---
name: "gcpGetLuminance"
section: "3"
platform: "linux"
package: "libggigcp1-dev"
version: "1.0.2+dfsg1-2"
release: "Debian 6.0 (Squeeze)"
platforms: ["linux"]
url: "https://new.carta.tech/gcpGetLuminance"
---

# gcpGetLuminance(3)

Manipulate Luminance

## NAME

**gcpGetLuminance** - Manipulate Luminance

## SYNOPSIS

```
#include <ggi/gcp.h>
ggi_float gcpGetLuminance(ggi_visual_t vis, const gcp_pixel pix);
```

## DESCRIPTION

**gcpGetLuminance** calculates the luminance of the *pix* pixel.

## RETURN VALUE

**gcpGetLuminance** returns the luminance of the pixel.