paintGrid method

@override void paintGrid(Canvas canvas, NodeFlowTheme theme, ({double bottom, double left, double right, double top}) gridArea)

Renders the style-specific grid pattern.

Each grid style implements this method to draw its specific pattern (lines, dots, crosses, etc.) using the pre-calculated gridArea.

Parameters:

• canvas: The canvas to paint on
• theme: Theme containing grid configuration
• gridArea: Pre-calculated grid-aligned area covering the visible region

Implementation

@override
void paintGrid(
  Canvas canvas,
  NodeFlowTheme theme,
  ({double left, double top, double right, double bottom}) gridArea,
) {
  final gridTheme = theme.gridTheme;
  final gridSize = gridTheme.size;

  // Create paint for the crosses
  final paint = createGridPaint(theme)
    ..strokeWidth = gridTheme.thickness.clamp(0.5, 1.5);

  // Calculate arm length
  final armLength = crossSize ?? (gridTheme.thickness * 3).clamp(2.0, 6.0);

  // Calculate grid-aligned start positions
  final startX = (gridArea.left / gridSize).floor() * gridSize;
  final startY = (gridArea.top / gridSize).floor() * gridSize;

  // Draw crosses at each grid intersection
  for (double x = startX; x <= gridArea.right; x += gridSize) {
    for (double y = startY; y <= gridArea.bottom; y += gridSize) {
      // Draw horizontal arm
      canvas.drawLine(
        Offset(x - armLength, y),
        Offset(x + armLength, y),
        paint,
      );

      // Draw vertical arm
      canvas.drawLine(
        Offset(x, y - armLength),
        Offset(x, y + armLength),
        paint,
      );
    }
  }
}