//Except where stated all code and programs in this project are the copyright of Jim Blackler, 2008.
//jimblackler@gmail.com
//
//This is free software. Libraries and programs are distributed under the terms of the GNU Lesser
//General Public License. Please see the files COPYING and COPYING.LESSER.

using System;
using System.Drawing;
using System.Windows.Forms;

namespace MiscControls
{
    /// <summary>
    /// A utility class that automatically adjusts the widths of a ListView's columns to fix text that
    /// is shown by the list view.
    /// </summary>
    public class ListViewColumns
    {
        /// <summary>
        /// Sets what the operation is allowed to do to the column widths.
        /// </summary>
        public enum SizeMode
        {
            /// <summary>
            /// The column is able to expand and shrink to fit the content width.
            /// </summary>
            ExpandAndShrink,

            /// <summary>
            /// The column is only able to shrink if the column is wider than the content.
            /// </summary>
            ShrinkOnly,

            /// <summary>
            /// The column is only able to expand if the column is narrower than the content.
            /// </summary>
            ExpandOnly
        };

        /// <summary>
        /// Adjust a list view's columns to fit the contained text
        /// </summary>
        /// <param name="listView">The list view to adjust</param>
        /// <param name="sizeMode">The acceptable operations to perform on the column widths</param>
        static public void AdjustToFit(ListView listView, SizeMode sizeMode)
        {
            // Only does anything in columns view
            if (listView.View != View.Details)
                return;

            int margin = 10;

            Graphics graphics = listView.CreateGraphics();

            int[] maxColumnSize = new int[listView.Columns.Count];

            // Measure the column widths
            foreach (ListViewItem item in listView.Items)
            {
                int idx = 0;
                foreach (ListViewItem.ListViewSubItem subItem in item.SubItems)
                {
                    int width = graphics.MeasureString(subItem.Text, subItem.Font).ToSize().Width + margin;

                    if (maxColumnSize[idx] < width)
                        maxColumnSize[idx] = width;

                    idx++;
                }
            }

            // Fix the column widths
            {
                int idx = 0;

                foreach (int width in maxColumnSize)
                {
                    if ((sizeMode != SizeMode.ExpandOnly || listView.Columns[idx].Width < width)
                        && (sizeMode != SizeMode.ShrinkOnly || listView.Columns[idx].Width > width))
                        listView.Columns[idx].Width = width;
                    idx++;
                }
            }
        }
    }
}