically e.g. resetting zoom or fitting all axis. Then I could add some visual button to call them or by necessity when reloading etc. This API calls could also be added to the exiting context menu!

There is #19 about initial pan/rot/zoom, I guess I would be talking about setting next.

Some suggestions may become doable by external developers without modifying the internals.
Would be more involved for them but could leverage work in the future and also be used to make interaction prototypes.

• e.g. Equal axes #22: set target zoom/pan/rotate by detecting which changed and apply to all axes
• e.g. 3D mouse input support #38: add target zoom/pan/rotate depending on input axes

Also could reference here #26, customizable interactions (e.g. panning with mouse wheel hold down instead of zooming). These could be potentially easier to implement with API present for the lib user too?

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AFAIK imPlot is not so configurable, I guess because this could make the codebase harder to maintain.
But also note that 3D plots are harder to navigate than 2D and are usually less intuitive for users.

Just wanted to drop this here for discussion!

[brenocq]

Thanks for the feedback!

First of all, this lib is looking lit! congrats and thanks a lot for sharing :)

❤️

So I guess I would love some additional API for simulating user interaction programmatically e.g. resetting zoom or fitting all axis

There is a Q&A about fitting all axes in #41. You could also use SetupAxesLimits in a similar way to reset zoom. Let me know if this is enough for you :)

There is #19 about initial pan/rot/zoom, I guess I would be talking about setting next.

Being able to set the Next rotation/axis limits sounds like a great idea! ImPlot does provide an API for that, and so should ImPlot3D

https://github.com/epezent/implot/blob/master/implot.h#L793-L803

I'll reply to #22 and #38 in their discussions

[brenocq]

There is #19 about initial pan/rot/zoom, I guess I would be talking about setting next.

I just discovered that the SetNextXXX API appears to be a bit cumbersome and ImPlot is favoring SetupXXX over SetNextXXX (comment this comment). I do agree that having these two types of setup API for the plot can be a bit messy...

For example, should we have a SetNextRotation that is called before the BeginPlot or a SetRotation that is called after BeginPlot? Maybe we could try to have both, but then we need to maintain two versions of the same setup.

I'll start the implementation of this user API as a SetupXXX now, I'm planning to implement the following methods:

• SetupBoxRotation
• SetupBoxInitialRotation

It is possible to set the pan/zoom using the existing SetupAxisLimits API
It is possible to fit axis to data using the existing SetupAxis API

[brenocq]

@dimateos I implemented the setup rotation functions in #61, I would love to get your input on it to make sure the API is intuitive.

[brenocq]

Hi @dimateos!

Rotation API

The PR #61 was just merged to expose an API to set the current and initial rotations. You can use the following methods for that:

• SetupBoxInitialRotation: Set the plot box initial rotation.
• SetupBoxRotation: Set the plot box current rotation
  There are methods to set the rotations with both quaternion and elevation/azimuth.

    if (ImPlot3D::BeginPlot("##BoxRotation")) {
        // Set initial rotation
        ImPlot3D::SetupBoxInitialRotation(init_elevation, init_azimuth);

        // Set the rotation using the specified elevation and azimuth
        if (setRotation)
            ImPlot3D::SetupBoxRotation(elevation, azimuth, animate, ImPlot3DCond_Always);
        ...
        ImPlot3d::EndPlot();
    }

Zoom/pan API

The zoom/pan can be currently set programmatically using the SetupAxesLimits API. You can set the minimum/maximum values for each axis with this method.

    if (ImPlot3D::BeginPlot("##BoxRotation")) {
        // Set initial limits
        ImPlot3D::SetupAxesLimits(x_min, x_max, y_min, y_max, z_min, z_max, ImPlot3DCond_Once);

        // Set the rotation using the specified elevation and azimuth
        if (setPanZoom)
            ImPlot3D::SetupAxesLimits(x_min, x_max, y_min, y_max, z_min, z_max, ImPlot3DCond_Always);
        ...
        ImPlot3d::EndPlot();
    }

Note that if you use ImPlot3DCond_Once, the limits will only be applied the first time the plot is created. If you want to modify the limits later programmatically you need to use ImPlot3DCond_Always.

I'll be closing this discussion for now since it is now possible to programmatically rotate/pan/zoom. Let me know if this works well for you. We can open this discussion again if more work is needed!