Question

我正在开发窗口电话应用程序。我想要删除图像的背景。我正在使用setpixel（）方法。但它删除背景非常慢。这是我的代码。

 private void Canvas_MouseMove_1(object sender, System.Windows.Input.MouseEventArgs e)
        {
            wrt = new WriteableBitmap(imag, null);
            try
            {
                System.Windows.Media.Color c = new System.Windows.Media.Color();
                c.A = 0;
                c.B = 0; c.R = 0; c.G = 0;
                currentPoint = e.GetPosition(this.imag);

            for (int degrees = 0; degrees <= 360; degrees++)
            {
                for (int distance = 0; distance <= erasersize; distance++)
                {
                    //double angle = Math.PI * degrees / 180.0;
                    double x = currentPoint.X + (distance * Math.Cos(degrees));
                    double y = currentPoint.Y + (distance * Math.Sin(degrees));
                    wrt.SetPixel(Convert.ToInt32(x), Convert.ToInt32(y) - offset, c);
                }
            }

        }

我在google搜索了很多文章，但没有人为我工作。 Bitmap.LockBits方法之一向我建议。但问题是我们无法将system.drawing添加到window phone app中，因为dll不受支持。任何人都可以帮我解决这个问题。提前谢谢。

Answer 1

WriteableBitmap具有名为Pixels的不错属性。它只是一个整数数组，但它可以更快地操作像素。

首先，您需要快速的color-to-int conventer：

public static int ColorToInt(Color color)
{
    return unchecked((int)((color.A << 24) | (color.R << 16) | (color.G << 8) | color.B));
}

然后你可以改变你的代码：

wrt = new WriteableBitmap(imag, null);
try
{
    System.Windows.Media.Color c = new System.Windows.Media.Color();
    c.A = 0;
    c.B = 0; c.R = 0; c.G = 0;
    currentPoint = e.GetPosition(this.imag);

    int width = wrt.PixelWidth;

    for (int degrees = 0; degrees <= 360; degrees++)
    {
        for (int distance = 0; distance <= erasersize; distance++)
        {
            //double angle = Math.PI * degrees / 180.0;
            double x = currentPoint.X + (distance * Math.Cos(degrees));
            double y = currentPoint.Y + (distance * Math.Sin(degrees));
            wrt.Pixels[(int)(y - offset) * width + (int)x] = ColorToInt(c);
        }
    }
}

SetPixel（）太慢，无法删除图像背景

1 个答案: