selectLayerAt method

String? selectLayerAt(
  1. Offset tapPosition,
  2. Size canvasSize
)

根据点击位置选择文本图层

Implementation

String? selectLayerAt(Offset tapPosition, Size canvasSize) {
  // 从最上层的图层开始检查（按添加顺序的逆序）
  final layersList = _layers.values.toList().reversed;
  for (final layer in layersList) {
    final bounds = getTextLayerBounds(layer, canvasSize);

    // 增加一些触摸范围判定，特别是对于较小的文字
    final touchBounds = bounds.inflate(8.0);

    if (touchBounds.contains(tapPosition)) {
      _selectedLayerId = layer.id;
      return layer.id;
    }
  }
  return null;
}