Rotate TouchVideoFrames

When a screen orientation change happens, the touch coordinates are
adjusted in InputReader to accomodate this rotation. When the user is
holding the device, the origin (0, 0) is always at the top left of the
screen.
However, currently, the TouchVideoFrames are not being rotated. This
presents a problem, because the touch coordinates cannot be directly
matched to the heatmap, as received in the HAL.

To account for this, we rotate the touch video frame.

Test: atest libinput_tests inputflinger_tests
Bug: 123241238
Change-Id: Iff45c68b1d2b237d2b1657ed76f50bb23ef8468a

1 files changed, 58 insertions, 0 deletions

diff --git a/libs/input/TouchVideoFrame.cpp b/libs/input/TouchVideoFrame.cpp
index 35cb4a73ea..8a4298a36f 100644
--- a/libs/input/TouchVideoFrame.cpp
+++ b/libs/input/TouchVideoFrame.cpp
@@ -39,4 +39,62 @@ const std::vector<int16_t>& TouchVideoFrame::getData() const { return mData; }
 
 const struct timeval& TouchVideoFrame::getTimestamp() const { return mTimestamp; }
 
+void TouchVideoFrame::rotate(int32_t orientation) {
+    switch (orientation) {
+        case DISPLAY_ORIENTATION_90:
+            rotateQuarterTurn(true /*clockwise*/);
+            break;
+        case DISPLAY_ORIENTATION_180:
+            rotate180();
+            break;
+        case DISPLAY_ORIENTATION_270:
+            rotateQuarterTurn(false /*clockwise*/);
+            break;
+    }
+}
+
+/**
+ * Rotate once clockwise by a quarter turn === rotate 90 degrees
+ * Rotate once counterclockwise by a quarter turn === rotate 270 degrees
+ * For a clockwise rotation:
+ *     An element at position (i, j) is rotated to (j, height - i - 1)
+ * For a counterclockwise rotation:
+ *     An element at position (i, j) is rotated to (width - j - 1, i)
+ */
+void TouchVideoFrame::rotateQuarterTurn(bool clockwise) {
+    std::vector<int16_t> rotated(mData.size());
+    for (size_t i = 0; i < mHeight; i++) {
+        for (size_t j = 0; j < mWidth; j++) {
+            size_t iRotated, jRotated;
+            if (clockwise) {
+                iRotated = j;
+                jRotated = mHeight - i - 1;
+            } else {
+                iRotated = mWidth - j - 1;
+                jRotated = i;
+            }
+            size_t indexRotated = iRotated * mHeight + jRotated;
+            rotated[indexRotated] = mData[i * mWidth + j];
+        }
+    }
+    mData = std::move(rotated);
+    std::swap(mHeight, mWidth);
+}
+
+/**
+ * An element at position (i, j) is rotated to (height - i - 1, width - j - 1)
+ * This is equivalent to moving element [i] to position [height * width - i - 1]
+ * Since element at [height * width - i - 1] would move to position [i],
+ * we can just swap elements [i] and [height * width - i - 1].
+ */
+void TouchVideoFrame::rotate180() {
+    if (mData.size() == 0) {
+        return;
+    }
+    // Just need to swap elements i and (height * width - 1 - i)
+    for (size_t i = 0; i < mData.size() / 2; i++) {
+        std::swap(mData[i], mData[mHeight * mWidth - 1 - i]);
+    }
+}
+
 } // namespace android