1 files changed, 127 insertions, 0 deletions
diff --git a/Source/WebCore/page/TouchDisambiguation.cpp b/Source/WebCore/page/TouchDisambiguation.cpp
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+++ b/Source/WebCore/page/TouchDisambiguation.cpp
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+/*
+ * Copyright (C) 2012 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#include "TouchDisambiguation.h"
+
+#include "Document.h"
+#include "Element.h"
+#include "Frame.h"
+#include "FrameView.h"
+#include "HTMLNames.h"
+#include "HitTestResult.h"
+#include <algorithm>
+#include <cmath>
+
+using namespace std;
+
+namespace WebCore {
+
+static IntRect boundingBoxForEventNodes(Node* eventNode)
+{
+    if (!eventNode->document()->view())
+        return IntRect();
+
+    IntRect result;
+    Node* node = eventNode;
+    while (node) {
+        // Skip the whole sub-tree if the node doesn't propagate events.
+        if (node != eventNode && node->willRespondToMouseClickEvents()) {
+            node = node->traverseNextSibling(eventNode);
+            continue;
+        }
+        result.unite(node->pixelSnappedBoundingBox());
+        node = node->traverseNextNode(eventNode);
+    }
+    return eventNode->document()->view()->contentsToWindow(result);
+}
+
+static float scoreTouchTarget(IntPoint touchPoint, int padding, IntRect boundingBox)
+{
+    if (boundingBox.isEmpty())
+        return 0;
+
+    float reciprocalPadding = 1.f / padding;
+    float score = 1;
+
+    IntSize distance = boundingBox.differenceToPoint(touchPoint);
+    score *= max((padding - abs(distance.width())) * reciprocalPadding, 0.f);
+    score *= max((padding - abs(distance.height())) * reciprocalPadding, 0.f);
+
+    return score;
+}
+
+struct TouchTargetData {
+    IntRect windowBoundingBox;
+    float score;
+};
+
+void findGoodTouchTargets(const IntRect& touchBox, Frame* mainFrame, float pageScaleFactor, Vector<IntRect>& goodTargets)
+{
+    goodTargets.clear();
+
+    int touchPointPadding = ceil(max(touchBox.width(), touchBox.height()) * 0.5);
+    // FIXME: Rect-based hit test doesn't transform the touch point size.
+    //        We have to pre-apply page scale factor here.
+    int padding = ceil(touchPointPadding / pageScaleFactor);
+
+    IntPoint touchPoint = touchBox.center();
+    IntPoint contentsPoint = mainFrame->view()->windowToContents(touchPoint);
+
+    HitTestResult result = mainFrame->eventHandler()->hitTestResultAtPoint(contentsPoint, HitTestRequest::ReadOnly | HitTestRequest::Active, IntSize(padding, padding));
+    const ListHashSet<RefPtr<Node> >& hitResults = result.rectBasedTestResult();
+
+    HashMap<Node*, TouchTargetData> touchTargets;
+    float bestScore = 0;
+    for (ListHashSet<RefPtr<Node> >::const_iterator it = hitResults.begin(); it != hitResults.end(); ++it) {
+        for (Node* node = it->get(); node; node = node->parentNode()) {
+            if (node->isDocumentNode() || node->hasTagName(HTMLNames::htmlTag) || node->hasTagName(HTMLNames::bodyTag))
+                break;
+            if (node->willRespondToMouseClickEvents()) {
+                TouchTargetData& targetData = touchTargets.add(node, TouchTargetData()).iterator->second;
+                targetData.windowBoundingBox = boundingBoxForEventNodes(node);
+                targetData.score = scoreTouchTarget(touchPoint, touchPointPadding, targetData.windowBoundingBox);
+                bestScore = max(bestScore, targetData.score);
+                break;
+            }
+        }
+    }
+
+    for (HashMap<Node*, TouchTargetData>::iterator it = touchTargets.begin(); it != touchTargets.end(); ++it) {
+        // Currently the scoring function uses the overlap area with the fat point as the score.
+        // We ignore the candidates that has less than 1/2 overlap (we consider not really ambiguous enough) than the best candidate to avoid excessive popups.
+        if (it->second.score < bestScore * 0.5)
+            continue;
+        goodTargets.append(it->second.windowBoundingBox);
+    }
+}
+
+} // namespace WebCore