Tracking SelectionBounds for all RenderWidgets on the Browser Side (Mac)

content/browser/renderer_host/text_input_manager.cc

 // Copyright 2016 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 "content/browser/renderer_host/text_input_manager.h"
 
 #include "base/strings/string16.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_view_base.h"
 #include "content/common/view_messages.h"
@@ skipping 43 matching lines @@
 RenderWidgetHostImpl* TextInputManager::GetActiveWidget() const {
   return !!active_view_ ? static_cast<RenderWidgetHostImpl*>(
                               active_view_->GetRenderWidgetHost())
                         : nullptr;
 }
 
 const TextInputState* TextInputManager::GetTextInputState() const {
   return !!active_view_ ? &text_input_state_map_.at(active_view_) : nullptr;
 }
 
-gfx::Rect TextInputManager::GetSelectionBoundsRect() const {
-  if (!active_view_)
-    return gfx::Rect();
-
-  return gfx::RectBetweenSelectionBounds(
-      selection_region_map_.at(active_view_).anchor,
-      selection_region_map_.at(active_view_).focus);
+const TextInputManager::SelectionRegion* TextInputManager::GetSelectionRegion(
+    RenderWidgetHostViewBase* view) const {
+  DCHECK(!view || IsRegistered(view));
+  if (!view)
+    view = active_view_;
+  return view ? &selection_region_map_.at(view) : nullptr;
 }
 
 const TextInputManager::CompositionRangeInfo*
 TextInputManager::GetCompositionRangeInfo(
     RenderWidgetHostViewBase* view) const {
   DCHECK(!view || IsRegistered(view));
   if (!view)
     view = active_view_;
   return active_view_ ? &composition_range_info_map_.at(active_view_) : nullptr;
 }
@@ skipping 61 matching lines @@
 void TextInputManager::ImeCancelComposition(RenderWidgetHostViewBase* view) {
   DCHECK(IsRegistered(view));
   FOR_EACH_OBSERVER(Observer, observer_list_,
                     OnImeCancelComposition(this, view));
 }
 
 void TextInputManager::SelectionBoundsChanged(
     RenderWidgetHostViewBase* view,
     const ViewHostMsg_SelectionBounds_Params& params) {
   DCHECK(IsRegistered(view));
-
-// TODO(ekaramad): Implement the logic for other platforms (crbug.com/578168).
+  // Converting the anchor point to root's coordinate space (for child frame
+  // views).
+  gfx::Point anchor_origin_transformed =
+      view->TransformPointToRootCoordSpace(params.anchor_rect.origin());
 #if defined(USE_AURA)
   gfx::SelectionBound anchor_bound, focus_bound;
-  // Converting the points to the |view|'s root coordinate space (for child
-  // frame views).
-  anchor_bound.SetEdge(gfx::PointF(view->TransformPointToRootCoordSpace(
-                           params.anchor_rect.origin())),
+
+  anchor_bound.SetEdge(gfx::PointF(anchor_origin_transformed),
                        gfx::PointF(view->TransformPointToRootCoordSpace(
                            params.anchor_rect.bottom_left())));
   focus_bound.SetEdge(gfx::PointF(view->TransformPointToRootCoordSpace(
                           params.focus_rect.origin())),
                       gfx::PointF(view->TransformPointToRootCoordSpace(
                           params.focus_rect.bottom_left())));
 
   if (params.anchor_rect == params.focus_rect) {
     anchor_bound.set_type(gfx::SelectionBound::CENTER);
     focus_bound.set_type(gfx::SelectionBound::CENTER);
@@ skipping 16 matching lines @@
       focus_bound.set_type(gfx::SelectionBound::LEFT);
     }
   }
 
   if (anchor_bound == selection_region_map_[view].anchor &&
       focus_bound == selection_region_map_[view].focus)
     return;
 
   selection_region_map_[view].anchor = anchor_bound;
   selection_region_map_[view].focus = focus_bound;
-
+#else
+  if (params.anchor_rect == params.focus_rect) {

[erikchen, 2016/08/17 23:31:16]

When this condition evaluates to false, why don't we need to update caret_rect?
I'm having trouble understanding the relationship between
params.anchor_rect/params.focus_rect and ....caret_rect and
first_selection_rect. Is there documentation/design doc somewhere I can look
into?

[EhsanK, 2016/08/22 14:48:28]

Sadly, I don't know of any. But here is what I figured out:
anchor_rect: First point of entry for selection.
focus_rect: the end of selection, i.e., were caret is now.

When the condition is true there is actually no selection (highlighted text)
which is where the caret is. Hence the caret_rect update.

For the most part, first_selection_rect is pretty much equal to caret_rect. The
only exception I found so far is Katakana IME (Japanese). For this IME, we have
a sequence of 'composition clauses' of different length. If during composition
we use the arrow keys to move in between them, the first selection rect will be
different than caret rect (it will be the beginning of the clause).

+    selection_region_map_[view].caret_rect.set_origin(
+        anchor_origin_transformed);
+    selection_region_map_[view].caret_rect.set_size(params.anchor_rect.size());
+  }
+  selection_region_map_[view].first_selection_rect.set_origin(
+      anchor_origin_transformed);
+  selection_region_map_[view].first_selection_rect.set_size(
+      params.anchor_rect.size());
+#endif  // USE_AURA
   FOR_EACH_OBSERVER(Observer, observer_list_,
                     OnSelectionBoundsChanged(this, view));
-#endif
 }
 
 // TODO(ekaramad): We use |range| only on Mac OS; but we still track its value
 // here for other platforms. See if there is a nice way around this with minimal
 // #ifdefs for platform specific code (https://crbug.com/602427).
 void TextInputManager::ImeCompositionRangeChanged(
     RenderWidgetHostViewBase* view,
     const gfx::Range& range,
     const std::vector<gfx::Rect>& character_bounds) {
   DCHECK(IsRegistered(view));
@@ skipping 100 matching lines @@
 
 TextInputManager::TextSelection::TextSelection()
     : offset(0), range(gfx::Range::InvalidRange()), text(base::string16()) {}
 
 TextInputManager::TextSelection::TextSelection(const TextSelection& other) =
     default;
 
 TextInputManager::TextSelection::~TextSelection() {}
 
 }  // namespace content