resizeImage static method

Uint8List resizeImage(Uint8List imageBytes, int width, int height, { Color? backgroundColor, bool removeAlpha = true, })

重新調整圖片大小 backgroundColor - 是否填補背景顏色 removeAlpha - 是否移除alpha通道

Implementation

static Uint8List resizeImage(
  Uint8List imageBytes,
  int width,
  int height, {
  Color? backgroundColor,
  bool removeAlpha = true,
}) {
  // Load the image
  var image = decodeImage(imageBytes);
  if (image == null) {
    print('Failed to load image.');
    throw Exception('Failed to load image.');
  }

  if (backgroundColor != null) {
    // 填補背景
    final background = Image(
      width: image.width,
      height: image.height,
      numChannels: image.numChannels,
    );
    fill(background, color: backgroundColor);
    image = compositeImage(background, image);
  }

  if (removeAlpha && image.hasAlpha) {
    image = _removeImageAlpha(image);
  }

  // Resize the image to a 120x? thumbnail (maintaining the aspect ratio).

  image = copyResize(
    image,
    width: width,
    height: height,
    interpolation: Interpolation.average,
  );

  // 取得圖片格式
  final imageFormat = ImageFormatDetector.detect(imageBytes);

  switch (imageFormat) {
    case ImageFormat.jpg:
      return encodeJpg(image);
    case ImageFormat.png:
      return encodePng(image);
    case ImageFormat.apng:
      return encodePng(image);
    case ImageFormat.gif:
      return encodeGif(image);
    case ImageFormat.bmp:
      return encodeBmp(image);
    case ImageFormat.tiff:
      return encodeTiff(image);
    case ImageFormat.ico:
      return encodeIco(image);
    default:
      // 其餘格式暫時不支持
      throw Exception('Unsupported image format. ($imageFormat)');
  }
}