C# 处理图片不规则图形裁剪

我会带着你远行 2022-05-16 07:29 178阅读 0赞

最近项目要求实现不规则裁剪功能。本来想用html5的canvas在前端实现的，但是发现有点困难，以下为C\#端对图对片的处理。

为了让大家知道下面内容是否是自己想要的，我先发效果图。

原图　　　　　　　　　　　　　　　　　　　　　通过下面代码中的坐标得到的截图

![061019167609196.jpg][]                  ![061021376827215.jpg][]

好了，那就开始贴代码了

以下为一个按钮的事件，为裁剪准备图片、裁剪路径、保存路径

using System.Drawing.Drawing2D;

private void button1_Click(object sender, EventArgs e)
            {
                GraphicsPath path = new GraphicsPath();
                Point[] p = {
                                new Point(424,244),
                                new Point(240,440),
                                new Point(340,552),
                                new Point(550,526),
                                new Point(478,366),
                                new Point(348,660),
                                new Point(424,244)
                            };
                path.AddLines(p);
                OpenFileDialog openFileDialog = new OpenFileDialog();
    
                openFileDialog.Filter = @"Bitmap文件(*.bmp)|*.bmp|Jpeg文件(*.jpg)|*.jpg|所有合适文件(*.bmp,*.jpg)|*.bmp;*.jpg";
    
                openFileDialog.FilterIndex = 3;
    
                openFileDialog.RestoreDirectory = true;
    
                if (DialogResult.OK == openFileDialog.ShowDialog())
                {
    
                    Bitmap bit = (Bitmap)Bitmap.FromFile(openFileDialog.FileName, false);
    
                    Bitmap newBit = null;
                    BitmapCrop(bit, path, out newBit);
                    newBit.Save(@"C:\Users\Public\Pictures\Sample Pictures\沙漠22.jpg");
                }
            }

以下为裁剪的关键代码

/// <summary>
            /// 图片截图
            /// </summary>
            /// <param name="bitmap">原图</param>
            /// <param name="path">裁剪路径</param>
            /// <param name="outputBitmap">输出图</param>
            /// <returns></returns>
            public static Bitmap BitmapCrop(Bitmap bitmap, GraphicsPath path, out Bitmap outputBitmap)
            {
                RectangleF rect = path.GetBounds();
                int left = (int)rect.Left;
                int top = (int)rect.Top;
                int width = (int)rect.Width;
                int height = (int)rect.Height;
                Bitmap image = (Bitmap)bitmap.Clone();
                outputBitmap = new Bitmap(width, height);
                for (int i = left; i < left + width; i++)
                {
                    for (int j = top; j < top + height; j++)
                    {
                        //判断坐标是否在路径中   
                        if (path.IsVisible(i, j))
                        {
                            //复制原图区域的像素到输出图片   
                            outputBitmap.SetPixel(i - left, j - top, image.GetPixel(i, j));
                            //设置原图这部分区域为透明   
                            image.SetPixel(i, j, Color.FromArgb(0, image.GetPixel(i, j)));
                        }
                        else
                        {
                            outputBitmap.SetPixel(i - left, j - top, Color.FromArgb(0, 255, 255, 255));
                        }
                    }
                }
                bitmap.Dispose();
                return image;
            }

[061019167609196.jpg]: https://images0.cnblogs.com/i/420449/201405/061019167609196.jpg
[061021376827215.jpg]: /images/20220516/4689adaa8c9a4e698757a14ac47ba590.png