YZones – warning bands for Y-axis

Used to set up horizontal warning regions on xy plots. Each region is defined by a colour (use colour names or the standard HTML syntax here), the start and end values for the region and an optional pattern number. You may set this as a single string (use ‘/’ to separate each zone, and ‘,’ to separate the parameters within each zone) or as an array of strings, one for each zone:

 ch.Set'yzones' 'Yellow,5,11,4/Green,7.5,8.5,5'
 ch.Set'yzones' 'Yellow,5,11,4' 'Green,7.5,8.5,5'

If you only give a start value, the end value defaults to the highest tickmark. Of course, zones may overlap – this is a convenient way of creating a set of bands with a ‘safe’ zone in the middle.

The pattern defaults to ‘solid fill’ (pattern 15) which would be appropriate with fairly light pastel colours. For the normal named colours, patterns 2,3,4 are good choices to produce a lightweight ‘wash’ effect.