Add PanelOverflowStrip to handle panel overflow.

chrome/browser/ui/panels/panel_overflow_strip.cc

+// Copyright (c) 2011 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/panels/panel_overflow_strip.h"
+
+#include "base/logging.h"
+#include "chrome/browser/ui/panels/panel_manager.h"
+#include "chrome/browser/ui/panels/panel_mouse_watcher.h"
+#include "chrome/browser/ui/panels/panel_strip.h"
+#include "ui/base/animation/slide_animation.h"
+
+namespace {
+// The width of the overflow area that is expanded to show more info, i.e.
+// titles, when the mouse hovers over the area.
+const int kOverflowAreaOverWidth = 200;

[jennb, 2011/12/02 21:16:58]

kOverflowStripExpandedWidth? kOverflowStripShowingTitlesWidth?  (everywhere
else, you call it titles-showing or showing-titles. "OverWidth" doesn't convey
any meaning to me.

[jianli, 2011/12/02 23:23:46]

Fixed. I mean kOverflowAreaHoverWidth indeed.

+
+// Maximium number of overflow panels allowed to show.

[jennb, 2011/12/02 21:16:58]

to be shown.

[jianli, 2011/12/02 23:23:46]

Done.

+const int kMaxVisibleOverflowPanelsAllowed = 6;
+
+// This value is experimental and subjective.
+const int kOverflowHoverAnimationMs = 180;
+}
+
+PanelOverflowStrip::PanelOverflowStrip(PanelManager* panel_manager)
+    : panel_manager_(panel_manager),
+      are_overflow_titles_shown_(false),
+      overflow_hover_animator_start_width_(0),
+      overflow_hover_animator_end_width_(0) {
+}
+
+PanelOverflowStrip::~PanelOverflowStrip() {
+  DCHECK(panels_.empty());
+}
+
+void PanelOverflowStrip::SetDisplayArea(const gfx::Rect& display_area) {
+  if (display_area_ == display_area)
+    return;
+
+  display_area_ = display_area;
+  Refresh();
+}
+
+void PanelOverflowStrip::AddPanel(Panel* panel, bool is_new) {
+  if (is_new)
+    panels_.push_back(panel);
+  else
+    panels_.insert(panels_.begin(), panel);

[jennb, 2011/12/02 21:16:58]

nit: not for this patch. vector is inefficient as every element is copied back a
slot every time we add/remove anything to/from the front of overflow.

[jianli, 2011/12/02 23:23:46]

Added TODO for this.

+
+  if (panels_.size() == 1)
+    panel_manager_->mouse_watcher()->AddObserver(this);
+
+  panel->SetExpansionState(Panel::IN_OVERFLOW);
+}
+
+bool PanelOverflowStrip::Remove(Panel* panel) {
+  size_t index = 0;
+  for (Panels::iterator iter = panels_.begin(); iter != panels_.end();

[jennb, 2011/12/02 21:16:58]

nit: would be easier to read if you use find() then delete found panel rather
than for loop. This for loop made me think you were removing more than one
panel.

[jianli, 2011/12/02 23:23:46]

I need to also find the index for the panel.

+       ++iter, ++index) {
+    if (*iter == panel) {
+      panels_.erase(iter);
+      DoRefresh(index, panels_.size() - 1);
+      panel_manager_->OnPanelRemoved(panel);
+      if (panels_.empty())
+        panel_manager_->mouse_watcher()->RemoveObserver(this);
+      return true;
+    }
+  }
+  return false;
+}
+
+void PanelOverflowStrip::RemoveAll() {
+  // Make a copy of the iterator as closing panels can modify the vector.
+  Panels panels_copy = panels_;
+
+  // Start from the bottom to avoid reshuffling.
+  for (Panels::reverse_iterator iter = panels_copy.rbegin();
+       iter != panels_copy.rend(); ++iter)
+    (*iter)->Close();
+}
+
+void PanelOverflowStrip::UpdatePanelRestoredSize(
+    Panel* panel, const gfx::Size& restored_size) {
+  panel->set_restored_size(restored_size);
+}
+
+void PanelOverflowStrip::OnPanelExpansionStateChanged(
+    Panel* panel, Panel::ExpansionState old_state) {
+  size_t panel_index = FindPanelIndex(panel);

[jennb, 2011/12/02 21:16:58]

Should make this method a no-op. Instead, in AddPanel(), call Refresh directly
as you already know if the panel is added to the front or the back of the strip.
Nowhere else will call SetExpansionState(IN_OVERFLOW) so it should be safe to
make the change.

[jianli, 2011/12/02 23:23:46]

Done.

+  DoRefresh(panel_index, panels_.size() - 1);
+}
+
+void PanelOverflowStrip::Refresh() {
+  if (panels_.empty())
+    return;
+  DoRefresh(0, panels_.size() - 1);

[jennb, 2011/12/02 21:16:58]

nit: There's only a few panels visible in overflow. Would be easier to read if
entire list is refreshed rather than save a few cycles.

The refresh logic and the way its broken up into subrs is very hard for me to
follow. Seems like it should be as simple as:

Refresh():
int bottom_position = display_bottom;
for first panel to last {
  if (current panel is within MaxVisible limit) {
    figure out bottom, height, x and y
    set width based on icon-only vs expanded width
    SetPanelBounds(new bounds)
    advance bottom_position;
  } else {
    make panel invisible somehow
  }
}

(Note, I'm following the pattern you set in panel_strip::Rearrange().)

[jianli, 2011/12/02 23:23:46]

I rather do a full layout computation to avoid any potential edge case. I also
like to update PanelStrip to follow this pattern.

Also, we might have a lot panels in overflow area, only first 6 of them are
visible.

+}
+
+void PanelOverflowStrip::DoRefresh(size_t start_index, size_t end_index) {
+  if (panels_.empty())
+    return;
+
+  DCHECK(start_index < panels_.size());
+  DCHECK(end_index < panels_.size());
+
+  for (size_t index = start_index; index <= end_index; ++index) {
+    Panel* panel = panels_[index];
+    gfx::Rect new_bounds = ComputeLayout(index,
+                                         panel->IconOnlySize(),
+                                         panel->restored_size());
+    DCHECK(!new_bounds.IsEmpty());
+    panel->SetPanelBounds(new_bounds);
+  }
+}
+
+size_t PanelOverflowStrip::FindPanelIndex(Panel* panel) const {
+  for (size_t i = 0; i < panels_.size(); ++i)
+    if (panels_[i] == panel)
+      return i;
+  return kInvalidPanelIndex;
+}
+
+gfx::Rect PanelOverflowStrip::ComputeLayout(
+    size_t index, const gfx::Size& iconified_size,
+    const gfx::Size& restored_size) const {
+  DCHECK(index != kInvalidPanelIndex);
+
+  gfx::Rect bounds;
+  int bottom = (index == 0) ? display_area_.bottom() :
+      panels_[index - 1]->GetBounds().y();
+  bounds.set_x(display_area_.x());
+  bounds.set_y(bottom - iconified_size.height());
+
+  if (are_overflow_titles_shown_) {
+    // Both icon and title are visible when the mouse hovers over the overflow
+    // area.
+    bounds.set_width(kOverflowAreaOverWidth);
+    bounds.set_height(iconified_size.height());
+  } else if (index < kMaxVisibleOverflowPanelsAllowed) {
+    // Only the icon is visible.
+    bounds.set_width(iconified_size.width());
+    bounds.set_height(iconified_size.height());
+  } else {
+    // Invisible for overflow-on-overflow.
+    bounds.set_width(0);

[jennb, 2011/12/02 21:16:58]

Using size(0, 0) seems wrong as that means panels can have a size that is less
than its min_size. Any other way to hide a panel? [Ok to wait til later patch to
find a better way.]

[jianli, 2011/12/02 23:23:46]

This is the only way for now.

+    bounds.set_height(0);
+  }
+
+  return bounds;
+}
+
+void PanelOverflowStrip::OnMouseMove(const gfx::Point& mouse_position) {
+  bool show_overflow_titles =  ShouldShowOverflowTitles(mouse_position);

[jennb, 2011/12/02 21:16:58]

extra space after =

[jianli, 2011/12/02 23:23:46]

Done.

+  ShowOverflowTitles(show_overflow_titles);
+}
+
+bool PanelOverflowStrip::ShouldShowOverflowTitles(
+    const gfx::Point& mouse_position) const {
+  if (panels_.empty())
+    return false;
+
+  int width = are_overflow_titles_shown_ ? kOverflowAreaOverWidth
+                                      : display_area_.width();
+  return display_area_.x() <= mouse_position.x() &&
+         mouse_position.x() <= display_area_.x() + width &&

[jennb, 2011/12/02 21:16:58]

display_area_.right()

[jianli, 2011/12/02 23:23:46]

width could be either kOverflowAreaHoverWidth or display_area_.width().

+         panels_.back()->GetBounds().y() <= mouse_position.y() &&
+         mouse_position.y() <= display_area_.bottom();
+}
+
+void PanelOverflowStrip::ShowOverflowTitles(bool show_overflow_titles) {
+  if (show_overflow_titles == are_overflow_titles_shown_)
+    return;
+  are_overflow_titles_shown_ = show_overflow_titles;
+
+  if (show_overflow_titles) {
+    overflow_hover_animator_start_width_ = display_area_.width();
+    overflow_hover_animator_end_width_ = kOverflowAreaOverWidth;
+
+    // We need to bring all overflow panels to the top of z-order again since

[jennb, 2011/12/02 21:16:58]

This comment makes no sense to me.

[jianli, 2011/12/02 23:23:46]

Changed.

+    // making an overflow panel expanded will cause it be activated and thus
+    // moved to the top of z-order.
+    for (Panels::iterator iter = panels_.begin();
+         iter != panels_.end(); ++iter) {
+      (*iter)->EnsureFullyVisible();
+    }
+  } else {
+    overflow_hover_animator_start_width_ = kOverflowAreaOverWidth;
+    overflow_hover_animator_end_width_ = display_area_.width();
+  }
+
+  if (!overflow_hover_animator_.get())
+    overflow_hover_animator_.reset(new ui::SlideAnimation(this));
+  if (overflow_hover_animator_->IsShowing())
+    overflow_hover_animator_->Reset();
+  overflow_hover_animator_->SetSlideDuration(kOverflowHoverAnimationMs);
+
+  overflow_hover_animator_->Show();
+}
+
+void PanelOverflowStrip::AnimationProgressed(const ui::Animation* animation) {
+  int current_width = overflow_hover_animator_->CurrentValueBetween(
+      overflow_hover_animator_start_width_, overflow_hover_animator_end_width_);
+  bool end_of_shrinking =
+      current_width == overflow_hover_animator_end_width_ &&
+      overflow_hover_animator_start_width_ > overflow_hover_animator_end_width_;

[jennb, 2011/12/02 21:16:58]

is this the same as current_width == display_area_.width()?

[jianli, 2011/12/02 23:23:46]

Yes. Thanks for suggesting the simple way to check for it.

+
+  // Update each overflow panel.

[jennb, 2011/12/02 21:16:58]

Could you replace all this with a call to Refresh() when current_width ==
overflow_hover_animator_end_width_? Maybe add a parameter to Refresh() for
whether the panels should animate their bounds changes.

[jianli, 2011/12/02 23:23:46]

I think adding another parameter to Refresh will make it harder to understand. I
prefer to keep the animation logic separate from the refresh logic.

+  for (size_t i = 0; i < panels_.size(); ++i) {
+    Panel* overflow_panel = panels_[i];
+    gfx::Rect bounds = overflow_panel->GetBounds();
+
+    if (i >= kMaxVisibleOverflowPanelsAllowed && end_of_shrinking) {
+      bounds.set_width(0);
+      bounds.set_height(0);
+    } else {
+      bounds.set_width(current_width);
+      bounds.set_height(overflow_panel->IconOnlySize().height());
+    }
+
+    overflow_panel->SetPanelBoundsInstantly(bounds);
+  }
+}
+
+bool PanelOverflowStrip::mouse_watcher_needed() const {
+  return !panels_.empty();
+}
+
+Panel* PanelOverflowStrip::first_panel() const {
+  return panels_.empty() ? NULL : panels_.front();
+}