Cogl.Texture.prototype.get_data

function get_data(format: Cogl.PixelFormat, rowstride: Number(guint), data: Number(guint8)): Number(gint) {
    // Gjs wrapper for cogl_texture_get_data()
}

Copies the pixel data from a cogl texture to system memory.

<note>Don't pass the value of cogl_texture_get_rowstride() as the rowstride argument, the rowstride should be the rowstride you want for the destination data buffer not the rowstride of the source texture</note>

format: the Cogl.PixelFormat to store the texture as.
rowstride: the rowstride of data in bytes or pass 0 to calculate from the bytes-per-pixel of format multiplied by the texture width.
data: memory location to write the texture's contents, or null to only query the data size through the return value.
Returns: the size of the texture data in bytes