如何有效地裁剪和缩放图像数据

我需要对图像中的像素值进行操作。 因此我写了这样一堂课：

public class image_class { #region property public int width { get; private set; } public int height { get; private set; } byte[] buffer; #endregion #region constructors public image_class() { ; } public image_class(int Width, int Height, byte[] data) { if (data.Count() == (Width * Height * 3)) { this.width = Width; this.height = Height; this.buffer = data; } else throw new Exception(); } #endregion #region get bitmap public ImageSource bmp { get { try { var pixelFormat = PixelFormats.Rgb24; var bytesPerPixel = (pixelFormat.BitsPerPixel + 7) / 8; var stride = bytesPerPixel * width; var bitmap = BitmapSource.Create(width, height, 96d, 96d, pixelFormat, null, buffer, stride); return bitmap; } catch { return null; } } } #endregion #region methods public void load_from_file(string path) { var bmp = new BitmapImage(); bmp.BeginInit(); bmp.UriSource = new Uri(ofd.FileName, UriKind.Absolute); bmp.EndInit(); height = (int)bmp.Height; width = (int)bmp.Width; int stride = width * ((bmp.Format.BitsPerPixel + 7) / 8); int size = height * stride; var buffer2 = new byte[size]; bmp.CopyPixels(buffer2, stride, 0); buffer = new byte[size * 3 / 4]; for (int i = 0, j = 0; i < size; i += 4, j += 3) { buffer[j] = buffer2[i + 2]; buffer[j + 1] = buffer2[i + 1]; buffer[j + 2] = buffer2[i]; } } public void load_from_file(string path, int Width, int Height) { this.width = Width; this.height = Height; var bmp = new BitmapImage(); bmp.BeginInit(); bmp.DecodePixelHeight = height; bmp.DecodePixelWidth = width; bmp.UriSource = new Uri(path, UriKind.Absolute); bmp.EndInit(); int stride = width * ((bmp.Format.BitsPerPixel + 7) / 8); int size = height * stride; var buffer2 = new byte[size]; bmp.CopyPixels(buffer2, stride, 0); buffer = new byte[size * 3 / 4]; for (int i = 0, j = 0; i = 0 & y0 >= 0 & x0 + dx <= width & y0 + dy <= height) { byte[] buffer3 = new byte[dx * dy * 3]; for (int y = 0, i = 0, j = -1; y < height; y++) for (int x = 0; x = x0 & x = y0 & y < y0 + dy) { buffer3[++j] = buffer[i]; buffer3[++j] = buffer[i + 1]; buffer3[++j] = buffer[i + 2]; } return new image_class(dx, dy, buffer3); } else throw new Exception(); } #endregion } 

缓冲区数组是我使用的。

这个课程完美无缺。 当我需要处理来自图像片段的数据时，我使用方法剪切，例如：

 image_class img1=new image_class(); image_class img2=img1.cut(5,5,20,20); 

我需要的是将剪切图像缩放到其他值并保持像素数据的格式。 例如，我希望图片中的50×50平方，缩放到20×20。 这就是我做的：

 image_class img1=new image_class(); image_class img2=img1.cut(5,5,50,50); img2.save_to_file(path); image_class img3=new image_class(); img3.load_from_file(path, 20,20); 

它有效，但当然非常无效。 谁能告诉我更好的解决方案？

Answer 1

你不需要这一切。 为了从源位图复制矩形部分，然后对其进行缩放，您可以简单地使用CroppedBitmap和TransformedBitmap ：

 BitmapSource original = ... var crop = new CroppedBitmap(original, new Int32Rect(5, 5, 50, 50)); var result = new TransformedBitmap(crop, new ScaleTransform(0.4, 0.4));