坐标轴和背景轴

不要被官方文档的说明给迷糊了，AXES和Background指的都是坐标轴，只是前者是细线条，后者是宽线条罢了。

分别通过backgraounds和axes来设置,每个backgrounds下可以有多个background模块。axes模块儿类似。

<plot>
...
# axes
<axes>
 <axis>
 ...
 </axis>
 <axis>
 ...
 </axis>
 ...
</axes>

# backgrounds
<backgrounds>
 <background>
 ...
 </background>
 <background>
 ...
 </background>
 ...
</backgrounds>

</plot>

AXES轴

与之前ticks的定义类似，axis的定义也是一组一组地。方向是从y0到y1具体地参数有：

• spacing - absolute or relative spacing of the axis
• position - fixed position (or positions) for axes
• position_skip - fixed position (or positions) to skip when drawing axis lines
• y0 - absolute or relative start of axis lines
• y1 - absolute or relative end of axis lines
• color - color of axis lines
• thickness - thickness of axis lines

<axes>

# Show axes only on ideograms that have data for this track
show = data

thickness = 1
color     = lgrey

<axis>
spacing   = 0.1r
</axis>

<axis>
spacing   = 0.2r
color     = grey
</axis>

<axis>
position  = 0.5r
color     = red
</axis>

<axis>
position  = 0.85r
color     = green
thickness = 2
</axis>

</axes>

Background粗线条轴

定义在backgraounds,方向是从y0到y1.每一条轴都要指定一次y0 y1，如果没有指定y1，就默认y1=1 具体用法看实战config文件分析.

独立于数据的轴

有的时候我们就是想画一些轴，跟数据无关，这时候我们可以用空的plot框

<plot>

# no file or type parameter

r0 = 0.5r
r1 = 0.75r

# use z to determine whether this block (axes,background) will be
# drawn on top of other plot blocks. 

z  = 10

<axes>
 ...
</axes>

<backgrounds>
 ...
</backgrounds>

</plot>

conf代码参考：

参考官方文档here