c# bitmap的拷贝及一个图像工具类

                using (Bitmap bmp = new Bitmap(scanImgPath))
                {
                    Bitmap bitmap = new Bitmap(bmp.Width, bmp.Height, PixelFormat.Format16bppRgb555);
                    using (Graphics draw = Graphics.FromImage(bitmap))
                    {
                        draw.DrawImage(bmp, 0, 0, bitmap.Width, bitmap.Height);
                        picScanImg.Image = bitmap as Image;
                    }
                }

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Text;

namespace TJCFinanceWriteOff.BizLogic.Common
{
    public class ImageUtil
    {
        /// <summary>
        /// 图片镜像翻转
        /// </summary>
        /// <param name="imagePath">图片路径</param>
        /// <param name="isCover">是否覆盖</param>
        /// <returns></returns>
        public static Image ImageFlip(string imagePath,bool isCover = false)
        {
            Bitmap bitmap = Bitmap.FromFile(imagePath) as Bitmap;
            bitmap.RotateFlip(RotateFlipType.Rotate180FlipY);  //图片镜像翻转
            if (isCover is true) bitmap.Save(imagePath,System.Drawing.Imaging.ImageFormat.Jpeg);
            return bitmap;
        }

        /// <summary>
        /// 图片顺时针旋转180度
        /// </summary>
        /// <param name="imagePath">图片路径</param>
        /// <param name="isCover">是否覆盖</param>
        /// <returns></returns>
        public static Image ImageRotate(string imagePath,bool isCover = false)
        {
            Bitmap bitmap = Bitmap.FromFile(imagePath) as Bitmap;
            bitmap.RotateFlip(RotateFlipType.Rotate180FlipNone);  //图片顺时针180度
            if (isCover is true) bitmap.Save(imagePath,System.Drawing.Imaging.ImageFormat.Jpeg);
            return bitmap;
        }

        /// <summary>
        /// 图片等比缩放
        /// </summary>
        /// <param name="imagePath"></param>
        /// <returns></returns>
        public static Image ImageScaleZoom(string imagePath, double process)
        {
            Bitmap bitmap = Bitmap.FromFile(imagePath) as Bitmap;
            double width = bitmap.Width * process; ;//图片最终的宽
            double height = bitmap.Height * process;//图片最终的高
            return bitmap.GetThumbnailImage((int)width, (int)height, () => { return false; }, IntPtr.Zero);
        }

        public static Image ImageScaleZoom(Image sourceImage, double process)
        {
            double width = sourceImage.Width * process; ;//图片最终的宽
            double height = sourceImage.Height * process;//图片最终的高
            try
            {
                System.Drawing.Imaging.ImageFormat format = sourceImage.RawFormat;
                Bitmap targetPicture = new Bitmap((int)width, (int)height);
                Graphics g = Graphics.FromImage(targetPicture);
                g.DrawImage(sourceImage, 0, 0, (int)width, (int)height);
                sourceImage.Dispose();
                return targetPicture;
            }
            catch (Exception ex)
            {

            }
            return null;
        }

        public static Image ImageAssignZoom(Image sourceImage, int targetWidth, int targetHeight)
        {
            int width;//图片最终的宽
            int height;//图片最终的高
            try
            {
                System.Drawing.Imaging.ImageFormat format = sourceImage.RawFormat;
                Bitmap targetPicture = new Bitmap(targetWidth, targetHeight);
                Graphics g = Graphics.FromImage(targetPicture);

                if (sourceImage.Width > targetWidth && sourceImage.Height <= targetHeight)
                {
                    width = targetWidth;
                    height = (width * sourceImage.Height) / sourceImage.Width;  //噶
                }
                else if (sourceImage.Width <= targetWidth && sourceImage.Height > targetHeight)
                {
                    height = targetHeight;
                    width = (height * sourceImage.Width) / sourceImage.Height;
                }
                else if (sourceImage.Width <= targetWidth && sourceImage.Height <= targetHeight)
                {
                    width = sourceImage.Width;
                    height = sourceImage.Height;
                }
                else
                {
                    width = targetWidth;
                    height = (width * sourceImage.Height) / sourceImage.Width;
                    if (height > targetHeight)
                    {
                        height = targetHeight;
                        width = (height * sourceImage.Width) / sourceImage.Height;
                    }
                }
                g.DrawImage(sourceImage, 0, 0, width, height);
                sourceImage.Dispose();

                return targetPicture;
            }
            catch (Exception ex)
            {

            }
            return null;
        }
    }
}