winform图片缩放

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
using System.Text;
using System.Windows.Forms;

namespace bitmaprerote
{
    public partial class suofang : Form
    {
        public suofang()
        {
            InitializeComponent();
        }
        /// <summary>
        /// Resize图片
        /// </summary>
        /// <param name="bmp">原始Bitmap</param>
        /// <param name="newW">新的宽度</param>
        /// <param name="newH">新的高度</param>
        /// <returns>处理以后的图片</returns>
        public static Bitmap KiResizeImage(Bitmap bmp, int newW, int newH, int Mode)
        {
            try
            {
                Bitmap map = new Bitmap(newW, newH);
                Graphics g = Graphics.FromImage(map);
                // 插值算法的质量
                g.InterpolationMode = InterpolationMode.HighQualityBicubic;
                g.DrawImage(bmp, new Rectangle(0, 0, newW, newH), new Rectangle(0, 0, bmp.Width, bmp.Height), GraphicsUnit.Pixel);
                g.Dispose();
                return map;
            }
            catch
            {
                return null;
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Bitmap map = new Bitmap("F:\\hj.jpg");
            map = KiResizeImage(map, 90, 90, 20);
            pictureBox1.Image = map;
        }
    }
}