Left-Align Tooltips

ui/views/corewm/tooltip_aura.cc

Index: ui/views/corewm/tooltip_aura.cc
diff --git a/ui/views/corewm/tooltip_aura.cc b/ui/views/corewm/tooltip_aura.cc
index 02117a8593d11df38dc6cf2a98e4d8a0ff0d50e8..27179e09ece82d4842ec243327d6594fe485c832 100644
--- a/ui/views/corewm/tooltip_aura.cc
+++ b/ui/views/corewm/tooltip_aura.cc
@@ -42,6 +42,26 @@ views::Widget* CreateTooltipWidget(aura::Window* tooltip_window) {
   return widget;
 }
 
+// Returns the appropriate label alignment based on the Locale direction and the
+// text direction.
+gfx::HorizontalAlignment GetTextHorizontalAlignment(const base::string16 text) {
+  base::i18n::TextDirection dir = base::i18n::GetStringDirection(text);

[sky, 2015/01/28 21:24:59]

I think you should be able to set the alignment to LEFT and have everything just
work. In other words it seems like label so deal with rtl and alignment for
text.

[afakhry, 2015/01/28 21:36:13]

That's true, but Label::SetHorizontalAlignment() only takes into account the
RTL/LTR of the UI, but the text directionality is ignored.

So for example, if the UI is set to be RTL,
Label::SetHorizontalAlignment(ALIGN_LEFT) will actually align right for all
texts. If we have a tool tip in English and the UI is in Arabic, the English
tooltip will be aligned right (which is wrong).

Similarly, if we have the UI in English, and a Tool tip in Arabic, Aligning left
will still align the Arabic tool tip left (which is also wrong).

+  gfx::HorizontalAlignment result = gfx::ALIGN_LEFT;
+
+  // The Label::SetHorizontalAlignment() will interpret right as left and vice
+  // versa based on the UI layout. we need to account for that when the text
+  // itself needs to be aligned in the opposite direction.
+  if (base::i18n::IsRTL()) {
+    result = (dir == base::i18n::RIGHT_TO_LEFT) ?
+        gfx::ALIGN_LEFT : gfx::ALIGN_RIGHT;
+  } else {
+    result = (dir == base::i18n::RIGHT_TO_LEFT) ?
+        gfx::ALIGN_RIGHT : gfx::ALIGN_LEFT;
+  }
+
+  return result;
+}
+
 }  // namespace
 
 namespace views {
@@ -190,6 +210,7 @@ void TooltipAura::SetText(aura::Window* window,
   TrimTooltipToFit(label_.font_list(), GetMaxWidth(location), &trimmed_text,
                    &max_width, &line_count);
   label_.SetText(trimmed_text);
+  label_.SetHorizontalAlignment(GetTextHorizontalAlignment(trimmed_text));
 
   if (!widget_) {
     widget_ = CreateTooltipWidget(tooltip_window_);