tor-browser

commit 6c760e75d2d1b4e5d17cb48d2a15a79e098ddb33
parent b281825aa31abcd936405ee269683bcb8ba70e4e
Author: Emilio Cobos Álvarez <emilio@crisal.io>
Date:   Tue, 16 Dec 2025 12:59:45 +0000

Bug 2001722 - Simplify X11 client margin computation. r=stransky

If there's no client area we're using topLevelBounds, but that's not
right since we expect the bounds to be relative to topLevelBounds (i.e.,
the bounds should've been moved to 0, 0.).

Fix the issue, but also derive the client margin from the client area
rather than the other way around, to avoid this mistake causing just
missing content.

This matches what we do for wayland and in general should be saner.

Differential Revision: https://phabricator.services.mozilla.com/D276552

Diffstat:
M
widget/gtk/nsWindow.cpp
 | 
66
++++++++++++++++++++++++------------------------------------------

1 file changed, 24 insertions(+), 42 deletions(-)
diff --git a/widget/gtk/nsWindow.cpp b/widget/gtk/nsWindow.cpp
@@ -3405,7 +3405,7 @@ void nsWindow::RecomputeBoundsX11(bool aMayChangeCsdMargin) {
     return result;
   };
 
-  // Window position and size with decoration byt WITHOUT system titlebar.
+  // Window position and size with decoration but WITHOUT system titlebar.
   auto GetBounds = [&](GdkWindow* aWin) {
     GdkRectangle b{0};
     if (IsTopLevelWidget() && aWin == toplevel) {
@@ -3428,57 +3428,39 @@ void nsWindow::RecomputeBoundsX11(bool aMayChangeCsdMargin) {
              ToString(toplevelBoundsWithTitlebar).c_str());
   LOGVERBOSE("  toplevelBounds %s", ToString(toplevelBounds).c_str());
 
-  // Unscaled bounds include decorations and titlebar (X11)
-  DesktopIntRect finalBounds = [&] {
-    auto bounds = toplevelBoundsWithTitlebar;
-    // The toplevelBoundsWithTitlebar should always really be as wide as the
-    // toplevel bounds, but when opening multiple windows in quick succession on
-    // X11 they might not (see bug 1988787). This prevents having a really small
-    // window in such case.
-    bounds.width = std::max(bounds.width, toplevelBounds.width);
-    bounds.height = std::max(bounds.height, toplevelBounds.height);
-    return bounds;
-  }();
-  LOGVERBOSE("  finalBounds %s", ToString(finalBounds).c_str());
+  // Offset from system decoration to gtk decoration.
+  const auto systemDecorationOffset =
+      toplevelBounds.TopLeft() - toplevelBoundsWithTitlebar.TopLeft();
+
+  // This is relative to our parent window, that is, to topLevelBounds.
+  mClientArea = GetBounds(mGdkWindow);
+  // Make it relative to topLevelBoundsWithTitlebar
+  mClientArea.MoveBy(systemDecorationOffset);
+  LOGVERBOSE("  mClientArea %s", ToString(mClientArea).c_str());
+
+  if (mClientArea.X() < 0 || mClientArea.Y() < 0 || mClientArea.Width() <= 1 ||
+      mClientArea.Height() <= 1) {
+    // If we don't have gdkwindow bounds, assume we take the whole toplevel
+    // except system decorations.
+    mClientArea = DesktopIntRect(systemDecorationOffset, toplevelBounds.Size());
+  }
+
   const bool decorated =
       IsTopLevelWidget() && mSizeMode != nsSizeMode_Fullscreen && !mUndecorated;
-  LOGVERBOSE("  decorated %d", decorated);
   if (!decorated) {
     mClientMargin = {};
   } else if (aMayChangeCsdMargin) {
-    // TODO: Do we really need so complex margin calculation on X11?
-    const DesktopIntRect clientRectRelativeToFrame = [&] {
-      auto topLevelBoundsRelativeToFrame = toplevelBounds;
-      topLevelBoundsRelativeToFrame -= toplevelBoundsWithTitlebar.TopLeft();
-
-      LOGVERBOSE("  topLevelBoundsRelativeToFrame %s",
-                 ToString(topLevelBoundsRelativeToFrame).c_str());
-      if (!mGdkWindow) {
-        return topLevelBoundsRelativeToFrame;
-      }
-      auto gdkWindowBounds = GetBounds(mGdkWindow);
-      if (gdkWindowBounds.X() < 0 || gdkWindowBounds.Y() < 0 ||
-          gdkWindowBounds.Width() <= 1 || gdkWindowBounds.Height() <= 1) {
-        // If we don't have gdkwindow bounds, assume we take the whole toplevel.
-        return topLevelBoundsRelativeToFrame;
-      }
-      LOGVERBOSE("  gdkWindowBounds %s", ToString(gdkWindowBounds).c_str());
-      // gdkWindowBounds is relative to topLevelBounds already.
-      return gdkWindowBounds + topLevelBoundsRelativeToFrame.TopLeft();
-    }();
-
-    auto relative = clientRectRelativeToFrame;
-    LOGVERBOSE("  clientRectRelativeToFrame %s", ToString(relative).c_str());
-    mClientMargin = DesktopIntRect(DesktopIntPoint(), finalBounds.Size()) -
-                    clientRectRelativeToFrame;
-    LOGVERBOSE("  mClientMargin %s", ToString(mClientMargin).c_str());
+    mClientMargin =
+        DesktopIntRect(DesktopIntPoint(), toplevelBoundsWithTitlebar.Size()) -
+        mClientArea;
     mClientMargin.EnsureAtLeast(DesktopIntMargin());
   } else {
     // Assume the client margin remains the same.
   }
 
-  mClientArea = finalBounds;
-  mClientArea.Deflate(mClientMargin);
+  // We want mClientArea in global coordinates. We derive everything from here,
+  // so move it to global coords.
+  mClientArea.MoveBy(toplevelBoundsWithTitlebar.TopLeft());
 }
 #endif
 #ifdef MOZ_WAYLAND