Add mirrored screen option

ash/display/root_window_transformers.cc

 // Copyright (c) 2013 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/display/root_window_transformers.h"
 
 #include <cmath>
 
+#include "ash/ash_switches.h"
 #include "ash/display/display_info.h"
 #include "ash/display/display_manager.h"
 #include "ash/host/root_window_transformer.h"
 #include "ash/magnifier/magnification_controller.h"
 #include "ash/shell.h"
 #include "base/basictypes.h"
+#include "base/command_line.h"
 #include "base/memory/scoped_ptr.h"
 #include "third_party/skia/include/utils/SkMatrix44.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/aura/window_property.h"
 #include "ui/compositor/dip_util.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/insets.h"
 #include "ui/gfx/size_conversions.h"
 #include "ui/gfx/transform.h"
 #include "ui/gfx/transform.h"
@@ skipping 90 matching lines @@
   if (insets.top() != 0 || insets.left() != 0) {
     float x_offset = insets.left() / device_scale_factor;
     float y_offset = insets.top() / device_scale_factor;
     transform.Translate(x_offset, y_offset);
   }
   float inverted_scale = 1.0f / ui_scale;
   transform.Scale(inverted_scale, inverted_scale);
   return transform;
 }
 
+gfx::Transform CreateMirrorTransform(const gfx::Display& display) {
+  gfx::Transform transform;
+  transform.matrix().set3x3(-1, 0, 0,
+                            0, 1, 0,
+                            0, 0, 1);
+  transform.Translate(-display.size().width(), 0);
+  return transform;
+}
+
 // RootWindowTransformer for ash environment.
 class AshRootWindowTransformer : public RootWindowTransformer {
  public:
   AshRootWindowTransformer(aura::Window* root,
                            const gfx::Display& display)
       : root_window_(root) {
     DisplayInfo info = Shell::GetInstance()->display_manager()->
         GetDisplayInfo(display.id());
     host_insets_ = info.GetOverscanInsetsInPixel();
     root_window_ui_scale_ = info.GetEffectiveUIScale();
     root_window_bounds_transform_ =
         CreateInsetsAndScaleTransform(host_insets_,
                                       display.device_scale_factor(),
                                       root_window_ui_scale_) *
         CreateRotationTransform(root, display);
+    if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+            switches::kAshEnableMirroredScreen)) {
+      // Apply the tranform that flips the screen image horizontally so that
+      // the screen looks normal when reflected on a mirror.
+      root_window_bounds_transform_ =
+          root_window_bounds_transform_ * CreateMirrorTransform(display);
+    }
     transform_ = root_window_bounds_transform_ * CreateMagnifierTransform(root);
+
     CHECK(transform_.GetInverse(&invert_transform_));
   }
 
   // aura::RootWindowTransformer overrides:
   gfx::Transform GetTransform() const override { return transform_; }
   gfx::Transform GetInverseTransform() const override {
     return invert_transform_;
   }
   gfx::Rect GetRootWindowBounds(const gfx::Size& host_size) const override {
     gfx::Rect bounds(host_size);
@@ skipping 112 matching lines @@
 }
 
 RootWindowTransformer* CreateRootWindowTransformerForMirroredDisplay(
     const DisplayInfo& source_display_info,
     const DisplayInfo& mirror_display_info) {
   return new MirrorRootWindowTransformer(source_display_info,
                                          mirror_display_info);
 }
 
 }  // namespace ash