addFrame method

void addFrame (
  1. Image image,
  2. {int duration}
)

Add a frame to be encoded. Call finish to encode the added frames. If only one frame is added, a single-image WebP is encoded; otherwise if there are more than one frame, a multi-frame animated WebP is encoded.

Implementation

void addFrame(Image image, {int duration}) {
  if (output == null) {
    output = OutputBuffer();

    if (duration != null) {
      delay = duration;
    }
    _lastImage = _encodeImage(image);
    _width = image.width;
    _height = image.height;
    return;
  }

  if (_encodedFrames == 0) {
    _writeHeader(_width, _height);
  }

  _addImage(_lastImage, _width, _height);
  _encodedFrames++;

  if (duration != null) {
    delay = duration;
  }

  _lastImage = _encodeImage(image);
}