Implements computation of touch calibration transform using user provided data

ash/touch/touch_transformer_controller_unittest.cc

 // Copyright 2014 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/touch/touch_transformer_controller.h"
 
 #include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
+#include "base/rand_util.h"
+#include "base/strings/string_number_conversions.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/events/devices/device_data_manager.h"
 
 namespace ash {
 
 namespace {
 
 display::ManagedDisplayInfo CreateDisplayInfo(int64_t id,
                                               unsigned int touch_device_id,
                                               const gfx::Rect& bounds) {
   display::ManagedDisplayInfo info(id, std::string(), false);
   info.SetBounds(bounds);
   info.AddInputDevice(touch_device_id);
 
   // Create a default mode.
   display::ManagedDisplayInfo::ManagedDisplayModeList default_modes(
       1, make_scoped_refptr(
              new display::ManagedDisplayMode(bounds.size(), 60, false, true)));
   info.SetManagedDisplayModes(default_modes);
 
   return info;
 }
 
 ui::TouchscreenDevice CreateTouchscreenDevice(unsigned int id,
                                               const gfx::Size& size) {
   return ui::TouchscreenDevice(id, ui::InputDeviceType::INPUT_DEVICE_EXTERNAL,
                                std::string(), size, 0);
 }
 
+std::string GetTouchPointString(
+    const display::TouchCalibrationData::CalibrationPointPairQuad& pts) {
+  std::string str = "For point pairs: ";
+  for (std::size_t row = 0; row < pts.size(); row++) {
+    str += "{(" + base::IntToString(pts[row].first.x()) + "," +
+           base::IntToString(pts[row].first.y()) + "), (" +
+           base::IntToString(pts[row].second.x()) + "," +
+           base::IntToString(pts[row].second.y()) + ")} ";
+  }
+  return str;
+}
+
+// Returns a point close to |point| with some error. This is to simulate human
+// input that is prone to a max delta error of |error.width()| or
+// |error.height()|.
+gfx::Point GetPointWithError(const gfx::Point& point, const gfx::Size& error) {
+  return gfx::Point(
+      point.x() + base::RandInt(-error.width() / 2, error.width() / 2),
+      point.y() + base::RandInt(-error.height() / 2, error.height() / 2));
+}
+
+// Checks if the touch input has been calibrated properly. The input is said to
+// be calibrated if any touch input is transformed to the correct corresponding
+// display point within an error delta of |max_error_delta.width()| along the X
+// axis and |max_error_delta.height()| along the Y axis;
+void CheckPointsOfInterests(const int touch_id,
+                            const gfx::Size& touch_size,
+                            const gfx::Size& display_size,
+                            const gfx::Size& max_error_delta,
+                            const std::string error_msg) {
+  ui::DeviceDataManager* device_manager = ui::DeviceDataManager::GetInstance();
+  float x, y;
+
+  // Origin of the touch device should correspond to origin of the display.
+  x = y = 0.0;
+  device_manager->ApplyTouchTransformer(touch_id, &x, &y);
+  EXPECT_NEAR(0, x, max_error_delta.width()) << error_msg;
+  EXPECT_NEAR(0, y, max_error_delta.height()) << error_msg;
+
+  // Center of the touch device should correspond to the center of the display
+  // device.
+  x = touch_size.width() / 2;
+  y = touch_size.height() / 2;
+  device_manager->ApplyTouchTransformer(touch_id, &x, &y);
+  EXPECT_NEAR(display_size.width() / 2, x, max_error_delta.width())
+      << error_msg;
+  EXPECT_NEAR(display_size.height() / 2, y, max_error_delta.height())
+      << error_msg;
+
+  // Bottom right corner of the touch device should correspond to rightmost
+  // corner of display device.
+  x = touch_size.width();
+  y = touch_size.height();
+  device_manager->ApplyTouchTransformer(touch_id, &x, &y);
+  EXPECT_NEAR(display_size.width(), x, max_error_delta.width()) << error_msg;
+  EXPECT_NEAR(display_size.height(), y, max_error_delta.height()) << error_msg;
+}
+
 }  //  namespace
 
 typedef test::AshTestBase TouchTransformerControllerTest;
 
 TEST_F(TouchTransformerControllerTest, MirrorModeLetterboxing) {
   // The internal display has native resolution of 2560x1700, and in
   // mirror mode it is configured as 1920x1200. This is in letterboxing
   // mode.
   display::ManagedDisplayInfo internal_display_info =
       CreateDisplayInfo(1, 10u, gfx::Rect(0, 0, 1920, 1200));
@@ skipping 301 matching lines @@
   ui::TouchscreenDevice touch_device =
       CreateTouchscreenDevice(5, gfx::Size(1001, 1001));
 
   TouchTransformerController* tt_controller =
       Shell::GetInstance()->touch_transformer_controller();
   // Default touchscreen position range is 1001x1001;
   EXPECT_EQ(sqrt((2560.0 * 1600.0) / (1001.0 * 1001.0)),
             tt_controller->GetTouchResolutionScale(display, touch_device));
 }
 
+TEST_F(TouchTransformerControllerTest, OzoneTranslation) {
+#if defined(USE_OZONE)
+  // The internal display has size 1920 x 1200. The external display has
+  // size 1920x1200. The total frame buffer is 1920x2450,
+  // where 2458 = 1200 + 50 (hidden gap) + 1200
+  // and the second monitor is translated to Point (0, 1250) in the
+  // framebuffer.
+  const gfx::Size kDisplaySize(1920, 1200);
+  const gfx::Size kTouchSize(1920, 1200);
+  const int kHiddenGap = 50;
+  const int kDisplayId1 = 1;
+  const int kDisplayId2 = 2;
+  const int kTouchId1 = 5;
+  const int kTouchId2 = 6;
+
+  display::ManagedDisplayInfo display1 = CreateDisplayInfo(
+      kDisplayId1, kTouchId1,
+      gfx::Rect(0, 0, kDisplaySize.width(), kDisplaySize.height()));
+  display::ManagedDisplayInfo display2 =
+      CreateDisplayInfo(kDisplayId2, kTouchId2,
+                        gfx::Rect(0, kDisplaySize.height() + kHiddenGap,
+                                  kDisplaySize.width(), kDisplaySize.height()));
+
+  gfx::Size fb_size(1920, 2450);
+
+  ui::TouchscreenDevice touchscreen1 =
+      CreateTouchscreenDevice(kTouchId1, kDisplaySize);
+  ui::TouchscreenDevice touchscreen2 =
+      CreateTouchscreenDevice(kTouchId2, kDisplaySize);
+
+  TouchTransformerController* tt_controller =
+      Shell::GetInstance()->touch_transformer_controller();
+  ui::DeviceDataManager* device_manager = ui::DeviceDataManager::GetInstance();
+
+  // Mirror displays. Touch screen 2 is associated to display 1.
+  device_manager->UpdateTouchInfoForDisplay(
+      display1.id(), touchscreen1.id,
+      tt_controller->GetTouchTransform(display1, display1, touchscreen1,
+                                       kTouchSize));
+
+  device_manager->UpdateTouchInfoForDisplay(
+      display1.id(), touchscreen2.id,
+      tt_controller->GetTouchTransform(display1, display2, touchscreen2,
+                                       kTouchSize));
+
+  EXPECT_EQ(kDisplayId1,
+            device_manager->GetTargetDisplayForTouchDevice(kTouchId1));
+  EXPECT_EQ(kDisplayId1,
+            device_manager->GetTargetDisplayForTouchDevice(kTouchId2));
+
+  float x, y;
+
+  x = y = 0.0;
+  device_manager->ApplyTouchTransformer(kTouchId1, &x, &y);
+  EXPECT_NEAR(0, x, 0.5);
+  EXPECT_NEAR(0, y, 0.5);
+
+  x = y = 0.0;
+  device_manager->ApplyTouchTransformer(kTouchId2, &x, &y);
+  EXPECT_NEAR(0, x, 0.5);
+  EXPECT_NEAR(0, y, 0.5);
+
+  x = 1920.0;
+  y = 1200.0;
+  device_manager->ApplyTouchTransformer(kTouchId1, &x, &y);
+  EXPECT_NEAR(1920, x, 0.5);
+  EXPECT_NEAR(1200, y, 0.5);
+
+  x = 1920.0;
+  y = 1200.0;
+  device_manager->ApplyTouchTransformer(kTouchId2, &x, &y);
+  EXPECT_NEAR(1920, x, 0.5);
+  EXPECT_NEAR(1200, y, 0.5);
+
+  // Remove mirroring of displays.
+  device_manager->UpdateTouchInfoForDisplay(
+      display2.id(), touchscreen2.id,
+      tt_controller->GetTouchTransform(display2, display2, touchscreen2,
+                                       kTouchSize));
+
+  x = 1920.0;
+  y = 1200.0;
+  device_manager->ApplyTouchTransformer(kTouchId1, &x, &y);
+  EXPECT_NEAR(1920, x, 0.5);
+  EXPECT_NEAR(1200, y, 0.5);
+
+  x = 1920.0;
+  y = 1200.0;
+  device_manager->ApplyTouchTransformer(kTouchId2, &x, &y);
+  EXPECT_NEAR(1920, x, 0.5);
+  EXPECT_NEAR(1200 + kDisplaySize.height() + kHiddenGap, y, 0.5);
+#endif
+}
+
+TEST_F(TouchTransformerControllerTest, AccurateUserTouchCalibration) {
+  const gfx::Size kDisplaySize(1920, 1200);
+  const gfx::Size kTouchSize(1920, 1200);
+  const int kDisplayId = 1;
+  const int kTouchId = 5;
+
+  display::ManagedDisplayInfo display = CreateDisplayInfo(
+      kDisplayId, kTouchId,
+      gfx::Rect(0, 0, kDisplaySize.width(), kDisplaySize.height()));
+
+  // Assuming the user provided accurate inputs during calibration. ie the user
+  // actually tapped (100,100) when asked to tap (100,100) with no human error.
+  display::TouchCalibrationData::CalibrationPointPairQuad user_input = {{
+      std::make_pair(gfx::Point(100, 100), gfx::Point(100, 100)),
+      std::make_pair(gfx::Point(1820, 100), gfx::Point(1820, 100)),
+      std::make_pair(gfx::Point(100, 1100), gfx::Point(100, 1100)),
+      std::make_pair(gfx::Point(1820, 1100), gfx::Point(1820, 1100)),
+  }};
+  display::TouchCalibrationData touch_data(user_input, kDisplaySize);
+  display.SetTouchCalibrationData(touch_data);
+  EXPECT_TRUE(display.has_touch_calibration_data());
+
+  const std::string msg = GetTouchPointString(user_input);
+
+  gfx::Size fb_size(1920, 1200);
+
+  ui::TouchscreenDevice touchscreen =
+      CreateTouchscreenDevice(kTouchId, kTouchSize);
+
+  TouchTransformerController* tt_controller =
+      Shell::GetInstance()->touch_transformer_controller();
+  ui::DeviceDataManager* device_manager = ui::DeviceDataManager::GetInstance();
+
+  device_manager->UpdateTouchInfoForDisplay(
+      display.id(), touchscreen.id,
+      tt_controller->GetTouchTransform(display, display, touchscreen,
+                                       kTouchSize));
+
+  EXPECT_EQ(kDisplayId,
+            device_manager->GetTargetDisplayForTouchDevice(kTouchId));
+
+  CheckPointsOfInterests(kTouchId, kTouchSize, kDisplaySize, gfx::Size(1, 1),
+                         msg);
+}
+
+TEST_F(TouchTransformerControllerTest, ErrorProneUserTouchCalibration) {
+  const gfx::Size kDisplaySize(1920, 1200);
+  const gfx::Size kTouchSize(1920, 1200);
+  const int kDisplayId = 1;
+  const int kTouchId = 5;
+  // User touch inputs have a max error of 5%.
+  const float kError = 0.05;
+  // The maximum user error rate is |kError|%. Since the calibration is
+  // performed with a best fit algorithm, the error rate observed should be less
+  // than |kError|.
+  const gfx::Size kMaxErrorDelta = gfx::ScaleToCeiledSize(kTouchSize, kError);
+
+  display::ManagedDisplayInfo display = CreateDisplayInfo(
+      kDisplayId, kTouchId,
+      gfx::Rect(0, 0, kDisplaySize.width(), kDisplaySize.height()));
+
+  // Assuming the user provided inaccurate inputs during calibration. ie the
+  // user did not tap (100,100) when asked to tap (100,100) due no human error.
+  display::TouchCalibrationData::CalibrationPointPairQuad user_input = {
+      {std::make_pair(gfx::Point(100, 100),
+                      GetPointWithError(gfx::Point(100, 100), kMaxErrorDelta)),
+       std::make_pair(gfx::Point(1820, 100),
+                      GetPointWithError(gfx::Point(1820, 100), kMaxErrorDelta)),
+       std::make_pair(gfx::Point(100, 1100),
+                      GetPointWithError(gfx::Point(100, 1100), kMaxErrorDelta)),
+       std::make_pair(
+           gfx::Point(1820, 1100),
+           GetPointWithError(gfx::Point(1820, 1100), kMaxErrorDelta))}};
+  display::TouchCalibrationData touch_data(user_input, kDisplaySize);
+  display.SetTouchCalibrationData(touch_data);
+  EXPECT_TRUE(display.has_touch_calibration_data());
+
+  const std::string msg = GetTouchPointString(user_input);
+
+  ui::TouchscreenDevice touchscreen =
+      CreateTouchscreenDevice(kTouchId, kTouchSize);
+
+  TouchTransformerController* tt_controller =
+      Shell::GetInstance()->touch_transformer_controller();
+  ui::DeviceDataManager* device_manager = ui::DeviceDataManager::GetInstance();
+
+  device_manager->UpdateTouchInfoForDisplay(
+      display.id(), touchscreen.id,
+      tt_controller->GetTouchTransform(display, display, touchscreen,
+                                       kTouchSize));
+
+  EXPECT_EQ(kDisplayId,
+            device_manager->GetTargetDisplayForTouchDevice(kTouchId));
+
+  CheckPointsOfInterests(kTouchId, kTouchSize, kDisplaySize, kMaxErrorDelta,
+                         msg);
+}
+
+TEST_F(TouchTransformerControllerTest, ResolutionChangeUserTouchCalibration) {
+  const gfx::Size kDisplaySize(2560, 1600);
+  const gfx::Size kTouchSize(1920, 1200);
+  const int kDisplayId = 1;
+  const int kTouchId = 5;
+  // User touch inputs have a max error of 5%.
+  const float kError = 0.05;
+  // The maximum user error rate is |kError|%. Since the calibration is
+  // performed with a best fit algorithm, the error rate observed should be less
+  // tha |kError|.
+  gfx::Size kMaxErrorDelta = gfx::ScaleToCeiledSize(kDisplaySize, kError);
+
+  display::ManagedDisplayInfo display = CreateDisplayInfo(
+      kDisplayId, kTouchId,
+      gfx::Rect(0, 0, kDisplaySize.width(), kDisplaySize.height()));
+
+  // The calibration was performed at a resolution different from the curent
+  // resolution of the display.
+  const gfx::Size CALIBRATION_SIZE(1920, 1200);
+  display::TouchCalibrationData::CalibrationPointPairQuad user_input = {
+      {std::make_pair(gfx::Point(100, 100),
+                      GetPointWithError(gfx::Point(100, 100), kMaxErrorDelta)),
+       std::make_pair(gfx::Point(1820, 100),
+                      GetPointWithError(gfx::Point(1820, 100), kMaxErrorDelta)),
+       std::make_pair(gfx::Point(100, 1100),
+                      GetPointWithError(gfx::Point(100, 1100), kMaxErrorDelta)),
+       std::make_pair(
+           gfx::Point(1820, 1100),
+           GetPointWithError(gfx::Point(1820, 1100), kMaxErrorDelta))}};
+  display::TouchCalibrationData touch_data(user_input, CALIBRATION_SIZE);
+  display.SetTouchCalibrationData(touch_data);
+  EXPECT_TRUE(display.has_touch_calibration_data());
+
+  const std::string msg = GetTouchPointString(user_input);
+
+  ui::TouchscreenDevice touchscreen =
+      CreateTouchscreenDevice(kTouchId, kTouchSize);
+
+  TouchTransformerController* tt_controller =
+      Shell::GetInstance()->touch_transformer_controller();
+  ui::DeviceDataManager* device_manager = ui::DeviceDataManager::GetInstance();
+
+  device_manager->UpdateTouchInfoForDisplay(
+      display.id(), touchscreen.id,
+      tt_controller->GetTouchTransform(display, display, touchscreen,
+                                       kTouchSize));
+
+  EXPECT_EQ(kDisplayId,
+            device_manager->GetTargetDisplayForTouchDevice(kTouchId));
+
+  CheckPointsOfInterests(kTouchId, kTouchSize, kDisplaySize, kMaxErrorDelta,
+                         msg);
+}
+
+TEST_F(TouchTransformerControllerTest, DifferentBoundsUserTouchCalibration) {
+  // The display bounds is different from the touch device bounds in this test.
+  const gfx::Size kDisplaySize(1024, 600);
+  const gfx::Size kTouchSize(4096, 4096);
+  const int kDisplayId = 1;
+  const int kTouchId = 5;
+  const float kAcceptableError = 0.04;
+  gfx::Size kMaxErrorDelta =
+      gfx::ScaleToCeiledSize(kDisplaySize, kAcceptableError);
+
+  display::ManagedDisplayInfo display = CreateDisplayInfo(
+      kDisplayId, kTouchId,
+      gfx::Rect(0, 0, kDisplaySize.width(), kDisplaySize.height()));
+
+  // Real world data.
+  display::TouchCalibrationData::CalibrationPointPairQuad user_input = {
+      {std::make_pair(gfx::Point(136, 136), gfx::Point(538, 931)),
+       std::make_pair(gfx::Point(873, 136), gfx::Point(3475, 922)),
+       std::make_pair(gfx::Point(136, 411), gfx::Point(611, 2800)),
+       std::make_pair(gfx::Point(873, 411), gfx::Point(3535, 2949))}};
+  display::TouchCalibrationData touch_data(user_input, kDisplaySize);
+  display.SetTouchCalibrationData(touch_data);
+  EXPECT_TRUE(display.has_touch_calibration_data());
+
+  const std::string msg = GetTouchPointString(user_input);
+
+  ui::TouchscreenDevice touchscreen =
+      CreateTouchscreenDevice(kTouchId, kTouchSize);
+
+  TouchTransformerController* tt_controller =
+      Shell::GetInstance()->touch_transformer_controller();
+  ui::DeviceDataManager* device_manager = ui::DeviceDataManager::GetInstance();
+
+  device_manager->UpdateTouchInfoForDisplay(
+      display.id(), touchscreen.id,
+      tt_controller->GetTouchTransform(display, display, touchscreen,
+                                       kTouchSize));
+
+  EXPECT_EQ(kDisplayId,
+            device_manager->GetTargetDisplayForTouchDevice(kTouchId));
+
+  CheckPointsOfInterests(kTouchId, kTouchSize, kDisplaySize, kMaxErrorDelta,
+                         msg);
+}
+
+TEST_F(TouchTransformerControllerTest, LetterboxingUserTouchCalibration) {
+  // The internal display has native resolution of 2560x1700, and in
+  // mirror mode it is configured as 1920x1200. This is in letterboxing
+  // mode.
+  const gfx::Size kNativeDisplaySize(2560, 1700);
+  const gfx::Size kDisplaySize(1920, 1200);
+  const gfx::Size kTouchSize(1920, 1200);
+  const int kDisplayId = 1;
+  const int kTouchId = 5;
+
+  display::ManagedDisplayInfo internal_display_info = CreateDisplayInfo(
+      kDisplayId, kTouchId,
+      gfx::Rect(0, 0, kDisplaySize.width(), kDisplaySize.height()));
+  internal_display_info.set_is_aspect_preserving_scaling(true);
+
+  display::ManagedDisplayInfo::ManagedDisplayModeList internal_modes;
+
+  internal_modes.push_back(make_scoped_refptr(new display::ManagedDisplayMode(
+      gfx::Size(kNativeDisplaySize.width(), kNativeDisplaySize.height()), 60,
+      false, true)));
+  internal_modes.push_back(make_scoped_refptr(new display::ManagedDisplayMode(
+      gfx::Size(kDisplaySize.width(), kDisplaySize.height()), 60, false,
+      false)));
+  internal_display_info.SetManagedDisplayModes(internal_modes);
+
+  gfx::Size fb_size(kDisplaySize);
+
+  // Create the touchscreens with the same size as the framebuffer so we can
+  // share the tests between Ozone & X11.
+  ui::TouchscreenDevice internal_touchscreen =
+      CreateTouchscreenDevice(kTouchId, fb_size);
+
+  TouchTransformerController* tt_controller =
+      Shell::GetInstance()->touch_transformer_controller();
+  ui::DeviceDataManager* device_manager = ui::DeviceDataManager::GetInstance();
+
+  // Assuming the user provided inaccurate inputs during calibration. ie the
+  // user did not tap (100,100) when asked to tap (100,100) due to human error.
+  // Since the display is of size 2560x1700 and the touch device is of size
+  // 1920x1200, the corresponding points have to be scaled.
+  display::TouchCalibrationData::CalibrationPointPairQuad user_input = {{
+      std::make_pair(gfx::Point(100, 100), gfx::Point(75, 71)),
+      std::make_pair(gfx::Point(2460, 100), gfx::Point(1845, 71)),
+      std::make_pair(gfx::Point(100, 1600), gfx::Point(75, 1130)),
+      std::make_pair(gfx::Point(2460, 1600), gfx::Point(1845, 1130)),
+  }};
+  // The calibration was performed at the native display resolution.
+  display::TouchCalibrationData touch_data(user_input, kNativeDisplaySize);
+  internal_display_info.SetTouchCalibrationData(touch_data);
+  EXPECT_TRUE(internal_display_info.has_touch_calibration_data());
+
+  device_manager->UpdateTouchInfoForDisplay(
+      internal_display_info.id(), internal_touchscreen.id,
+      tt_controller->GetTouchTransform(internal_display_info,
+                                       internal_display_info,
+                                       internal_touchscreen, fb_size));
+
+  EXPECT_EQ(kDisplayId,
+            device_manager->GetTargetDisplayForTouchDevice(kTouchId));
+
+  float x, y;
+  // In letterboxing, there is (1-2560*(1200/1920)/1700)/2 = 2.95% of the
+  // height on both the top & bottom region of the screen is blank.
+  // When touch events coming at Y range [0, 1200), the mapping should be
+  // [0, ~35] ---> < 0
+  // [~35, ~1165] ---> [0, 1200)
+  // [~1165, 1200] ---> >= 1200
+  x = 100.0;
+  y = 35.0;
+  device_manager->ApplyTouchTransformer(kTouchId, &x, &y);
+  EXPECT_NEAR(100, x, 0.5);
+  EXPECT_NEAR(0, y, 0.5);
+
+  x = 100.0;
+  y = 1165.0;
+  device_manager->ApplyTouchTransformer(kTouchId, &x, &y);
+  EXPECT_NEAR(100, x, 0.5);
+  EXPECT_NEAR(1200, y, 0.5);
+}
+
+TEST_F(TouchTransformerControllerTest, PillarBoxingUserTouchCalibration) {
+  // The internal display has native resolution of 2560x1700, and in
+  // mirror mode it is configured as 1920x1200. This is in letterboxing
+  // mode.
+  const gfx::Size kNativeDisplaySize(2560, 1600);
+  const gfx::Size kDisplaySize(1920, 1400);
+  const gfx::Size kTouchSize(1920, 1400);
+  const int kDisplayId = 1;
+  const int kTouchId = 5;
+
+  display::ManagedDisplayInfo internal_display_info = CreateDisplayInfo(
+      kDisplayId, kTouchId,
+      gfx::Rect(0, 0, kDisplaySize.width(), kDisplaySize.height()));
+  internal_display_info.set_is_aspect_preserving_scaling(true);
+
+  display::ManagedDisplayInfo::ManagedDisplayModeList internal_modes;
+
+  internal_modes.push_back(make_scoped_refptr(new display::ManagedDisplayMode(
+      gfx::Size(kNativeDisplaySize.width(), kNativeDisplaySize.height()), 60,
+      false, true)));
+  internal_modes.push_back(make_scoped_refptr(new display::ManagedDisplayMode(
+      gfx::Size(kDisplaySize.width(), kDisplaySize.height()), 60, false,
+      false)));
+  internal_display_info.SetManagedDisplayModes(internal_modes);
+
+  gfx::Size fb_size(kDisplaySize);
+
+  // Create the touchscreens with the same size as the framebuffer so we can
+  // share the tests between Ozone & X11.
+  ui::TouchscreenDevice internal_touchscreen =
+      CreateTouchscreenDevice(kTouchId, fb_size);
+
+  TouchTransformerController* tt_controller =
+      Shell::GetInstance()->touch_transformer_controller();
+  ui::DeviceDataManager* device_manager = ui::DeviceDataManager::GetInstance();
+
+  // Assuming the user provided accurate inputs during calibration. ie the user
+  // actually tapped (100,100) when asked to tap (100,100) with no human error.
+  // Since the display is of size 2560x1600 and the touch device is of size
+  // 1920x1400, the corresponding points have to be scaled.
+  display::TouchCalibrationData::CalibrationPointPairQuad user_input = {{
+      std::make_pair(gfx::Point(100, 100), gfx::Point(75, 88)),
+      std::make_pair(gfx::Point(2460, 100), gfx::Point(1845, 88)),
+      std::make_pair(gfx::Point(100, 1500), gfx::Point(75, 1313)),
+      std::make_pair(gfx::Point(2460, 1500), gfx::Point(1845, 1313)),
+  }};
+  // The calibration was performed at the native display resolution.
+  display::TouchCalibrationData touch_data(user_input, kNativeDisplaySize);
+  internal_display_info.SetTouchCalibrationData(touch_data);
+  EXPECT_TRUE(internal_display_info.has_touch_calibration_data());
+
+  device_manager->UpdateTouchInfoForDisplay(
+      internal_display_info.id(), internal_touchscreen.id,
+      tt_controller->GetTouchTransform(internal_display_info,
+                                       internal_display_info,
+                                       internal_touchscreen, fb_size));
+
+  EXPECT_EQ(kDisplayId,
+            device_manager->GetTargetDisplayForTouchDevice(kTouchId));
+
+  float x, y;
+  // In pillarboxing, there is (1-1600*(1920/1400)/2560)/2 = 7.14% of the
+  // width on both the left & region region of the screen is blank.
+  // When touch events coming at X range [0, 1920), the mapping should be
+  // [0, ~137] ---> < 0
+  // [~137, ~1782] ---> [0, 1920)
+  // [~1782, 1920] ---> >= 1920
+  x = 137.0;
+  y = 0.0;
+  device_manager->ApplyTouchTransformer(kTouchId, &x, &y);
+  EXPECT_NEAR(0, x, 0.5);
+  EXPECT_NEAR(0, y, 0.5);
+
+  x = 1782.0;
+  y = 0.0;
+  device_manager->ApplyTouchTransformer(kTouchId, &x, &y);
+  EXPECT_NEAR(1920, x, 0.5);
+  EXPECT_NEAR(0, y, 0.5);
+}
+
 }  // namespace ash