performLayout method

@override dynamic performLayout(PrinterConstraints constraints, PrinterCanvas canvas)

布局

Implementation

@override
performLayout(PrinterConstraints constraints, PrinterCanvas canvas) {
  assert(constraints.maxHeight.isInfinite, '高度必须是浮动的');
  cells.clear();

  Map<int, TableCellData> mergeColumnMap = <int, TableCellData>{};

  List data = this.dataSource!.execExpressionToValue(binding);
  _rowCount = data.length;

  double bottom = 0;

  double rowHeight = this.size!.height ?? 0;
  for (int y = 0; y < data.length; y++) {
    final rowData = data[y];

    var rowDataSource = RowDataSource(rowData, this.dataSource!, y);
    if (condition != null && condition != '') {
      var value = rowDataSource.execExpressionToValue(condition!);
      if (value != true) {
        continue;
      }
    }
    double offsetX = 0;
    for (int x = 0; x < children.length; x++) {
      final child = children[x];
      if (child.columnMerge == true) {
        var mergeText = child.getDisplayText(rowDataSource);
        if (mergeColumnMap.containsKey(x) &&
            mergeColumnMap[x]!.mergeText == mergeText) {
          mergeColumnMap[x]!.mergeRow++;
          mergeColumnMap[x]!.size = PrinterSize(mergeColumnMap[x]!.size!.width,
              mergeColumnMap[x]!.size!.height! + rowHeight);
        } else {
          var cell = TableCellData();
          cell.rowData = rowDataSource;
          cell.column = child;
          cell.mergeRow = 1;
          cell.mergeText = mergeText;
          cell.rowIndex = y;
          cell.columnIndex = x;
          cell.offset = PrinterOffset(offsetX, bottom);
          cell.size = PrinterSize(child.size!.width, rowHeight);
          mergeColumnMap[x] = cell;
          cells.add(cell);
        }
      } else {
        var cell = TableCellData();
        cell.rowData = rowDataSource;
        cell.column = child;
        cell.mergeRow = 1;
        cell.rowIndex = y;
        cell.columnIndex = x;
        cell.offset = PrinterOffset(offsetX, bottom);
        cell.size = PrinterSize(child.size!.width, rowHeight);
        cells.add(cell);
      }
      offsetX += child.size!.width!;
    }

    bottom += rowHeight;
  }

  double rowWidth = 0;

  for (var child in this.children) {
    rowWidth += child.size!.width!;
  }

  actualOffset = this.offset;
  actualSize = PrinterSize(rowWidth, bottom);
}