Silverlight/WPF 截图保存功能的实现

╰半夏微凉° 2022-01-14 04:49 287阅读 0赞

图片的截取和压缩主要通过WriteableBitmap 这个类实现的，对它进行相应的变换就可以实现截取和压缩。 由WriteableBitmap转换成byte我调用了FluxJpeg这个三方的。

这个在博客园上有很多说明，在博客园上搜索“FluxJpeg”就可以找的到

using System.IO;
    using System.Windows;
    using System.Windows.Controls;
    using System.Windows.Media;
    using System.Windows.Media.Imaging;
    
    namespace SinoChemBI.Tools
    {
        public class ImageTools
        {
            #region 将内容保存为图片
    
            /// <summary>
            /// 将内容保存为图片
            /// </summary>
            /// <param name="_UIElement">控件</param>
            /// <returns>true:成功；false：失败</returns>
            public bool? PrintScreen(UIElement _UIElement)
            {
                try
                {
                    //截图  
                    WriteableBitmap wBitmap = new WriteableBitmap(_UIElement, new MatrixTransform());
                    Image img = new Image();
                    //img.Width = 450;
                    //img.Margin = new Thickness(2);
                    img.Source = wBitmap;
                    //保存图片  
                    if (wBitmap == null)
                    {
                        return false;
                    }
                    SaveFileDialog saveDlg = new SaveFileDialog();
                    saveDlg.Filter = "JPEG Files (*.jpeg)|*.jpeg";
                    saveDlg.DefaultExt = ".jpeg";
    
                    if (!(bool)saveDlg.ShowDialog())
                    {
                        return null;
                    }
                    using (Stream fs = saveDlg.OpenFile())
                    {
                        savePicToFile(wBitmap, fs);
                        return true;
                    }
                }
                catch (System.Exception ex)
                {
                    return false;
                }
            }
            private void savePicToFile(WriteableBitmap bitmap, Stream fs)
            {
                int width = bitmap.PixelWidth;
                int height = bitmap.PixelHeight;
                int bands = 3;
                byte[][,] raster = new byte[bands][,];  //用来保存bitmap中每个像素点的RGB分量的数组
                for (int i = 0; i < bands; i++)
                {
                    raster[i] = new byte[width, height];
                }
                for (int row = 0; row < height; row++)
                {
                    for (int column = 0; column < width; column++)
                    {
                        int pixel = bitmap.Pixels[width * row + column];
                        raster[0][column, row] = (byte)(pixel >> 16);  //R
                        raster[1][column, row] = (byte)(pixel >> 8);   //G
                        raster[2][column, row] = (byte)pixel;          //B
                    }
                }
                FluxJpeg.Core.ColorModel model = new FluxJpeg.Core.ColorModel { colorspace = FluxJpeg.Core.ColorSpace.RGB };
                FluxJpeg.Core.Image img = new FluxJpeg.Core.Image(model, raster);
    
                //使用jpeg编码方式
                MemoryStream stream = new MemoryStream();
                FluxJpeg.Core.Encoder.JpegEncoder encoder = new FluxJpeg.Core.Encoder.JpegEncoder(img, 100, stream);
                encoder.Encode();
                //回到stream的起始
                stream.Seek(0, SeekOrigin.Begin);
                //读取stream中的内容放入binaryData中，然后通过fs参数写到本地磁盘上，图片保存完成。
                byte[] binaryData = new byte[stream.Length];
                long bytesRead = stream.Read(binaryData, 0, (int)stream.Length);
                fs.Write(binaryData, 0, binaryData.Length);
            }
    
            #endregion
        }
    }