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使用Graphics 保存圖片質(zhì)量很差，怎么回事？

.NET

喵喵時(shí)光機(jī) 2018-12-07 04:11:23

原本寬度為300 的圖片ImagePhoto 大小為 30KB FixedSize(ImagePhoto,300) 之后圖片變?yōu)?20KB 了，圖片質(zhì)量下降了很多怎么弄讓圖片質(zhì)量和原來的一樣呢？ public static Image FixedSize(Image imgPhoto, int Width) { int sourceWidth = imgPhoto.Width; int sourceHeight = imgPhoto.Height; int w, h; if (sourceWidth > Width) { decimal nPercent = (decimal)sourceWidth / Width; w = Width; h = (int)Math.Round((decimal)sourceHeight / nPercent, 0); } else { w = sourceWidth; h = sourceHeight; } Bitmap bmPhoto = new Bitmap(w, h, imgPhoto.PixelFormat); bmPhoto.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution); Graphics grPhoto = Graphics.FromImage(bmPhoto); grPhoto.CompositingQuality = CompositingQuality.HighQuality; grPhoto.SmoothingMode = SmoothingMode.HighQuality; grPhoto.InterpolationMode = InterpolationMode.HighQualityBicubic; grPhoto.DrawImage(imgPhoto, new Rectangle(0, 0, w, h), new Rectangle(0, 0, sourceWidth, sourceHeight), GraphicsUnit.Pixel); grPhoto.Dispose(); return bmPhoto; }

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1 回答

斯蒂芬大帝

TA貢獻(xiàn)1827條經(jīng)驗(yàn) 獲得超8個(gè)贊

如果是JPG的話，參考以下代碼：

var imageCodeInfo = GetEncoderInfo("image/jpeg");
var myEncoder = System.Drawing.Imaging.Encoder.Quality;
var myEncoderParameters = new EncoderParameters(1);
var myEncoderParameters.Param[0] = new EncoderParameter(myEncoder, 99L);
thumbNail.Save(thumbUrl, imageCodeInfo, myEncoderParameters);