Chart Data Label Positions

[David Faure <faure@kde.org>]

Here's the revised proposal for chart label auto position:

<define name="labelPositions">
    <choice>
        <value>auto</value>
        <value>center</value>
        <value>north</value>
        <value>north-west</value>
        <value>west</value>
        <value>south-west</value>
        <value>south</value>
        <value>south-east</value>
        <value>east</value>
        <value>north-east</value>
        <value>inside</value>
        <value>outside</value>
        </choice>
</define>
<define name="style-chart-properties-attlist" combine="interleave">
    <optional>
        <attribute name="chart:label-position">
            <ref name="labelPositions">
        </attribute>
    </optional>
</define>
This attribute defines the position of the labels in the chart.
The values inside and outside are only meaningful for pie charts,
the other values are only meaningful for other types of charts than pie charts.

<define name="style-chart-properties-attlist" combine="interleave">
    <optional>
        <attribute name="chart:label-alignment">
            <list>
                <ref name="horiBackPos"/>
                <ref name="vertBackPos"/>
            </list>
        </attribute>
    </optional>
</define>
This attribute defines the alignment of the label relatively to the position point defined by label-position.

[I found horiBackPos and vertBackPos in the existing RelaxNG schema; the first one is "left or center or right",
the second one is "top or center or bottom".]

<define name="style-chart-properties-attlist" combine="interleave">
    <optional>
        <attribute name="chart:label-position-negative">
            <ref name="labelPositions">
        </attribute>
    </optional>
</define>
This attribute, if set, defines the label position for negative values.
Otherwise, chart:label-position is used for both positive and negative values.

<define name="style-chart-properties-attlist" combine="interleave">
    <optional>
        <attribute name="chart:label-alignment-negative">
            <ref name="labelPositions">
        </attribute>
    </optional>
</define>
This attribute, if set, defines the alignment of the label for negative values.
Otherwise, chart:label-alignment is used for both positive and negative values.


[In kdchart we also have the notion of gap or distance between the position point and the label,
do you agree with having this as well in the specification? I'm not sure which unit to use for it though
(kdchart uses pixels but of course that doesn't work in office suites; I'm happy with leaving that
aside for now to avoid complexifying the matter).]

-- 
David Faure, faure@kde.org, sponsored by Trolltech to work on KDE,
Konqueror (http://www.konqueror.org), and KOffice (http://www.koffice.org).