using System; using System.Collections.Generic; using System.Drawing; using System.Drawing.Drawing2D; using System.Drawing.Imaging; using System.Linq; using System.Text; using System.Threading.Tasks; namespace ZoomImage.Utils { /// <summary> /// 图片缩放 /// </summary> public class ZoomImageUtil { /// <summary> /// 图片缩放 /// </summary> /// <param>图片</param> /// <param>目标宽度，，若为0，表示宽度按比例缩放</param> /// <param>目标长度，若为0，表示长度按比例缩放</param> public static Bitmap GetThumbnail(Bitmap bmp, int width, int height) { if (width == 0) { width = height * bmp.Width / bmp.Height; } if (height == 0) { height = width * bmp.Height / bmp.Width; } Image imgSource = bmp; Bitmap outBmp = new Bitmap(width, height); Graphics g = Graphics.FromImage(outBmp); g.Clear(Color.Transparent); // 设置画布的描绘质量 g.CompositingQuality = CompositingQuality.HighQuality; g.SmoothingMode = SmoothingMode.HighQuality; g.InterpolationMode = InterpolationMode.HighQualityBicubic; g.DrawImage(imgSource, new Rectangle(0, 0, width, height + 1), 0, 0, imgSource.Width, imgSource.Height, GraphicsUnit.Pixel); g.Dispose(); imgSource.Dispose(); bmp.Dispose(); return outBmp; } } }