Files
ChrisKaczor.Wpf.Windows.Sna…/SnappingWindow.cs
2023-04-07 17:20:52 -04:00

451 lines
18 KiB
C#

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Interop;
using JetBrains.Annotations;
using WpfScreenHelper;
using Rectangle = System.Drawing.Rectangle;
namespace ChrisKaczor.Wpf.Windows
{
[PublicAPI]
public class SnappingWindow : Window
{
#region Member variables
private HwndSource? _hWndSource;
private bool _inSizeMove;
private PInvoke.WindowPosition _lastWindowPosition;
private List<WindowInformation>? _otherWindows;
#endregion
private class WindowBorderRectangles
{
public WindowBorderRectangles(Rectangle windowPosition, int width, bool inside)
{
var offset = inside ? width : 0;
var actualWidth = inside ? width * 2 : width;
Top = new Rectangle(windowPosition.Left, windowPosition.Top - offset, windowPosition.Width, actualWidth);
Bottom = new Rectangle(windowPosition.Left, windowPosition.Bottom - offset, windowPosition.Width, actualWidth);
Left = new Rectangle(windowPosition.Left - offset, windowPosition.Top, actualWidth, windowPosition.Height);
Right = new Rectangle(windowPosition.Right - offset, windowPosition.Top, actualWidth, windowPosition.Height);
}
public WindowBorderRectangles(PInvoke.WindowPosition windowPosition, int width, bool inside)
{
var offset = inside ? width : 0;
var actualWidth = inside ? width * 2 : width;
Top = new Rectangle(windowPosition.Left, windowPosition.Top - offset, windowPosition.Width, actualWidth);
Bottom = new Rectangle(windowPosition.Left, windowPosition.Bottom - offset, windowPosition.Width, actualWidth);
Left = new Rectangle(windowPosition.Left - offset, windowPosition.Top, actualWidth, windowPosition.Height);
Right = new Rectangle(windowPosition.Right - offset, windowPosition.Top, actualWidth, windowPosition.Height);
}
public Rectangle Top { get; }
public Rectangle Bottom { get; }
public Rectangle Left { get; }
public Rectangle Right { get; }
}
private class ResizeSide
{
public ResizeSide(PInvoke.WindowPosition position1, PInvoke.WindowPosition position2)
{
if (position1.IsSameSize(position2))
return;
IsTop = position1.Top != position2.Top;
IsBottom = position1.Bottom != position2.Bottom;
IsLeft = position1.Left != position2.Left;
IsRight = position1.Right != position2.Right;
}
public bool IsTop { get; }
public bool IsBottom { get; }
public bool IsLeft { get; }
public bool IsRight { get; }
}
#region Enumerations
private enum SnapMode
{
Move,
Resize
}
#endregion
#region Properties
protected virtual int SnapDistance => 20;
protected virtual List<WindowInformation>? OtherWindows => null;
#endregion
#region Window overrides
protected override void OnSourceInitialized(EventArgs e)
{
base.OnSourceInitialized(e);
// Store the window handle
_hWndSource = PresentationSource.FromVisual(this) as HwndSource;
// Add a hook
_hWndSource?.AddHook(WndProc);
}
protected override void OnClosed(EventArgs e)
{
base.OnClosed(e);
// Unhook the window procedure
_hWndSource?.RemoveHook(WndProc);
_hWndSource?.Dispose();
}
#endregion
#region Window procedure
protected virtual nint WndProc(nint hWnd, int msg, nint wParam, nint lParam, ref bool handled)
{
switch (msg)
{
case (int) PInvoke.WindowMessage.WindowPositionChanging:
return OnWindowPositionChanging(lParam, ref handled);
case (int) PInvoke.WindowMessage.EnterSizeMove:
// Initialize the last window position
_lastWindowPosition = new PInvoke.WindowPosition
{
Left = (int) Left,
Width = (int) Width,
Height = (int) Height,
Top = (int) Top
};
// Store the current other windows
_otherWindows = OtherWindows;
_inSizeMove = true;
break;
case (int) PInvoke.WindowMessage.ExitSizeMove:
_inSizeMove = false;
break;
}
return nint.Zero;
}
#endregion
#region Snapping
private nint OnWindowPositionChanging(nint lParam, ref bool handled)
{
if (!_inSizeMove)
return nint.Zero;
var snapDistance = SnapDistance;
// Initialize whether we've updated the position
var updated = false;
// Convert the lParam into the current structure
var windowPosition = (PInvoke.WindowPosition) Marshal.PtrToStructure(lParam, typeof(PInvoke.WindowPosition))!;
// If the window flags indicate no movement then do nothing
if ((windowPosition.Flags & PInvoke.WindowPositionFlags.NoMove) != 0)
return nint.Zero;
// If nothing changed then do nothing
if (_lastWindowPosition.IsSameLocationAndSize(windowPosition))
return nint.Zero;
// Figure out if the window is being moved or resized
var snapMode = _lastWindowPosition.IsSameSize(windowPosition) ? SnapMode.Move : SnapMode.Resize;
// Figure out what side is resizing
var resizeSide = new ResizeSide(windowPosition, _lastWindowPosition);
// Get the screen the cursor is currently on
var screen = Screen.FromPoint(MouseHelper.MousePosition);
// Create a rectangle based on the current working area of the screen
var snapToBorder = screen.WorkingArea;
// Deflate the rectangle based on the snap distance
snapToBorder.Inflate(-snapDistance, -snapDistance);
if (snapMode == SnapMode.Resize)
{
// See if we need to snap on the left
if (windowPosition.Left < snapToBorder.Left)
{
windowPosition.Width += windowPosition.Left - (int) screen.WorkingArea.Left;
windowPosition.Left = (int) screen.WorkingArea.Left;
updated = true;
}
// See if we need to snap on the right
if (windowPosition.Right > snapToBorder.Right)
{
windowPosition.Width += (int) screen.WorkingArea.Right - windowPosition.Right;
updated = true;
}
// See if we need to snap to the top
if (windowPosition.Top < snapToBorder.Top)
{
windowPosition.Height += windowPosition.Top - (int) screen.WorkingArea.Top;
windowPosition.Top = (int) screen.WorkingArea.Top;
updated = true;
}
// See if we need to snap to the bottom
if (windowPosition.Bottom > snapToBorder.Bottom)
{
windowPosition.Height += (int) screen.WorkingArea.Bottom - windowPosition.Bottom;
updated = true;
}
}
else
{
// See if we need to snap on the left
if (windowPosition.Left < snapToBorder.Left)
{
windowPosition.Left = (int) screen.WorkingArea.Left;
updated = true;
}
// See if we need to snap on the top
if (windowPosition.Top < snapToBorder.Top)
{
windowPosition.Top = (int) screen.WorkingArea.Top;
updated = true;
}
// See if we need to snap on the right
if (windowPosition.Right > snapToBorder.Right)
{
windowPosition.Left = (int) screen.WorkingArea.Right - windowPosition.Width;
updated = true;
}
// See if we need to snap on the bottom
if (windowPosition.Bottom > snapToBorder.Bottom)
{
windowPosition.Top = (int) screen.WorkingArea.Bottom - windowPosition.Height;
updated = true;
}
}
var otherWindows = _otherWindows;
if (otherWindows is { Count: > 0 })
{
// Get the snap source rectangles for the window being changed
var sourceRectangles = new WindowBorderRectangles(windowPosition, 1, false);
// Loop over all other windows looking to see if we should stick
foreach (var otherWindow in otherWindows)
{
// Get a rectangle with the bounds of the other window
var otherWindowRect = otherWindow.Location;
// Get the snap target rectangles for the current window
var targetRectangles = new WindowBorderRectangles(otherWindow.Location, snapDistance, true);
if (snapMode == SnapMode.Move)
{
if (sourceRectangles.Left.IntersectsWith(targetRectangles.Right))
{
windowPosition.Left = otherWindowRect.Right;
updated = true;
}
if (sourceRectangles.Right.IntersectsWith(targetRectangles.Left))
{
windowPosition.Left = otherWindowRect.Left - windowPosition.Width;
updated = true;
}
if (sourceRectangles.Top.IntersectsWith(targetRectangles.Bottom))
{
windowPosition.Top = otherWindowRect.Bottom;
updated = true;
}
if (sourceRectangles.Bottom.IntersectsWith(targetRectangles.Top))
{
windowPosition.Top = otherWindowRect.Top - windowPosition.Height;
updated = true;
}
if (windowPosition.Top == otherWindowRect.Bottom || windowPosition.Bottom == otherWindowRect.Top)
{
if (Math.Abs(windowPosition.Left - otherWindowRect.Left) <= snapDistance)
{
windowPosition.Left = otherWindowRect.Left;
updated = true;
}
if (Math.Abs(windowPosition.Right - otherWindowRect.Right) <= snapDistance)
{
windowPosition.Left = otherWindowRect.Right - windowPosition.Width;
updated = true;
}
}
if (windowPosition.Left == otherWindowRect.Right || windowPosition.Right == otherWindowRect.Left)
{
if (Math.Abs(otherWindowRect.Bottom - windowPosition.Bottom) <= snapDistance)
{
windowPosition.Top = otherWindowRect.Bottom - windowPosition.Height;
updated = true;
}
if (Math.Abs(otherWindowRect.Top - windowPosition.Top) <= snapDistance)
{
windowPosition.Top = otherWindowRect.Top;
updated = true;
}
}
}
else
{
if (resizeSide.IsLeft)
{
// Check the current window left against the other window right
if (sourceRectangles.Left.IntersectsWith(targetRectangles.Right))
{
var sign = windowPosition.Left < otherWindowRect.Right ? -1 : 1;
windowPosition.Width += Math.Abs(otherWindowRect.Right - windowPosition.Left) * sign;
windowPosition.Left = otherWindowRect.Right;
updated = true;
}
else if (windowPosition.Top == otherWindowRect.Bottom || windowPosition.Bottom == otherWindowRect.Top)
{
if (Math.Abs(windowPosition.Left - otherWindowRect.Left) <= snapDistance)
{
var sign = windowPosition.Left < otherWindowRect.Left ? -1 : 1;
windowPosition.Width += Math.Abs(otherWindowRect.Left - windowPosition.Left) * sign;
windowPosition.Left = otherWindowRect.Left;
updated = true;
}
}
}
else if (resizeSide.IsRight)
{
// Check the current window right against the other window left
if (sourceRectangles.Right.IntersectsWith(targetRectangles.Left))
{
var sign = windowPosition.Right < otherWindowRect.Left ? 1 : -1;
windowPosition.Width += Math.Abs(otherWindowRect.Left - windowPosition.Right) * sign;
updated = true;
}
else if (windowPosition.Top == otherWindowRect.Bottom || windowPosition.Bottom == otherWindowRect.Top)
{
if (Math.Abs(windowPosition.Right - otherWindowRect.Right) <= snapDistance)
{
var sign = windowPosition.Right < otherWindowRect.Right ? 1 : -1;
windowPosition.Width += Math.Abs(otherWindowRect.Right - windowPosition.Right) * sign;
updated = true;
}
}
}
if (resizeSide.IsBottom)
{
// Check the current window bottom against the other window top
if (sourceRectangles.Bottom.IntersectsWith(targetRectangles.Top))
{
var sign = windowPosition.Bottom < otherWindowRect.Top ? 1 : -1;
windowPosition.Height += Math.Abs(otherWindowRect.Top - windowPosition.Bottom) * sign;
updated = true;
}
else if (windowPosition.Left == otherWindowRect.Right || windowPosition.Right == otherWindowRect.Left)
{
if (Math.Abs(otherWindowRect.Bottom - windowPosition.Bottom) <= snapDistance)
{
var sign = windowPosition.Bottom < otherWindowRect.Bottom ? 1 : -1;
windowPosition.Height += Math.Abs(otherWindowRect.Bottom - windowPosition.Bottom) * sign;
updated = true;
}
}
}
else if (resizeSide.IsTop)
{
// Check the current window top against the other window bottom
if (sourceRectangles.Top.IntersectsWith(targetRectangles.Bottom))
{
var sign = windowPosition.Top < otherWindowRect.Bottom ? 1 : -1;
windowPosition.Height -= Math.Abs(otherWindowRect.Bottom - windowPosition.Top) * sign;
windowPosition.Top = otherWindowRect.Bottom;
updated = true;
}
else if (windowPosition.Left == otherWindowRect.Right || windowPosition.Right == otherWindowRect.Left)
{
if (Math.Abs(otherWindowRect.Top - windowPosition.Top) <= snapDistance)
{
var sign = windowPosition.Top < otherWindowRect.Top ? -1 : 1;
windowPosition.Height += Math.Abs(otherWindowRect.Top - windowPosition.Top) * sign;
windowPosition.Top = otherWindowRect.Top;
updated = true;
}
}
}
}
}
}
// Update the last window position
_lastWindowPosition = windowPosition;
if (!updated) return nint.Zero;
Marshal.StructureToPtr(windowPosition, lParam, true);
handled = true;
return nint.Zero;
}
#endregion
}
}