using System;
using System.Collections.Generic;using System.Drawing;using System.Linq;using System.Text;using System.Threading.Tasks;namespace HF.SHOP.Common{ public class ImageHelper { /// <summary> /// 缩放图片 /// </summary> /// <param name="img"></param> /// <param name="w"></param> /// <param name="h"></param> /// <returns></returns> public static Bitmap ResizeImage(Image img, int w, int h) { Bitmap resizeBitmap = new Bitmap(img, w, h); return resizeBitmap; } /// <summary> /// 生成缩略图 /// </summary> /// <param Name="originalImagePath">源图路径（物理路径）</param> /// <param Name="thumbnailPath">缩略图路径（物理路径）</param> /// <param Name="width">缩略图宽度</param> /// <param Name="height">缩略图高度</param> /// <param Name="mode">生成缩略图的方式</param> public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode) { System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath); int towidth = width; int toheight = height; int x = 0; int y = 0; int ow = originalImage.Width; int oh = originalImage.Height; switch (mode) { case "HW"://指定高宽缩放（可能变形） break; case "W"://指定宽，高按比例 toheight = originalImage.Height * width / originalImage.Width; break; case "H"://指定高，宽按比例 towidth = originalImage.Width * height / originalImage.Height; break; case "Cut"://指定高宽裁减（不变形） if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight) { oh = originalImage.Height; ow = originalImage.Height * towidth / toheight; y = 0; x = (originalImage.Width - ow) / 2; } else { ow = originalImage.Width; oh = originalImage.Width * height / towidth; x = 0; y = (originalImage.Height - oh) / 2; } break; default: break; }//新建一个bmp图片 System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight); System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap); //设置高质量插值法 g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; //设置高质量,低速度呈现平滑程度 g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; //清空画布并以透明背景色填充 g.Clear(System.Drawing.Color.Transparent); //在指定位置并且按指定大小绘制原图片的指定部分 g.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, towidth, toheight), new System.Drawing.Rectangle(x, y, ow, oh), System.Drawing.GraphicsUnit.Pixel); try { //以jpg格式保存缩略图 bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg); } catch (System.Exception e) { throw e; } finally { originalImage.Dispose(); bitmap.Dispose(); g.Dispose(); // File.Delete(originalImagePath);//删除原图 } } /// <summary> /// 剪切图片 /// </summary> /// <param name="img"></param> /// <param name="x"></param> /// <param name="y"></param> /// <param name="w"></param> /// <param name="h"></param> /// <returns></returns> public static Bitmap CropImage(Image img, int x, int y, int w, int h) { Rectangle resizeRect = new Rectangle(x, y, w, h); Bitmap cropBitmap = new Bitmap(w, h); Graphics cropG = Graphics.FromImage(cropBitmap); cropG.DrawImage(img, 0, 0, resizeRect, GraphicsUnit.Pixel); cropG.Dispose(); return cropBitmap; } /// <summary> /// 获取图片文件名 /// </summary> /// <returns></returns> public static string GetAutoImageName() { //Random rad = new Random(); //return string.Format("{0}_{1}", DateTime.Now.ToString("yyyyMMddHHmmss"), rad.Next(1000, 10000).ToString()); return DateTime.Now.Ticks.ToString(); } }}