WPF：在屏幕坐标和WPF坐标之间转换 [英] WPF: Converting between screen coordinates and WPF coordinates

问题描述

我知道，如果计算机未使用默认的DPI设置，则WPF坐标与实际屏幕的坐标（像素坐标）不同。在我的程序中，我想（1）确定哪个监视器打开了WPF窗口，并且（2）在同一监视器的左下角打开另一个窗口。我听说没有屏幕 WPF，所以我使用WinForms版本，如下所示，它在默认的96 DPI下可以正常工作：

I understand that WPF coordinates are different from "real" screen coodinates (pixel coordinates) if the computer is not using the default DPI setting. In my program I want to (1) figure out which monitor a WPF window is on and (2) open another window in the bottom-left corner of the same monitor. I heard there is no equivalent of Screen for WPF so I use the WinForms version, as follows, which works fine at the default 96 DPI:

public void ChooseInitialPosition(Window w) // w is some other window
{
    var scr = System.Windows.Forms.Screen.FromRectangle(
          new System.Drawing.Rectangle((int)w.Left, (int)w.Top, (int)w.Width, (int)w.Height))
          .WorkingArea;

    this.Left = scr.Right - Width;
    this.Top = scr.Bottom - Height;
}

但是在其他DPI上，这两个步骤均无法正常工作，并且可能会使窗口完全消失

But at other DPIs, both steps work incorrectly, and may put the window completely off-screen.

到目前为止，看来我可以使用 Visual.PointToScreen 第一部分：

So far, it looks like I can use Visual.PointToScreen for the first part:

var p1 = w.PointToScreen(new Point(0,0));
var p2 = w.PointToScreen(new Point(w.Width,w.Height));
var scr = System.Windows.Forms.Screen.FromRectangle(
    new System.Drawing.Rectangle((int)p1.X, (int)p1.Y, (int)(p2.X - p1.X), (int)(p2.Y - p1.Y))).WorkingArea;

我不确定这是否正确，因为它可能无法正确说明边界。但是第二部分更重要。如何将屏幕矩形 scr转换为WPF空间，以便正确设置 Left和 Top？

I'm not sure if this is quite right, as it may not account for the borders correctly. But the second part is more important. How do I convert the screen rectangle "scr" into WPF space, in order to set Left and Top correctly?

推荐答案

1. 打开了WPF窗口的哪个屏幕：

1. Which screen a WPF window is on:

private static Screen GetScreen(Window window)
{
   return Screen.FromHandle(new WindowInteropHelper(window).Handle);
}

在同一屏幕的左下角打开另一个窗口：

Open another window in the bottom-left corner of the same screen:

static Point RealPixelsToWpf(Window w, Point p)
{
    var t = PresentationSource.FromVisual(w).CompositionTarget.TransformFromDevice;
    return t.Transform(p);
}
private static void SetPositionBottomLeftCorner(Window sourceWindow, Window targetWindow)
{
    var workingArea = GetScreen(sourceWindow).WorkingArea;
    var corner = RealPixelsToWpf(sourceWindow, new Point(workingArea.Left, workingArea.Bottom));
    targetWindow.Left = corner.X;
    targetWindow.Top = corner.Y - targetWindow.ActualHeight;
}

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