Report gui::DisplayInfo to clients with window info changes

InputFlinger needs to know specifications about displays such as
orientation and projection from SurfaceFlinger to support the
MotionEvent#getRaw API, which returns coordinates in logical display
space at the moment.

Since dispatcher gets window information from SF, we need to send the
display information that affects input dispatching at the same time as
updating window information to ensure those two pieces of information
remain in sync.

Instead of sending display information along with each window, we
attempt to reduce the amount of information sent through binder by
sending DisplayInfo separately to WindowInfos. The newly added
DisplayInfo struct should only be used by InputFlinger to support raw
coordinates for now, with the goal of removing it altogether in the
future.

Bug: 179274888
Test: atest libgui_test inputflinger_tests
Test: manual, ensure input works

Change-Id: I87429ca4ced5f105f49a117c676cba29f8a5c4da

1 files changed, 28 insertions, 0 deletions

diff --git a/services/surfaceflinger/DisplayDevice.cpp b/services/surfaceflinger/DisplayDevice.cpp
index 802a17d981..fd93b2d8f7 100644
--- a/services/surfaceflinger/DisplayDevice.cpp
+++ b/services/surfaceflinger/DisplayDevice.cpp
@@ -139,6 +139,34 @@ uint32_t DisplayDevice::getPageFlipCount() const {
     return mCompositionDisplay->getRenderSurface()->getPageFlipCount();
 }
 
+std::pair<gui::DisplayInfo, ui::Transform> DisplayDevice::getInputInfo() const {
+    gui::DisplayInfo info;
+    info.displayId = getLayerStack().id;
+
+    // The physical orientation is set when the orientation of the display panel is
+    // different than the default orientation of the device. Other services like
+    // InputFlinger do not know about this, so we do not need to expose the physical
+    // orientation of the panel outside of SurfaceFlinger.
+    const ui::Rotation inversePhysicalOrientation = ui::ROTATION_0 - mPhysicalOrientation;
+    auto width = getWidth();
+    auto height = getHeight();
+    if (inversePhysicalOrientation == ui::ROTATION_90 ||
+        inversePhysicalOrientation == ui::ROTATION_270) {
+        std::swap(width, height);
+    }
+    const ui::Transform undoPhysicalOrientation(ui::Transform::toRotationFlags(
+                                                        inversePhysicalOrientation),
+                                                width, height);
+    const auto& displayTransform = undoPhysicalOrientation * getTransform();
+    // Send the inverse display transform to input so it can convert display coordinates to
+    // logical display.
+    info.transform = displayTransform.inverse();
+
+    info.logicalWidth = getLayerStackSpaceRect().width();
+    info.logicalHeight = getLayerStackSpaceRect().height();
+    return {info, displayTransform};
+}
+
 // ----------------------------------------------------------------------------
 void DisplayDevice::setPowerMode(hal::PowerMode mode) {
     mPowerMode = mode;