Proposal for charts: Regression Curve Equation

[Lars Oppermann <Lars.Oppermann@Sun.COM>]

Dear TC members,

I am forwarding the following proposal created by the
OpenOffice.org-Chart development team concerning display of regression 
curve equation for inclusion into OpenDocument 1.2...

----------------------------------------------------------------------

Chart: Regression Curve Equation

Expand the regression curve element to allow the display of the 
according equation:

The properties of regression-lines are stored in the 
<chart:regression-curve> elements which may be part of a series.

10.14 Regression Curves

<define name="chart-regression-curve">
    <element name="chart:regression-curve">
       <ref name="chart-regression-curve-attlist"/>
       <optional>
          <ref name="chart-equation"/>
       </optional>
    </element>
</define>

Style Name The chart:style-name attribute references a chart style that 
contains the properties for the regression curve. The chart style 
especially may contain the regression curve properties specified in 
section 15.35.

<define name="chart-regression-curve-attlist" combine="interleave">
    <optional>
       <attribute name="chart:style-name">
          <ref name="styleNameRef"/>
       </attribute>
    </optional>
</define>

10.14.1 Equation

The <chart:equation> element represents the equation for the belonging 
regression curve. This element can contain fixed text. When no fixed 
text is provided or chart:automatic-content property is set to true the 
current calculated equation is displayed automatically.

<define name="chart-equation">
    <element name="chart:equation">
       <ref name="chart-equation-attlist"/>
       <optional>
          <ref name="text-p"/>
       </optional>
    </element>
</define>

Automatic Content

The chart:automatic-content property indicates whether a user defined 
text should be kept or instead the current content should be calculated 
automatically.

<define name="chart-equation-attlist" combine="interleave">
    <optional>
       <attribute name="chart:automatic-content" a:defaultValue="true">
           <ref name="boolean"/>
       </attribute>
    </optional>
</define>

Display R-squareThe chart:display-r-square property determines whether 
the R-square value should be displayed or not in case of automatic display.

<define name="chart-equation-attlist" combine="interleave">
    <optional>
       <attribute name="chart:display-r-square" a:defaultValue="false">
          <ref name="boolean"/>
       </attribute>
    </optional>
</define>

Position

The common positioning attributes for drawing objects can be used on 
<chart:equation> elements.

<define name="chart-equation-attlist" combine="interleave">
    <ref name="common-draw-position-attlist"/>
</define>

Style Name

The chart:style-name attribute specifies a chart style for the 
<chart:equation> element. Within the referenced style, fill and stroke 
properties may be used. See sections 15.14 and 15.13 for more 
information. In addition to this, text properties may be used. See 
section 15.4. Also a data style can be referenced by the 
style:data-style-name attribute. See section 14.7 for details.

<define name="chart-equation-attlist" combine="interleave">
    <optional>
        <attribute name="chart:style-name">
           <ref name="styleNameRef"/>
        </attribute>
    </optional>
</define>

-- 
Lars Oppermann <lars.oppermann@sun.com>               Sun Microsystems
Software Engineer                                         Nagelsweg 55
Phone: +49 40 23646 959                         20097 Hamburg, Germany
Fax:   +49 40 23646 550                  http://www.sun.com/staroffice