From f2b35fb7dc0b69ce60e740f2305f6ae510adbee3 Mon Sep 17 00:00:00 2001
From: kornes <28986062+kornes@users.noreply.github.com>
Date: Fri, 25 Nov 2022 20:32:45 +0000
Subject: [PATCH] Fix white border appearing around maximized window (#4190)

Co-authored-by: pajlada <rasmus.karlsson@pajlada.com>
fixes https://github.com/Chatterino/chatterino2/issues/2205
---
 CHANGELOG.md               |  1 +
 src/widgets/BaseWindow.cpp | 21 ++++++++++-----------
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2b803e1dc..81d0f6857 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@
 - Bugfix: Fixed messages where Right-to-Left order is mixed in multiple lines. (#4173)
 - Bugfix: Fixed the wrong right-click menu showing in the chat input box. (#4177)
 - Bugfix: Fixed popup windows not appearing/minimizing correctly on the Windows taskbar. (#4181)
+- Bugfix: Fixed white border appearing around maximized window on Windows. (#4190)
 
 ## 2.4.0-beta
 
diff --git a/src/widgets/BaseWindow.cpp b/src/widgets/BaseWindow.cpp
index 06fa9c07d..ef0ca8412 100644
--- a/src/widgets/BaseWindow.cpp
+++ b/src/widgets/BaseWindow.cpp
@@ -793,8 +793,9 @@ bool BaseWindow::handleSHOWWINDOW(MSG *msg)
         {
             this->shown_ = true;
 
-            const MARGINS shadow = {8, 8, 8, 8};
-            DwmExtendFrameIntoClientArea(HWND(this->winId()), &shadow);
+            // disable OS window border
+            const MARGINS margins = {-1};
+            DwmExtendFrameIntoClientArea(HWND(this->winId()), &margins);
         }
         if (!this->initalBounds_.isNull())
         {
@@ -819,17 +820,15 @@ bool BaseWindow::handleNCCALCSIZE(MSG *msg, long *result)
 #ifdef USEWINSDK
     if (this->hasCustomWindowFrame())
     {
-        // int cx = GetSystemMetrics(SM_CXSIZEFRAME);
-        // int cy = GetSystemMetrics(SM_CYSIZEFRAME);
-
         if (msg->wParam == TRUE)
         {
-            NCCALCSIZE_PARAMS *ncp =
-                (reinterpret_cast<NCCALCSIZE_PARAMS *>(msg->lParam));
-            ncp->lppos->flags |= SWP_NOREDRAW;
-            RECT *clientRect = &ncp->rgrc[0];
-
-            clientRect->top -= 1;
+            // remove 1 extra pixel on top of custom frame
+            auto *ncp = reinterpret_cast<NCCALCSIZE_PARAMS *>(msg->lParam);
+            if (ncp)
+            {
+                ncp->lppos->flags |= SWP_NOREDRAW;
+                ncp->rgrc[0].top -= 1;
+            }
         }
 
         *result = 0;