Bug 611556 - Add persistent zoom history sessions. r=roc, r=snorp

dom/base/nsDOMWindowUtils.cpp

@@ -538,8 +538,17 @@ nsDOMWindowUtils::SetResolution(float aXResolution, float aYResolution)
   }
 
   nsIPresShell* presShell = GetPresShell();
-  return presShell ? presShell->SetResolution(aXResolution, aYResolution)
-                   : NS_ERROR_FAILURE;
+  if (!presShell) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsIScrollableFrame* sf = presShell->GetRootScrollFrameAsScrollable();
+  if (sf) {
+    sf->SetResolution(gfxSize(aXResolution, aYResolution));
+    presShell->SetResolution(aXResolution, aYResolution);
+  }
+
+  return NS_OK;
 }
 
 NS_IMETHODIMP
@@ -550,13 +559,21 @@ nsDOMWindowUtils::GetResolution(float* aXResolution, float* aYResolution)
   }
 
   nsIPresShell* presShell = GetPresShell();
+  if (!presShell) {
+    return NS_ERROR_FAILURE;
+  }
 
-  if (presShell) {
+  nsIScrollableFrame* sf = presShell->GetRootScrollFrameAsScrollable();
+  if (sf) {
+    const gfxSize& res = sf->GetResolution();
+    *aXResolution = res.width;
+    *aYResolution = res.height;
+  } else {
     *aXResolution = presShell->GetXResolution();
     *aYResolution = presShell->GetYResolution();
-    return NS_OK;
   }
-  return NS_ERROR_FAILURE;
+
+  return NS_OK;
 }
 
 NS_IMETHODIMP

layout/base/nsPresState.h

@@ -12,6 +12,7 @@
 #define nsPresState_h_
 
 #include "nsPoint.h"
+#include "gfxPoint.h"
 #include "nsAutoPtr.h"
 
 class nsPresState
@@ -20,6 +21,7 @@ public:
   nsPresState()
     : mContentData(nullptr)
     , mScrollState(0, 0)
+    , mResolution(1.0, 1.0)
     , mDisabledSet(false)
     , mDisabled(false)
   {}
@@ -29,18 +31,28 @@ public:
     mScrollState = aState;
   }
 
-  nsPoint GetScrollState()
+  nsPoint GetScrollState() const
   {
     return mScrollState;
   }
 
+  void SetResolution(const gfxSize& aSize)
+  {
+    mResolution = aSize;
+  }
+
+  gfxSize GetResolution() const
+  {
+    return mResolution;
+  }
+
   void ClearNonScrollState()
   {
     mContentData = nullptr;
     mDisabledSet = false;
   }
 
-  bool GetDisabled()
+  bool GetDisabled() const
   {
     return mDisabled;
   }
@@ -51,12 +63,12 @@ public:
     mDisabledSet = true;
   }
 
-  bool IsDisabledSet()
+  bool IsDisabledSet() const
   {
     return mDisabledSet;
   }
 
-  nsISupports* GetStateProperty()
+  nsISupports* GetStateProperty() const
   {
     return mContentData;
   }
@@ -70,6 +82,7 @@ public:
 protected:
   nsCOMPtr<nsISupports> mContentData;
   nsPoint mScrollState;
+  gfxSize mResolution;
   bool mDisabledSet;
   bool mDisabled;
 };

layout/generic/nsGfxScrollFrame.cpp

@@ -1600,6 +1600,7 @@ ScrollFrameHelper::ScrollFrameHelper(nsContainerFrame* aOuter,
   , mScrollPosAtLastPaint(0, 0)
   , mRestorePos(-1, -1)
   , mLastPos(-1, -1)
+  , mResolution(1.0, 1.0)
   , mScrollPosForLayerPixelAlignment(-1, -1)
   , mLastUpdateImagesPos(-1, -1)
   , mNeverHasVerticalScrollbar(false)
@@ -2786,6 +2787,18 @@ ScrollFrameHelper::GetScrollPositionClampingScrollPortSize() const
   return mScrollPort.Size();
 }
 
+gfxSize
+ScrollFrameHelper::GetResolution() const
+{
+  return mResolution;
+}
+
+void
+ScrollFrameHelper::SetResolution(const gfxSize& aResolution)
+{
+  mResolution = aResolution;
+}
+
 static void
 AdjustForWholeDelta(int32_t aDelta, nscoord* aCoord)
 {
@@ -4486,7 +4499,7 @@ ScrollFrameHelper::GetCoordAttribute(nsIFrame* aBox, nsIAtom* aAtom,
 }
 
 nsPresState*
-ScrollFrameHelper::SaveState()
+ScrollFrameHelper::SaveState() const
 {
   nsIScrollbarMediator* mediator = do_QueryFrame(GetScrolledFrame());
   if (mediator) {
@@ -4511,6 +4524,7 @@ ScrollFrameHelper::SaveState()
     pt = mRestorePos;
   }
   state->SetScrollState(pt);
+  state->SetResolution(mResolution);
   return state;
 }
 
@@ -4520,6 +4534,11 @@ ScrollFrameHelper::RestoreState(nsPresState* aState)
   mRestorePos = aState->GetScrollState();
   mDidHistoryRestore = true;
   mLastPos = mScrolledFrame ? GetLogicalScrollPosition() : nsPoint(0,0);
+  mResolution = aState->GetResolution();
+
+  if (mIsRoot) {
+    mOuter->PresContext()->PresShell()->SetResolution(mResolution.width, mResolution.height);
+  }
 }
 
 void

layout/generic/nsGfxScrollFrame.h

@@ -163,6 +163,9 @@ public:
   // Get the scroll range assuming the scrollport has size (aWidth, aHeight).
   nsRect GetScrollRange(nscoord aWidth, nscoord aHeight) const;
   nsSize GetScrollPositionClampingScrollPortSize() const;
+  gfxSize GetResolution() const;
+  void SetResolution(const gfxSize& aResolution);
+
 protected:
   nsRect GetScrollRangeForClamping() const;
 
@@ -207,7 +210,7 @@ public:
   nsSize GetLineScrollAmount() const;
   nsSize GetPageScrollAmount() const;
 
-  nsPresState* SaveState();
+  nsPresState* SaveState() const;
   void RestoreState(nsPresState* aState);
 
   nsIFrame* GetScrolledFrame() const { return mScrolledFrame; }
@@ -348,6 +351,9 @@ public:
   // other than trying to restore mRestorePos.
   nsPoint mLastPos;
 
+  // The current resolution derived from the zoom level and device pixel ratio.
+  gfxSize mResolution;
+
   nsExpirationState mActivityExpirationState;
 
   nsCOMPtr<nsITimer> mScrollActivityTimer;
@@ -577,6 +583,12 @@ public:
   virtual nsSize GetScrollPositionClampingScrollPortSize() const MOZ_OVERRIDE {
     return mHelper.GetScrollPositionClampingScrollPortSize();
   }
+  virtual gfxSize GetResolution() const MOZ_OVERRIDE {
+    return mHelper.GetResolution();
+  }
+  virtual void SetResolution(const gfxSize& aResolution) MOZ_OVERRIDE {
+    return mHelper.SetResolution(aResolution);
+  }
   virtual nsSize GetLineScrollAmount() const MOZ_OVERRIDE {
     return mHelper.GetLineScrollAmount();
   }
@@ -887,6 +899,12 @@ public:
   virtual nsSize GetScrollPositionClampingScrollPortSize() const MOZ_OVERRIDE {
     return mHelper.GetScrollPositionClampingScrollPortSize();
   }
+  virtual gfxSize GetResolution() const MOZ_OVERRIDE {
+    return mHelper.GetResolution();
+  }
+  virtual void SetResolution(const gfxSize& aResolution) MOZ_OVERRIDE {
+    return mHelper.SetResolution(aResolution);
+  }
   virtual nsSize GetLineScrollAmount() const MOZ_OVERRIDE {
     return mHelper.GetLineScrollAmount();
   }

layout/generic/nsIScrollableFrame.h

@@ -134,7 +134,14 @@ public:
    * position.
    */
   virtual nsSize GetScrollPositionClampingScrollPortSize() const = 0;
-
+  /**
+   * Get the element resolution.
+   */
+  virtual gfxSize GetResolution() const = 0;
+  /**
+   * Set the element resolution.
+   */
+  virtual void SetResolution(const gfxSize& aResolution) = 0;
   /**
    * Return how much we would try to scroll by in each direction if
    * asked to scroll by one "line" vertically and horizontally.

mobile/android/chrome/content/browser.js

@@ -2882,6 +2882,7 @@ function Tab(aURL, aParams) {
   this.lastTouchedAt = Date.now();
   this._zoom = 1.0;
   this._drawZoom = 1.0;
+  this._restoreZoom = false;
   this._fixedMarginLeft = 0;
   this._fixedMarginTop = 0;
   this._fixedMarginRight = 0;
@@ -3486,6 +3487,7 @@ Tab.prototype = {
 
     let win = this.browser.contentWindow;
     win.scrollTo(x, y);
+    this.saveSessionZoom(aViewport.zoom);
 
     this.userScrollPos.x = win.scrollX;
     this.userScrollPos.y = win.scrollY;
@@ -3535,12 +3537,13 @@ Tab.prototype = {
   getViewport: function() {
     let screenW = gScreenWidth - gViewportMargins.left - gViewportMargins.right;
     let screenH = gScreenHeight - gViewportMargins.top - gViewportMargins.bottom;
+    let zoom = this.restoredSessionZoom() || this._zoom;
 
     let viewport = {
       width: screenW,
       height: screenH,
-      cssWidth: screenW / this._zoom,
-      cssHeight: screenH / this._zoom,
+      cssWidth: screenW / zoom,
+      cssHeight: screenH / zoom,
       pageLeft: 0,
       pageTop: 0,
       pageRight: screenW,
@@ -3548,13 +3551,13 @@ Tab.prototype = {
       // We make up matching css page dimensions
       cssPageLeft: 0,
       cssPageTop: 0,
-      cssPageRight: screenW / this._zoom,
-      cssPageBottom: screenH / this._zoom,
+      cssPageRight: screenW / zoom,
+      cssPageBottom: screenH / zoom,
       fixedMarginLeft: this._fixedMarginLeft,
       fixedMarginTop: this._fixedMarginTop,
       fixedMarginRight: this._fixedMarginRight,
       fixedMarginBottom: this._fixedMarginBottom,
-      zoom: this._zoom,
+      zoom: zoom,
     };
 
     // Set the viewport offset to current scroll offset
@@ -4186,6 +4189,9 @@ Tab.prototype = {
       tabID: this.id,
     };
 
+    // Restore zoom only when moving in session history, not for new page loads.
+    this._restoreZoom = aMessage != "New";
+
     if (aParams) {
       if ("url" in aParams)
         message.url = aParams.url;
@@ -4198,6 +4204,22 @@ Tab.prototype = {
     sendMessageToJava(message);
   },
 
+  saveSessionZoom: function(aZoom) {
+    let cwu = this.browser.contentWindow.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindowUtils);
+    cwu.setResolution(aZoom / window.devicePixelRatio, aZoom / window.devicePixelRatio);
+  },
+
+  restoredSessionZoom: function() {
+    if (!this._restoreZoom) {
+      return null;
+    }
+
+    let cwu = this.browser.contentWindow.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindowUtils);
+    let res = {x: {}, y: {}};
+    cwu.getResolution(res.x, res.y);
+    return res.x.value * window.devicePixelRatio;
+  },
+
   OnHistoryNewEntry: function(aUri) {
     this._sendHistoryEvent("New", { url: aUri.spec });
   },
@@ -4322,8 +4344,11 @@ Tab.prototype = {
     // In all of these cases, we maintain how much actual content is visible
     // within the screen width. Note that "actual content" may be different
     // with respect to CSS pixels because of the CSS viewport size changing.
-    let zoomScale = (screenW * oldBrowserWidth) / (aOldScreenWidth * viewportW);
-    let zoom = (aInitialLoad && metadata.defaultZoom) ? metadata.defaultZoom : this.clampZoom(this._zoom * zoomScale);
+    let zoom = this.restoredSessionZoom() || metadata.defaultZoom;
+    if (!zoom || !aInitialLoad) {
+      let zoomScale = (screenW * oldBrowserWidth) / (aOldScreenWidth * viewportW);
+      zoom = this.clampZoom(this._zoom * zoomScale);
+    }
     this.setResolution(zoom, false);
     this.setScrollClampingSize(zoom);
 
@@ -4459,7 +4484,8 @@ Tab.prototype = {
           // and zoom when calculating the new ones, so we need to reset these
           // things here before calling updateMetadata.
           this.setBrowserSize(kDefaultCSSViewportWidth, kDefaultCSSViewportHeight);
-          this.setResolution(gScreenWidth / this.browserWidth, false);
+          let zoom = this.restoredSessionZoom() || gScreenWidth / this.browserWidth;
+          this.setResolution(zoom, true);
           ViewportHandler.updateMetadata(this, true);
 
           // Note that if we draw without a display-port, things can go wrong. By the