[chart] Proposal: chart legend size

1. RATIONALE 1.1 Use cases: Size of chart legends cannot be controlled in ODF 1.2. The size is automatically calculated, it can expand vertically, horizontally, or to both directions controlled by respective attributes. Sometimes it is desirable to use fixed legend size and/or resize the legend manually. Therefore this proposal suggests including svg:width and svg:height into the attribute list of chart:legend element when style:legend-expansion attribute is "custom". In this case style:legend-expansion-aspect-ratio attribute should be the proportion of svg:width and svg:height. This also improves interoperability with Office Open XML. 1.2 Alternatives considered: None. 2. REQUESTED CHANGES TO THE ODF STANDARD 2.1 Text changes/additions: Update 11.3 chart:legend section as following: The <chart:legend> element has the following attributes: chart:legend-align 19.22, chart:legend-position 19.23, chart:style-name 19.27, style:legend-expansion 19.492, style:legend-expansion-aspect-ratio 19.493, svg:height 19.541.2, svg:width 19.573.3, svg:x 19.575.1 and svg:y 19.579.1 Add new subsections: 19.541.2 <chart:legend> The svg:height attribute defines the height of the legend. The svg:height attribute is usable with the following element: <chart:legend> 11.3. The svg:height attribute has the data type length 18.3.18. 19.573.3 <chart:legend> The svg:width attribute defines the width of a plot-area. The svg:width attribute is usable with the following element: <chart:legend> 11.3. The svg:width attribute has the data type length 18.3.18. 2.2 Schema changes/additions: --- OpenDocument-v1.2-os-schema.rng 2015-03-19 10:26:06.218679000 +0100 +++ OpenDocument-v1.2-os-schema_chartlegend.rng 2015-04-13 09:36:39.051080100 +0200 @@ -8438,6 +8438,7 @@ <attribute name="style:legend-expansion-aspect-ratio"> <ref name="double"/> </attribute> + <ref name="common-draw-size-attlist"/> </group> <empty/> </choice> 3. IMPACTS 3.1 Conformance: This proposal will not add any mandatory features or behaviors. 3.2 Backwards compatibility: This element was not available in previous versions and is optional. Existing ODF processors may ignore it. 3.3 Accessibility impact: None.