正确使用绘图.带有指定点的矩形c# winforms

Question

我试图获得扫描文档的每个角落的图像(左上角和右下角，左下角和右下角)。下面是我如何尝试实现，但当我看到保存的图像，他们都是不同的部分，但左上角，而不是整个文档。有什么建议我可以改变这一点吗?

 Bitmap result = fullImg;
 //top-left
 var bandImg1 = result.Clone(new System.Drawing.Rectangle(0, 0, 375, 375), fullImg.PixelFormat);
 //top-right
 var bandImg2 = result.Clone(new System.Drawing.Rectangle(100, 50, 375, 375), fullImg.PixelFormat);
 //bottom-left
 var bandImg3 = result.Clone(new System.Drawing.Rectangle(0, 50, 375, 375), fullImg.PixelFormat);
 //bottom-right
 var bandImg4 = result.Clone(new System.Drawing.Rectangle(100, 100, 375, 375), fullImg.PixelFormat);
                    bandImg1.Save("c:\bandImg1.gif", System.Drawing.Imaging.ImageFormat.Gif);
                    bandImg2.Save("c:\bandImg2.gif", System.Drawing.Imaging.ImageFormat.Gif);
                    bandImg3.Save("c:\bandImg3.gif", System.Drawing.Imaging.ImageFormat.Gif);
                    bandImg4.Save("c:\bandImg4.gif", System.Drawing.Imaging.ImageFormat.Gif);

-----根据下面的答案添加了更新的代码------

Bitmap result = fullImg;
                    //top-left
                    var bandImg1 = result.Clone(new System.Drawing.Rectangle(0, 0, result.Width/2, result.Height/2), fullImg.PixelFormat);
                    //top-right
                    var bandImg2 = result.Clone(new System.Drawing.Rectangle(result.Width / 2, 0, result.Width / 2, result.Height / 2), fullImg.PixelFormat);
                    //bottom-left
                    var bandImg3 = result.Clone(new System.Drawing.Rectangle(0, result.Height / 2, result.Width / 2, result.Height / 2), fullImg.PixelFormat);
                    //bottom-right
                    var bandImg4 = result.Clone(new System.Drawing.Rectangle(result.Width / 2, result.Height / 2, result.Width / 2, result.Height / 2), fullImg.PixelFormat);
                    bandImg1.Save("c:\bandImg1.gif", System.Drawing.Imaging.ImageFormat.Gif);
                    bandImg2.Save("c:\bandImg2.gif", System.Drawing.Imaging.ImageFormat.Gif);
                    bandImg3.Save("c:\bandImg3.gif", System.Drawing.Imaging.ImageFormat.Gif);
                    bandImg4.Save("c:\bandImg4.gif", System.Drawing.Imaging.ImageFormat.Gif);

                    string QRinfo = Process(bandImg1);

过程方法:

public string Process(Bitmap bitmap)
    {
        var reader = new com.google.zxing.qrcode.QRCodeReader();
        try
        {
            LuminanceSource source = new RGBLuminanceSource(bitmap, bitmap.Width, bitmap.Height);
            var binarizer = new HybridBinarizer(source);
            var binBitmap = new BinaryBitmap(binarizer);
            return reader.decode(binBitmap).Text;
        }
        catch (Exception e)
        {
            return e.Message;
        }
    }

Answer 1

我的猜测是，在计算矩形坐标时，您需要考虑result或fullImg的宽度和高度，而不是像您这样硬编码值。像这样:

//top left
var bandImg1 = result.Clone(new Rectangle(0, 0, result.Width / 2, result.Height / 2), result.PixelFormat);
//top right
var bandImg2 = result.Clone(new Rectangle(result.Width / 2, 0, result.Width / 2, result.Height / 2), result.PixelFormat);
//bottom left
var bandImg3 = result.Clone(new Rectangle(0, result.Height / 2, result.Width / 2, result.Height / 2), result.PixelFormat);
//bottom right
var bandImg4 = result.Clone(new Rectangle(result.Width / 2, result.Height / 2, result.Width / 2, result.Height / 2), result.PixelFormat);

你现在所做的可能不工作，因为你是硬编码的值。例如，对于bandImg1，你使用(0,0,375,375)作为矩形，基本上是说"从左上角开始，向右移动375像素，向下移动375像素"。相反，你想使用(0, 0, result.Width / 2, result.Height / 2)，它表示"从左上角开始，穿过图像的一半，然后沿着图像的一半"，这将给你左上角。