do a better job of finding closest selectable text

Measure the closest to the edge, instead of closest to the center.

Identify vertical overlaps, and use them to discount characters
which are vertically closer.

Add more debugging.

bug:3183434
Change-Id: I80a14be25260113220e446b876868566440be252

1 files changed, 24 insertions, 11 deletions

diff --git a/WebKit/android/nav/SelectText.cpp b/WebKit/android/nav/SelectText.cpp
index 352ec7e..aa97ff6 100644
--- a/WebKit/android/nav/SelectText.cpp
+++ b/WebKit/android/nav/SelectText.cpp
@@ -421,25 +421,38 @@ public:
          * centerX = (rect.L + rect.R) / 2
          * multiply centerX and comparison x by 2 to retain better precision
          */
-        int dx = rect.fLeft + rect.fRight - (mFocusX << 1);
-        int dy = top() + bottom() - (mFocusY << 1);
-        dx = abs(dx);
-        dy = abs(dy);
+        SkIRect testBounds = {rect.fLeft, top(), rect.fRight, bottom()};
+        int dx = std::max(0, std::max(testBounds.fLeft - mFocusX,
+            mFocusX - testBounds.fRight));
+        int dy = std::max(0, std::max(testBounds.fTop - mFocusY,
+            mFocusY - testBounds.fBottom));
+        bool overlaps = testBounds.fTop < mBestBounds.fBottom
+            && testBounds.fBottom > mBestBounds.fTop;
 #ifdef EXTRA_NOISY_LOGGING
-        if (dy < 15)
-            DBG_NAV_LOGD("FirstCheck dx/y=(%d, %d) mDx/y=(%d, %d)",
-                dx>>1, dy>>1, mDx>>1, mDy>>1);
+        if (dy < 10) {
+            SkUnichar ch = getUniChar(rec);
+            DBG_NAV_LOGD("FirstCheck dx/y=(%d,%d) mDx/y=(%d,%d)"
+                " testBounds=(%d,%d,r=%d,b=%d) mBestBounds=(%d,%d,r=%d,b=%d)"
+                " overlaps=%s ch=%c", dx, dy, mDx, mDy,
+                testBounds.fLeft, testBounds.fTop, testBounds.fRight,
+                testBounds.fBottom, mBestBounds.fLeft, mBestBounds.fTop,
+                mBestBounds.fRight, mBestBounds.fBottom,
+                overlaps ? "true" : "false", ch < 0x7f ? ch : '?');
+        }
 #endif
-        if (mDy > dy || (mDy == dy && mDx > dx)) {
+        if ((mDy > dy && !overlaps)
+            || ((mDy == dy || overlaps) && mDx > dx)) {
             mBestBase = base();
-            mBestBounds.set(rect.fLeft, top(), rect.fRight, bottom());
+            mBestBounds = testBounds;
 #ifndef EXTRA_NOISY_LOGGING
             if (dy < 10 && dx < 10)
 #endif
             {
-                DBG_NAV_LOGD("FirstCheck mBestBounds={%d,%d,r=%d,b=%d} dx/y=(%d, %d)",
+                DBG_NAV_LOGD("FirstCheck dx/y=(%d,%d) mFocus=(%d,%d)"
+                    " mBestBounds={%d,%d,r=%d,b=%d}",
+                    dx, dy, mFocusX, mFocusY,
                     mBestBounds.fLeft, mBestBounds.fTop,
-                    mBestBounds.fRight, mBestBounds.fBottom, dx>>1, dy>>1);
+                    mBestBounds.fRight, mBestBounds.fBottom);
             }
             mDx = dx;
             mDy = dy;