class mola::VizInterface

Overview

Virtual visualization interface.

Implemented by MolaViz (nanogui backend) and MolaVizImGui (Dear ImGui docking-branch backend). Clients should program against this interface exclusively and avoid toolkit-specific types.

#include <VizInterface.h>

class VizInterface
{
public:
    // typedefs

    typedef std::shared_ptr<VizInterface> Ptr;

    // construction

    VizInterface();
    VizInterface(const VizInterface&);
    VizInterface(VizInterface&&);

    // methods

    virtual std::future<void> create_subwindow_from_description(
        const mola::gui::WindowDescription& desc,
        const std::string& parentWindow = "main"
        ) = 0;

    virtual std::future<void> enqueue_custom_gui_code(const std::function<void()>& userCode) = 0;
    virtual const std::string& gui_backend() const = 0;

    virtual std::future<void> set_menu_bar(
        const mola::gui::MenuBar& bar,
        const std::string& parentWindow = "main"
        ) = 0;

    virtual void* get_subwindow_handle(
        const std::string& subWindowTitle,
        const std::string& parentWindow = "main"
        ) = 0;

    virtual std::future<bool> update_3d_object(
        const std::string& objName,
        const std::shared_ptr<mrpt::opengl::CSetOfObjects>& obj,
        const std::string& viewportName = "main",
        const std::string& parentWindow = "main",
        const std::string& parentFrame = ""
        ) = 0;

    virtual std::future<bool> update_3d_object_frame(
        const std::string& frameName,
        const mrpt::math::TPose3D& pose,
        const std::string& viewportName = "main",
        const std::string& parentWindow = "main"
        ) = 0;

    virtual std::future<bool> insert_point_cloud_with_decay(
        const std::shared_ptr<mrpt::opengl::CPointCloudColoured>& cloud,
        double decay_time_seconds,
        const std::string& viewportName = "main",
        const std::string& parentWindow = "main",
        const std::string& parentFrame = ""
        ) = 0;

    virtual std::future<bool> clear_all_point_clouds_with_decay(
        const std::string& viewportName = "main",
        const std::string& parentWindow = "main"
        ) = 0;

    virtual std::future<bool> update_viewport_look_at(
        const mrpt::math::TPoint3Df& lookAt,
        const std::string& viewportName = "main",
        const std::string& parentWindow = "main",
        const std::string& parentFrame = ""
        ) = 0;

    virtual std::future<bool> update_viewport_camera_azimuth(
        double azimuth,
        bool absolute_falseForRelative = true,
        const std::string& viewportName = "main",
        const std::string& parentWindow = "main"
        ) = 0;

    virtual std::future<bool> update_viewport_camera_orthographic(
        bool orthographic,
        const std::string& viewportName = "main",
        const std::string& parentWindow = "main"
        ) = 0;

    virtual std::future<bool> execute_custom_code_on_background_scene(
        const std::function<void(mrpt::opengl::Scene&)>& userCode,
        const std::string& parentWindow = "main"
        ) = 0;

    virtual std::future<bool> subwindow_update_visualization(
        const mrpt::rtti::CObject::Ptr& obj,
        const std::string& subWindowTitle,
        const mrpt::containers::yaml* extra_parameters = nullptr,
        const std::string& parentWindow = "main"
        ) = 0;

    virtual std::future<bool> output_console_message(
        const std::string& msg,
        const std::string& parentWindow = "main"
        ) = 0;

    virtual std::future<std::optional<std::string>> open_file_dialog(
        const std::string& title,
        bool save,
        const std::vector<std::pair<std::string, std::string>>& filters = {},
        const std::string& default_path = "",
        const std::string& parentWindow = "main"
        ) = 0;

    virtual MetricChannel::Ptr register_metric(const std::string& name, const std::string& unit = "") = 0;
    virtual void push_metric(const std::string& name, double t, double value) = 0;
    VizInterface& operator = (const VizInterface&);
    VizInterface& operator = (VizInterface&&);
};

// direct descendants

class MolaViz;
class MolaVizImGui;
class MolaVizImGuiCore;

Methods

virtual std::future<void> create_subwindow_from_description(
    const mola::gui::WindowDescription& desc,
    const std::string& parentWindow = "main"
    ) = 0

Creates a sub-window described by a GuiWidgetDescription.

The description carries the window title, initial position/size hints, tab structure, and all widget definitions including their initial values and on_change callbacks.

The returned future resolves once the window has been created in the GUI thread and all widgets are live. Callers that need to know when construction is complete should call .get() on the future.

Position and size in the description are treated as first-use hints :

• nanogui backend : applied unconditionally via setPosition/setFixedWidth.

• ImGui backend : passed as ImGuiCond_FirstUseEver, so the dock manager and imgui.ini take over from the second run.

Label text is updated at any time and from any thread by calling LiveString::set() on the LiveString instances embedded in the description. The backend polls them on each frame / spinOnce tick.

Parameters:

desc	Full window and widget description.
parentWindow	Name of the parent host window (default: “main”).

Returns:

future<void> that resolves when the window is live.

See also:

mola::gui::WindowDescription, mola::gui::LiveString

virtual std::future<void> enqueue_custom_gui_code(const std::function<void()>& userCode) = 0

Enqueues arbitrary code to run on the GUI thread at the next available opportunity.

Use this for any GUI-thread work that is not covered by the widget description API: e.g. updating widget enable/disable state, changing slider ranges at runtime, or interacting with toolkit-specific objects via a cast of the opaque handle returned by get_subwindow_handle().

The callable is executed in the GUI thread; do not call blocking operations inside it.

This replaces the deprecated enqueue_custom_nanogui_code().

virtual const std::string& gui_backend() const = 0

Returns a short identifier string for the active GUI backend.

Clients may use this to conditionally tune their GUIs - for example to choose between an Entypo icon (nanogui) and a FontAwesome codepoint (ImGui), or to skip features not yet supported on a given backend.

Canonical values are provided as static constants below: VizInterface::BACKEND_NANOGUI → “nanogui” VizInterface::BACKEND_IMGUI → “imgui”

Comparison example:

if (visualizer_->gui_backend() == VizInterface::BACKEND_IMGUI) { ... }

The method is pure virtual so each concrete backend is forced to declare its identity explicitly. It is noexcept and const so it is safe to call from any context, including hot loops.

virtual std::future<void> set_menu_bar(
    const mola::gui::MenuBar& bar,
    const std::string& parentWindow = "main"
    ) = 0

Installs or replaces the menu bar of a parent window.

Menu bars are a first-class feature of the Dear ImGui docking branch (ImGui::BeginMainMenuBar / BeginMenuBar). The nanogui backend has no native equivalent and provides a no-op stub that resolves the future immediately without rendering anything. Callers should guard with gui_backend() if the menus are essential to their workflow:

if (visualizer_->gui_backend() == VizInterface::BACKEND_IMGUI)
    visualizer_->set_menu_bar(bar);

Parameters:

bar	Full menu bar description.
parentWindow	Host window whose menu bar is replaced.

Returns:

future<void> resolving when the menu bar is live.

virtual void* get_subwindow_handle(
    const std::string& subWindowTitle,
    const std::string& parentWindow = "main"
    ) = 0

Returns an opaque handle to a previously created sub-window.

The handle type depends on the backend:

• MolaViz (nanogui) : cast to nanogui::Window*

• MolaVizImGui : the handle is not meaningful as a pointer; use enqueue_custom_gui_code() with ImGui calls keyed on the window title instead.

Returns nullptr if the window does not exist yet or the backend does not support retained window objects.

This is an intentional “escape hatch” for toolkit-specific code that cannot be expressed through the description API. Prefer enqueue_custom_gui_code() over casting this pointer wherever possible, as that keeps the calling module’s cpp file free of GUI toolkit headers.

virtual std::future<bool> update_3d_object(
    const std::string& objName,
    const std::shared_ptr<mrpt::opengl::CSetOfObjects>& obj,
    const std::string& viewportName = "main",
    const std::string& parentWindow = "main",
    const std::string& parentFrame = ""
    ) = 0

Updates or inserts a 3D object in the background scene.

The update is performed in the GUI thread. If the named object already exists, its contents are replaced by copying the shared pointers inside obj.

Parameters:

objName	Name used to identify the object (upsert key).
obj	Object to display.
viewportName	Viewport inside the parent window.
parentWindow	Host window name.
parentFrame	Optional name of a movable reference-frame node previously created via update_3d_object_frame(). When non-empty, the object is attached as a child of that frame (so moving the frame moves the object without re-rendering it); the frame node is auto-created at the identity pose if it does not exist yet. Empty (default) attaches to the viewport root, as before.

Returns:

future<bool>; resolves to true when executed.

virtual std::future<bool> update_3d_object_frame(
    const std::string& frameName,
    const mrpt::math::TPose3D& pose,
    const std::string& viewportName = "main",
    const std::string& parentWindow = "main"
    ) = 0

Creates or repositions a named movable “reference frame” node.

A frame node is an (initially empty) container placed at the viewport root. Objects can be attached to it via the parentFrame argument of update_3d_object(); moving the frame then relocates all attached objects at once, without re-uploading their geometry. This is how a back end such as mola_mapper_3d keeps a front end’s dense clouds / local map (drawn once in its own {odom_i} frame) correctly placed in {map} as it estimates the T_map_to_odom_i transform online.

Idempotent: the first call creates the node; later calls only update its pose, preserving any already-attached children.

Parameters:

frameName	Name of the frame node (upsert key). Must be non-empty.
pose	Pose of the frame in the viewport (i.e. in {map}).
viewportName	Viewport inside the parent window.
parentWindow	Host window name.

Returns:

future<bool>; resolves to true when executed.

virtual std::future<bool> insert_point_cloud_with_decay(
    const std::shared_ptr<mrpt::opengl::CPointCloudColoured>& cloud,
    double decay_time_seconds,
    const std::string& viewportName = "main",
    const std::string& parentWindow = "main",
    const std::string& parentFrame = ""
    ) = 0

Inserts a temporary point cloud visible for decay_time_seconds.

Parameters:

cloud	Cloud to display.
decay_time_seconds	Lifetime in seconds before the cloud fades out.
viewportName	Target viewport.
parentWindow	Host window name.
parentFrame	If non-empty, the cloud is attached as a child of the named movable frame node (same semantics as the parentFrame argument of update_3d_object()).

Returns:

future<bool> resolving to true when executed.

virtual std::future<bool> clear_all_point_clouds_with_decay(
    const std::string& viewportName = "main",
    const std::string& parentWindow = "main"
    ) = 0

Removes all clouds previously inserted with insert_point_cloud_with_decay().

virtual std::future<bool> update_viewport_look_at(
    const mrpt::math::TPoint3Df& lookAt,
    const std::string& viewportName = "main",
    const std::string& parentWindow = "main",
    const std::string& parentFrame = ""
    ) = 0

Moves the viewport camera look-at point.

Parameters:

lookAt	Target point in the local coordinate frame of parentFrame (if given) or in world/scene space.
parentFrame	If non-empty, the backend looks up the named movable frame node, applies its current scene pose to lookAt, and uses the resulting world-space point as the target. This makes the camera follow a vehicle rendered under a frame node rather than chasing its odom-frame coords.

virtual std::future<bool> update_viewport_camera_azimuth(
    double azimuth,
    bool absolute_falseForRelative = true,
    const std::string& viewportName = "main",
    const std::string& parentWindow = "main"
    ) = 0

Rotates the viewport camera around the vertical axis.

Parameters:

azimuth	Angle in radians.
absolute_falseForRelative	true → set absolute azimuth; false → add increment to current value.

virtual std::future<bool> update_viewport_camera_orthographic(
    bool orthographic,
    const std::string& viewportName = "main",
    const std::string& parentWindow = "main"
    ) = 0

Switches the viewport camera between perspective and orthographic.

virtual std::future<bool> execute_custom_code_on_background_scene(
    const std::function<void(mrpt::opengl::Scene&)>& userCode,
    const std::string& parentWindow = "main"
    ) = 0

Executes arbitrary user code on the mrpt::opengl::Scene of the background viewport.

Use this to modify viewport properties, add sub-viewports, change background colour, etc. The callable runs in the GUI thread.

This method operates on the mrpt OpenGL scene, not on GUI toolkit widgets, so it is backend-agnostic: both nanogui and ImGui backends embed an mrpt scene in their OpenGL canvas.

virtual std::future<bool> subwindow_update_visualization(
    const mrpt::rtti::CObject::Ptr& obj,
    const std::string& subWindowTitle,
    const mrpt::containers::yaml* extra_parameters = nullptr,
    const std::string& parentWindow = "main"
    ) = 0

Updates a sub-window’s content from an MRPT object.

The correct handler is selected based on the runtime type of obj. Custom handlers can be registered via MolaViz::register_gui_handler().

Returns:

future<bool> resolving to false if no handler exists for the object’s type.

virtual std::future<bool> output_console_message(
    const std::string& msg,
    const std::string& parentWindow = "main"
    ) = 0

Appends a line of text to the on-screen console overlay.

virtual std::future<std::optional<std::string>> open_file_dialog(
    const std::string& title,
    bool save,
    const std::vector<std::pair<std::string, std::string>>& filters = {},
    const std::string& default_path = "",
    const std::string& parentWindow = "main"
    ) = 0

Opens a modal file-picker dialog on the GUI thread.

The call is non-blocking: it enqueues the dialog to open on the GUI thread and returns a future that resolves when the user dismisses it.

Parameters:

title	Dialog window title, e.g. “Open point cloud”.
save	true → “Save as” dialog (prompts before overwrite). false → “Open” dialog (validates file exists).
filters	List of {description, comma-separated-extensions} pairs. Example: {{“LAS files”,”las,laz”},{“All files”,”*”}} Pass an empty vector to show all files.
default_path	Initial directory or full path suggestion. Empty string means the backend’s default (usually the current working directory).
parentWindow	Host window name.

Returns:

future resolving to the chosen absolute path, or std::nullopt if the user cancelled.

virtual MetricChannel::Ptr register_metric(const std::string& name, const std::string& unit = "") = 0

Registers (or returns the existing) metric channel by unique name.

Idempotent: repeated calls with the same name return the same channel.

Parameters:

name	Unique id, also the default legend label. Use a namespaced form like “lidar_odom/icp_delay_ms” to avoid collisions.
unit	Optional unit string shown on axis/legend (e.g. “ms”, “%”).

Returns:

A channel handle; never null (no-op handle on backends without plotting).

virtual void push_metric(const std::string& name, double t, double value) = 0

One-shot convenience: register-if-needed then push.

For rarely-updated metrics; prefer holding the handle returned by register_metric() on hot paths to avoid a name lookup per sample.