eZ component: Graph: Interactive data points, Requirements
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:Author:   $Author$
:Revision: $Rev$
:Date:     $Date$

Introduction
============

Description
-----------

Interactive data points describe a feature in charts, that the viewer of the
chart can interactively get more information about data, when viewing the
chart, or moving his mouse pointer over points of interest in the chart.

Requirements
============

There are two major sets of features to implement

Value indication
----------------

The value indication means, that at the position of the mouse pointer lines
are drawn, depeding on the chart type, to indicate the current data value at
this poistion in the chart. In a line chart this would mean a horizontal and a
vertical line to the axis and some coordinate information at the current
position of the mouse pointer, while in radar chart a line to the center of
the chart and an ellipse, indicating the value on the y axis, needs to be
drawn.

SVG
	No real problem.

GD / Cairo / IMagick
	Not possible without large effort.

Flash
	No really big deal with flash and ext/ming.

Additional data point information
---------------------------------

When hovering or clicking on a data point or a legenda ite, a box with 
additional information should be displayed. The box should contain text or
user defined content.

SVG
	With only user defined inlined SVGs or Text in a box no big deal.

GD / Cairo / IMagick
	With a tool script generating HTML and javascript to use with the image
	map, it should be possible to use HTML and text in boxes. This is similar
	to the currently used mechanism to create image maps.

Flash
	Possible with user provided SWFMovies or shapes.

Special consideration
=====================

It is impossible to implement natively more then simple text in a box for the
additional information in highlighted data points, because this would require
a complete redering model like HTML uses.

Formats
=======

The integration of HTML, Flash or SVG documents should be possible, but would
be a non driver generic mechanism. It seems not easily possible to convert
user defined Flash, HTML and SVG to the respective other format.


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