Implement disambiguation popup

This patch implements the renderer-process side of disambiguation popup.
Individual platforms shall provide its own browser-side handling.

Correspoding WebKit CL: https://bugs.webkit.org/show_bug.cgi?id=94182

BUG=100752


Review URL: https://chromiumcodereview.appspot.com/10885004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@162612 0039d316-1c4b-4281-b951-d872f2087c98

10 files changed, 307 insertions, 0 deletions

diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 4fcdff0..ee008ca 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -316,6 +316,8 @@ bool RenderWidgetHostImpl::OnMessageReceived(const IPC::Message &msg) {
                         OnMsgDidActivateAcceleratedCompositing)
     IPC_MESSAGE_HANDLER(ViewHostMsg_LockMouse, OnMsgLockMouse)
     IPC_MESSAGE_HANDLER(ViewHostMsg_UnlockMouse, OnMsgUnlockMouse)
+    IPC_MESSAGE_HANDLER(ViewHostMsg_ShowDisambiguationPopup,
+                        OnMsgShowDisambiguationPopup)
 #if defined(OS_POSIX) || defined(USE_AURA)
     IPC_MESSAGE_HANDLER(ViewHostMsg_GetWindowRect, OnMsgGetWindowRect)
     IPC_MESSAGE_HANDLER(ViewHostMsg_GetRootWindowRect, OnMsgGetRootWindowRect)
@@ -1825,6 +1827,19 @@ void RenderWidgetHostImpl::OnMsgUnlockMouse() {
   RejectMouseLockOrUnlockIfNecessary();
 }
 
+void RenderWidgetHostImpl::OnMsgShowDisambiguationPopup(
+    const gfx::Rect& rect,
+    const gfx::Size& size,
+    const TransportDIB::Id& id) {
+  TransportDIB* dib = process_->GetTransportDIB(id);
+
+  // TODO(trchen): implement the platform-specific disambiguation popup
+  NOTIMPLEMENTED();
+
+  Send(new ViewMsg_ReleaseDisambiguationPopupDIB(GetRoutingID(),
+                                                 dib->handle()));
+}
+
 #if defined(OS_POSIX) || defined(USE_AURA)
 void RenderWidgetHostImpl::OnMsgGetWindowRect(gfx::NativeViewId window_id,
                                               gfx::Rect* results) {
diff --git a/content/browser/renderer_host/render_widget_host_impl.h b/content/browser/renderer_host/render_widget_host_impl.h
index 223535b..673b485 100644
--- a/content/browser/renderer_host/render_widget_host_impl.h
+++ b/content/browser/renderer_host/render_widget_host_impl.h
@@ -574,6 +574,10 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
                       bool privileged);
   void OnMsgUnlockMouse();
 
+  void OnMsgShowDisambiguationPopup(const gfx::Rect& rect,
+                                    const gfx::Size& size,
+                                    const TransportDIB::Id& id);
+
 #if defined(OS_POSIX) || defined(USE_AURA)
   void OnMsgGetWindowRect(gfx::NativeViewId window_id, gfx::Rect* results);
   void OnMsgGetRootWindowRect(gfx::NativeViewId window_id, gfx::Rect* results);
diff --git a/content/common/view_messages.h b/content/common/view_messages.h
index 1b77c74..261bda4 100644
--- a/content/common/view_messages.h
+++ b/content/common/view_messages.h
@@ -1431,6 +1431,11 @@ IPC_MESSAGE_ROUTED1(ViewMsg_SelectPopupMenuItem,
                     int /* selected index, -1 means no selection */)
 #endif
 
+// An acknowledge to ViewHostMsg_MultipleTargetsTouched to notify the renderer
+// process to release the magnified image.
+IPC_MESSAGE_ROUTED1(ViewMsg_ReleaseDisambiguationPopupDIB,
+                    TransportDIB::Handle /* DIB handle */)
+
 // -----------------------------------------------------------------------------
 // Messages sent from the renderer to the browser.
 
@@ -2395,3 +2400,10 @@ IPC_MESSAGE_ROUTED3(ViewHostMsg_FindMatchRects_Reply,
 IPC_MESSAGE_ROUTED1(ViewHostMsg_StartContentIntent,
                     GURL /* content_url */)
 #endif
+
+// Notifies that multiple touch targets may have been pressed, and to show
+// the disambiguation popup.
+IPC_MESSAGE_ROUTED3(ViewHostMsg_ShowDisambiguationPopup,
+                    gfx::Rect, /* Border of touched targets */
+                    gfx::Size, /* Size of zoomed image */
+                    TransportDIB::Id /* DIB of zoomed image */)
diff --git a/content/content_renderer.gypi b/content/content_renderer.gypi
index 2a96e10..56d80d8 100644
--- a/content/content_renderer.gypi
+++ b/content/content_renderer.gypi
@@ -68,6 +68,8 @@
     'renderer/devtools_agent_filter.h',
     'renderer/devtools_client.cc',
     'renderer/devtools_client.h',
+    'renderer/disambiguation_popup_helper.cc',
+    'renderer/disambiguation_popup_helper.h',
     'renderer/do_not_track_bindings.cc',
     'renderer/do_not_track_bindings.h',
     'renderer/dom_automation_controller.cc',
diff --git a/content/content_tests.gypi b/content/content_tests.gypi
index 5473342..ad82ddb 100644
--- a/content/content_tests.gypi
+++ b/content/content_tests.gypi
@@ -352,6 +352,7 @@
         'renderer/active_notification_tracker_unittest.cc',
         'renderer/android/email_detector_unittest.cc',
         'renderer/android/phone_number_detector_unittest.cc',
+        'renderer/disambiguation_popup_helper_unittest.cc',
         'renderer/gpu/input_event_filter_unittest.cc',
         'renderer/hyphenator/hyphenator_unittest.cc',
         'renderer/media/audio_message_filter_unittest.cc',
diff --git a/content/renderer/disambiguation_popup_helper.cc b/content/renderer/disambiguation_popup_helper.cc
new file mode 100644
index 0000000..1a55414
--- /dev/null
+++ b/content/renderer/disambiguation_popup_helper.cc
@@ -0,0 +1,106 @@
+// 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 "content/renderer/disambiguation_popup_helper.h"
+
+#include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebRect.h"
+#include "ui/gfx/size_conversions.h"
+
+using WebKit::WebRect;
+using WebKit::WebVector;
+
+namespace {
+
+// The amount of padding to add to the disambiguation popup to show
+// content around the possible elements, adding some context.
+const int kDisambiguationPopupPadding = 8;
+
+// Constants used for fitting the disambiguation popup inside the bounds of
+// the view. Note that there are mirror constants in PopupZoomer.java.
+const int kDisambiguationPopupBoundsMargin = 25;
+
+// The smallest allowable touch target used for disambiguation popup.
+// This value is used to determine the minimum amount we need to scale to
+// make all targets touchable.
+const int kDisambiguationPopupMinimumTouchSize = 40;
+const float kDisambiguationPopupMaxScale = 5.0;
+const float kDisambiguationPopupMinScale = 2.0;
+
+// Compute the scaling factor to ensure the smallest touch candidate reaches
+// a certain clickable size after zooming
+float FindOptimalScaleFactor(const WebVector<WebRect>& target_rects) {
+  using std::min;
+  using std::max;
+  if (!target_rects.size()) // shall never reach
+    return kDisambiguationPopupMinScale;
+  int smallest_target = min(target_rects[0].width, target_rects[0].height);
+  for (size_t i = 1; i < target_rects.size(); i++) {
+    smallest_target = min(smallest_target, target_rects[i].width);
+    smallest_target = min(smallest_target, target_rects[i].height);
+  }
+  smallest_target = max(smallest_target, 1);
+  return min(kDisambiguationPopupMaxScale, max(kDisambiguationPopupMinScale,
+      static_cast<float>(kDisambiguationPopupMinimumTouchSize)
+          / smallest_target));
+}
+
+void TrimEdges(int *e1, int *e2, int max_combined) {
+  if (*e1 + *e2 <= max_combined)
+    return;
+
+  if (std::min(*e1, *e2) * 2 >= max_combined)
+    *e1 = *e2 = max_combined / 2;
+  else if (*e1 > *e2)
+    *e1 = max_combined - *e2;
+  else
+    *e2 = max_combined - *e1;
+}
+
+// Ensure the disambiguation popup fits inside the screen,
+// clip the edges farthest to the touch point if needed.
+gfx::Rect CropZoomArea(const gfx::Rect& zoom_rect,
+                       const gfx::Size& viewport_size,
+                       const gfx::Point& touch_point,
+                       float scale) {
+  gfx::Size max_size = viewport_size;
+  max_size.Enlarge(-2 * kDisambiguationPopupBoundsMargin,
+                   -2 * kDisambiguationPopupBoundsMargin);
+  max_size = ToCeiledSize(max_size.Scale(1.0 / scale));
+
+  int left = touch_point.x() - zoom_rect.x();
+  int right = zoom_rect.right() - touch_point.x();
+  int top = touch_point.y() - zoom_rect.y();
+  int bottom = zoom_rect.bottom() - touch_point.y();
+  TrimEdges(&left, &right, max_size.width());
+  TrimEdges(&top, &bottom, max_size.height());
+
+  return gfx::Rect(touch_point.x() - left,
+                   touch_point.y() - top,
+                   left + right,
+                   top + bottom);
+}
+
+} // unnamed namespace
+
+namespace content {
+
+float DisambiguationPopupHelper::ComputeZoomAreaAndScaleFactor(
+    const gfx::Rect& tap_rect,
+    const WebVector<WebRect>& target_rects,
+    const gfx::Size& viewport_size,
+    gfx::Rect* zoom_rect) {
+  *zoom_rect = tap_rect;
+  for (size_t i = 0; i < target_rects.size(); i++)
+    *zoom_rect = zoom_rect->Union(gfx::Rect(target_rects[i]));
+  zoom_rect->Inset(-kDisambiguationPopupPadding, -kDisambiguationPopupPadding);
+  *zoom_rect = zoom_rect->Intersect(gfx::Rect(viewport_size));
+
+  float scale = FindOptimalScaleFactor(target_rects);
+  *zoom_rect = CropZoomArea(
+      *zoom_rect, viewport_size, tap_rect.CenterPoint(), scale);
+
+  return scale;
+}
+
+} // namespace content
diff --git a/content/renderer/disambiguation_popup_helper.h b/content/renderer/disambiguation_popup_helper.h
new file mode 100644
index 0000000..84ee049
--- /dev/null
+++ b/content/renderer/disambiguation_popup_helper.h
@@ -0,0 +1,34 @@
+// 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.
+
+#ifndef CONTENT_RENDERER_DISAMBIGUATION_POPUP_HELPER_H_
+#define CONTENT_RENDERER_DISAMBIGUATION_POPUP_HELPER_H_
+
+#include "content/common/content_export.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebVector.h"
+
+namespace gfx {
+class Rect;
+class Size;
+}
+
+namespace WebKit {
+struct WebRect;
+}
+
+namespace content {
+
+// Contains functions to calculate proper scaling factor and popup size
+class DisambiguationPopupHelper {
+ public:
+  CONTENT_EXPORT static float ComputeZoomAreaAndScaleFactor(
+      const gfx::Rect& tap_rect,
+      const WebKit::WebVector<WebKit::WebRect>& target_rects,
+      const gfx::Size& viewport_size,
+      gfx::Rect* zoom_rect);
+};
+
+} // namespace content
+
+#endif // CONTENT_RENDERER_DISAMBIGUATION_POPUP_HELPER_H_
diff --git a/content/renderer/disambiguation_popup_helper_unittest.cc b/content/renderer/disambiguation_popup_helper_unittest.cc
new file mode 100644
index 0000000..2aaeb84
--- /dev/null
+++ b/content/renderer/disambiguation_popup_helper_unittest.cc
@@ -0,0 +1,81 @@
+// 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 "content/renderer/disambiguation_popup_helper.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebRect.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebVector.h"
+#include "ui/gfx/rect.h"
+#include "ui/gfx/size.h"
+#include "ui/gfx/size_conversions.h"
+
+// these constants are copied from the implementation class
+namespace {
+const float kDisambiguationPopupMaxScale = 5.0;
+const float kDisambiguationPopupMinScale = 2.0;
+} // unnamed namespace
+
+namespace content {
+
+class DisambiguationPopupHelperUnittest : public testing::Test {
+ public:
+  DisambiguationPopupHelperUnittest()
+      : kViewportSize_(640, 480) { }
+ protected:
+  const gfx::Size kViewportSize_;
+};
+
+TEST_F(DisambiguationPopupHelperUnittest, ClipByViewport) {
+  gfx::Rect tap_rect(1000, 1000, 10, 10);
+  WebKit::WebVector<WebKit::WebRect> target_rects(static_cast<size_t>(1));
+  target_rects[0] = gfx::Rect(-20, -20, 10, 10);
+
+  gfx::Rect zoom_rect;
+  float scale = DisambiguationPopupHelper::ComputeZoomAreaAndScaleFactor(
+      tap_rect, target_rects, kViewportSize_, &zoom_rect);
+
+  EXPECT_TRUE(gfx::Rect(kViewportSize_).Contains(zoom_rect));
+  EXPECT_LE(kDisambiguationPopupMinScale, scale);
+
+  gfx::Size scaled_size = ToCeiledSize(zoom_rect.size().Scale(scale));
+  EXPECT_TRUE(gfx::Rect(kViewportSize_).Contains(gfx::Rect(scaled_size)));
+}
+
+TEST_F(DisambiguationPopupHelperUnittest, MiniTarget) {
+  gfx::Rect tap_rect(-5, -5, 20, 20);
+  WebKit::WebVector<WebKit::WebRect> target_rects(static_cast<size_t>(1));
+  target_rects[0] = gfx::Rect(10, 10, 1, 1);
+
+  gfx::Rect zoom_rect;
+  float scale = DisambiguationPopupHelper::ComputeZoomAreaAndScaleFactor(
+      tap_rect, target_rects, kViewportSize_, &zoom_rect);
+
+  EXPECT_TRUE(gfx::Rect(kViewportSize_).Contains(zoom_rect));
+  EXPECT_EQ(kDisambiguationPopupMaxScale, scale);
+  EXPECT_TRUE(zoom_rect.Contains(target_rects[0]));
+
+  gfx::Size scaled_size = ToCeiledSize(zoom_rect.size().Scale(scale));
+  EXPECT_TRUE(gfx::Rect(kViewportSize_).Contains(gfx::Rect(scaled_size)));
+}
+
+TEST_F(DisambiguationPopupHelperUnittest, LongLinks) {
+  gfx::Rect tap_rect(10, 10, 20, 20);
+  WebKit::WebVector<WebKit::WebRect> target_rects(static_cast<size_t>(2));
+  target_rects[0] = gfx::Rect(15, 15, 1000, 5);
+  target_rects[1] = gfx::Rect(15, 25, 1000, 5);
+
+  gfx::Rect zoom_rect;
+  float scale = DisambiguationPopupHelper::ComputeZoomAreaAndScaleFactor(
+      tap_rect, target_rects, kViewportSize_, &zoom_rect);
+
+  EXPECT_TRUE(gfx::Rect(kViewportSize_).Contains(zoom_rect));
+  EXPECT_EQ(kDisambiguationPopupMaxScale, scale);
+  EXPECT_TRUE(zoom_rect.Contains(tap_rect));
+
+  gfx::Size scaled_size = ToCeiledSize(zoom_rect.size().Scale(scale));
+  EXPECT_TRUE(gfx::Rect(kViewportSize_).Contains(gfx::Rect(scaled_size)));
+}
+
+} // namespace content
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index e8cf050..0d82ff6 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -68,6 +68,7 @@
 #include "content/renderer/browser_plugin/old/guest_to_embedder_channel.h"
 #include "content/renderer/device_orientation_dispatcher.h"
 #include "content/renderer/devtools_agent.h"
+#include "content/renderer/disambiguation_popup_helper.h"
 #include "content/renderer/dom_automation_controller.h"
 #include "content/renderer/dom_storage/webstoragenamespace_impl.h"
 #include "content/renderer/do_not_track_bindings.h"
@@ -180,6 +181,7 @@
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/point.h"
 #include "ui/gfx/rect.h"
+#include "ui/gfx/size_conversions.h"
 #include "v8/include/v8.h"
 #include "webkit/appcache/web_application_cache_host_impl.h"
 #include "webkit/dom_storage/dom_storage_types.h"
@@ -1059,6 +1061,8 @@ bool RenderViewImpl::OnMessageReceived(const IPC::Message& message) {
     IPC_MESSAGE_HANDLER(ViewMsg_SetWindowVisibility, OnSetWindowVisibility)
     IPC_MESSAGE_HANDLER(ViewMsg_WindowFrameChanged, OnWindowFrameChanged)
 #endif
+    IPC_MESSAGE_HANDLER(ViewMsg_ReleaseDisambiguationPopupDIB,
+                        OnReleaseDisambiguationPopupDIB)
 
     // Have the super handle all other messages.
     IPC_MESSAGE_UNHANDLED(handled = RenderWidget::OnMessageReceived(message))
@@ -6388,3 +6392,46 @@ void RenderViewImpl::OnUpdatedFrameTree(
 
   updating_frame_tree_ = false;
 }
+
+bool RenderViewImpl::didTapMultipleTargets(
+    const WebKit::WebGestureEvent& event,
+    const WebVector<WebRect>& target_rects) {
+  using content::DisambiguationPopupHelper;
+  gfx::Rect finger_rect(
+      event.x - event.data.tap.width / 2, event.y - event.data.tap.height / 2,
+      event.data.tap.width, event.data.tap.height);
+  gfx::Rect zoom_rect;
+  float scale = DisambiguationPopupHelper::ComputeZoomAreaAndScaleFactor(
+      finger_rect, target_rects, GetSize(), &zoom_rect);
+  if (!scale)
+    return false;
+
+  gfx::Size canvas_size = zoom_rect.size();
+  canvas_size = ToCeiledSize(canvas_size.Scale(scale));
+  TransportDIB* transport_dib = NULL;
+  {
+    scoped_ptr<skia::PlatformCanvas> canvas(
+        RenderProcess::current()->GetDrawingCanvas(&transport_dib,
+                                                   gfx::Rect(canvas_size)));
+    if (!canvas.get())
+      return false;
+
+    canvas->scale(scale, scale);
+
+    canvas->translate(-zoom_rect.x(), -zoom_rect.y());
+    webwidget_->paint(webkit_glue::ToWebCanvas(canvas.get()), zoom_rect,
+        WebWidget::ForceSoftwareRenderingAndIgnoreGPUResidentContent);
+  }
+  Send(new ViewHostMsg_ShowDisambiguationPopup(routing_id_,
+                                               zoom_rect,
+                                               canvas_size,
+                                               transport_dib->id()));
+
+  return true;
+}
+
+void RenderViewImpl::OnReleaseDisambiguationPopupDIB(
+    TransportDIB::Handle dib_handle) {
+  TransportDIB* dib = TransportDIB::CreateWithHandle(dib_handle);
+  RenderProcess::current()->ReleaseTransportDIB(dib);
+}
diff --git a/content/renderer/render_view_impl.h b/content/renderer/render_view_impl.h
index 773c242..6ea0985 100644
--- a/content/renderer/render_view_impl.h
+++ b/content/renderer/render_view_impl.h
@@ -153,6 +153,7 @@ class WebDOMMessageEvent;
 class WebDataSource;
 class WebDragData;
 class WebGeolocationClient;
+class WebGestureEvent;
 #if defined(OS_ANDROID)
 class WebHitTestResult;
 #endif
@@ -495,6 +496,9 @@ class RenderViewImpl : public RenderWidget,
   virtual void numberOfWheelEventHandlersChanged(unsigned num_handlers);
   virtual void hasTouchEventHandlers(bool has_handlers);
   virtual void didUpdateLayout();
+  virtual bool didTapMultipleTargets(
+      const WebKit::WebGestureEvent& event,
+      const WebKit::WebVector<WebKit::WebRect>& target_rects);
   virtual void navigateBackForwardSoon(int offset);
   virtual int historyBackListCount();
   virtual int historyForwardListCount();
@@ -987,6 +991,7 @@ class RenderViewImpl : public RenderWidget,
   void OnPasteAndMatchStyle();
   void OnPostMessageEvent(const ViewMsg_PostMessage_Params& params);
   void OnRedo();
+  void OnReleaseDisambiguationPopupDIB(TransportDIB::Handle dib_handle);
   void OnReloadFrame();
   void OnReplace(const string16& text);
   CONTENT_EXPORT void OnReplaceAll(const string16& text);