magickSigmoidalContrastImage method

Future<bool> magickSigmoidalContrastImage({
  1. required bool sharpen,
  2. required double alpha,
  3. required double beta,
})

MagickSigmoidalContrastImage() adjusts the contrast of an image with a non-linear sigmoidal contrast algorithm. Increase the contrast of the image using a sigmoidal transfer function without saturating highlights or shadows. Contrast indicates how much to increase the contrast (0 is none; 3 is typical; 20 is pushing it); mid-point indicates where midtones fall in the resultant image (0 is white; 50 is middle-gray; 100 is black). Set sharpen to true to increase the image contrast otherwise the contrast is reduced.

This method runs inside an isolate different from the main isolate.

  • sharpen: Increase or decrease image contrast.
  • alpha: strength of the contrast, the larger the number the more 'threshold-like' it becomes.
  • beta: midpoint of the function as a color value 0 to QuantumRange.

Implementation

Future<bool> magickSigmoidalContrastImage({
  required bool sharpen,
  required double alpha,
  required double beta,
}) async =>
    await _magickCompute(
      _magickSigmoidalContrastImage,
      _MagickSigmoidalContrastImageParams(
        _wandPtr.address,
        sharpen,
        alpha,
        beta,
      ),
    );