From f058b08fdebcbe127640482c704f56a6731f27a0 Mon Sep 17 00:00:00 2001
From: Mike Griese <migrie@microsoft.com>
Date: Wed, 28 Jul 2021 17:18:58 -0500
Subject: [PATCH] Account for the window borders when restoring from fullscreen
 (#10737)

## Summary of the Pull Request

When we're restoring from fullscreen, we do a little adjustment to make sure to clamp the window bounds within the bounds of the active monitor. We unfortunately didn't account for the size of the non-client area (the invisible borders around our 1px border). This didn't matter most of the time, but if the window was within ~8px of the side of the monitor (any side), then restoring from fullscreen would actually move it to the wrong place.

As it turns out, the `_quake` window is within ~8px of the edges of the monitor _very often_.

## References
* regressed in #9737

## PR Checklist
* [x] Closes #10199
* [x] I work here
* [ ] Tests added/passed
* [n/a] Requires documentation to be updated

## Validation Steps Performed
The repro in the bug was fairly straightforward. It doesn't happen anymore.
---
 src/cascadia/WindowsTerminal/IslandWindow.cpp | 32 ++++++++++++++-----
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/src/cascadia/WindowsTerminal/IslandWindow.cpp b/src/cascadia/WindowsTerminal/IslandWindow.cpp
index 230b9f6bf..27ed12f1e 100644
--- a/src/cascadia/WindowsTerminal/IslandWindow.cpp
+++ b/src/cascadia/WindowsTerminal/IslandWindow.cpp
@@ -884,23 +884,39 @@ void IslandWindow::_RestoreFullscreenPosition(const RECT rcWork)
                rcWork.left - _rcWorkBeforeFullscreen.left,
                rcWork.top - _rcWorkBeforeFullscreen.top);
 
+    const til::size ncSize{ GetTotalNonClientExclusiveSize(dpiWindow) };
+
+    RECT rcWorkAdjusted = rcWork;
+
+    // GH#10199 - adjust the size of the "work" rect by the size of our borders.
+    // We want to make sure the window is restored within the bounds of the
+    // monitor we're on, but it's totally fine if the invisible borders are
+    // outside the monitor.
+    const auto halfWidth{ ncSize.width<long>() / 2 };
+    const auto halfHeight{ ncSize.height<long>() / 2 };
+
+    rcWorkAdjusted.left -= halfWidth;
+    rcWorkAdjusted.right += halfWidth;
+    rcWorkAdjusted.top -= halfHeight;
+    rcWorkAdjusted.bottom += halfHeight;
+
     // Enforce that our position is entirely within the bounds of our work area.
     // Prefer the top-left be on-screen rather than bottom-right (right before left, bottom before top).
-    if (rcRestore.right > rcWork.right)
+    if (rcRestore.right > rcWorkAdjusted.right)
     {
-        OffsetRect(&rcRestore, rcWork.right - rcRestore.right, 0);
+        OffsetRect(&rcRestore, rcWorkAdjusted.right - rcRestore.right, 0);
     }
-    if (rcRestore.left < rcWork.left)
+    if (rcRestore.left < rcWorkAdjusted.left)
     {
-        OffsetRect(&rcRestore, rcWork.left - rcRestore.left, 0);
+        OffsetRect(&rcRestore, rcWorkAdjusted.left - rcRestore.left, 0);
     }
-    if (rcRestore.bottom > rcWork.bottom)
+    if (rcRestore.bottom > rcWorkAdjusted.bottom)
     {
-        OffsetRect(&rcRestore, 0, rcWork.bottom - rcRestore.bottom);
+        OffsetRect(&rcRestore, 0, rcWorkAdjusted.bottom - rcRestore.bottom);
     }
-    if (rcRestore.top < rcWork.top)
+    if (rcRestore.top < rcWorkAdjusted.top)
     {
-        OffsetRect(&rcRestore, 0, rcWork.top - rcRestore.top);
+        OffsetRect(&rcRestore, 0, rcWorkAdjusted.top - rcRestore.top);
     }
 
     // Show the window at the computed position.