Merge webkit.org at r58033 : Initial merge by git

Change-Id: If006c38561af287c50cd578d251629b51e4d8cd1

1 files changed, 530 insertions, 0 deletions

diff --git a/WebCore/page/SpatialNavigation.cpp b/WebCore/page/SpatialNavigation.cpp
new file mode 100644
index 0000000..890eacd
--- /dev/null
+++ b/WebCore/page/SpatialNavigation.cpp
@@ -0,0 +1,530 @@
+/*
+ * Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies)
+ * Copyright (C) 2009 Antonio Gomes <tonikitoo@webkit.org>
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``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 APPLE COMPUTER, INC. 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 "SpatialNavigation.h"
+
+#include "Frame.h"
+#include "FrameTree.h"
+#include "FrameView.h"
+#include "HTMLFrameOwnerElement.h"
+#include "IntRect.h"
+#include "Node.h"
+#include "Page.h"
+
+namespace WebCore {
+
+static long long spatialDistance(FocusDirection, const IntRect&, const IntRect&);
+static IntRect renderRectRelativeToRootDocument(RenderObject*);
+static RectsAlignment alignmentForRects(FocusDirection, const IntRect&, const IntRect&);
+static bool areRectsFullyAligned(FocusDirection, const IntRect&, const IntRect&);
+static bool areRectsPartiallyAligned(FocusDirection, const IntRect&, const IntRect&);
+static bool isRectInDirection(FocusDirection, const IntRect&, const IntRect&);
+static void deflateIfOverlapped(IntRect&, IntRect&);
+static bool checkNegativeCoordsForNode(Node*, const IntRect&);
+
+void distanceDataForNode(FocusDirection direction, Node* start, FocusCandidate& candidate)
+{
+    RenderObject* startRender = start->renderer();
+    if (!startRender) {
+        candidate.distance = maxDistance();
+        return;
+    }
+
+    RenderObject* destRender = candidate.node->renderer();
+    if (!destRender) {
+        candidate.distance = maxDistance();
+        return;
+    }
+
+    IntRect curRect = renderRectRelativeToRootDocument(startRender);
+    IntRect targetRect  = renderRectRelativeToRootDocument(destRender);
+
+    // The bounding rectangle of two consecutive nodes can overlap. In such cases,
+    // deflate both.
+    deflateIfOverlapped(curRect, targetRect);
+
+    // If empty rects or negative width or height, bail out.
+    if (curRect.isEmpty() || targetRect.isEmpty()
+     || targetRect.width() <= 0 || targetRect.height() <= 0) {
+        candidate.distance = maxDistance();
+        return;
+    }
+
+    // Negative coordinates can be used if node is scrolled up offscreen.
+    if (!checkNegativeCoordsForNode(start, curRect)) {
+        candidate.distance = maxDistance();
+        return;
+    }
+
+    if (!checkNegativeCoordsForNode(candidate.node, targetRect)) {
+        candidate.distance = maxDistance();
+        return;
+    }
+
+    if (!isRectInDirection(direction, curRect, targetRect)) {
+        candidate.distance = maxDistance();
+        return;
+    }
+
+    // The distance between two nodes is not to be considered alone when evaluating/looking
+    // for the best focus candidate node. Alignment of rects can be also a good point to be
+    // considered in order to make the algorithm to behavior in a more intuitive way.
+    candidate.alignment = alignmentForRects(direction, curRect, targetRect);
+    candidate.distance = spatialDistance(direction, curRect, targetRect);
+}
+
+// FIXME: This function does not behave correctly with transformed frames.
+static IntRect renderRectRelativeToRootDocument(RenderObject* render)
+{
+    ASSERT(render);
+
+    IntRect rect(render->absoluteClippedOverflowRect());
+
+    if (rect.isEmpty()) {
+        Element* e = static_cast<Element*>(render->node());
+        rect = e->getRect();
+    }
+
+    // In cases when the |render|'s associated node is in a scrollable inner
+    // document, we only consider its scrollOffset if it is not offscreen.
+    Node* node = render->node();
+    Document* mainDocument = node->document()->page()->mainFrame()->document();
+    bool considerScrollOffset = !(hasOffscreenRect(node) && node->document() != mainDocument);
+
+    if (considerScrollOffset) {
+        if (FrameView* frameView = render->node()->document()->view())
+            rect.move(-frameView->scrollOffset());
+    }
+
+    // Handle nested frames.
+    for (Frame* frame = render->document()->frame(); frame; frame = frame->tree()->parent()) {
+        if (HTMLFrameOwnerElement* ownerElement = frame->ownerElement())
+            rect.move(ownerElement->offsetLeft(), ownerElement->offsetTop());
+    }
+
+    return rect;
+}
+
+static RectsAlignment alignmentForRects(FocusDirection direction, const IntRect& curRect, const IntRect& targetRect)
+{
+    if (areRectsFullyAligned(direction, curRect, targetRect))
+        return Full;
+
+    if (areRectsPartiallyAligned(direction, curRect, targetRect))
+        return Partial;
+
+    return None;
+}
+
+static inline bool isHorizontalMove(FocusDirection direction)
+{
+    return direction == FocusDirectionLeft || direction == FocusDirectionRight;
+}
+
+static inline int start(FocusDirection direction, const IntRect& rect)
+{
+    return isHorizontalMove(direction) ? rect.y() : rect.x();
+}
+
+static inline int middle(FocusDirection direction, const IntRect& rect)
+{
+    IntPoint center(rect.center());
+    return isHorizontalMove(direction) ? center.y(): center.x();
+}
+
+static inline int end(FocusDirection direction, const IntRect& rect)
+{
+    return isHorizontalMove(direction) ? rect.bottom() : rect.right();
+}
+
+// This method checks if rects |a| and |b| are fully aligned either vertically or
+// horizontally. In general, rects whose central point falls between the top or
+// bottom of each other are considered fully aligned.
+// Rects that match this criteria are preferable target nodes in move focus changing
+// operations.
+// * a = Current focused node's rect.
+// * b = Focus candidate node's rect.
+static bool areRectsFullyAligned(FocusDirection direction, const IntRect& a, const IntRect& b)
+{
+    int aStart, bStart, aEnd, bEnd;
+
+    switch (direction) {
+    case FocusDirectionLeft:
+        aStart = a.x();
+        bEnd = b.right();
+        break;
+    case FocusDirectionRight:
+        aStart = b.x();
+        bEnd = a.right();
+        break;
+    case FocusDirectionUp:
+        aStart = a.y();
+        bEnd = b.y();
+        break;
+    case FocusDirectionDown:
+        aStart = b.y();
+        bEnd = a.y();
+        break;
+    default:
+        ASSERT_NOT_REACHED();
+        return false;
+    }
+
+    if (aStart < bEnd)
+        return false;
+
+    aStart = start(direction, a);
+    bStart = start(direction, b);
+
+    int aMiddle = middle(direction, a);
+    int bMiddle = middle(direction, b);
+
+    aEnd = end(direction, a);
+    bEnd = end(direction, b);
+
+    // Picture of the totally aligned logic:
+    //
+    //     Horizontal    Vertical        Horizontal     Vertical
+    //  ****************************  *****************************
+    //  *  _          *   _ _ _ _  *  *         _   *      _ _    *
+    //  * |_|     _   *  |_|_|_|_| *  *  _     |_|  *     |_|_|   *
+    //  * |_|....|_|  *      .     *  * |_|....|_|  *       .     *
+    //  * |_|    |_| (1)     .     *  * |_|    |_| (2)      .     *
+    //  * |_|         *     _._    *  *        |_|  *    _ _._ _  *
+    //  *             *    |_|_|   *  *             *   |_|_|_|_| *
+    //  *             *            *  *             *             *
+    //  ****************************  *****************************
+
+    //     Horizontal    Vertical        Horizontal     Vertical
+    //  ****************************  *****************************
+    //  *  _......_   *   _ _ _ _  *  *  _          *    _ _ _ _  *
+    //  * |_|    |_|  *  |_|_|_|_| *  * |_|     _   *   |_|_|_|_| *
+    //  * |_|    |_|  *  .         *  * |_|    |_|  *           . *
+    //  * |_|        (3) .         *  * |_|....|_| (4)          . *
+    //  *             *  ._ _      *  *             *        _ _. *
+    //  *             *  |_|_|     *  *             *       |_|_| *
+    //  *             *            *  *             *             *
+    //  ****************************  *****************************
+
+    return ((bMiddle >= aStart && bMiddle <= aEnd) // (1)
+            || (aMiddle >= bStart && aMiddle <= bEnd) // (2)
+            || (bStart == aStart) // (3)
+            || (bEnd == aEnd)); // (4)
+}
+
+// This method checks if |start| and |dest| have a partial intersection, either
+// horizontally or vertically.
+// * a = Current focused node's rect.
+// * b = Focus candidate node's rect.
+static bool areRectsPartiallyAligned(FocusDirection direction, const IntRect& a, const IntRect& b)
+{
+    int aStart  = start(direction, a);
+    int bStart  = start(direction, b);
+    int bMiddle = middle(direction, b);
+    int aEnd = end(direction, a);
+    int bEnd = end(direction, b);
+
+    // Picture of the partially aligned logic:
+    //
+    //    Horizontal       Vertical
+    // ********************************
+    // *  _            *   _ _ _      *
+    // * |_|           *  |_|_|_|     *
+    // * |_|.... _     *      . .     *
+    // * |_|    |_|    *      . .     *
+    // * |_|....|_|    *      ._._ _  *
+    // *        |_|    *      |_|_|_| *
+    // *        |_|    *              *
+    // *               *              *
+    // ********************************
+    //
+    // ... and variants of the above cases.
+    return ((bStart >= aStart && bStart <= aEnd)
+            || (bStart >= aStart && bStart <= aEnd)
+            || (bEnd >= aStart && bEnd <= aEnd)
+            || (bMiddle >= aStart && bMiddle <= aEnd)
+            || (bEnd >= aStart && bEnd <= aEnd));
+}
+
+// Return true if rect |a| is below |b|. False otherwise.
+static inline bool below(const IntRect& a, const IntRect& b)
+{
+    return a.y() > b.bottom();
+}
+
+// Return true if rect |a| is on the right of |b|. False otherwise.
+static inline bool rightOf(const IntRect& a, const IntRect& b)
+{
+    return a.x() > b.right();
+}
+
+// * a = Current focused node's rect.
+// * b = Focus candidate node's rect.
+static long long spatialDistance(FocusDirection direction, const IntRect& a, const IntRect& b)
+{
+    int x1 = 0, y1 = 0, x2 = 0, y2 = 0;
+
+    if (direction == FocusDirectionLeft) {
+        // #1  |--|
+        //
+        // #2  |--|  |--|
+        //
+        // #3  |--|
+
+        x1 = a.x();
+        x2 = b.right();
+
+        if (below(a, b)) {
+            // #1 The a rect is below b.
+            y1 = a.y();
+            y2 = b.bottom();
+        } else if (below(b, a)) {
+            // #3 The b rect is below a.
+            y1 = a.bottom();
+            y2 = b.y();
+        } else {
+            // #2 Both b and a share some common y's.
+            y1 = 0;
+            y2 = 0;
+        }
+    } else if (direction == FocusDirectionRight) {
+        //        |--|  #1
+        //
+        //  |--|  |--|  #2
+        //
+        //        |--|  #3
+
+        x1 = a.right();
+        x2 = b.x();
+
+        if (below(a, b)) {
+            // #1 The b rect is above a.
+            y1 = a.y();
+            y2 = b.bottom();
+        } else if (below(b, a)) {
+            // #3 The b rect is below a.
+            y1 = a.bottom();
+            y2 = b.y();
+        } else {
+            // #2 Both b and a share some common y's.
+            y1 = 0;
+            y2 = 0;
+        }
+    } else if (direction == FocusDirectionUp) {
+        //
+        //   #1    #2    #3
+        //
+        //  |--|  |--|  |--|
+        //
+        //        |--|
+
+        y1 = a.y();
+        y2 = b.bottom();
+
+        if (rightOf(a, b)) {
+            // #1 The b rect is to the left of a.
+            x1 = a.x();
+            x2 = b.right();
+        } else if (rightOf(b, a)) {
+            // #3 The b rect is to the right of a.
+            x1 = a.right();
+            x2 = b.x();
+        } else {
+            // #2 Both b and a share some common x's.
+            x1 = 0;
+            x2 = 0;
+        }
+    } else if (direction == FocusDirectionDown) {
+        //        |--|
+        //
+        //  |--|  |--|  |--|
+        //
+        //   #1    #2    #3
+
+        y1 = a.bottom();
+        y2 = b.y();
+
+        if (rightOf(a, b)) {
+            // #1 The b rect is to the left of a.
+            x1 = a.x();
+            x2 = b.right();
+        } else if (rightOf(b, a)) {
+            // #3 The b rect is to the right of a
+            x1 = a.right();
+            x2 = b.x();
+        } else {
+            // #2 Both b and a share some common x's.
+            x1 = 0;
+            x2 = 0;
+        }
+    }
+
+    long long dx = x1 - x2;
+    long long dy = y1 - y2;
+
+    long long distance = (dx * dx) + (dy * dy);
+
+    if (distance < 0)
+        distance *= -1;
+
+    return distance;
+}
+
+static bool isRectInDirection(FocusDirection direction, const IntRect& curRect, const IntRect& targetRect)
+{
+    IntPoint center(targetRect.center());
+    int targetMiddle = isHorizontalMove(direction) ? center.x() : center.y();
+
+    switch (direction) {
+    case FocusDirectionLeft:
+        return targetMiddle < curRect.x();
+    case FocusDirectionRight:
+        return targetMiddle > curRect.right();
+    case FocusDirectionUp:
+        return targetMiddle < curRect.y();
+    case FocusDirectionDown:
+        return targetMiddle > curRect.bottom();
+    default:
+        ASSERT_NOT_REACHED();
+    }
+
+    return false;
+}
+
+// Checks if |node| is offscreen the visible area (viewport) of its container
+// document. In case it is, one can scroll in direction or take any different
+// desired action later on.
+bool hasOffscreenRect(Node* node)
+{
+    // Get the FrameView in which |node| is (which means the current viewport if |node|
+    // is not in an inner document), so we can check if its content rect is visible
+    // before we actually move the focus to it.
+    FrameView* frameView = node->document()->view();
+    if (!frameView)
+        return true;
+
+    IntRect containerViewportRect = frameView->visibleContentRect();
+
+    RenderObject* render = node->renderer();
+    if (!render)
+        return true;
+
+    IntRect rect(render->absoluteClippedOverflowRect());
+    if (rect.isEmpty())
+        return true;
+
+    return !containerViewportRect.intersects(rect);
+}
+
+// In a bottom-up way, this method tries to scroll |frame| in a given direction
+// |direction|, going up in the frame tree hierarchy in case it does not succeed.
+bool scrollInDirection(Frame* frame, FocusDirection direction)
+{
+    if (!frame)
+        return false;
+
+    ScrollDirection scrollDirection;
+
+    switch (direction) {
+    case FocusDirectionLeft:
+        scrollDirection = ScrollLeft;
+        break;
+    case FocusDirectionRight:
+        scrollDirection = ScrollRight;
+        break;
+    case FocusDirectionUp:
+        scrollDirection = ScrollUp;
+        break;
+    case FocusDirectionDown:
+        scrollDirection = ScrollDown;
+        break;
+    default:
+        return false;
+    }
+
+    return frame->eventHandler()->scrollRecursively(scrollDirection, ScrollByLine);
+}
+
+void scrollIntoView(Element* element)
+{
+    // NOTE: Element's scrollIntoView method could had been used here, but
+    // it is preferable to inflate |element|'s bounding rect a bit before
+    // scrolling it for accurate reason.
+    // Element's scrollIntoView method does not provide this flexibility.
+    static const int fudgeFactor = 2;
+    IntRect bounds = element->getRect();
+    bounds.inflate(fudgeFactor);
+    element->renderer()->enclosingLayer()->scrollRectToVisible(bounds);
+}
+
+bool isInRootDocument(Node* node)
+{
+    if (!node)
+        return false;
+
+    Document* rootDocument = node->document()->page()->mainFrame()->document();
+    return node->document() == rootDocument;
+}
+
+static void deflateIfOverlapped(IntRect& a, IntRect& b)
+{
+    if (!a.intersects(b) || a.contains(b) || b.contains(a))
+        return;
+
+    static const int fudgeFactor = -2;
+
+    // Avoid negative width or height values.
+    if ((a.width() + 2 * fudgeFactor > 0) && (a.height() + 2 * fudgeFactor > 0))
+        a.inflate(fudgeFactor);
+
+    if ((b.width() + 2 * fudgeFactor > 0) && (b.height() + 2 * fudgeFactor > 0))
+        b.inflate(fudgeFactor);
+}
+
+static bool checkNegativeCoordsForNode(Node* node, const IntRect& curRect)
+{
+    ASSERT(node || node->renderer());
+
+    if (curRect.x() > 0 && curRect.y() > 0)
+        return true;
+
+    bool canBeScrolled = false;
+
+    RenderObject* renderer = node->renderer();
+    for (; renderer; renderer = renderer->parent()) {
+        if (renderer->isBox() && toRenderBox(renderer)->canBeScrolledAndHasScrollableArea()) {
+            canBeScrolled = true;
+            break;
+        }
+    }
+
+    return canBeScrolled;
+}
+
+} // namespace WebCore