ExternalGraphic's Format not set (geostyyler -> sld)

[joserwan]

Bug

Describe the bug

The <Format> tag is missing when converting from geostyler to SLD.

To Reproduce

const { SldStyleParser } = await import("geostyler-sld-parser");
const geostyle = {
  rules: [
    {
      name: 'MissingFormat',
      symbolizers: [{kind: "Icon", image: '/path/to/icon.png'}],
    },
  ]
}
const parser = new SldStyleParser({ builderOptions: { format: true }});

parser.writeStyle(geostyle).then(({ output: sld }) => console.log(sld));

Result:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<StyledLayerDescriptor version="1.0.0" xsi:schemaLocation="http://www.opengis.net/sld StyledLayerDescriptor.xsd" xmlns="http://www.opengis.net/sld" xmlns:ogc="http://www.opengis.net/ogc" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:se="http://www.opengis.net/se">
  <NamedLayer>
    <Name/>
    <UserStyle>
      <Name/>
      <Title/>
      <FeatureTypeStyle>
        <Rule>
          <Name>MissingFormat</Name>
          <PointSymbolizer>
            <Graphic>
              <ExternalGraphic>
                <OnlineResource xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="/path/to/icon.png"/>
              </ExternalGraphic>
            </Graphic>
          </PointSymbolizer>
        </Rule>
      </FeatureTypeStyle>
    </UserStyle>
  </NamedLayer>
</StyledLayerDescriptor>

Expected behavior

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<StyledLayerDescriptor version="1.0.0" xsi:schemaLocation="http://www.opengis.net/sld StyledLayerDescriptor.xsd" xmlns="http://www.opengis.net/sld" xmlns:ogc="http://www.opengis.net/ogc" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:se="http://www.opengis.net/se">
  <NamedLayer>
    <Name/>
    <UserStyle>
      <Name/>
      <Title/>
      <FeatureTypeStyle>
        <Rule>
          <Name>MissingFormat</Name>
          <PointSymbolizer>
            <Graphic>
              <ExternalGraphic>
                <OnlineResource xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="/path/to/icon.png"/>
                <Format>image/png</Format>
              </ExternalGraphic>
            </Graphic>
          </PointSymbolizer>
        </Rule>
      </FeatureTypeStyle>
    </UserStyle>
  </NamedLayer>
</StyledLayerDescriptor>

Additional context
Node v20.8.0
Debian
geostler-sld-parser v5.1.0

My fix

diff --git a/src/SldStyleParser.ts b/src/SldStyleParser.ts
index 0373158..eb0ccfa 100644
--- a/src/SldStyleParser.ts
+++ b/src/SldStyleParser.ts
@@ -1739,13 +1739,13 @@ export class SldStyleParser implements StyleParser<string> {
         case 'png':
         case 'jpeg':
         case 'gif':
-          graphic[0][ExternalGraphic][0][Format] = [`image/${iconExt}`];
+          graphic[0][ExternalGraphic][1] = { [Format]:  [{ '#text': `image/${iconExt}` }] };
           break;
         case 'jpg':
-          graphic[0][ExternalGraphic][0][Format] = ['image/jpeg'];
+          graphic[0][ExternalGraphic][1] = { [Format]:  [{ '#text': `image/jpeg` }] };
           break;
         case 'svg':
-          graphic[0][ExternalGraphic][0][Format] = ['image/svg+xml'];
+          graphic[0][ExternalGraphic][1] = { [Format]:  [{ '#text': `image/svg+xml` }] };
           break;
         default:
           break;

PS: Thank you for your awesome work !!

[jansule]

Thanks for the info @joserwan!

We actually do provide a format property in geostyler-style (see https://github.com/geostyler/geostyler-style/blob/master/style.ts#L431). However, it seems like we do not use it yet in geostyler-sld-parser.

I would suggest to adjust following things:

• could you make use of this.getTagName('format'), so that we support both SLD versions?
• could you also check if the format property on the geostyler style is set, and only derive the format from the file name as fallback?

Also, it would be great if you could create a Pull Request for this 🚀

[joserwan]

Sorry for the delay, I missed the notification.

I'll have a look on that in the next weeks, for now I'm too busy. Thank you for your feedback !

[KaiVolland]

@joserwan are you still planing on providing a PR here? Otherwise we might have the chance to fix this during the next codes sprint.