Custom Input Map

[brenocq]

Currently, ImPlot3D uses a hardcoded input map for mouse and keyboard interactions. To improve flexibility, it would be useful to create a customizable input map and expose it to the user.

ImPlot has a well-designed input mapping system that could serve as inspiration. Below is the structure of their input map for reference:

// Input mapping structure. Default values listed. See also MapInputDefault, MapInputReverse.
struct ImPlotInputMap {
    ImGuiMouseButton Pan;           // LMB    enables panning when held,
    int              PanMod;        // none   optional modifier that must be held for panning/fitting
    ImGuiMouseButton Fit;           // LMB    initiates fit when double clicked
    ImGuiMouseButton Select;        // RMB    begins box selection when pressed and confirms selection when released
    ImGuiMouseButton SelectCancel;  // LMB    cancels active box selection when pressed; cannot be same as Select
    int              SelectMod;     // none   optional modifier that must be held for box selection
    int              SelectHorzMod; // Alt    expands active box selection horizontally to plot edge when held
    int              SelectVertMod; // Shift  expands active box selection vertically to plot edge when held
    ImGuiMouseButton Menu;          // RMB    opens context menus (if enabled) when clicked
    int              OverrideMod;   // Ctrl   when held, all input is ignored; used to enable axis/plots as DND sources
    int              ZoomMod;       // none   optional modifier that must be held for scroll wheel zooming
    float            ZoomRate;      // 0.1f   zoom rate for scroll (e.g. 0.1f = 10% plot range every scroll click); make negative to invert
    IMPLOT_API ImPlotInputMap();
};

It would also be useful to include default input maps. Just like users can switch between dark, light, and classic themes, they should be able to choose from input maps that replicate the behavior of tools like Matlab, Matplotlib, or others.