.. _CronoFilter:

CronoFilter
===========

.. seealso::

   In the Extended Matrix language manual:

   - :doc:`em-doc:canvas` — how epochs (the building blocks of every
     CronoFilter horizon) are formalised on the canvas.
   - :doc:`em-doc:alternate_hypotheses` — Time Branches Groups, the
     formal counterpart of the alternative chronological hypotheses this
     panel lets users navigate.

The CronoFilter panel manages custom chronological horizons (time periods) that can be used for temporal filtering and exported with Heriverse context data. The panel appears in the **EM** tab when **Landscape mode** is active.

Panel Layout
------------

**Header**:

- Label: ``Chronological Horizons``

**Operations**:

- ``Auto from Epochs`` button: automatically generates horizons from the epoch data of all loaded graphs
- ``Save`` button: exports horizons to a ``.cf.json`` file
- ``Load`` button: imports horizons from a previously saved ``.cf.json`` file

**Horizons List**:

Each row in the list displays:

- **Enabled checkbox**: toggle whether the horizon is included in exports
- **Color swatch**: click to change the horizon color
- **Label**: editable name of the horizon
- **Time range**: ``start_time - end_time`` displayed on the right

List controls on the right side:

- ``+`` button: add a new empty horizon
- ``-`` button: remove the selected horizon
- Up/Down arrows: reorder horizons in the list

**Edit Selected Horizon** (when an item is selected):

- ``Label`` text field
- ``Start Time`` and ``End Time`` integer fields (negative values for BC dates)
- ``Color`` picker and ``Enabled`` checkbox

**Status**:

- Shows the count of enabled horizons vs total: ``Status: N/M horizons enabled``

Workflow
--------

**Auto-generating horizons from epochs:**

1. Load one or more GraphML files in Landscape mode (each may contain EpochNodes with time boundaries)
2. Click ``Auto from Epochs``
3. The system collects all epoch time boundaries, creates breakpoints, and generates a horizon for each interval
4. Each horizon is assigned a label and color from the best-matching epoch
5. Edit labels, colors, and time boundaries as needed

**Manually creating horizons:**

1. Click the ``+`` button to add a new horizon
2. Set the label, start time, end time, and color in the edit area
3. Toggle the enabled checkbox to include or exclude the horizon

**Saving and loading:**

- Click ``Save`` to export all horizons to a ``.cf.json`` file
- Click ``Load`` to import horizons from a file, replacing the current list
- The file format stores version, type, and all horizon data (label, start, end, color as hex, enabled status)