# LegendMixin

Auto-generated @jbrowse/mobx-state-tree API for the current JBrowse release —
see [pluggable elements](https://jbrowse.org/jb2-staging/docs/developer_guide/) for concepts. Built into
JBrowse core.
[View source](https://github.com/GMOD/jbrowse-components/blob/main/packages/display-kit/src/LegendMixin.ts).

#crossCuttingMixin A legend the user can turn off. A promotable `showLegend`
config slot, whose `promotedBase` sets whether this display type's legend is on
by default. Brings the resolved `showLegend` getter, the
`showLegendDisplayTypeDefault` pin `showLegendCheckboxItem` takes, and
`setShowLegend`

Six displays carried a character-identical copy of these three members —
alignments, Hi-C, multi-row features, multi-wiggle, the multi-sample variant
base and the shared LD model — reading and writing one slot name through the
promotable cascade. **Both ends of that were already shared**: the track-menu
row is `showLegendCheckboxItem` and the thing it shows is `FloatingLegend`, so
this was the middle link between two pieces of common code.

**The config slot stays per display, and deliberately** — `promotedBase`
legitimately differs (a Hi-C color scale is off by default, a variant genotype
key on) and each description describes a genuinely different legend. That
decision is `showLegendCheckboxItem`'s docstring and this does not disturb it:
the slot is what the composing display still supplies, and the mixin only stops
it hand-writing the accessors over it.

`setShowLegend` is overridable, and one display overrides it: the multi-sample
variant base also clears `dismissedLegendSections`, since re-showing the whole
legend is what un-dismisses the sections inside it.

## Getters

<!-- prettier-ignore -->
| Member | Description |
| --- | --- |
| <span id="getter-showlegend">**showLegend**</span><br><code>boolean</code> | Whether the legend is drawn. Resolved through the promotable-slot tiers (`resolveConf`): an explicit track value customizes it either way, otherwise it follows the session-wide default for this display type, falling back to the slot's `promotedBase`. |
| <span id="getter-showlegenddisplaytypedefault">**showLegendDisplayTypeDefault**</span><br><code>Pin</code> | The "make the current legend visibility the default for all tracks" control. Symmetric, so it promotes whichever value the track currently shows. `showLegendCheckboxItem` takes this as its `pin`. |

## Actions

<!-- prettier-ignore -->
| Member | Description |
| --- | --- |
| <span id="action-setshowlegend">**setShowLegend**</span><br><code>(arg: boolean) =&gt; void</code> |  |