如何正确居中叠加位图？

Question

我从代码生成 QR 码，然后将其叠加在另一个图像上。问题是它没有按照我的预期排列。

/// <summary>
/// Draw one bitmap over another.
/// </summary>
/// <param name="largeBmp"></param>
/// <param name="smallBmp"></param>
/// <returns></returns>
public Bitmap Superimpose(Bitmap largeBmp, Bitmap smallBmp) {

    Graphics g = Graphics.FromImage(largeBmp);
    g.CompositingMode = CompositingMode.SourceOver;
    
    // Resize it so it fists
    smallBmp = ResizeBitmap(smallBmp, smallBmp.Width / 4, smallBmp.Height / 4);

    var x = (largeBmp.Width -  smallBmp.Width) / 2;
    var y = (largeBmp.Height - smallBmp.Height)/ 2;

    g.DrawImage(smallBmp, new Point(x, y));

    return largeBmp;
}

/// <summary>
/// Resize the bitmap
/// </summary>
/// <param name="bmp"></param>
/// <param name="width"></param>
/// <param name="height"></param>
/// <returns></returns>
public Bitmap ResizeBitmap(Bitmap bmp, int width, int height)
{
    Bitmap result = new Bitmap(width, height);
    using (Graphics g = Graphics.FromImage(result))
    {
        g.DrawImage(bmp, 0, 0, width, height);
    }

    return result;
}

Answer 1

我在 win forms 项目中尝试了你的代码，代码工作正常，我使用 png 格式来表示大图像和小图像，我认为你应该检查你的 QR 代码，它周围可能有一些空白