diff --git a/libs/gui/ISurfaceComposer.cpp b/libs/gui/ISurfaceComposer.cpp
index ab4d51e..d34fe3b 100644
--- a/libs/gui/ISurfaceComposer.cpp
+++ b/libs/gui/ISurfaceComposer.cpp
@@ -110,10 +110,10 @@
     }
 
     virtual status_t captureScreen(const sp<IBinder>& display, sp<GraphicBuffer>* outBuffer,
-                                   bool& outCapturedSecureLayers, const ui::Dataspace reqDataspace,
-                                   const ui::PixelFormat reqPixelFormat, Rect sourceCrop,
+                                   bool& outCapturedSecureLayers, ui::Dataspace reqDataspace,
+                                   ui::PixelFormat reqPixelFormat, const Rect& sourceCrop,
                                    uint32_t reqWidth, uint32_t reqHeight, bool useIdentityTransform,
-                                   ISurfaceComposer::Rotation rotation, bool captureSecureLayers) {
+                                   ui::Rotation rotation, bool captureSecureLayers) {
         Parcel data, reply;
         data.writeInterfaceToken(ISurfaceComposer::getInterfaceDescriptor());
         data.writeStrongBinder(display);
@@ -1214,8 +1214,7 @@
             bool capturedSecureLayers = false;
             status_t res = captureScreen(display, &outBuffer, capturedSecureLayers, reqDataspace,
                                          reqPixelFormat, sourceCrop, reqWidth, reqHeight,
-                                         useIdentityTransform,
-                                         static_cast<ISurfaceComposer::Rotation>(rotation),
+                                         useIdentityTransform, ui::toRotation(rotation),
                                          captureSecureLayers);
 
             reply->writeInt32(res);
diff --git a/libs/gui/LayerState.cpp b/libs/gui/LayerState.cpp
index e033f93..a7c4f46 100644
--- a/libs/gui/LayerState.cpp
+++ b/libs/gui/LayerState.cpp
@@ -203,7 +203,6 @@
 DisplayState::DisplayState() :
     what(0),
     layerStack(0),
-    orientation(eOrientationDefault),
     viewport(Rect::EMPTY_RECT),
     frame(Rect::EMPTY_RECT),
     width(0),
@@ -215,7 +214,7 @@
     output.writeStrongBinder(IInterface::asBinder(surface));
     output.writeUint32(what);
     output.writeUint32(layerStack);
-    output.writeUint32(orientation);
+    output.writeUint32(toRotationInt(orientation));
     output.write(viewport);
     output.write(frame);
     output.writeUint32(width);
@@ -228,7 +227,7 @@
     surface = interface_cast<IGraphicBufferProducer>(input.readStrongBinder());
     what = input.readUint32();
     layerStack = input.readUint32();
-    orientation = input.readUint32();
+    orientation = ui::toRotation(input.readUint32());
     input.read(viewport);
     input.read(frame);
     width = input.readUint32();
diff --git a/libs/gui/SurfaceComposerClient.cpp b/libs/gui/SurfaceComposerClient.cpp
index f378fc5..1dac70a 100644
--- a/libs/gui/SurfaceComposerClient.cpp
+++ b/libs/gui/SurfaceComposerClient.cpp
@@ -1399,9 +1399,9 @@
 }
 
 void SurfaceComposerClient::Transaction::setDisplayProjection(const sp<IBinder>& token,
-        uint32_t orientation,
-        const Rect& layerStackRect,
-        const Rect& displayRect) {
+                                                              ui::Rotation orientation,
+                                                              const Rect& layerStackRect,
+                                                              const Rect& displayRect) {
     DisplayState& s(getDisplayState(token));
     s.orientation = orientation;
     s.viewport = layerStackRect;
@@ -1773,28 +1773,26 @@
 
 // ----------------------------------------------------------------------------
 
-status_t ScreenshotClient::capture(const sp<IBinder>& display, const ui::Dataspace reqDataSpace,
-                                   const ui::PixelFormat reqPixelFormat, Rect sourceCrop,
+status_t ScreenshotClient::capture(const sp<IBinder>& display, ui::Dataspace reqDataSpace,
+                                   ui::PixelFormat reqPixelFormat, const Rect& sourceCrop,
                                    uint32_t reqWidth, uint32_t reqHeight, bool useIdentityTransform,
-                                   uint32_t rotation, bool captureSecureLayers,
+                                   ui::Rotation rotation, bool captureSecureLayers,
                                    sp<GraphicBuffer>* outBuffer, bool& outCapturedSecureLayers) {
     sp<ISurfaceComposer> s(ComposerService::getComposerService());
     if (s == nullptr) return NO_INIT;
-    status_t ret =
-            s->captureScreen(display, outBuffer, outCapturedSecureLayers, reqDataSpace,
-                             reqPixelFormat, sourceCrop, reqWidth, reqHeight, useIdentityTransform,
-                             static_cast<ISurfaceComposer::Rotation>(rotation),
-                             captureSecureLayers);
+    status_t ret = s->captureScreen(display, outBuffer, outCapturedSecureLayers, reqDataSpace,
+                                    reqPixelFormat, sourceCrop, reqWidth, reqHeight,
+                                    useIdentityTransform, rotation, captureSecureLayers);
     if (ret != NO_ERROR) {
         return ret;
     }
     return ret;
 }
 
-status_t ScreenshotClient::capture(const sp<IBinder>& display, const ui::Dataspace reqDataSpace,
-                                   const ui::PixelFormat reqPixelFormat, Rect sourceCrop,
+status_t ScreenshotClient::capture(const sp<IBinder>& display, ui::Dataspace reqDataSpace,
+                                   ui::PixelFormat reqPixelFormat, const Rect& sourceCrop,
                                    uint32_t reqWidth, uint32_t reqHeight, bool useIdentityTransform,
-                                   uint32_t rotation, sp<GraphicBuffer>* outBuffer) {
+                                   ui::Rotation rotation, sp<GraphicBuffer>* outBuffer) {
     bool ignored;
     return capture(display, reqDataSpace, reqPixelFormat, sourceCrop, reqWidth, reqHeight,
                    useIdentityTransform, rotation, false, outBuffer, ignored);
@@ -1807,9 +1805,8 @@
     return s->captureScreen(displayOrLayerStack, outDataspace, outBuffer);
 }
 
-status_t ScreenshotClient::captureLayers(const sp<IBinder>& layerHandle,
-                                         const ui::Dataspace reqDataSpace,
-                                         const ui::PixelFormat reqPixelFormat, Rect sourceCrop,
+status_t ScreenshotClient::captureLayers(const sp<IBinder>& layerHandle, ui::Dataspace reqDataSpace,
+                                         ui::PixelFormat reqPixelFormat, const Rect& sourceCrop,
                                          float frameScale, sp<GraphicBuffer>* outBuffer) {
     sp<ISurfaceComposer> s(ComposerService::getComposerService());
     if (s == nullptr) return NO_INIT;
@@ -1819,8 +1816,8 @@
 }
 
 status_t ScreenshotClient::captureChildLayers(
-        const sp<IBinder>& layerHandle, const ui::Dataspace reqDataSpace,
-        const ui::PixelFormat reqPixelFormat, Rect sourceCrop,
+        const sp<IBinder>& layerHandle, ui::Dataspace reqDataSpace, ui::PixelFormat reqPixelFormat,
+        const Rect& sourceCrop,
         const std::unordered_set<sp<IBinder>, ISurfaceComposer::SpHash<IBinder>>& excludeHandles,
         float frameScale, sp<GraphicBuffer>* outBuffer) {
     sp<ISurfaceComposer> s(ComposerService::getComposerService());
@@ -1830,5 +1827,5 @@
                              excludeHandles, frameScale, true /* childrenOnly */);
     return ret;
 }
-// ----------------------------------------------------------------------------
-}; // namespace android
+
+} // namespace android
diff --git a/libs/gui/include/gui/ISurfaceComposer.h b/libs/gui/include/gui/ISurfaceComposer.h
index 998973c..9804c92 100644
--- a/libs/gui/include/gui/ISurfaceComposer.h
+++ b/libs/gui/include/gui/ISurfaceComposer.h
@@ -34,6 +34,7 @@
 #include <ui/GraphicTypes.h>
 #include <ui/PhysicalDisplayId.h>
 #include <ui/PixelFormat.h>
+#include <ui/Rotation.h>
 
 #include <utils/Errors.h>
 #include <utils/RefBase.h>
@@ -81,13 +82,6 @@
         eEarlyWakeup = 0x04
     };
 
-    enum Rotation {
-        eRotateNone = 0,
-        eRotate90   = 1,
-        eRotate180  = 2,
-        eRotate270  = 3
-    };
-
     enum VsyncSource {
         eVsyncSourceApp = 0,
         eVsyncSourceSurfaceFlinger = 1
@@ -249,10 +243,10 @@
      * it) around its center.
      */
     virtual status_t captureScreen(const sp<IBinder>& display, sp<GraphicBuffer>* outBuffer,
-                                   bool& outCapturedSecureLayers, const ui::Dataspace reqDataspace,
-                                   const ui::PixelFormat reqPixelFormat, Rect sourceCrop,
+                                   bool& outCapturedSecureLayers, ui::Dataspace reqDataspace,
+                                   ui::PixelFormat reqPixelFormat, const Rect& sourceCrop,
                                    uint32_t reqWidth, uint32_t reqHeight, bool useIdentityTransform,
-                                   Rotation rotation = eRotateNone,
+                                   ui::Rotation rotation = ui::ROTATION_0,
                                    bool captureSecureLayers = false) = 0;
     /**
      * Capture the specified screen. This requires READ_FRAME_BUFFER
@@ -276,8 +270,9 @@
      * it) around its center.
      */
     virtual status_t captureScreen(const sp<IBinder>& display, sp<GraphicBuffer>* outBuffer,
-                                   Rect sourceCrop, uint32_t reqWidth, uint32_t reqHeight,
-                                   bool useIdentityTransform, Rotation rotation = eRotateNone) {
+                                   const Rect& sourceCrop, uint32_t reqWidth, uint32_t reqHeight,
+                                   bool useIdentityTransform,
+                                   ui::Rotation rotation = ui::ROTATION_0) {
         bool outIgnored;
         return captureScreen(display, outBuffer, outIgnored, ui::Dataspace::V0_SRGB,
                              ui::PixelFormat::RGBA_8888, sourceCrop, reqWidth, reqHeight,
@@ -301,8 +296,7 @@
      */
     virtual status_t captureLayers(
             const sp<IBinder>& layerHandleBinder, sp<GraphicBuffer>* outBuffer,
-            const ui::Dataspace reqDataspace, const ui::PixelFormat reqPixelFormat,
-            const Rect& sourceCrop,
+            ui::Dataspace reqDataspace, ui::PixelFormat reqPixelFormat, const Rect& sourceCrop,
             const std::unordered_set<sp<IBinder>, SpHash<IBinder>>& excludeHandles,
             float frameScale = 1.0, bool childrenOnly = false) = 0;
 
diff --git a/libs/gui/include/gui/LayerState.h b/libs/gui/include/gui/LayerState.h
index c2b5119..fb18639 100644
--- a/libs/gui/include/gui/LayerState.h
+++ b/libs/gui/include/gui/LayerState.h
@@ -35,6 +35,7 @@
 #include <ui/GraphicTypes.h>
 #include <ui/Rect.h>
 #include <ui/Region.h>
+#include <ui/Rotation.h>
 
 namespace android {
 
@@ -218,15 +219,6 @@
 
 struct DisplayState {
     enum {
-        eOrientationDefault = 0,
-        eOrientation90 = 1,
-        eOrientation180 = 2,
-        eOrientation270 = 3,
-        eOrientationUnchanged = 4,
-        eOrientationSwapMask = 0x01
-    };
-
-    enum {
         eSurfaceChanged = 0x01,
         eLayerStackChanged = 0x02,
         eDisplayProjectionChanged = 0x04,
@@ -252,7 +244,7 @@
     // 0, layers will be scaled by a factor of 2 and translated by (20, 10).
     // When orientation is 1, layers will be additionally rotated by 90
     // degrees around the origin clockwise and translated by (W, 0).
-    uint32_t orientation;
+    ui::Rotation orientation = ui::ROTATION_0;
     Rect viewport;
     Rect frame;
 
diff --git a/libs/gui/include/gui/SurfaceComposerClient.h b/libs/gui/include/gui/SurfaceComposerClient.h
index 86468a4..44f29ea 100644
--- a/libs/gui/include/gui/SurfaceComposerClient.h
+++ b/libs/gui/include/gui/SurfaceComposerClient.h
@@ -35,6 +35,7 @@
 #include <ui/FrameStats.h>
 #include <ui/GraphicTypes.h>
 #include <ui/PixelFormat.h>
+#include <ui/Rotation.h>
 
 #include <gui/CpuConsumer.h>
 #include <gui/ISurfaceComposer.h>
@@ -531,10 +532,8 @@
          * mapped to. displayRect is specified post-orientation, that is
          * it uses the orientation seen by the end-user.
          */
-        void setDisplayProjection(const sp<IBinder>& token,
-                uint32_t orientation,
-                const Rect& layerStackRect,
-                const Rect& displayRect);
+        void setDisplayProjection(const sp<IBinder>& token, ui::Rotation orientation,
+                                  const Rect& layerStackRect, const Rect& displayRect);
         void setDisplaySize(const sp<IBinder>& token, uint32_t width, uint32_t height);
         void setAnimationTransaction();
         void setEarlyWakeup();
@@ -548,10 +547,8 @@
     static status_t getHdrCapabilities(const sp<IBinder>& display,
             HdrCapabilities* outCapabilities);
 
-    static void setDisplayProjection(const sp<IBinder>& token,
-            uint32_t orientation,
-            const Rect& layerStackRect,
-            const Rect& displayRect);
+    static void setDisplayProjection(const sp<IBinder>& token, ui::Rotation orientation,
+                                     const Rect& layerStackRect, const Rect& displayRect);
 
     inline sp<ISurfaceComposerClient> getClient() { return mClient; }
 
@@ -583,23 +580,23 @@
 public:
     // if cropping isn't required, callers may pass in a default Rect, e.g.:
     //   capture(display, producer, Rect(), reqWidth, ...);
-    static status_t capture(const sp<IBinder>& display, const ui::Dataspace reqDataSpace,
-                            const ui::PixelFormat reqPixelFormat, Rect sourceCrop,
+    static status_t capture(const sp<IBinder>& display, ui::Dataspace reqDataSpace,
+                            ui::PixelFormat reqPixelFormat, const Rect& sourceCrop,
                             uint32_t reqWidth, uint32_t reqHeight, bool useIdentityTransform,
-                            uint32_t rotation, bool captureSecureLayers,
+                            ui::Rotation rotation, bool captureSecureLayers,
                             sp<GraphicBuffer>* outBuffer, bool& outCapturedSecureLayers);
-    static status_t capture(const sp<IBinder>& display, const ui::Dataspace reqDataSpace,
-                            const ui::PixelFormat reqPixelFormat, Rect sourceCrop,
+    static status_t capture(const sp<IBinder>& display, ui::Dataspace reqDataSpace,
+                            ui::PixelFormat reqPixelFormat, const Rect& sourceCrop,
                             uint32_t reqWidth, uint32_t reqHeight, bool useIdentityTransform,
-                            uint32_t rotation, sp<GraphicBuffer>* outBuffer);
+                            ui::Rotation rotation, sp<GraphicBuffer>* outBuffer);
     static status_t capture(uint64_t displayOrLayerStack, ui::Dataspace* outDataspace,
                             sp<GraphicBuffer>* outBuffer);
-    static status_t captureLayers(const sp<IBinder>& layerHandle, const ui::Dataspace reqDataSpace,
-                                  const ui::PixelFormat reqPixelFormat, Rect sourceCrop,
+    static status_t captureLayers(const sp<IBinder>& layerHandle, ui::Dataspace reqDataSpace,
+                                  ui::PixelFormat reqPixelFormat, const Rect& sourceCrop,
                                   float frameScale, sp<GraphicBuffer>* outBuffer);
     static status_t captureChildLayers(
-            const sp<IBinder>& layerHandle, const ui::Dataspace reqDataSpace,
-            const ui::PixelFormat reqPixelFormat, Rect sourceCrop,
+            const sp<IBinder>& layerHandle, ui::Dataspace reqDataSpace,
+            ui::PixelFormat reqPixelFormat, const Rect& sourceCrop,
             const std::unordered_set<sp<IBinder>, ISurfaceComposer::SpHash<IBinder>>&
                     excludeHandles,
             float frameScale, sp<GraphicBuffer>* outBuffer);
diff --git a/libs/gui/tests/BLASTBufferQueue_test.cpp b/libs/gui/tests/BLASTBufferQueue_test.cpp
index 0f618f1..85cf62f 100644
--- a/libs/gui/tests/BLASTBufferQueue_test.cpp
+++ b/libs/gui/tests/BLASTBufferQueue_test.cpp
@@ -127,7 +127,7 @@
         ASSERT_EQ(NO_ERROR,
                   igbProducer->connect(new DummyProducerListener, NATIVE_WINDOW_API_CPU, false,
                                        &qbOutput));
-        ASSERT_NE(ui::Transform::orientation_flags::ROT_INVALID, qbOutput.transformHint);
+        ASSERT_NE(ui::Transform::ROT_INVALID, qbOutput.transformHint);
         producer = igbProducer;
     }
 
@@ -266,7 +266,7 @@
                                                    NATIVE_WINDOW_SCALING_MODE_FREEZE, 0,
                                                    Fence::NO_FENCE);
     igbProducer->queueBuffer(slot, input, &qbOutput);
-    ASSERT_NE(ui::Transform::orientation_flags::ROT_INVALID, qbOutput.transformHint);
+    ASSERT_NE(ui::Transform::ROT_INVALID, qbOutput.transformHint);
 
     adapter.waitForCallbacks();
 
@@ -349,7 +349,7 @@
                                                    NATIVE_WINDOW_SCALING_MODE_FREEZE, 0,
                                                    Fence::NO_FENCE);
     igbProducer->queueBuffer(slot, input, &qbOutput);
-    ASSERT_NE(ui::Transform::orientation_flags::ROT_INVALID, qbOutput.transformHint);
+    ASSERT_NE(ui::Transform::ROT_INVALID, qbOutput.transformHint);
 
     adapter.waitForCallbacks();
     // capture screen and verify that it is red
@@ -410,7 +410,7 @@
                                                    NATIVE_WINDOW_SCALING_MODE_SCALE_CROP, 0,
                                                    Fence::NO_FENCE);
     igbProducer->queueBuffer(slot, input, &qbOutput);
-    ASSERT_NE(ui::Transform::orientation_flags::ROT_INVALID, qbOutput.transformHint);
+    ASSERT_NE(ui::Transform::ROT_INVALID, qbOutput.transformHint);
 
     adapter.waitForCallbacks();
     // capture screen and verify that it is red
@@ -456,7 +456,7 @@
                                                        NATIVE_WINDOW_SCALING_MODE_FREEZE, tr,
                                                        Fence::NO_FENCE);
         igbProducer->queueBuffer(slot, input, &qbOutput);
-        ASSERT_NE(ui::Transform::orientation_flags::ROT_INVALID, qbOutput.transformHint);
+        ASSERT_NE(ui::Transform::ROT_INVALID, qbOutput.transformHint);
 
         adapter.waitForCallbacks();
         bool capturedSecureLayers;
diff --git a/libs/gui/tests/Surface_test.cpp b/libs/gui/tests/Surface_test.cpp
index 0445755..f9540b2 100644
--- a/libs/gui/tests/Surface_test.cpp
+++ b/libs/gui/tests/Surface_test.cpp
@@ -742,11 +742,10 @@
     status_t setActiveColorMode(const sp<IBinder>& /*display*/,
         ColorMode /*colorMode*/) override { return NO_ERROR; }
     status_t captureScreen(const sp<IBinder>& /*display*/, sp<GraphicBuffer>* /*outBuffer*/,
-                           bool& /* outCapturedSecureLayers */,
-                           const ui::Dataspace /*reqDataspace*/,
-                           const ui::PixelFormat /*reqPixelFormat*/, Rect /*sourceCrop*/,
+                           bool& /*outCapturedSecureLayers*/, ui::Dataspace /*reqDataspace*/,
+                           ui::PixelFormat /*reqPixelFormat*/, const Rect& /*sourceCrop*/,
                            uint32_t /*reqWidth*/, uint32_t /*reqHeight*/,
-                           bool /*useIdentityTransform*/, Rotation /*rotation*/,
+                           bool /*useIdentityTransform*/, ui::Rotation,
                            bool /*captureSecureLayers*/) override {
         return NO_ERROR;
     }
@@ -766,7 +765,7 @@
     }
     virtual status_t captureLayers(
             const sp<IBinder>& /*parentHandle*/, sp<GraphicBuffer>* /*outBuffer*/,
-            const ui::Dataspace /*reqDataspace*/, const ui::PixelFormat /*reqPixelFormat*/,
+            ui::Dataspace /*reqDataspace*/, ui::PixelFormat /*reqPixelFormat*/,
             const Rect& /*sourceCrop*/,
             const std::unordered_set<sp<IBinder>,
                                      ISurfaceComposer::SpHash<IBinder>>& /*excludeHandles*/,
diff --git a/libs/input/TouchVideoFrame.cpp b/libs/input/TouchVideoFrame.cpp
index 8a4298a..145b4ae 100644
--- a/libs/input/TouchVideoFrame.cpp
+++ b/libs/input/TouchVideoFrame.cpp
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+#include <input/DisplayViewport.h>
 #include <input/TouchVideoFrame.h>
 
 namespace android {
diff --git a/libs/input/tests/TouchVideoFrame_test.cpp b/libs/input/tests/TouchVideoFrame_test.cpp
index 815424e..1ec9358 100644
--- a/libs/input/tests/TouchVideoFrame_test.cpp
+++ b/libs/input/tests/TouchVideoFrame_test.cpp
@@ -16,6 +16,7 @@
 
 #include <gtest/gtest.h>
 
+#include <input/DisplayViewport.h>
 #include <input/TouchVideoFrame.h>
 
 namespace android {
diff --git a/libs/ui/include/ui/DisplayInfo.h b/libs/ui/include/ui/DisplayInfo.h
index 0772210..38f8d6b 100644
--- a/libs/ui/include/ui/DisplayInfo.h
+++ b/libs/ui/include/ui/DisplayInfo.h
@@ -20,6 +20,7 @@
 #include <stdint.h>
 #include <sys/types.h>
 
+#include <ui/Rotation.h>
 #include <utils/Timers.h>
 
 namespace android {
@@ -33,7 +34,7 @@
     float ydpi{0};
     float fps{0};
     float density{0};
-    uint8_t orientation{0};
+    ui::Rotation orientation{ui::ROTATION_0};
     bool secure{false};
     nsecs_t appVsyncOffset{0};
     nsecs_t presentationDeadline{0};
@@ -42,14 +43,6 @@
     uint32_t layerStack{NO_LAYER_STACK};
 };
 
-/* Display orientations as defined in Surface.java and ISurfaceComposer.h. */
-enum {
-    DISPLAY_ORIENTATION_0 = 0,
-    DISPLAY_ORIENTATION_90 = 1,
-    DISPLAY_ORIENTATION_180 = 2,
-    DISPLAY_ORIENTATION_270 = 3
-};
-
 } // namespace android
 
 #endif // ANDROID_COMPOSER_DISPLAY_INFO_H
diff --git a/libs/ui/include/ui/Rotation.h b/libs/ui/include/ui/Rotation.h
new file mode 100644
index 0000000..89008f6
--- /dev/null
+++ b/libs/ui/include/ui/Rotation.h
@@ -0,0 +1,57 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <type_traits>
+
+namespace android::ui {
+
+enum class Rotation { Rotation0 = 0, Rotation90 = 1, Rotation180 = 2, Rotation270 = 3 };
+
+// Equivalent to Surface.java constants.
+constexpr auto ROTATION_0 = Rotation::Rotation0;
+constexpr auto ROTATION_90 = Rotation::Rotation90;
+constexpr auto ROTATION_180 = Rotation::Rotation180;
+constexpr auto ROTATION_270 = Rotation::Rotation270;
+
+constexpr auto toRotation(std::underlying_type_t<Rotation> rotation) {
+    return static_cast<Rotation>(rotation);
+}
+
+constexpr auto toRotationInt(Rotation rotation) {
+    return static_cast<std::underlying_type_t<Rotation>>(rotation);
+}
+
+constexpr Rotation operator+(Rotation lhs, Rotation rhs) {
+    constexpr auto N = toRotationInt(ROTATION_270) + 1;
+    return toRotation((toRotationInt(lhs) + toRotationInt(rhs)) % N);
+}
+
+constexpr const char* toCString(Rotation rotation) {
+    switch (rotation) {
+        case ROTATION_0:
+            return "ROTATION_0";
+        case ROTATION_90:
+            return "ROTATION_90";
+        case ROTATION_180:
+            return "ROTATION_180";
+        case ROTATION_270:
+            return "ROTATION_270";
+    }
+}
+
+} // namespace android::ui
diff --git a/libs/ui/include/ui/Transform.h b/libs/ui/include/ui/Transform.h
index de07684..c6bb598 100644
--- a/libs/ui/include/ui/Transform.h
+++ b/libs/ui/include/ui/Transform.h
@@ -14,8 +14,7 @@
  * limitations under the License.
  */
 
-#ifndef ANDROID_TRANSFORM_H
-#define ANDROID_TRANSFORM_H
+#pragma once
 
 #include <stdint.h>
 #include <sys/types.h>
@@ -28,6 +27,7 @@
 #include <math/vec3.h>
 #include <ui/Point.h>
 #include <ui/Rect.h>
+#include <ui/Rotation.h>
 
 namespace android {
 
@@ -42,13 +42,13 @@
     explicit Transform(uint32_t orientation, int w = 0, int h = 0);
     ~Transform();
 
-    enum orientation_flags {
-        ROT_0   = 0x00000000,
-        FLIP_H  = HAL_TRANSFORM_FLIP_H,
-        FLIP_V  = HAL_TRANSFORM_FLIP_V,
-        ROT_90  = HAL_TRANSFORM_ROT_90,
-        ROT_180 = FLIP_H|FLIP_V,
-        ROT_270 = ROT_180|ROT_90,
+    enum RotationFlags : uint32_t {
+        ROT_0 = 0,
+        FLIP_H = HAL_TRANSFORM_FLIP_H,
+        FLIP_V = HAL_TRANSFORM_FLIP_V,
+        ROT_90 = HAL_TRANSFORM_ROT_90,
+        ROT_180 = FLIP_H | FLIP_V,
+        ROT_270 = ROT_180 | ROT_90,
         ROT_INVALID = 0x80
     };
 
@@ -100,6 +100,8 @@
     void dump(std::string& result, const char* name) const;
     void dump(const char* name) const;
 
+    static RotationFlags toRotationFlags(Rotation);
+
 private:
     struct mat33 {
         vec3 v[3];
@@ -117,13 +119,26 @@
     mutable uint32_t    mType;
 };
 
-static inline void PrintTo(const Transform& t, ::std::ostream* os) {
+inline void PrintTo(const Transform& t, ::std::ostream* os) {
     std::string out;
     t.dump(out, "ui::Transform");
     *os << out;
 }
 
+inline Transform::RotationFlags Transform::toRotationFlags(Rotation rotation) {
+    switch (rotation) {
+        case ROTATION_0:
+            return ROT_0;
+        case ROTATION_90:
+            return ROT_90;
+        case ROTATION_180:
+            return ROT_180;
+        case ROTATION_270:
+            return ROT_270;
+        default:
+            return ROT_INVALID;
+    }
+}
+
 }  // namespace ui
 }  // namespace android
-
-#endif /* ANDROID_TRANSFORM_H */
diff --git a/libs/ui/include_vndk/ui/Rotation.h b/libs/ui/include_vndk/ui/Rotation.h
new file mode 120000
index 0000000..d84fb4b
--- /dev/null
+++ b/libs/ui/include_vndk/ui/Rotation.h
@@ -0,0 +1 @@
+../../include/ui/Rotation.h
\ No newline at end of file