/// <summary> /// 获取缩放后图片 /// </summary> /// <param name="originalImage">原始图片</param> /// <param name="fixedWidth">固定宽度</param> /// <param name="fixedHeight">固定高度</param> /// <param name="changedMode">改变模式</param> /// <param name="disposeOriginalImage">释放原始照片</param> /// <returns></returns> public Bitmap ZoomBitmap(Bitmap originalImage, int fixedWidth, int fixedHeight, ImageChangedMode changedMode, bool disposeOriginalImage) { int towidth = fixedWidth; int toheight = fixedHeight; int x = 0; int y = 0; int ow = originalImage.Width; int oh = originalImage.Height; switch (changedMode) { case ImageChangedMode.FixedWH: //指定高宽缩放(可能变形) break; case ImageChangedMode.ZoomHByW: //指定宽,高按比例 toheight = originalImage.Height * fixedWidth / originalImage.Width; break; case ImageChangedMode.ZoomWByH: //指定高,宽按比例 towidth = originalImage.Width * fixedHeight / originalImage.Height; break; case ImageChangedMode.ZoomBySacle: //根据源/目标 的宽高比例,哪个指标大,固定哪个指标,缩放另一个指标 double scaleW = originalImage.Width / fixedWidth; double scaleH = originalImage.Height / fixedHeight; if (scaleW > scaleH) { toheight = originalImage.Height * fixedWidth / originalImage.Width; } else { towidth = originalImage.Width * fixedHeight / originalImage.Height; } break; case ImageChangedMode.CutByFixedWH: //指定高宽裁减(不变形) default: 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 * fixedHeight / towidth; x = 0; y = (originalImage.Height - oh) / 2; } break; } //新建一个bmp图片 System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(towidth, toheight); //新建一个画板 Graphics g = System.Drawing.Graphics.FromImage(bitmap); try { //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(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 Rectangle(0, 0, towidth, toheight), new Rectangle(x, y, ow, oh), GraphicsUnit.Pixel); } catch (System.Exception e) { throw e; } finally { if (disposeOriginalImage) { originalImage.Dispose(); } g.Dispose(); } return(bitmap); }
public Bitmap ZoomBitmap(Bitmap originalImage, Size fixedSize, ImageChangedMode changedMode, bool disposeOriginalImage) { return(ZoomBitmap(originalImage, fixedSize.Width, fixedSize.Height, changedMode, disposeOriginalImage)); }