multiple_axis.txt (1.9 kb) added by Kore Nordmann
Description: Second revision of multiple axis requirements document.
eZ component: Graph: Multiple axis, Requirements
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Introduction
============
Description
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Multiple axis are used in two different cases.
- In stock chart, for example, they are used to show a different meaning of
the displayed data, for example the value of a single stock option and the
value sum of the complete company.
- Another case multiple axis may be used, is displaying relating data in one
chart which has completely different scalings or units, like the used RAM
and the load on a machine.
A third case multiple axis could be used for, are named separators to
highlight data borders in your chart. In this case the step labels should be
at least optional.
Requirements
============
To act as additional axis and seperators it is required, that additional axis
can be placed at any position in the chart, especially at the very end and
beginning of the charts data.
It should be possible to associate a data set with a non default axis, to
calculate the position of its data points based on a diffenrent scaling, then
the default one.
It should also be possible to add axis not depending on any data set and
define the scaling manually. Those axis can be placed at any position in the
chart, and if no scaling was explicitely given and no data set is associated,
those axis will omit drawing steps or step labeling and just display a single
line with the (optional) axis label.
Special consideration
=====================
An API for assigning data sets to axis other then the default one will be
defined in the design document. The calculation of the poistion of a data
point in a chart is completely done in the chart classes, so it will be no
problem to use another axis for this. No changes or additions in the renderers
will be required.
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