Initial patch set to implement improved touch support for screen magnification

ash/magnifier/magnification_controller.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 "ash/magnifier/magnification_controller.h"
 
 #include <memory>
 #include <utility>
 
 #include "ash/common/accelerators/accelerator_controller.h"
 #include "ash/common/accessibility_delegate.h"
 #include "ash/common/system/tray/system_tray_delegate.h"
 #include "ash/common/wm_shell.h"
 #include "ash/display/root_window_transformers.h"
 #include "ash/host/ash_window_tree_host.h"
 #include "ash/host/root_window_transformer.h"
 #include "ash/root_window_controller.h"
 #include "ash/screen_util.h"
 #include "ash/shell.h"
 #include "base/command_line.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/timer/timer.h"
+#include "chromeos/chromeos_switches.h"
 #include "ui/aura/client/cursor_client.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/base/ime/input_method.h"
 #include "ui/base/ime/input_method_observer.h"
 #include "ui/base/ime/text_input_client.h"
 #include "ui/compositor/dip_util.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_animation_observer.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
 #include "ui/events/event.h"
 #include "ui/events/event_handler.h"
+#include "ui/events/gesture_event_details.h"
 #include "ui/gfx/geometry/point3_f.h"
 #include "ui/gfx/geometry/point_conversions.h"
 #include "ui/gfx/geometry/point_f.h"
 #include "ui/gfx/geometry/rect_conversions.h"
 #include "ui/wm/core/compound_event_filter.h"
 #include "ui/wm/core/coordinate_conversion.h"
 
 namespace {
 
 const float kMaxMagnifiedScale = 4.0f;
@@ skipping 137 matching lines @@
   // Returns the size of the root window.
   gfx::Size GetHostSizeDIP() const;
 
   // Correct the given scale value if necessary.
   void ValidateScale(float* scale);
 
   // ui::EventHandler overrides:
   void OnMouseEvent(ui::MouseEvent* event) override;
   void OnScrollEvent(ui::ScrollEvent* event) override;
   void OnTouchEvent(ui::TouchEvent* event) override;
+  void OnGestureEvent(ui::GestureEvent* event) override;
 
   // Moves the view port when |point| is located within
   // |x_panning_margin| and |y_pannin_margin| to the edge of the visible
   // window region. The view port will be moved so that the |point| will be
   // moved to the point where it has |x_target_margin| and |y_target_margin|
   // to the edge of the visible region.
   void MoveMagnifierWindowFollowPoint(const gfx::Point& point,
                                       int x_panning_margin,
                                       int y_panning_margin,
                                       int x_target_margin,
@@ skipping 479 matching lines @@
 void MagnificationControllerImpl::OnTouchEvent(ui::TouchEvent* event) {
   aura::Window* target = static_cast<aura::Window*>(event->target());
   aura::Window* current_root = target->GetRootWindow();
   if (current_root == root_window_) {
     gfx::Rect root_bounds = current_root->bounds();
     if (root_bounds.Contains(event->root_location()))
       point_of_interest_ = event->root_location();
   }
 }
 
+void MagnificationControllerImpl::OnGestureEvent(ui::GestureEvent* event) {
+  if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
+          chromeos::switches::kEnableTouchSupportForScreenMagnifier)) {
+    return;
+  }
+
+  const ui::GestureEventDetails& details = event->details();
+  if (details.type() == ui::ET_GESTURE_SCROLL_UPDATE &&
+      details.touch_points() == 2) {
+    gfx::Rect viewport_rect_in_dip = GetViewportRect();
+    viewport_rect_in_dip.Offset(details.scroll_x() * -1,

[oshima, 2017/02/09 07:15:44]

- details.scroll_x()

[yawano, 2017/02/10 05:32:47]

Done.

+                                details.scroll_y() * -1);
+    const gfx::Rect& viewport_rect_in_pixel =

[oshima, 2017/02/09 07:15:44]

IIRC, it returns a object, so it shouldn't be reference.

[yawano, 2017/02/10 05:32:47]

Done.

+        ui::ConvertRectToPixel(root_window_->layer(), viewport_rect_in_dip);
+    MoveWindow(viewport_rect_in_pixel.origin(), false);
+    event->SetHandled();
+  } else if (details.type() == ui::ET_GESTURE_PINCH_UPDATE &&
+             details.touch_points() == 3) {
+    float scale = GetScale() * details.scale();
+
+    if (scale < kMinMagnifiedScaleThreshold) {

[oshima, 2017/02/09 07:15:45]

or min/max to up you tho.

[yawano, 2017/02/10 05:32:47]

Done.

+      scale = kMinMagnifiedScaleThreshold;
+    } else if (scale > kMaxMagnifiedScaleThreshold) {
+      scale = kMaxMagnifiedScaleThreshold;
+    }
+
+    point_of_interest_ = event->root_location();
+    SetScale(scale, false);
+    event->SetHandled();
+  }
+}
+
 void MagnificationControllerImpl::MoveMagnifierWindowFollowPoint(
     const gfx::Point& point,
     int x_panning_margin,
     int y_panning_margin,
     int x_target_margin,
     int y_target_margin) {
   DCHECK(root_window_);
   bool start_zoom = false;
 
   const gfx::Rect window_rect = GetViewportRect();
@@ skipping 154 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // MagnificationController:
 
 // static
 MagnificationController* MagnificationController::CreateInstance() {
   return new MagnificationControllerImpl();
 }
 
 }  // namespace ash