# `GSGlyph setPlainMetricsKey:side:`

*Instance Method*

Sets the glyph-level metrics key for a metric side.

## Declaration

```swift
func setPlainMetricsKey(_ key: String?, side: GSMetricNumbers)
```

```objc
- (void) setPlainMetricsKey:(NSString *) key side:(GSMetricNumbers) side;
```

```python
setPlainMetricsKey_side_(key: str, side: GSMetricNumbers)
```

## Parameters

- `key` — The metrics key, or `nil` to remove it.
- `side` — The metric side whose key should be changed.

## Discussion

Layer-specific metrics keys continue to override this value.

## See Also

### Metrics Keys

- [`GSGlyph.leftMetricsKey`](/Core/GlyphsCore/GSGlyph/leftMetricsKey) — Glyph-level metrics key for the left side bearing.
- [`GSGlyph.widthMetricsKey`](/Core/GlyphsCore/GSGlyph/widthMetricsKey) — Glyph-level metrics key for the advance width.
- [`GSGlyph.rightMetricsKey`](/Core/GlyphsCore/GSGlyph/rightMetricsKey) — Glyph-level metrics key for the right side bearing.
- [`GSGlyph.topMetricsKey`](/Core/GlyphsCore/GSGlyph/topMetricsKey) — Glyph-level metrics key for the top side bearing.
- [`GSGlyph.vertOriginMetricsKey`](/Core/GlyphsCore/GSGlyph/vertOriginMetricsKey) — Glyph-level metrics key for the vertical origin.
- [`GSGlyph.vertWidthMetricsKey`](/Core/GlyphsCore/GSGlyph/vertWidthMetricsKey) — Glyph-level metrics key for the vertical advance width.
- [`GSGlyph.bottomMetricsKey`](/Core/GlyphsCore/GSGlyph/bottomMetricsKey) — Glyph-level metrics key for the bottom side bearing.
- [`GSGlyph plainMetricsKey:`](/Core/GlyphsCore/GSGlyph/plainMetricsKey:) — The stored glyph-level metrics key for a metric side, or `nil` when none is set.
- [`GSGlyph validateMetricsKey:error:`](/Core/GlyphsCore/GSGlyph/validateMetricsKey:error:) — Validates the syntax of a proposed metrics key.