root/chrome/browser/ui/views/dropdown_bar_host.cc

DEFINITIONS

1. is_visible_
2. Init
3. Show
4. SetFocusAndSelection
5. IsAnimating
6. Hide
7. StopAnimation
8. IsVisible
9. OnWillChangeFocus
10. OnDidChangeFocus
11. AnimationProgressed
12. AnimationEnded
13. ResetFocusTracker
14. OnVisibilityChanged
15. GetWidgetBounds
16. UpdateWindowEdges
17. RegisterAccelerators
18. UnregisterAccelerators

// 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/dropdown_bar_host.h"

#include <algorithm>

#include "chrome/browser/ui/view_ids.h"
#include "chrome/browser/ui/views/dropdown_bar_host_delegate.h"
#include "chrome/browser/ui/views/dropdown_bar_view.h"
#include "chrome/browser/ui/views/frame/browser_view.h"
#include "ui/events/keycodes/keyboard_codes.h"
#include "ui/gfx/animation/slide_animation.h"
#include "ui/gfx/path.h"
#include "ui/gfx/scrollbar_size.h"
#include "ui/views/focus/external_focus_tracker.h"
#include "ui/views/focus/view_storage.h"
#include "ui/views/widget/widget.h"

#if defined(USE_AURA)
#include "ui/gfx/scoped_sk_region.h"
#elif defined(OS_WIN)
#include "base/win/scoped_gdi_object.h"
#endif

namespace {

#if defined(USE_AURA)
typedef gfx::ScopedSkRegion ScopedPlatformRegion;
#elif defined(OS_WIN)
typedef base::win::ScopedRegion ScopedPlatformRegion;
#endif

}  // namespace

using gfx::Path;

// static
bool DropdownBarHost::disable_animations_during_testing_ = false;

////////////////////////////////////////////////////////////////////////////////
// DropdownBarHost, public:

DropdownBarHost::DropdownBarHost(BrowserView* browser_view)
    : browser_view_(browser_view),
      view_(NULL),
      delegate_(NULL),
      animation_offset_(0),
      focus_manager_(NULL),
      esc_accel_target_registered_(false),
      is_visible_(false) {
}

void DropdownBarHost::Init(views::View* host_view,
                           views::View* view,
                           DropdownBarHostDelegate* delegate) {
  DCHECK(view);
  DCHECK(delegate);

  view_ = view;
  delegate_ = delegate;

  // Initialize the host.
  host_.reset(new views::Widget);
  views::Widget::InitParams params(views::Widget::InitParams::TYPE_CONTROL);
  params.ownership = views::Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
  params.parent = browser_view_->GetWidget()->GetNativeView();
#if defined(USE_AURA)
  params.opacity = views::Widget::InitParams::TRANSLUCENT_WINDOW;
#endif
  host_->Init(params);
  host_->SetContentsView(view_);

  SetHostViewNative(host_view);

  // Start listening to focus changes, so we can register and unregister our
  // own handler for Escape.
  focus_manager_ = host_->GetFocusManager();
  if (focus_manager_) {
    focus_manager_->AddFocusChangeListener(this);
  } else {
    // In some cases (see bug http://crbug.com/17056) it seems we may not have
    // a focus manager.  Please reopen the bug if you hit this.
    NOTREACHED();
  }

  // Start the process of animating the opening of the widget.
  animation_.reset(new gfx::SlideAnimation(this));
}

DropdownBarHost::~DropdownBarHost() {
  focus_manager_->RemoveFocusChangeListener(this);
  focus_tracker_.reset(NULL);
}

void DropdownBarHost::Show(bool animate) {
  // Stores the currently focused view, and tracks focus changes so that we can
  // restore focus when the dropdown widget is closed.
  focus_tracker_.reset(new views::ExternalFocusTracker(view_, focus_manager_));

  bool was_visible = is_visible_;
  is_visible_ = true;
  if (!animate || disable_animations_during_testing_) {
    animation_->Reset(1);
    AnimationProgressed(animation_.get());
  } else if (!was_visible) {
    // Don't re-start the animation.
    animation_->Reset();
    animation_->Show();
  }

  if (!was_visible)
    OnVisibilityChanged();
}

void DropdownBarHost::SetFocusAndSelection() {
  delegate_->SetFocusAndSelection(true);
}

bool DropdownBarHost::IsAnimating() const {
  return animation_->is_animating();
}

void DropdownBarHost::Hide(bool animate) {
  if (!IsVisible())
    return;
  if (animate && !disable_animations_during_testing_ &&
      !animation_->IsClosing()) {
    animation_->Hide();
  } else {
    if (animation_->IsClosing()) {
      // If we're in the middle of a close animation, skip immediately to the
      // end of the animation.
      StopAnimation();
    } else {
      // Otherwise we need to set both the animation state to ended and the
      // DropdownBarHost state to ended/hidden, otherwise the next time we try
      // to show the bar, it might refuse to do so. Note that we call
      // AnimationEnded ourselves as Reset does not call it if we are not
      // animating here.
      animation_->Reset();
      AnimationEnded(animation_.get());
    }
  }
}

void DropdownBarHost::StopAnimation() {
  animation_->End();
}

bool DropdownBarHost::IsVisible() const {
  return is_visible_;
}

////////////////////////////////////////////////////////////////////////////////
// DropdownBarHost, views::FocusChangeListener implementation:
void DropdownBarHost::OnWillChangeFocus(views::View* focused_before,
                                        views::View* focused_now) {
  // First we need to determine if one or both of the views passed in are child
  // views of our view.
  bool our_view_before = focused_before && view_->Contains(focused_before);
  bool our_view_now = focused_now && view_->Contains(focused_now);

  // When both our_view_before and our_view_now are false, it means focus is
  // changing hands elsewhere in the application (and we shouldn't do anything).
  // Similarly, when both are true, focus is changing hands within the dropdown
  // widget (and again, we should not do anything). We therefore only need to
  // look at when we gain initial focus and when we loose it.
  if (!our_view_before && our_view_now) {
    // We are gaining focus from outside the dropdown widget so we must register
    // a handler for Escape.
    RegisterAccelerators();
  } else if (our_view_before && !our_view_now) {
    // We are losing focus to something outside our widget so we restore the
    // original handler for Escape.
    UnregisterAccelerators();
  }
}

void DropdownBarHost::OnDidChangeFocus(views::View* focused_before,
                                       views::View* focused_now) {
}

////////////////////////////////////////////////////////////////////////////////
// DropdownBarHost, gfx::AnimationDelegate implementation:

void DropdownBarHost::AnimationProgressed(const gfx::Animation* animation) {
  // First, we calculate how many pixels to slide the widget.
  gfx::Size pref_size = view_->GetPreferredSize();
  animation_offset_ = static_cast<int>((1.0 - animation_->GetCurrentValue()) *
                                       pref_size.height());

  // This call makes sure it appears in the right location, the size and shape
  // is correct and that it slides in the right direction.
  gfx::Rect dlg_rect = GetDialogPosition(gfx::Rect());
  SetDialogPosition(dlg_rect, false);

  // Let the view know if we are animating, and at which offset to draw the
  // edges.
  delegate_->SetAnimationOffset(animation_offset_);
  view_->SchedulePaint();
}

void DropdownBarHost::AnimationEnded(const gfx::Animation* animation) {
  // Place the dropdown widget in its fully opened state.
  animation_offset_ = 0;

  if (!animation_->IsShowing()) {
    // Animation has finished closing.
    host_->Hide();
    is_visible_ = false;
    OnVisibilityChanged();
  } else {
    // Animation has finished opening.
  }
}

////////////////////////////////////////////////////////////////////////////////
// DropdownBarHost protected:

void DropdownBarHost::ResetFocusTracker() {
  focus_tracker_.reset(NULL);
}

void DropdownBarHost::OnVisibilityChanged() {
}

void DropdownBarHost::GetWidgetBounds(gfx::Rect* bounds) {
  DCHECK(bounds);
  *bounds = browser_view_->bounds();
}

void DropdownBarHost::UpdateWindowEdges(const gfx::Rect& new_pos) {
  // |w| is used to make it easier to create the part of the polygon that curves
  // the right side of the Find window. It essentially keeps track of the
  // x-pixel position of the right-most background image inside the view.
  // TODO(finnur): Let the view tell us how to draw the curves or convert
  // this to a CustomFrameWindow.
  int w = new_pos.width() - 6;  // -6 positions us at the left edge of the
                                // rightmost background image of the view.
  int h = new_pos.height();

  // This polygon array represents the outline of the background image for the
  // window. Basically, it encompasses only the visible pixels of the
  // concatenated find_dlg_LMR_bg images (where LMR = [left | middle | right]).
  const Path::Point polygon[] = {
      {2, 0}, {3, 1}, {3, h - 2}, {4, h - 1},
        {4, h}, {w+0, h},
      {w+2, h - 1}, {w+3, h - 2}, {w+3, 1}, {w+4, 0}
  };

  // Find the largest x and y value in the polygon.
  int max_x = 0, max_y = 0;
  for (size_t i = 0; i < arraysize(polygon); i++) {
    max_x = std::max(max_x, static_cast<int>(polygon[i].x));
    max_y = std::max(max_y, static_cast<int>(polygon[i].y));
  }

  // We then create the polygon and use SetWindowRgn to force the window to draw
  // only within that area. This region may get reduced in size below.
  Path path(polygon, arraysize(polygon));
  ScopedPlatformRegion region(path.CreateNativeRegion());
  // Are we animating?
  if (animation_offset() > 0) {
    // The animation happens in two steps: First, we clip the window and then in
    // GetWidgetPosition we offset the window position so that it still looks
    // attached to the toolbar as it grows. We clip the window by creating a
    // rectangle region (that gradually increases as the animation progresses)
    // and find the intersection between the two regions using CombineRgn.

    // |y| shrinks as the animation progresses from the height of the view down
    // to 0 (and reverses when closing).
    int y = animation_offset();
    // |y| shrinking means the animation (visible) region gets larger. In other
    // words: the rectangle grows upward (when the widget is opening).
    Path animation_path;
    SkRect animation_rect = { SkIntToScalar(0), SkIntToScalar(y),
                              SkIntToScalar(max_x), SkIntToScalar(max_y) };
    animation_path.addRect(animation_rect);
    ScopedPlatformRegion animation_region(
        animation_path.CreateNativeRegion());
    region.Set(Path::IntersectRegions(animation_region.Get(), region.Get()));

    // Next, we need to increase the region a little bit to account for the
    // curved edges that the view will draw to make it look like grows out of
    // the toolbar.
    Path::Point left_curve[] = {
      {2, y+0}, {3, y+1}, {3, y+0}, {2, y+0}
    };
    Path::Point right_curve[] = {
      {w+3, y+1}, {w+4, y+0}, {w+3, y+0}, {w+3, y+1}
    };

    // Combine the region for the curve on the left with our main region.
    Path left_path(left_curve, arraysize(left_curve));
    ScopedPlatformRegion r(left_path.CreateNativeRegion());
    region.Set(Path::CombineRegions(r.Get(), region.Get()));

    // Combine the region for the curve on the right with our main region.
    Path right_path(right_curve, arraysize(right_curve));
    region.Set(Path::CombineRegions(r.Get(), region.Get()));
  }

  // Now see if we need to truncate the region because parts of it obscures
  // the main window border.
  gfx::Rect widget_bounds;
  GetWidgetBounds(&widget_bounds);

  // Calculate how much our current position overlaps our boundaries. If we
  // overlap, it means we have too little space to draw the whole widget and
  // we allow overwriting the scrollbar before we start truncating our widget.
  //
  // TODO(brettw) this constant is evil. This is the amount of room we've added
  // to the window size, when we set the region, it can change the size.
  static const int kAddedWidth = 7;
  int difference = new_pos.right() - kAddedWidth - widget_bounds.right() -
      gfx::scrollbar_size() + 1;
  if (difference > 0) {
    Path::Point exclude[4];
    exclude[0].x = max_x - difference;  // Top left corner.
    exclude[0].y = 0;

    exclude[1].x = max_x;               // Top right corner.
    exclude[1].y = 0;

    exclude[2].x = max_x;               // Bottom right corner.
    exclude[2].y = max_y;

    exclude[3].x = max_x - difference;  // Bottom left corner.
    exclude[3].y = max_y;

    // Subtract this region from the original region.
    gfx::Path exclude_path(exclude, arraysize(exclude));
    ScopedPlatformRegion exclude_region(exclude_path.CreateNativeRegion());
    region.Set(Path::SubtractRegion(region.Get(), exclude_region.Get()));
  }

  // Window takes ownership of the region.
  host()->SetShape(region.release());
}

void DropdownBarHost::RegisterAccelerators() {
  DCHECK(!esc_accel_target_registered_);
  ui::Accelerator escape(ui::VKEY_ESCAPE, ui::EF_NONE);
  focus_manager_->RegisterAccelerator(
      escape, ui::AcceleratorManager::kNormalPriority, this);
  esc_accel_target_registered_ = true;
}

void DropdownBarHost::UnregisterAccelerators() {
  DCHECK(esc_accel_target_registered_);
  ui::Accelerator escape(ui::VKEY_ESCAPE, ui::EF_NONE);
  focus_manager_->UnregisterAccelerator(escape, this);
  esc_accel_target_registered_ = false;
}