# Draw an erp x axis

### Description

This function plots an x axis for an erp waveform. Numbers and tick positions are determined according to three parameters: `length.erp`

, `startmsec`

and `endmsec`

(the function calls `msectopoints`

).

### Usage

1 2 3 4 5 6 | ```
erp.xaxis(length.erp = NULL, startmsec=-200, endmsec = 1200,
x.tick = seq(-200, 1200, 200), x.labels = x.tick, x.las=0,
draw.x.ticks = TRUE, x.pos = NA, x.outer = FALSE, x.font = NA,
x.lty = "solid", x.lwd = 1, x.lwd.ticks = 1, x.col = NULL,
x.col.ticks = NULL, x.hadj = NA, x.padj = NA, x.tcl = -0.5,
x.tick.both= FALSE, x.cex = 1)
``` |

### Arguments

`length.erp` |
the length of the ERP vector the axis refers to. |

`startmsec` |
start time (in ms) of the ERP vector. |

`endmsec` |
end time (in ms) of the ERP vector. |

`x.tick` |
the position (in ms) of x ticks. |

`x.labels` |
the labels (usually a vector of numbers) to be plotted on the x axis. |

`x.las` |
the style of x axis labels. |

`draw.x.ticks` |
a logical value specifying whether x tickmarks and an axis line should be drawn. |

`x.pos` |
the position of x axis, in terms of y axis coordinates. Default is |

`x.outer` |
a logical value indicating whether the x axis should be drawn in the outer plot margin, rather than the standard plot margin. |

`x.font` |
font for text of x labels. Default is par("font"). |

`x.lty` |
line type of both the x axis line and the x tick marks. |

`x.lwd` |
line width of the x axis line. |

`x.lwd.ticks` |
line width of the x tick marks. |

`x.col` |
colors of the x axis line and the x tick marks. |

`x.col.ticks` |
the color of the x tick marks (if specified, overrides x.col) |

`x.hadj` |
adjustment (see |

`x.padj` |
adjustment for each x tick label purpendicular to the reading direction. For labels parallel to the axes, padj = 0 means right or top alignment, and padj = 1 means left or bottom alignment. This can be a vector given a value for each string, and will be recycled as necessary. |

`x.tcl` |
The length of tick marks as a fraction of the height of a line of text. The default value is |

`x.tick.both` |
Logical. Should the tick marks be drawn both above and below the x axis? |

`x.cex` |
The magnification to be used for the x labels. |

### Value

An erp x axis is drawn on an existing plot.

### Note

This function is called internally by the `erp`

function.

### Author(s)

Giorgio Arcara

### See Also

`erp`

, `erp.yaxis`

### Examples

1 2 3 4 5 |