/// <summary> /// 生成缩略图 /// </summary> /// <param name="sourceImagePath">源图路径(带文件名的完整物理路径)</param> /// <param name="thumbImagePath">缩略图路径(带文件名的完整物理路径)</param> /// <param name="width">缩略图宽度</param> /// <param name="height">缩略图高度</param> /// <param name="thumbMode">生成缩略图的方式</param> public static void MakeThumb(string sourceImagePath, string thumbImagePath, int width, int height, ThumbMode thumbMode) { if (string.IsNullOrEmpty(sourceImagePath)) { throw new SourceImagePathIsNullOrEmptyException(); } if (!File.Exists(sourceImagePath)) { throw new SourceFileNotExistException(); } if (string.IsNullOrEmpty(thumbImagePath)) { throw new ThumbImagePathIsNullOrEmptyException(); } string directory = Path.GetDirectoryName(thumbImagePath); if (!Directory.Exists(directory)) { throw new ThumbImagePathNotExistException(); } try { using (Image sourceImage = Image.FromFile(sourceImagePath)) { if (width <= 0 && width >= sourceImage.Width) { throw new ThumbImageWidthIsErrorException(); } if (height <= 0 && height >= sourceImage.Height) { throw new ThumbImageHeigthIsErrorException(); } int towidth = width; int toheight = height; int x = 0; int y = 0; int ow = sourceImage.Width; int oh = sourceImage.Height; switch (thumbMode) { case ThumbMode.HW: //指定高宽缩放(不变形) int tempheight = sourceImage.Height * width / sourceImage.Width; if (tempheight > height) { towidth = sourceImage.Width * height / sourceImage.Height; } else { toheight = sourceImage.Height * width / sourceImage.Width; } break; case ThumbMode.W: //指定宽,高按比例 toheight = sourceImage.Height * width / sourceImage.Width; break; case ThumbMode.H: //指定高,宽按比例 towidth = sourceImage.Width * height / sourceImage.Height; break; case ThumbMode.CUT: //指定高宽裁减(不变形) if ((double)sourceImage.Width / (double)sourceImage.Height > (double)towidth / (double)toheight) { oh = sourceImage.Height; ow = sourceImage.Height * towidth / toheight; y = 0; x = (sourceImage.Width - ow) / 2; } else { ow = sourceImage.Width; oh = sourceImage.Width * height / towidth; x = 0; y = (sourceImage.Height - oh) / 2; } break; } //新建一个bmp图片 using (Image bitmap = new Bitmap(towidth, toheight)) { //新建一个画板 using (Graphics g = Graphics.FromImage(bitmap)) { //设置高质量插值法 g.InterpolationMode = InterpolationMode.High; //设置高质量,低速度呈现平滑程度 g.SmoothingMode = SmoothingMode.HighQuality; //清空画布并以透明背景色填充 g.Clear(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(sourceImage, new Rectangle(0, 0, towidth, toheight), new Rectangle(x, y, ow, oh), GraphicsUnit.Pixel); } //验证缩略图的保存路径是否带有文件名,如果没有带文件名则用 thumb_原文件名 if (!Regex.IsMatch(thumbImagePath, @"[^\\\/:\*\?""<>\|]+\.[^\\\/:\*\?""<>\|]+$", RegexOptions.Compiled)) { thumbImagePath = thumbImagePath + "thumb_" + sourceImagePath.Remove(0, sourceImagePath.LastIndexOf(@"\") + 1); } //以源文件相同的格式保存缩略图 bitmap.Save(thumbImagePath, sourceImage.RawFormat); } } } catch (OutOfMemoryException) { throw new SourceFileIsNotImageException(); } }
public void resetlog() { //w.Close() File.WriteAllText(this.fn, string.Empty); }