从屏幕上的鼠标光标位置获取图像坐标(WPF 图像控件)

问题描述：

我一直在寻找一种解决方案来透明地添加平移和;WPF 图像控件的缩放功能，我找到了解决方案 https://stackoverflow.com/a/6782715/584180，由 Wiesław Šoltés 和 Konrad Viltersten，非常出色.

I was looking for a solution to transparently add panning & zooming capability to a WPF Image control and I have found the solution https://stackoverflow.com/a/6782715/584180, developed by Wiesław Šoltés and Konrad Viltersten, which is outstanding.

现在我想给控件添加一个鼠标点击"事件，这样我就可以在原始图像坐标系中获得点击点的坐标，这样我就可以使用它们来检索像素颜色.

Now I would like to add a 'mouse click' event to the control so that I can the coordinates of the clicked point in the original image coordinate system, so I can use them to retrieve the pixel color.

我知道会有一些四舍五入，如果图像被缩小，颜色将与屏幕上显示的实际颜色不符.我也知道用户可能会在图像边框外单击，在这种情况下，我希望返回空点或负坐标.

I understand there will be some rounding and if the image is zoomed out the color will not correspond to the actual one displayed on screen. I also understand that the user may click outside the image borders, in that case I expect a null Point or negative coords to be returned.

我不是 C# 转换方式的专家，目前我坚持使用这个方法(添加到 ZoomBorder.cs 类中):

I am not an expert of the C# way of doing transforms and at the moment I am stuck with this (to be added inside the ZoomBorder.cs class):

public Point GetImageCoordsAt(MouseButtonEventArgs e)
{
    if (child != null)
    {
        var tt = GetTranslateTransform(child);
        var mousePos = e.GetPosition(this);
        var transformOrigin = new Point(tt.X, tt.Y);

        return mousePos; // Wrong: how do I transform this?
    }

    return null;
}

答

正如 mm8 建议的那样，您可以使用 e.GetPosition(child); 获取您想要的位置，无需执行任何转换.出于测试目的，我覆盖了重置行为.使用您提供的链接中的代码，更改

As mm8 suggests you can get the location you want using e.GetPosition(child); , there's no need to perform any transformations. For testing purposes I've overwritten the reset behaviour. Using the code from the link you provided, change

void child_PreviewMouseRightButtonDown(object sender, MouseButtonEventArgs e)
{
    this.Reset();
}

到

public Point GetImageCoordsAt(MouseButtonEventArgs e)
{
    if (child != null && child.IsMouseOver)
    {
        return e.GetPosition(child);
    }
    return new Point(-1, -1);
}

void child_PreviewMouseRightButtonDown(object sender, MouseButtonEventArgs e)
{
    MessageBox.Show(GetImageCoordsAt(e).ToString());
}

如果您在图像中的同一位置右键单击，无论平移和缩放如何，您都将获得(大约)相同的坐标.

If you rightclick at the same location in the image, you'll get (approximately) the same coordinates, regardless of the pan and zoom.

从屏幕上的鼠标光标位置获取图像坐标(WPF 图像控件)

相关推荐