async renderImage()

in client/src/services/image-rendering.ts [77:111]
35 lines of code
4 McCabe index (conditional complexity)

  async renderImage(imageData: Blob, word: WordTranslation, sourceLanguage: Language,
                    endangeredLanguage: EndangeredLanguage, width: number, height: number): Promise<Blob> {
    const imageURL = URL.createObjectURL(imageData);
    let image: HTMLImageElement;
    try {
      image = await ImageRenderingService._loadImage(imageURL);
    } catch(ex) {
      URL.revokeObjectURL(imageURL);
      throw ex;
    }
    const canvas: HTMLCanvasElement = document.createElement('canvas');
    canvas.width = width;
    canvas.height = height;
    const imageWidth = image.naturalWidth;
    const imageHeight = image.naturalHeight;
    const context = canvas.getContext('2d');
    if (!context) {
      throw new Error('Unable to create canvas context');
    }
    // multiplier to scale canvas down to contain image dimensions
    const imageScale = Math.min(imageWidth / width, imageHeight / height);
    const croppedImageWidth = Math.round(width * imageScale);
    const croppedImageHeight = Math.round(height * imageScale);
    const croppedImageDx = (imageWidth - croppedImageWidth) * 0.5;
    const croppedImageDy = (imageHeight - croppedImageHeight) * 0.5;
    context.drawImage(image, croppedImageDx, croppedImageDy, croppedImageWidth, croppedImageHeight, 0, 0, width, height);
    const scale = Math.min(width / window.innerWidth, height / window.innerHeight);
    await this._renderBanner(context, width, scale);
    if (!word) {
      return canvasToBlob(canvas);
    }
    context.setTransform(scale, 0, 0, scale, 0, 0);
    this._renderTranslations(context, word, sourceLanguage, endangeredLanguage, width, height, scale);
    return canvasToBlob(canvas);
  }