Fix bug 105043: Panels [WIN]: For minimize panels, taskbar hover preview show the 4-pixel represent…

chrome/browser/ui/panels/panel_browser_view.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/panels/panel_browser_view.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "chrome/browser/native_window_notification_source.h"
 #include "chrome/browser/ui/panels/display_settings_provider.h"
 #include "chrome/browser/ui/panels/panel.h"
 #include "chrome/browser/ui/panels/panel_bounds_animation.h"
 #include "chrome/browser/ui/panels/panel_browser_frame_view.h"
 #include "chrome/browser/ui/panels/panel_manager.h"
 #include "chrome/browser/ui/panels/panel_strip.h"
 #include "chrome/browser/ui/views/frame/browser_frame.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "content/public/browser/notification_service.h"
 #include "grit/chromium_strings.h"
+#include "skia/ext/image_operations.h"
 #include "ui/base/l10n/l10n_util.h"
+#include "ui/gfx/canvas.h"
 #include "ui/views/controls/button/image_button.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/widget/widget.h"
 
+#if defined(OS_WIN)
+#include "base/win/windows_version.h"
+#endif
+
 using content::WebContents;
 
 NativePanel* Panel::CreateNativePanel(Browser* browser, Panel* panel,
                                       const gfx::Rect& bounds) {
   PanelBrowserView* view = new PanelBrowserView(browser, panel, bounds);
   (new BrowserFrame(view))->InitBrowserFrame();
   return view;
 }
 
 PanelBrowserView::PanelBrowserView(Browser* browser, Panel* panel,
                                    const gfx::Rect& bounds)
   : BrowserView(browser),
     panel_(panel),
     bounds_(bounds),
     closed_(false),
     focused_(false),
     mouse_pressed_(false),
     mouse_dragging_state_(NO_DRAGGING),
     is_drawing_attention_(false),
+    force_to_paint_as_inactive_(false),
     old_focused_view_(NULL) {
 }
 
 PanelBrowserView::~PanelBrowserView() {
 }
 
 void PanelBrowserView::Init() {
   if (!panel_->manager()->display_settings_provider()->is_full_screen()) {
     // TODO(prasadt): Implement this code.
     // HideThePanel.
@@ skipping 180 matching lines @@
 }
 
 bool PanelBrowserView::WillProcessWorkAreaChange() const {
   return true;
 }
 
 void PanelBrowserView::OnWindowBeginUserBoundsChange() {
   panel_->OnPanelStartUserResizing();
 }
 
+SkBitmap PanelBrowserView::GetPreviewImage(const gfx::Size& size, bool live) {

[Ben Goodger (Google), 2012/05/21 21:45:12]

rather than add all this win32-specific code to windowdelegate, browserview
etc... why not create a new delegate interface in views that NWW uses. this code
can own or use an object that implements this interface.

+#if defined(OS_WIN) && !defined(USE_AURA)
+  // Returns the live captured image if requested.
+  if (live)
+    return CaptureWindowImage();
+
+  // No need to scale if the requested size matches.
+  int width = size.width();
+  int height = size.height();
+  if (capture_bitmap_->width() == width || capture_bitmap_->height() == height)
+    return *capture_bitmap_;
+
+  SkBitmap scaled_bitmap;
+  double x_scale = static_cast<double>(width) / capture_bitmap_->width();
+  double y_scale = static_cast<double>(height) / capture_bitmap_->height();
+  double scale = std::min(x_scale, y_scale);
+  width = capture_bitmap_->width() * scale;
+  height = capture_bitmap_->height() * scale;
+  scaled_bitmap = skia::ImageOperations::Resize(
+      *capture_bitmap_, skia::ImageOperations::RESIZE_GOOD, width, height);
+
+  return scaled_bitmap;
+#else
+  return SkBitmap();
+#endif
+}
+
 void PanelBrowserView::OnWindowEndUserBoundsChange() {
   bounds_ = GetBounds();
   panel_->IncreaseMaxSize(bounds_.size());
   panel_->set_full_size(bounds_.size());
 
   panel_->OnPanelEndUserResizing();
   panel_->panel_strip()->RefreshLayout();
 }
 
 void PanelBrowserView::ShowPanel() {
@@ skipping 257 matching lines @@
   return bounds_animator_.get() && bounds_animator_->is_animating();
 }
 
 void PanelBrowserView::EnableResizeByMouse(bool enable) {
 }
 
 void PanelBrowserView::UpdatePanelMinimizeRestoreButtonVisibility() {
   GetFrameView()->UpdateTitleBarMinimizeRestoreButtonVisibility();
 }
 
-
 #if defined(OS_WIN) && !defined(USE_AURA)
 void PanelBrowserView::UpdateWindowAttribute(int attribute_index,
                                              int attribute_value,
                                              bool to_set) {
   gfx::NativeWindow native_window = GetNativePanelHandle();
   int value = ::GetWindowLong(native_window, attribute_index);
   int expected_value;
   if (to_set)
     expected_value = value |  attribute_value;
   else
     expected_value = value &  ~attribute_value;
   if (value != expected_value)
     ::SetWindowLong(native_window, attribute_index, expected_value);
 }
+
+SkBitmap PanelBrowserView::CaptureWindowImage() {
+  // Transfer the contents of the panel window to the screen-shot canvas' DIB.
+  HWND native_window = GetNativeHandle();
+  gfx::Canvas canvas(bounds_.size(), false);
+  HDC target_dc = canvas.BeginPlatformPaint();
+  HDC source_dc = ::GetDC(native_window);
+  ::BitBlt(target_dc, 0, 0, bounds_.width(), bounds_.height(), source_dc,
+           0, 0, SRCCOPY);
+  ::ReleaseDC(native_window, source_dc);
+  canvas.EndPlatformPaint();
+
+  return canvas.ExtractBitmap();
+}
 #endif
 
+void PanelBrowserView::PanelExpansionStateChanging(
+    Panel::ExpansionState old_state, Panel::ExpansionState new_state) {
+#if defined(OS_WIN) && !defined(USE_AURA)
+  // Live preview is only available since Windows 7.
+  if (base::win::GetVersion() < base::win::VERSION_WIN7)
+    return;
+
+  bool is_minimized = old_state != Panel::EXPANDED;
+  bool will_be_minimized = new_state != Panel::EXPANDED;
+  if (is_minimized == will_be_minimized)
+    return;
+
+  HWND native_window = GetNativeHandle();
+
+  // Cache the image at this point.
+  if (will_be_minimized) {
+    // If the panel is still active (we will deactivate the minimizd panel at
+    // later time), we need to paint it immediately as inactive so that we can
+    // take a snapshot of inactive panel.
+    if (focused_) {
+      force_to_paint_as_inactive_ = true;
+      ::RedrawWindow(native_window, NULL, NULL,
+                     RDW_NOCHILDREN | RDW_INVALIDATE | RDW_UPDATENOW);
+    }
+
+    capture_bitmap_.reset(new SkBitmap(CaptureWindowImage()));
+  } else {
+    capture_bitmap_.reset();
+    force_to_paint_as_inactive_ = false;
+  }
+
+  // We need to provide static bitmap to show the bitmap of the panel
+  // before it is minimized.
+  BOOL enable = will_be_minimized;
+  ::DwmSetWindowAttribute(native_window,
+                          DWMWA_FORCE_ICONIC_REPRESENTATION,
+                          &enable,
+                          sizeof(enable));
+  ::DwmSetWindowAttribute(native_window,
+                          DWMWA_HAS_ICONIC_BITMAP,
+                          &enable,
+                          sizeof(enable));
+#endif
+}
+
 // NativePanelTesting implementation.
 class NativePanelTestingWin : public NativePanelTesting {
  public:
   explicit NativePanelTestingWin(PanelBrowserView* panel_browser_view);
 
  private:
   virtual void PressLeftMouseButtonTitlebar(
       const gfx::Point& mouse_location, panel::ClickModifier modifier) OVERRIDE;
   virtual void ReleaseMouseButtonTitlebar(
       panel::ClickModifier modifier) OVERRIDE;
@@ skipping 81 matching lines @@
       return frame_view->close_button_->visible();
     case MINIMIZE_BUTTON:
       return frame_view->minimize_button_->visible();
     case RESTORE_BUTTON:
       return frame_view->restore_button_->visible();
     default:
       NOTREACHED();
   }
   return false;
 }