本文實例講述了C#實現縮放和剪裁圖片的方法。分享給大家供大家參考，具體如下：
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using System;using System.Collections.Generic;using System.Text;using System.Drawing;using System.Drawing.Drawing2D;using System.Drawing.Imaging;namespace Project{ class ImageOperation { /// <summary> /// Resize圖片 /// </summary> /// <param name="bmp">原始Bitmap </param> /// <param name="newW">新的寬度</param> /// <param name="newH">新的高度</param> /// <param name="Mode">保留著，暫時未用</param> /// <returns>處理以后的圖片</returns> public static Bitmap ResizeImage(Bitmap bmp, int newW, int newH, int Mode) { try { Bitmap b = new Bitmap(newW, newH); Graphics g = Graphics.FromImage(b); // 插值算法的質量 g.InterpolationMode = InterpolationMode.HighQualityBicubic; g.DrawImage(bmp, new Rectangle(0, 0, newW, newH), new Rectangle(0, 0, bmp.Width, bmp.Height), GraphicsUnit.Pixel); g.Dispose(); return b; } catch { return null; } } /// <summary> /// 剪裁 -- 用GDI+ /// </summary> /// <param name="b">原始Bitmap</param> /// <param name="StartX">開始坐標X</param> /// <param name="StartY">開始坐標Y</param> /// <param name="iWidth">寬度</param> /// <param name="iHeight">高度</param> /// <returns>剪裁后的Bitmap</returns> public static Bitmap Cut(Bitmap b, int StartX, int StartY, int iWidth, int iHeight) { if (b == null) { return null; } int w = b.Width; int h = b.Height; if (StartX >= w || StartY >= h) { return null; } if (StartX + iWidth > w) { iWidth = w - StartX; } if (StartY + iHeight > h) { iHeight = h - StartY; } try { Bitmap bmpOut = new Bitmap(iWidth, iHeight, PixelFormat.Format24bppRgb); Graphics g = Graphics.FromImage(bmpOut); g.DrawImage(b, new Rectangle(0, 0, iWidth, iHeight), new Rectangle(StartX, StartY, iWidth, iHeight), GraphicsUnit.Pixel); g.Dispose(); return bmpOut; } catch { return null; } } }} |
目標其實都是new Rectangle(0, 0, iWidth, iHeight)，縮放算法把整個原始圖都往目標區域里塞new Rectangle(0, 0, bmp.Width, bmp.Height)，而剪裁只是把原始區域上等寬等高的那個區域new Rectangle(StartX, StartY, iWidth, iHeight)1:1的塞到目標區域里。
希望本文所述對大家C#程序設計有所幫助。
