From d41cff2d3a95963a7aa348e502c6d42bae367235 Mon Sep 17 00:00:00 2001
From: Jeff Brown <jeffbrown@google.com>
Date: Thu, 3 Mar 2011 02:09:54 -0800
Subject: Fix off by one errors in touch motion ranges.

Report inclusive minimum and maximum ranges for all
axes including X and Y.

Set mouse pointer bounds to 0..width-1, 0..height-1.

Rotate touch and mouse positions more carefully, paying attention
to the maximum bounds when calculating the complement of an axis.

Simplified the InputReader somewhat and removed support for a
couple of poorly defined input device configuration parameters.
We now assume that the touch device provides useful absolute axis
ranges for the X and Y axes since the alternative does not actually
make sense.

Bug: 3413541
Change-Id: I682ce3729e4473de7f1bcf8addb49a3f4484126f
---
 services/input/PointerController.cpp | 61 +++++++++++++++++++-----------------
 1 file changed, 33 insertions(+), 28 deletions(-)

(limited to 'services/input/PointerController.cpp')

diff --git a/services/input/PointerController.cpp b/services/input/PointerController.cpp
index 954872b2aa46..a4ee295a73b1 100644
--- a/services/input/PointerController.cpp
+++ b/services/input/PointerController.cpp
@@ -109,12 +109,12 @@ bool PointerController::getBoundsLocked(float* outMinX, float* outMinY,
     switch (mLocked.displayOrientation) {
     case DISPLAY_ORIENTATION_90:
     case DISPLAY_ORIENTATION_270:
-        *outMaxX = mLocked.displayHeight;
-        *outMaxY = mLocked.displayWidth;
+        *outMaxX = mLocked.displayHeight - 1;
+        *outMaxY = mLocked.displayWidth - 1;
         break;
     default:
-        *outMaxX = mLocked.displayWidth;
-        *outMaxY = mLocked.displayHeight;
+        *outMaxX = mLocked.displayWidth - 1;
+        *outMaxY = mLocked.displayHeight - 1;
         break;
     }
     return true;
@@ -309,48 +309,53 @@ void PointerController::setDisplayOrientation(int32_t orientation) {
     AutoMutex _l(mLock);
 
     if (mLocked.displayOrientation != orientation) {
-        float absoluteX, absoluteY;
-
-        // Map from oriented display coordinates to absolute display coordinates.
+        // Apply offsets to convert from the pixel top-left corner position to the pixel center.
+        // This creates an invariant frame of reference that we can easily rotate when
+        // taking into account that the pointer may be located at fractional pixel offsets.
+        float x = mLocked.pointerX + 0.5f;
+        float y = mLocked.pointerY + 0.5f;
+        float temp;
+
+        // Undo the previous rotation.
         switch (mLocked.displayOrientation) {
         case DISPLAY_ORIENTATION_90:
-            absoluteX = mLocked.displayWidth - mLocked.pointerY;
-            absoluteY = mLocked.pointerX;
+            temp = x;
+            x = mLocked.displayWidth - y;
+            y = temp;
             break;
         case DISPLAY_ORIENTATION_180:
-            absoluteX = mLocked.displayWidth - mLocked.pointerX;
-            absoluteY = mLocked.displayHeight - mLocked.pointerY;
+            x = mLocked.displayWidth - x;
+            y = mLocked.displayHeight - y;
             break;
         case DISPLAY_ORIENTATION_270:
-            absoluteX = mLocked.pointerY;
-            absoluteY = mLocked.displayHeight - mLocked.pointerX;
-            break;
-        default:
-            absoluteX = mLocked.pointerX;
-            absoluteY = mLocked.pointerY;
+            temp = x;
+            x = y;
+            y = mLocked.displayHeight - temp;
             break;
         }
 
-        // Map from absolute display coordinates to oriented display coordinates.
+        // Perform the new rotation.
         switch (orientation) {
         case DISPLAY_ORIENTATION_90:
-            mLocked.pointerX = absoluteY;
-            mLocked.pointerY = mLocked.displayWidth - absoluteX;
+            temp = x;
+            x = y;
+            y = mLocked.displayWidth - x;
             break;
         case DISPLAY_ORIENTATION_180:
-            mLocked.pointerX = mLocked.displayWidth - absoluteX;
-            mLocked.pointerY = mLocked.displayHeight - absoluteY;
+            x = mLocked.displayWidth - x;
+            y = mLocked.displayHeight - y;
             break;
         case DISPLAY_ORIENTATION_270:
-            mLocked.pointerX = mLocked.displayHeight - absoluteY;
-            mLocked.pointerY = absoluteX;
-            break;
-        default:
-            mLocked.pointerX = absoluteX;
-            mLocked.pointerY = absoluteY;
+            temp = x;
+            x = mLocked.displayHeight - y;
+            y = temp;
             break;
         }
 
+        // Apply offsets to convert from the pixel center to the pixel top-left corner position
+        // and save the results.
+        mLocked.pointerX = x - 0.5f;
+        mLocked.pointerY = y - 0.5f;
         mLocked.displayOrientation = orientation;
 
         updateLocked();
-- 
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