Left-Align Tooltips

ui/views/corewm/tooltip_aura.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/corewm/tooltip_aura.h"
 
 #include "base/strings/string_split.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/gfx/screen.h"
@@ skipping 24 matching lines @@
   // auto-parented to the right container.
   params.type = views::Widget::InitParams::TYPE_TOOLTIP;
   params.context = tooltip_window;
   DCHECK(params.context);
   params.keep_on_top = true;
   params.accept_events = false;
   widget->Init(params);
   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 {
 namespace corewm {
 
 TooltipAura::TooltipAura(gfx::ScreenType screen_type)
     : screen_type_(screen_type),
       widget_(NULL),
       tooltip_window_(NULL) {
   label_.set_owned_by_client();
@@ skipping 128 matching lines @@
 void TooltipAura::SetText(aura::Window* window,
                           const base::string16& tooltip_text,
                           const gfx::Point& location) {
   tooltip_window_ = window;
   int max_width = 0;
   int line_count = 0;
   base::string16 trimmed_text(tooltip_text);
   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_);
     widget_->SetContentsView(&label_);
     widget_->AddObserver(this);
   }
 
   label_.SizeToFit(max_width + label_.GetInsets().width());
   SetTooltipBounds(location, label_.size());
 
@@ skipping 26 matching lines @@
 }
 
 void TooltipAura::OnWidgetDestroying(views::Widget* widget) {
   DCHECK_EQ(widget_, widget);
   widget_ = NULL;
   tooltip_window_ = NULL;
 }
 
 }  // namespace corewm
 }  // namespace views