heli-agri/lib/render/canvas/LineStringBuilder.js

HeliAgri is a high-performance, feature-packed library for creating interactive maps on the web. It can display map tiles, vector data and markers loaded from any source on any web page. OpenLayers has been developed to further the use of geographic infor

/**
 * @module ol/render/canvas/LineStringBuilder
 */
import CanvasBuilder from './Builder.js';
import CanvasInstruction, {
  beginPathInstruction,
  strokeInstruction,
} from './Instruction.js';
import {defaultLineDash, defaultLineDashOffset} from '../canvas.js';

class CanvasLineStringBuilder extends CanvasBuilder {
  /**
   * @param {number} tolerance Tolerance.
   * @param {import("../../extent.js").Extent} maxExtent Maximum extent.
   * @param {number} resolution Resolution.
   * @param {number} pixelRatio Pixel ratio.
   */
  constructor(tolerance, maxExtent, resolution, pixelRatio) {
    super(tolerance, maxExtent, resolution, pixelRatio);
  }

  /**
   * @param {Array<number>} flatCoordinates Flat coordinates.
   * @param {number} offset Offset.
   * @param {number} end End.
   * @param {number} stride Stride.
   * @private
   * @return {number} end.
   */
  drawFlatCoordinates_(flatCoordinates, offset, end, stride) {
    const myBegin = this.coordinates.length;
    const myEnd = this.appendFlatLineCoordinates(
      flatCoordinates,
      offset,
      end,
      stride,
      false,
      false
    );
    const moveToLineToInstruction = [
      CanvasInstruction.MOVE_TO_LINE_TO,
      myBegin,
      myEnd,
    ];
    this.instructions.push(moveToLineToInstruction);
    this.hitDetectionInstructions.push(moveToLineToInstruction);
    return end;
  }

  /**
   * @param {import("../../geom/LineString.js").default|import("../Feature.js").default} lineStringGeometry Line string geometry.
   * @param {import("../../Feature.js").FeatureLike} feature Feature.
   */
  drawLineString(lineStringGeometry, feature) {
    const state = this.state;
    const strokeStyle = state.strokeStyle;
    const lineWidth = state.lineWidth;
    if (strokeStyle === undefined || lineWidth === undefined) {
      return;
    }
    this.updateStrokeStyle(state, this.applyStroke);
    this.beginGeometry(lineStringGeometry, feature);
    this.hitDetectionInstructions.push(
      [
        CanvasInstruction.SET_STROKE_STYLE,
        state.strokeStyle,
        state.lineWidth,
        state.lineCap,
        state.lineJoin,
        state.miterLimit,
        defaultLineDash,
        defaultLineDashOffset,
      ],
      beginPathInstruction
    );
    const flatCoordinates = lineStringGeometry.getFlatCoordinates();
    const stride = lineStringGeometry.getStride();
    this.drawFlatCoordinates_(
      flatCoordinates,
      0,
      flatCoordinates.length,
      stride
    );
    this.hitDetectionInstructions.push(strokeInstruction);
    this.endGeometry(feature);
  }

  /**
   * @param {import("../../geom/MultiLineString.js").default|import("../Feature.js").default} multiLineStringGeometry MultiLineString geometry.
   * @param {import("../../Feature.js").FeatureLike} feature Feature.
   */
  drawMultiLineString(multiLineStringGeometry, feature) {
    const state = this.state;
    const strokeStyle = state.strokeStyle;
    const lineWidth = state.lineWidth;
    if (strokeStyle === undefined || lineWidth === undefined) {
      return;
    }
    this.updateStrokeStyle(state, this.applyStroke);
    this.beginGeometry(multiLineStringGeometry, feature);
    this.hitDetectionInstructions.push(
      [
        CanvasInstruction.SET_STROKE_STYLE,
        state.strokeStyle,
        state.lineWidth,
        state.lineCap,
        state.lineJoin,
        state.miterLimit,
        state.lineDash,
        state.lineDashOffset,
      ],
      beginPathInstruction
    );
    const ends = multiLineStringGeometry.getEnds();
    const flatCoordinates = multiLineStringGeometry.getFlatCoordinates();
    const stride = multiLineStringGeometry.getStride();
    let offset = 0;
    for (let i = 0, ii = ends.length; i < ii; ++i) {
      offset = this.drawFlatCoordinates_(
        flatCoordinates,
        offset,
        /** @type {number} */ (ends[i]),
        stride
      );
    }
    this.hitDetectionInstructions.push(strokeInstruction);
    this.endGeometry(feature);
  }

  /**
   * @return {import("../canvas.js").SerializableInstructions} the serializable instructions.
   */
  finish() {
    const state = this.state;
    if (
      state.lastStroke != undefined &&
      state.lastStroke != this.coordinates.length
    ) {
      this.instructions.push(strokeInstruction);
    }
    this.reverseHitDetectionInstructions();
    this.state = null;
    return super.finish();
  }

  /**
   * @param {import("../canvas.js").FillStrokeState} state State.
   */
  applyStroke(state) {
    if (
      state.lastStroke != undefined &&
      state.lastStroke != this.coordinates.length
    ) {
      this.instructions.push(strokeInstruction);
      state.lastStroke = this.coordinates.length;
    }
    state.lastStroke = 0;
    super.applyStroke(state);
    this.instructions.push(beginPathInstruction);
  }
}

export default CanvasLineStringBuilder;