Offset property is being ignored on MarkSymbolizer

[florentsuc]

Bug

Describe the bug
Converting from SLD to OpenLayers style, offsets on MarkSymbolizer are no longer handled, even though the SLD uses displacement. Displacement is transformed to undefined.

To Reproduce
Steps to reproduce the behavior:

• Create an SLD with a Mark style and Displacement.
• Convert the style to geostyler and then to OpenLayers
• Style a vector layer with the OL style.

Example:

<Rule>
	<Name>selected property</Name>
	<PointSymbolizer>
		<Graphic>
			<Mark>
				<WellKnownName>circle</WellKnownName>
				<Fill>
					<CssParameter name="fill">#FFFFFF</CssParameter>
				</Fill>
			</Mark>
			<Size>45.0</Size>
			<Displacement>
				<DisplacementX>1</DisplacementX>
				<DisplacementY>1</DisplacementY>
			</Displacement>
		</Graphic>
	</PointSymbolizer>
</Rule>

Expected behavior
offset property should not be undefined

Desktop (please complete the following information):
OS: Mac OS
Browser: Chrome
Version: 122.0

Additional context
The bug has been introduced here:

geostyler-openlayers-parser/src/OlStyleParser.ts

Line 1046 in 2d8a804

displacement: typeof(markSymbolizer.offset) === 'number' ? markSymbolizer.offset : undefined

Proposed solution

• offset is not a number, it is an array, so we could check Array.isArray(offset)
• we should update the unit tests and introduce an offset + displacement into the mocked data

[KaiVolland]

Thanks for the detailed report.

As you always got so far with the research it would be nice if you could provide a PR with the adjustment and the corresponding tests.
Otherwise this might need some time to be fixed.