Method prepareTileParts

src/image.js:15–57

* Prepare all tiles to fit the baselayer

(data)

   * Prepare all tiles to fit the baselayer
   */
  prepareTileParts(data) {
    return new Promise((resolve) => {
      const tile = sharp(data.body);
      tile
        .metadata()
        .then((metadata) => {
          const x = data.box[0];
          const y = data.box[1];
          const sx = x < 0 ? 0 : x;
          const sy = y < 0 ? 0 : y;
          const dx = x < 0 ? -x : 0;
          const dy = y < 0 ? -y : 0;
          const extraWidth = x + (metadata.width - this.width);
          const extraHeight = y + (metadata.width - this.height);
          const w = metadata.width + (x < 0 ? x : 0) - (extraWidth > 0 ? extraWidth : 0);
          const h = metadata.height + (y < 0 ? y : 0) - (extraHeight > 0 ? extraHeight : 0);

          // Fixed #20 https://github.com/StephanGeorg/staticmaps/issues/20
          if (!w || !h) {
            resolve({ success: false });
            return null;
          }

          return tile
            .extract({
              left: dx,
              top: dy,
              width: w,
              height: h,
            })
            .toBuffer()
            .then((part) => {
              resolve({
                success: true,
                position: { top: Math.round(sy), left: Math.round(sx) },
                data: part,
              });
            })
            .catch(() => resolve({ success: false }));
        })
        .catch(() => resolve({ success: false }));
    });
  }

  async draw(tiles) {
    this.tempBuffer = null;