Bug 1712669 - Make Windows tooltip margin depend on cursor size. r=yjuglaret,win-reviewers,desktop-theme-reviewers,dao

I think we should start off with this. Other platforms can implement
this too, but exposing this to content seems like quite the rabbit hole.

Differential Revision: https://phabricator.services.mozilla.com/D203405

layout/xul/nsMenuPopupFrame.cpp

@@ -2186,6 +2186,12 @@ nsMargin nsMenuPopupFrame::GetMargin() const {
     margin.left += auOffset.x;
     margin.right += auOffset.x;
   }
+  if (mPopupType == PopupType::Tooltip) {
+    const auto auOffset =
+        CSSPixel::ToAppUnits(LookAndFeel::TooltipOffsetVertical());
+    margin.top += auOffset;
+    margin.bottom += auOffset;
+  }
   return margin;
 }
 

toolkit/content/tests/chrome/window_tooltip.xhtml

@@ -30,6 +30,8 @@ var gOriginalWidth = -1;
 var gOriginalHeight = -1;
 var gButton = null;
 
+const kTooltipOffsetVertical = 10;
+
 function runTest()
 {
   startPopupTests(popupTests);
@@ -112,7 +114,7 @@ var popupTests = [
        Math.round(buttonrect.left + parseFloat(popupstyle.marginLeft) + 6),
        testname + " left position of tooltip");
     is(Math.round(rect.top),
-       Math.round(buttonrect.top + parseFloat(popupstyle.marginTop) + 6),
+       Math.round(buttonrect.top + parseFloat(popupstyle.marginTop) + 6 + kTooltipOffsetVertical),
        testname + " top position of tooltip");
 
     var labelrect = document.getElementById("label").getBoundingClientRect();
@@ -159,7 +161,7 @@ var popupTests = [
        Math.round(buttonrect.left + parseFloat(popupstyle.marginLeft) + 4),
        testname + " left position of tooltip");
     is(Math.round(rect.top),
-       Math.round(buttonrect.top + parseFloat(popupstyle.marginTop) + 4),
+       Math.round(buttonrect.top + parseFloat(popupstyle.marginTop) + 4 + kTooltipOffsetVertical),
        testname + " top position of tooltip");
 
     var labelrect = document.getElementById("label").getBoundingClientRect();
@@ -204,7 +206,7 @@ var popupTests = [
        Math.round(buttonrect.left + parseFloat(popupstyle.marginLeft) + 6),
        testname + " left position of tooltip");
     is(Math.round(rect.top),
-       Math.round(buttonrect.top + parseFloat(popupstyle.marginTop) + 6),
+       Math.round(buttonrect.top + parseFloat(popupstyle.marginTop) + 6 + kTooltipOffsetVertical),
        testname + " top position of tooltip");
 
     var labelrect = document.getElementById("label").getBoundingClientRect();
@@ -359,7 +361,14 @@ function moveWindowTo(x, y, callback, arg)
   }
 }
 
-window.arguments[0].SimpleTest.waitForFocus(runTest, window);
+(async function() {
+  let parent = window.arguments[0];
+  await Promise.all([
+    parent.SimpleTest.promiseFocus(window),
+    parent.SpecialPowers.pushPrefEnv({set: [["ui.tooltipOffsetVertical", kTooltipOffsetVertical]]}),
+  ]);
+  runTest();
+})();
 ]]>
 </script>
 

toolkit/content/xul.css

@@ -389,10 +389,6 @@ tooltip {
   pointer-events: none;
 }
 
-tooltip:not([position]) {
-  margin-top: 21px;
-}
-
 /**
  * It's important that these styles are in a UA sheet, because the default
  * tooltip is native anonymous content

widget/LookAndFeel.h

@@ -186,6 +186,7 @@ class LookAndFeel {
      */
     ContextMenuOffsetVertical,
     ContextMenuOffsetHorizontal,
+    TooltipOffsetVertical,
 
     /*
      * A boolean value indicating whether client-side decorations are
@@ -321,6 +322,11 @@ class LookAndFeel {
     return GetInt(IntID::UseOverlayScrollbars);
   }
 
+  static constexpr int32_t kDefaultTooltipOffset = 21;
+  static int32_t TooltipOffsetVertical() {
+    return GetInt(IntID::TooltipOffsetVertical, kDefaultTooltipOffset);
+  }
+
   // Returns keyCode value of a modifier key which is used for accesskey.
   // Returns 0 if the platform doesn't support access key.
   static uint32_t GetMenuAccessKey();

widget/nsXPLookAndFeel.cpp

@@ -167,6 +167,7 @@ static const char sIntPrefs[][45] = {
     "ui.scrollbarFadeDuration",
     "ui.contextMenuOffsetVertical",
     "ui.contextMenuOffsetHorizontal",
+    "ui.tooltipOffsetVertical",
     "ui.GtkCSDAvailable",
     "ui.GtkCSDMinimizeButton",
     "ui.GtkCSDMaximizeButton",

widget/windows/nsLookAndFeel.cpp

@@ -36,6 +36,17 @@ static int32_t GetSystemParam(long flag, int32_t def) {
   return ::SystemParametersInfo(flag, 0, &value, 0) ? value : def;
 }
 
+static int32_t GetTooltipOffsetVertical() {
+  static constexpr DWORD kDefaultCursorSize = 32;
+  const DWORD cursorSize =
+      GetSystemParam(MOZ_SPI_CURSORSIZE, kDefaultCursorSize);
+  if (cursorSize == kDefaultCursorSize) {
+    return LookAndFeel::kDefaultTooltipOffset;
+  }
+  return std::ceilf(float(LookAndFeel::kDefaultTooltipOffset) *
+                    float(cursorSize) / float(kDefaultCursorSize));
+}
+
 static bool SystemWantsDarkTheme() {
   if (nsUXThemeData::IsHighContrastOn()) {
     return LookAndFeel::IsDarkColor(
@@ -523,6 +534,9 @@ nsresult nsLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
     case IntID::ContextMenuOffsetHorizontal:
       aResult = 2;
       break;
+    case IntID::TooltipOffsetVertical:
+      aResult = GetTooltipOffsetVertical();
+      break;
     case IntID::SystemUsesDarkTheme:
       aResult = SystemWantsDarkTheme();
       break;

widget/windows/nsLookAndFeel.h

@@ -40,6 +40,10 @@
 #define SYS_COLOR_MAX 30
 #define SYS_COLOR_COUNT (SYS_COLOR_MAX - SYS_COLOR_MIN + 1)
 
+// Undocumented SPI, see bug 1712669 comment 4.
+#define MOZ_SPI_CURSORSIZE 0x2028
+#define MOZ_SPI_SETCURSORSIZE 0x2029
+
 namespace mozilla::widget::WinRegistry {
 class KeyWatcher;
 }

widget/windows/nsWindow.cpp

@@ -78,6 +78,7 @@
 #include <limits>
 
 #include "mozilla/widget/WinMessages.h"
+#include "nsLookAndFeel.h"
 #include "nsWindow.h"
 #include "nsWindowTaskbarConcealer.h"
 #include "nsAppRunner.h"
@@ -4939,10 +4940,12 @@ bool nsWindow::ProcessMessageInternal(UINT msg, WPARAM& wParam, LPARAM& lParam,
 
     case WM_SETTINGCHANGE: {
       if (wParam == SPI_SETCLIENTAREAANIMATION ||
-          wParam == SPI_SETKEYBOARDDELAY || wParam == SPI_SETMOUSEVANISH) {
+          wParam == SPI_SETKEYBOARDDELAY || wParam == SPI_SETMOUSEVANISH ||
+          wParam == MOZ_SPI_SETCURSORSIZE) {
         // These need to update LookAndFeel cached values.
         // They affect reduced motion settings / caret blink count / show
-        // pointer while typing, so no need to invalidate style / layout.
+        // pointer while typing / tooltip offset, so no need to invalidate style
+        // / layout.
         NotifyThemeChanged(widget::ThemeChangeKind::MediaQueriesOnly);
         break;
       }