Function aspectRatio

src/core/constraints.ts:202–239

(ratio: number)

 * ```
 */
export function aspectRatio(ratio: number): LayoutConstraint {
  return {
    name: `aspectRatio(${ratio})`,

    constrainSize(
      _item: LayoutItem,
      w: number,
      _h: number,
      _handle: ResizeHandleAxis,
      context: ConstraintContext
    ): { w: number; h: number } {
      const { cols, containerWidth, rowHeight, margin } = context;
      // Calculate column width in pixels
      // colWidth = (containerWidth - margin[0] * (cols - 1)) / cols
      // Note: simplified formula assumes no container padding
      const colWidth = (containerWidth - margin[0] * (cols - 1)) / cols;

      // Calculate pixel width of the item
      // pixelWidth = colWidth * w + margin[0] * (w - 1)
      const pixelWidth = colWidth * w + margin[0] * Math.max(0, w - 1);

      // Calculate required pixel height for aspect ratio
      const pixelHeight = pixelWidth / ratio;

      // Convert pixel height back to grid units
      // pixelHeight = rowHeight * h + margin[1] * (h - 1)
      // Solving for h:
      // pixelHeight = h * (rowHeight + margin[1]) - margin[1]
      // h = (pixelHeight + margin[1]) / (rowHeight + margin[1])
      const h = Math.max(
        1,
        Math.round((pixelHeight + margin[1]) / (rowHeight + margin[1]))
      );

      return { w, h };
    }
  };
}

/**
 * Create a snap-to-grid constraint.