setGrid method

void setGrid({ double? leftWidth, double? rightWidth, double? topHeight, double? bottomHeight, })

Set different sizes for each of the fixed size rows and columns

A nine-box is a grid with 3 rows and 3 columns. The outer-most columns, leftWidth and rightWidth, are a fixed-width. As the nine-box is resized, those columns remain fixed-width and the center column stretches to take up the remaining space. In the same way, the outer-most rows, topHeight and bottomHeight, are a fixed-height. As the nine-box is resized, those rows remain fixed-height and the center row stretches to take up the remaining space.

Any widths or heights that are not specified remain unchanged.

Implementation

void setGrid({
  double? leftWidth,
  double? rightWidth,
  double? topHeight,
  double? bottomHeight,
}) {
  if (leftWidth != null && rightWidth != null) {
    assert(
      leftWidth + rightWidth <= sprite.src.width,
      'The left and right columns ($leftWidth + $rightWidth) do '
      'not fit in the width of the sprite (${sprite.src.width})',
    );
  } else if (leftWidth != null) {
    assert(
      leftWidth <= center.right,
      'The left column ($leftWidth) is too large '
      '(max ${center.right})',
    );
  } else if (rightWidth != null) {
    assert(
      rightWidth + center.left <= sprite.src.width,
      'The right column ($rightWidth) is too large '
      '(max ${sprite.src.width - center.left})',
    );
  }
  if (topHeight != null && bottomHeight != null) {
    assert(
      topHeight + bottomHeight <= sprite.src.height,
      'The top and bottom rows ($topHeight + $bottomHeight) do not fit '
      'in the height of the sprite (${sprite.src.height})',
    );
  } else if (topHeight != null) {
    assert(
      topHeight <= center.bottom,
      'The top row ($topHeight) is too large '
      '(max ${center.bottom})',
    );
  } else if (bottomHeight != null) {
    assert(
      bottomHeight + center.top <= sprite.src.height,
      'The bottom row ($bottomHeight) is too large '
      '(max ${sprite.src.height - center.top})',
    );
  }

  final left = leftWidth ?? center.left;
  final top = topHeight ?? center.top;
  late final double right;
  if (rightWidth == null) {
    right = center.right;
  } else {
    right = sprite.src.width - rightWidth;
  }
  late final double bottom;
  if (bottomHeight == null) {
    bottom = center.bottom;
  } else {
    bottom = sprite.src.height - bottomHeight;
  }
  center = Rect.fromLTRB(
    left,
    top,
    right,
    bottom,
  );
}