alternate ntp: implement right-aligned search token

chrome/browser/ui/views/location_bar/location_bar_layout.cc

 // Copyright (c) 2012 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 "chrome/browser/ui/views/location_bar/location_bar_layout.h"
 
 #include "chrome/browser/ui/views/location_bar/location_bar_view.h"
 #include "ui/gfx/rect.h"
 #include "ui/views/view.h"
 
+namespace {
+
+enum DecorationType {
+  // Decoration is always visible.
+  NORMAL = 0,
+  // If there is not enough available space in the location bar, the decoration
+  // will reduce its width either to its minimal width or to zero (making it
+  // invisible), whichever fits.  |LocationBarDecoration::max_fraction| must be
+  // 0.
+  AUTO_COLLAPSE,
+  // Decoration is a separator, only visible if it's not leading, or not
+  // trailing, or not next to another separator.
+  SEPARATOR,
+};
+
+}  // namespace
+
+
 // Description of a decoration to be added inside the location bar, either to
 // the left or to the right.
 struct LocationBarDecoration {
-  LocationBarDecoration(int y,
+  LocationBarDecoration(DecorationType type,
+                        int y,
                         int height,
-                        bool auto_collapse,
                         double max_fraction,
                         int edge_item_padding,
                         int item_padding,
                         int builtin_padding,
                         views::View* view);
 
+  // The type of decoration.
+  DecorationType type;
+
   // The y position of the view inside its parent.
   int y;
 
   // If 0, will use the preferred height of the view.
   int height;
 
-  // True means that, if there is not enough available space in the location
-  // bar, the view will reduce its width either to its minimal width or to zero
-  // (making it invisible), whichever fits. If true, |max_fraction| must be 0.
-  bool auto_collapse;
-
   // Used for resizeable decorations, indicates the maximum fraction of the
   // location bar that can be taken by this decoration, 0 for non-resizable
-  // decorations. If non-zero, |auto_collapse| must be false.
+  // decorations. If non-zero, |type| must not be AUTO_COLLAPSE.
   double max_fraction;
 
   // Padding to use if the decoration is the first element next to the edge.
   int edge_item_padding;
 
   // Padding to use if the decoration follows another decoration.
   int item_padding;
 
   // Padding built into the decoration and that should be removed, on
   // both sides, during layout.
   int builtin_padding;
 
   views::View* view;
 
   // The width computed by the layout process.
   double computed_width;
 };
 
-LocationBarDecoration::LocationBarDecoration(int y,
+LocationBarDecoration::LocationBarDecoration(DecorationType type,
+                                             int y,
                                              int height,
-                                             bool auto_collapse,
                                              double max_fraction,
                                              int edge_item_padding,
                                              int item_padding,
                                              int builtin_padding,
                                              views::View* view)
-    : y(y),
+    : type(type),
+      y(y),
       height(height),
-      auto_collapse(auto_collapse),
       max_fraction(max_fraction),
       edge_item_padding(edge_item_padding),
       item_padding(item_padding),
       builtin_padding(builtin_padding),
       view(view),
       computed_width(0) {
-  DCHECK(!auto_collapse || max_fraction == 0.0);
+  DCHECK(type != AUTO_COLLAPSE || max_fraction == 0.0);

[beaudoin, 2013/01/12 05:47:15]

DCHECK(type == NORMAL || max_fraction == 0.0);

[kuan, 2013/01/14 16:47:47]

Done.

   DCHECK(max_fraction >= 0.0);
 }
 
 
 // LocationBarLayout ---------------------------------------------------------
 
 LocationBarLayout::LocationBarLayout(Position position,
                                      int item_edit_padding,
                                      int edge_edit_padding)
     : position_(position),
       item_edit_padding_(item_edit_padding),
       edge_edit_padding_(edge_edit_padding) {}
 
 
 LocationBarLayout::~LocationBarLayout() {
 }
 
 void LocationBarLayout::AddDecoration(int y,
                                       int height,
                                       bool auto_collapse,
                                       double max_fraction,
                                       int edge_item_padding,
                                       int item_padding,
                                       int builtin_padding,
                                       views::View* view) {
-  decorations_.push_back(new LocationBarDecoration(y, height, auto_collapse,
-      max_fraction, edge_item_padding, item_padding, builtin_padding, view));
+  decorations_.push_back(new LocationBarDecoration(
+      auto_collapse ? AUTO_COLLAPSE : NORMAL, y, height, max_fraction,
+      edge_item_padding, item_padding, builtin_padding, view));
 }
 
 void LocationBarLayout::AddDecoration(int height,
                                       int builtin_padding,
                                       views::View* view) {
-  decorations_.push_back(new LocationBarDecoration(
-      LocationBarView::kVerticalEdgeThickness, height, false, 0,
+  decorations_.push_back(new LocationBarDecoration(NORMAL,
+      LocationBarView::kVerticalEdgeThickness, height, 0,
       LocationBarView::GetEdgeItemPadding(), LocationBarView::GetItemPadding(),
       builtin_padding, view));
 }
 
+void LocationBarLayout::AddSeparator(int y,
+                                     int height,
+                                     int padding,
+                                     views::View* view) {
+  // Edge item padding won't apply since a separator won't be by the edge, so
+  // use the same as item padding to simplify calculation in LayoutPass1().
+  decorations_.push_back(new LocationBarDecoration(SEPARATOR, y, height, 0,
+      padding, padding, 0, view));

[beaudoin, 2013/01/12 05:47:15]

edge_item_padding can be 0 because edge separators will necessarily be removed.
It's not a big deal but it will lead to slightly more accurate evaluation of
entry_width in Pass1.

[kuan, 2013/01/14 16:47:47]

Done.

+}
+
 void LocationBarLayout::LayoutPass1(int* entry_width) {
-
   bool first_item = true;
   bool at_least_one_visible = false;
   for (ScopedVector<LocationBarDecoration>::iterator it(decorations_.begin());
        it != decorations_.end(); ++it) {
     // Autocollapsing decorations are ignored in this pass.
-    if (!(*it)->auto_collapse) {
+    if ((*it)->type != AUTO_COLLAPSE) {
       at_least_one_visible = true;
       *entry_width -= -2 * (*it)->builtin_padding +
           (first_item ? (*it)->edge_item_padding : (*it)->item_padding);
     }
     first_item = false;
     // Resizing decorations are ignored in this pass.
-    if (!(*it)->auto_collapse && (*it)->max_fraction == 0.0) {
+    if ((*it)->type != AUTO_COLLAPSE && (*it)->max_fraction == 0.0) {
       (*it)->computed_width = (*it)->view->GetPreferredSize().width();
       *entry_width -= (*it)->computed_width;
     }
   }
   *entry_width -= at_least_one_visible ? item_edit_padding_ :
       edge_edit_padding_;
 }
 
 void LocationBarLayout::LayoutPass2(int *entry_width) {
   for (ScopedVector<LocationBarDecoration>::iterator it(decorations_.begin());
        it != decorations_.end(); ++it) {
     if ((*it)->max_fraction > 0.0) {
       int max_width = static_cast<int>(*entry_width * (*it)->max_fraction);
       (*it)->computed_width = std::min((*it)->view->GetPreferredSize().width(),
           std::max((*it)->view->GetMinimumSize().width(), max_width));
       *entry_width -= (*it)->computed_width;
     }
   }
 }
 
 void LocationBarLayout::LayoutPass3(gfx::Rect* bounds, int* available_width) {
+  SetVisibilityForDecorations(available_width);
+  SetSeparatorsInvisible(available_width);
+  SetBoundsForDecorations(bounds);
+}
+
+void LocationBarLayout::SetVisibilityForDecorations(int* available_width) {
   bool first_visible = true;
   for (ScopedVector<LocationBarDecoration>::iterator it(decorations_.begin());
        it != decorations_.end(); ++it) {
     // Collapse decorations if needed.
-    if ((*it)->auto_collapse) {
+    if ((*it)->type == AUTO_COLLAPSE) {
       int padding = -2 * (*it)->builtin_padding +
           (first_visible ? (*it)->edge_item_padding : (*it)->item_padding);
-      // Try preferred size, if it fails try minimum size, if it fails collapse.
+      // Try preferred size, if it fails try minimum size, if it fails
+      // collapse.
       (*it)->computed_width = (*it)->view->GetPreferredSize().width();
       if ((*it)->computed_width + padding > *available_width)
         (*it)->computed_width = (*it)->view->GetMinimumSize().width();
       if ((*it)->computed_width + padding > *available_width) {
         (*it)->computed_width = 0;
         (*it)->view->SetVisible(false);
       } else {
         (*it)->view->SetVisible(true);
         (*available_width) -= (*it)->computed_width + padding;
       }
     } else {
       (*it)->view->SetVisible(true);
     }
-    // Layout visible decorations.
-    if ((*it)->view->visible()) {
-      int padding = -(*it)->builtin_padding +
-          (first_visible ? (*it)->edge_item_padding : (*it)->item_padding);
+
+    if ((*it)->view->visible())
       first_visible = false;
-      int x;
-      if (position_ == LEFT_EDGE)
-        x = bounds->x() + padding;
-      else
-        x = bounds->x() + bounds->width() - padding - (*it)->computed_width;
-      int height = (*it)->height == 0 ?
-          (*it)->view->GetPreferredSize().height() : (*it)->height;
-      (*it)->view->SetBounds(x, (*it)->y, (*it)->computed_width, height);
-      bounds->set_width(bounds->width() - padding - (*it)->computed_width +
-                        (*it)->builtin_padding);
-      if (position_ == LEFT_EDGE) {
-        bounds->set_x(bounds->x() + padding + (*it)->computed_width -
+  }
+}
+
+void LocationBarLayout::SetSeparatorsInvisible(int* available_width) {

[beaudoin, 2013/01/12 05:47:15]

Maybe rename to: HideUnneededSeparators

[kuan, 2013/01/14 16:47:47]

Done.

+  ScopedVector<LocationBarDecoration>::iterator prev = decorations_.end();
+  ScopedVector<LocationBarDecoration>::iterator last_visible_separator =
+      decorations_.end();
+  ScopedVector<LocationBarDecoration>::iterator last_visible_decoration =
+      decorations_.end();
+  for (ScopedVector<LocationBarDecoration>::iterator it(decorations_.begin());
+       it != decorations_.end(); ++it) {
+    if ((*it)->type == SEPARATOR) {
+      bool visible = prev != decorations_.end() &&  // Not first item.
+          // Previous item is a visible non-spearator decoration.

[beaudoin, 2013/01/12 05:47:15]

typo: separator

[kuan, 2013/01/14 16:47:47]

Done.

+          ((*prev)->type != SEPARATOR && (*prev)->view->visible());

[beaudoin, 2013/01/12 05:47:15]

Not sure the logic is correct here. If the list is:
  Decorator (visible), Decorator (not-visible), Separator, Decorator (visible)
Then visible = false, but you would like it to be visible.

Instead of "prev" consider initialising outside the loop:
bool last_visible_was_a_separator = false;

Then, inside the loop:
if ((*it)->type == SEPARATOR) {
  if (last_visible_was_a_separator) {
    // Hide this separator.
  } else {
    // Show this separator.
  }
} else if ((*it)->view->visible()) {
  last_visible_was_a_separator = false;
}

[kuan, 2013/01/14 16:47:47]

Done.  i added one more bool at_least_one_non_separator_visible to track leading
separator.

[beaudoin, 2013/01/14 18:12:14]

I though last_visible_was_a_separator would be enough? Start it at "true" and
the leading separators should be hidden.

[kuan, 2013/01/14 18:33:11]

Done.  i thot of that, but worried that it might be misleading to init that to
true; i added comment as to why it's init to true.

+      if (!visible) {
+        (*it)->view->SetVisible(false);
+        // Add back what was subtracted when setting this separator visible in
+        // LayoutPass1().
+        (*available_width) += (*it)->item_padding + (*it)->computed_width;
+      } else {
+        DCHECK(last_visible_decoration != decorations_.end());
+        last_visible_separator = it;
+      }
+    } else if ((*it)->view->visible()) {
+      last_visible_decoration = it;
+    }
+    prev = it;
+  }
+  // If last visible separator is trailing, hide it.
+  if (last_visible_separator != decorations_.end() &&
+      last_visible_separator > last_visible_decoration) {

[beaudoin, 2013/01/12 05:47:15]

I think it would be simpler to keep just one extra iterator:
  trailing_separator
In the loop, set
  trailing_separator = it;
when you have a visible separator and set
  trailing_separator = decorations_.end()
when you have a visible decoration.

Then you just have to check if trailing_separator != decorations_.end()

[kuan, 2013/01/14 16:47:47]

Done.

+    (*last_visible_separator)->view->SetVisible(false);
+    // Add back what was subtracted when setting this separator visible in
+    // LayoutPass1().
+    (*available_width) += (*last_visible_separator)->item_padding +
+                          (*last_visible_separator)->computed_width;
+  }
+}
+
+void LocationBarLayout::SetBoundsForDecorations(gfx::Rect* bounds) {
+  bool first_visible = true;
+  for (ScopedVector<LocationBarDecoration>::iterator it(decorations_.begin());
+       it != decorations_.end(); ++it) {
+     if (!(*it)->view->visible())
+       continue;

[beaudoin, 2013/01/12 05:47:15]

indentation (2 lines above)

[kuan, 2013/01/14 16:47:47]

Done.

+    int padding = -(*it)->builtin_padding +
+        (first_visible ? (*it)->edge_item_padding : (*it)->item_padding);
+    first_visible = false;
+    int x;
+    if (position_ == LEFT_EDGE)
+      x = bounds->x() + padding;
+    else
+      x = bounds->right() - padding - (*it)->computed_width;
+    int height = (*it)->height == 0 ?
+        (*it)->view->GetPreferredSize().height() : (*it)->height;
+    (*it)->view->SetBounds(x, (*it)->y, (*it)->computed_width, height);
+    bounds->set_width(bounds->width() - padding - (*it)->computed_width +
                       (*it)->builtin_padding);
-      }
+    if (position_ == LEFT_EDGE) {
+      bounds->set_x(bounds->x() + padding + (*it)->computed_width -
+                    (*it)->builtin_padding);
     }
   }
   int final_padding = first_visible ? edge_edit_padding_ : item_edit_padding_;
   bounds->set_width(bounds->width() - final_padding);
   if (position_ == LEFT_EDGE)
     bounds->set_x(bounds->x() + final_padding);
 }