图片帮助类
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();
}
}
}