public async getOverlayImage()

in source/image-handler/image-handler.ts [260:299]
36 lines of code
7 McCabe index (conditional complexity)

  public async getOverlayImage(bucket: string, key: string, wRatio: string, hRatio: string, alpha: string, sourceImageMetadata: sharp.Metadata): Promise<Buffer> {
    const params = { Bucket: bucket, Key: key };
    try {
      const { width, height } = sourceImageMetadata;
      const overlayImage: S3.GetObjectOutput = await this.s3Client.getObject(params).promise();
      const resizeOptions: ResizeOptions = {
        fit: ImageFitTypes.INSIDE
      };

      // Set width and height of the watermark image based on the ratio
      const zeroToHundred = /^(100|[1-9]?[0-9])$/;
      if (zeroToHundred.test(wRatio)) {
        resizeOptions.width = Math.floor((width * parseInt(wRatio)) / 100);
      }
      if (zeroToHundred.test(hRatio)) {
        resizeOptions.height = Math.floor((height * parseInt(hRatio)) / 100);
      }

      // If alpha is not within 0-100, the default alpha is 0 (fully opaque).
      const alphaValue = zeroToHundred.test(alpha) ? parseInt(alpha) : 0;
      const imageBuffer = Buffer.isBuffer(overlayImage.Body) ? overlayImage.Body : Buffer.from(overlayImage.Body as Uint8Array);
      return await sharp(imageBuffer)
        .resize(resizeOptions)
        .composite([
          {
            input: Buffer.from([255, 255, 255, 255 * (1 - alphaValue / 100)]),
            raw: {
              width: 1,
              height: 1,
              channels: 4
            },
            tile: true,
            blend: 'dest-in'
          }
        ])
        .toBuffer();
    } catch (error) {
      throw new ImageHandlerError(error.statusCode ? error.statusCode : StatusCodes.INTERNAL_SERVER_ERROR, error.code, error.message);
    }
  }