dyomedea/src/components/gpx/styles.ts

import { Fill, Text, Icon, Stroke, Style } from 'ol/style';
import startIcon from '../../icons/flag-start-b-svgrepo-com-green.svg';
import finishIcon from '../../icons/flag-finish-b-o-svgrepo-com-red.svg';
import wptIcon from '../../icons/location-pin-svgrepo-com-red.svg';
import { Feature } from 'ol';
import memoize from 'memoizee';

interface StyleParameters {
  type: string;
  isSelected: boolean;
}

const textStroke = new Stroke({
  color: '#fff',
  width: 3,
});
const textFill = new Fill({
  color: '#000',
});

const styles = {
  default: {
    trkseg: {
      stroke: new Stroke({
        color: 'blue',
        width: 3,
      }),
    },
    'trkseg-start': {
      image: new Icon({
        src: startIcon,
        scale: 0.2,
        opacity: 0.6,
        anchor: [0.5, 1],
      }),
    },
    'trkseg-finish': {
      image: new Icon({
        src: finishIcon,
        scale: 0.2,
        opacity: 0.6,
        anchor: [0.5, 1],
      }),
    },
    wpt: {
      image: new Icon({
        src: wptIcon,
        scale: 0.1,
        opacity: 0.9,
        anchor: [0.5, 1],
      }),
      text: (feature: Feature) =>
        new Text({
          font: '16px Calibri,sans-serif',
          text: feature.get('name'),
          fill: textFill,
          stroke: textStroke,
          offsetY: -40,
        }),
    },
  },
  selected: {
    trkseg: {
      stroke: new Stroke({
        color: 'red',
        width: 3,
      }),
    },
  },
};

const styleRequiresFeature = memoize((type: keyof typeof styles.default) => {
  const defaults = styles.default[type];
  const selected = styles.selected[type];
  const all = { ...defaults, ...selected };
  for (const key of Object.keys(all)) {
    if (all[key] instanceof Function) {
      return true;
    }
  }
  return false;
});

const getStyle = memoize(
  (
    type: keyof typeof styles.default,
    isSelected: boolean = false,
    params: any
  ) => {
    const defaults = styles.default[type];
    const selected = styles.selected[type];
    const all = isSelected ? { ...defaults, ...selected } : { ...defaults };
    console.log({
      caller: 'style / getStyle',
      type,
      isSelected,
      params,
      defaults,
      selected,
      all,
    });
    for (const key of Object.keys(all)) {
      if (all[key] instanceof Function) {
        all[key] = all[key](params);
      }
    }
    return new Style(all);
  },
  { length: 3, max: 1024 }
);

export const style = (feature: Feature, resolution: number) => {
  const type = feature.get('type');
  const isSelected = feature.get('isSelected') === true;
  console.log({ caller: 'style', type, isSelected });
  if (styleRequiresFeature(type)) {
    return getStyle(type, isSelected, feature);
  }
  return getStyle(type, isSelected, null);
};

export default style;