openlayers/src/ol/renderer/canvas/VectorImageLayer.js

/**
 * @module ol/renderer/canvas/VectorImageLayer
 */
import CanvasImageLayerRenderer from './ImageLayer.js';
import CanvasVectorLayerRenderer from './VectorLayer.js';
import EventType from '../../events/EventType.js';
import ImageCanvas from '../../ImageCanvas.js';
import ImageState from '../../ImageState.js';
import ViewHint from '../../ViewHint.js';
import {apply, compose, create} from '../../transform.js';
import {assign} from '../../obj.js';
import {getHeight, getWidth, isEmpty, scaleFromCenter} from '../../extent.js';
import {renderDeclutterItems} from '../../render.js';

/**
 * @classdesc
 * Canvas renderer for image layers.
 * @api
 */
class CanvasVectorImageLayerRenderer extends CanvasImageLayerRenderer {
  /**
   * @param {import("../../layer/VectorImage.js").default} layer Vector image layer.
   */
  constructor(layer) {
    super(layer);

    /**
     * @private
     * @type {import("./VectorLayer.js").default}
     */
    this.vectorRenderer_ = new CanvasVectorLayerRenderer(layer);

    /**
     * @private
     * @type {number}
     */
    this.layerImageRatio_ = layer.getImageRatio();

    /**
     * @private
     * @type {import("../../transform.js").Transform}
     */
    this.coordinateToVectorPixelTransform_ = create();

    /**
     * @private
     * @type {import("../../transform.js").Transform}
     */
    this.renderedPixelToCoordinateTransform_ = null;
  }

  /**
   * Clean up.
   */
  disposeInternal() {
    this.vectorRenderer_.dispose();
    super.disposeInternal();
  }

  /**
   * Asynchronous layer level hit detection.
   * @param {import("../../pixel.js").Pixel} pixel Pixel.
   * @return {Promise<Array<import("../../Feature").default>>} Promise that resolves with an array of features.
   */
  getFeatures(pixel) {
    if (this.vectorRenderer_) {
      const vectorPixel = apply(
        this.coordinateToVectorPixelTransform_,
        apply(this.renderedPixelToCoordinateTransform_, pixel.slice())
      );
      return this.vectorRenderer_.getFeatures(vectorPixel);
    } else {
      const promise = new Promise(function (resolve, reject) {
        resolve([]);
      });
      return promise;
    }
  }

  /**
   * Perform action necessary to get the layer rendered after new fonts have loaded
   */
  handleFontsChanged() {
    this.vectorRenderer_.handleFontsChanged();
  }

  /**
   * Determine whether render should be called.
   * @param {import("../../PluggableMap.js").FrameState} frameState Frame state.
   * @return {boolean} Layer is ready to be rendered.
   */
  prepareFrame(frameState) {
    const pixelRatio = frameState.pixelRatio;
    const viewState = frameState.viewState;
    const viewResolution = viewState.resolution;

    const hints = frameState.viewHints;
    const vectorRenderer = this.vectorRenderer_;
    let renderedExtent = frameState.extent;
    if (this.layerImageRatio_ !== 1) {
      renderedExtent = renderedExtent.slice(0);
      scaleFromCenter(renderedExtent, this.layerImageRatio_);
    }
    const width = getWidth(renderedExtent) / viewResolution;
    const height = getHeight(renderedExtent) / viewResolution;

    if (
      !hints[ViewHint.ANIMATING] &&
      !hints[ViewHint.INTERACTING] &&
      !isEmpty(renderedExtent)
    ) {
      vectorRenderer.useContainer(null, null, 1);
      const context = vectorRenderer.context;
      const imageFrameState = /** @type {import("../../PluggableMap.js").FrameState} */ (assign(
        {},
        frameState,
        {
          coordinateToPixelTransform: create(),
          declutterItems: [],
          extent: renderedExtent,
          size: [width, height],
          viewState: /** @type {import("../../View.js").State} */ (assign(
            {},
            frameState.viewState,
            {
              rotation: 0,
            }
          )),
        }
      ));
      const image = new ImageCanvas(
        renderedExtent,
        viewResolution,
        pixelRatio,
        context.canvas,
        function (callback) {
          if (
            vectorRenderer.prepareFrame(imageFrameState) &&
            vectorRenderer.replayGroupChanged
          ) {
            vectorRenderer.renderFrame(imageFrameState, null);
            renderDeclutterItems(imageFrameState, null);
            callback();
          }
        }
      );

      image.addEventListener(
        EventType.CHANGE,
        function () {
          if (image.getState() === ImageState.LOADED) {
            this.image_ = image;
            const imageResolution = image.getResolution();
            const imagePixelRatio = image.getPixelRatio();
            const renderedResolution =
              (imageResolution * pixelRatio) / imagePixelRatio;
            this.renderedResolution = renderedResolution;
            this.coordinateToVectorPixelTransform_ = compose(
              this.coordinateToVectorPixelTransform_,
              width / 2,
              height / 2,
              1 / renderedResolution,
              -1 / renderedResolution,
              0,
              -viewState.center[0],
              -viewState.center[1]
            );
          }
        }.bind(this)
      );
      image.load();
    }

    if (this.image_) {
      this.renderedPixelToCoordinateTransform_ = frameState.pixelToCoordinateTransform.slice();
    }

    return !!this.image_;
  }

  /**
   */
  preRender() {}

  /**
   */
  postRender() {}

  /**
   * @param {import("../../coordinate.js").Coordinate} coordinate Coordinate.
   * @param {import("../../PluggableMap.js").FrameState} frameState Frame state.
   * @param {number} hitTolerance Hit tolerance in pixels.
   * @param {function(import("../../Feature.js").FeatureLike, import("../../layer/Layer.js").default): T} callback Feature callback.
   * @param {Array<import("../../Feature.js").FeatureLike>} declutteredFeatures Decluttered features.
   * @return {T|void} Callback result.
   * @template T
   */
  forEachFeatureAtCoordinate(
    coordinate,
    frameState,
    hitTolerance,
    callback,
    declutteredFeatures
  ) {
    if (this.vectorRenderer_) {
      return this.vectorRenderer_.forEachFeatureAtCoordinate(
        coordinate,
        frameState,
        hitTolerance,
        callback,
        declutteredFeatures
      );
    } else {
      return super.forEachFeatureAtCoordinate(
        coordinate,
        frameState,
        hitTolerance,
        callback,
        declutteredFeatures
      );
    }
  }
}

export default CanvasVectorImageLayerRenderer;