Made double-tap zoom work in pinch virtual viewport mode. (Blink-side)

Source/core/frame/PinchViewport.cpp

 /*
  * Copyright (C) 2013 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
@@ skipping 63 matching lines @@
 PinchViewport::~PinchViewport() { }
 
 void PinchViewport::setSize(const IntSize& size)
 {
     if (m_size == size)
         return;
 
     TRACE_EVENT2("blink", "PinchViewport::setSize", "width", size.width(), "height", size.height());
     m_size = size;
 
-    // Make sure we clamp the offset to within the new bounds.
-    setLocation(m_offset);
+    clampToBoundaries();
 
     if (m_innerViewportContainerLayer) {
         m_innerViewportContainerLayer->setSize(m_size);
 
         // Need to re-compute sizes for the overlay scrollbars.
         setupScrollbar(WebScrollbar::Horizontal);
         setupScrollbar(WebScrollbar::Vertical);
     }
 }
 
 void PinchViewport::reset()
 {
-    setLocation(FloatPoint());
-    setScale(1);
+    setScaleAndLocation(1, FloatPoint());
 }
 
 void PinchViewport::mainFrameDidChangeSize()
 {
     TRACE_EVENT0("blink", "PinchViewport::mainFrameDidChangeSize");
 
     // In unit tests we may not have initialized the layer tree.
     if (m_innerViewportScrollLayer)
         m_innerViewportScrollLayer->setSize(contentsSize());
 
-    // Make sure the viewport's offset is clamped within the newly sized main frame.
-    setLocation(m_offset);
+    clampToBoundaries();
 }
 
 FloatRect PinchViewport::visibleRect() const
 {
     FloatSize scaledSize(m_size);
     scaledSize.scale(1 / m_scale);
     return FloatRect(m_offset, scaledSize);
 }
 
 FloatRect PinchViewport::visibleRectInDocument() const
@@ skipping 22 matching lines @@
         rect.y() - centeringOffsetY - visibleRect().y());
 
     view->setScrollPosition(flooredIntPoint(targetOffset));
 
     FloatPoint remainder = FloatPoint(targetOffset - view->scrollPosition());
     move(remainder);
 }
 
 void PinchViewport::setLocation(const FloatPoint& newLocation)
 {
-    FloatPoint clampedOffset(clampOffsetToBoundaries(newLocation));
-
-    if (clampedOffset == m_offset)
-        return;
-
-    m_offset = clampedOffset;
-
-    ScrollingCoordinator* coordinator = m_frameHost.page().scrollingCoordinator();
-    ASSERT(coordinator);
-    coordinator->scrollableAreaScrollLayerDidChange(this);
-
-    mainFrame()->loader().saveScrollState();
+    setScaleAndLocation(m_scale, newLocation);
 }
 
 void PinchViewport::move(const FloatPoint& delta)
 {
     setLocation(m_offset + delta);
 }
 
 void PinchViewport::setScale(float scale)
 {
-    if (scale == m_scale)
+    setScaleAndLocation(scale, m_offset);
+}
+
+void PinchViewport::setScaleAndLocation(float scale, const FloatPoint& location)
+{
+    bool valuesChanged = false;
+
+    if (scale != m_scale) {
+        m_scale = scale;
+        valuesChanged = true;
+    }
+
+    FloatPoint clampedOffset(clampOffsetToBoundaries(location));
+
+    if (clampedOffset != m_offset) {
+        m_offset = clampedOffset;
+
+        ScrollingCoordinator* coordinator = m_frameHost.page().scrollingCoordinator();
+        ASSERT(coordinator);
+        coordinator->scrollableAreaScrollLayerDidChange(this);
+
+        valuesChanged = true;
+    }
+
+    if (!valuesChanged)
         return;
 
-    m_scale = scale;
-
-    if (mainFrame())
-        mainFrame()->loader().saveScrollState();
+    mainFrame()->loader().saveScrollState();
 
     // Old-style pinch sets scale here but we shouldn't call into the
-    // clamping code below.
+    // clamping code below. Can be removed when there's no old-style pinch.
     if (!m_innerViewportScrollLayer)
         return;
 
-    // Ensure we clamp so we remain within the bounds.
-    setLocation(visibleRect().location());
-
-    // TODO: We should probably be calling scaleDidChange type functions here.
-    // see Page::setPageScaleFactor.
+    clampToBoundaries();
 }
 
 // Modifies the top of the graphics layer tree to add layers needed to support
 // the inner/outer viewport fixed-position model for pinch zoom. When finished,
 // the tree will look like this (with * denoting added layers):
 //
 // *rootTransformLayer
 //  +- *innerViewportContainerLayer (fixed pos container)
 //      +- *pageScaleLayer
 //  |       +- *innerViewportScrollLayer
@@ skipping 141 matching lines @@
 IntPoint PinchViewport::minimumScrollPosition() const
 {
     return IntPoint();
 }
 
 IntPoint PinchViewport::maximumScrollPosition() const
 {
     return flooredIntPoint(FloatSize(contentsSize()) - visibleRect().size());
 }
 
+IntPoint PinchViewport::clampDocumentOffsetAtScale(const IntPoint& offset, float scale)
+{
+    if (!mainFrame() || !mainFrame()->view())
+        return IntPoint();
+
+    FrameView* view = mainFrame()->view();
+
+    FloatSize scaledSize(m_size);
+    scaledSize.scale(1 / scale);
+
+    IntPoint pinchViewportMax = flooredIntPoint(FloatSize(contentsSize()) - scaledSize);
+    IntPoint max = view->maximumScrollPosition() + pinchViewportMax;
+    IntPoint min = view->minimumScrollPosition(); // PinchViewportMin should be (0, 0)
+
+    IntPoint clamped = offset;
+    clamped = clamped.shrunkTo(max);
+    clamped = clamped.expandedTo(min);
+    return clamped;
+}
+
 IntRect PinchViewport::scrollableAreaBoundingBox() const
 {
     // This method should return the bounding box in the parent view's coordinate
     // space; however, PinchViewport technically isn't a child of any Frames.
     // Nonetheless, the PinchViewport always occupies the entire main frame so just
     // return that.
     LocalFrame* frame = mainFrame();
 
     if (!frame || !frame->view())
         return IntRect();
@@ skipping 57 matching lines @@
 }
 
 FloatPoint PinchViewport::clampOffsetToBoundaries(const FloatPoint& offset)
 {
     FloatPoint clampedOffset(offset);
     clampedOffset = clampedOffset.shrunkTo(FloatPoint(maximumScrollPosition()));
     clampedOffset = clampedOffset.expandedTo(FloatPoint(minimumScrollPosition()));
     return clampedOffset;
 }
 
+void PinchViewport::clampToBoundaries()
+{
+    setLocation(m_offset);
+}
+
 String PinchViewport::debugName(const GraphicsLayer* graphicsLayer)
 {
     String name;
     if (graphicsLayer == m_innerViewportContainerLayer.get()) {
         name = "Inner Viewport Container Layer";
     } else if (graphicsLayer == m_pageScaleLayer.get()) {
         name =  "Page Scale Layer";
     } else if (graphicsLayer == m_innerViewportScrollLayer.get()) {
         name =  "Inner Viewport Scroll Layer";
     } else if (graphicsLayer == m_overlayScrollbarHorizontal.get()) {
         name =  "Overlay Scrollbar Horizontal Layer";
     } else if (graphicsLayer == m_overlayScrollbarVertical.get()) {
         name =  "Overlay Scrollbar Vertical Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink