From ecd53983ef8e143ad101eac16c97e4fa32f2f677 Mon Sep 17 00:00:00 2001
From: "sharparrow1%yahoo.com"
 <sharparrow1%yahoo.com@18797224-902f-48f8-a5cc-f745e15eee43>
Date: Fri, 24 Aug 2007 17:46:59 +0000
Subject: [PATCH] Bug 391494: full page zoom causes scrollbars to be cut off.
 r+sr+a=roc

git-svn-id: svn://10.0.0.236/trunk@233024 18797224-902f-48f8-a5cc-f745e15eee43
---
 mozilla/layout/base/nsPresContext.cpp | 9 ++++++---
 mozilla/layout/base/nsPresContext.h   | 1 +
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/mozilla/layout/base/nsPresContext.cpp b/mozilla/layout/base/nsPresContext.cpp
index bde693e6ee9..158296bc286 100644
--- a/mozilla/layout/base/nsPresContext.cpp
+++ b/mozilla/layout/base/nsPresContext.cpp
@@ -798,6 +798,8 @@ nsPresContext::Init(nsIDeviceContext* aDeviceContext)
   mDeviceContext = aDeviceContext;
   NS_ADDREF(mDeviceContext);
 
+  mCurAppUnitsPerDevPixel = AppUnitsPerDevPixel();
+
   if (!mImageLoaders.Init())
     return NS_ERROR_OUT_OF_MEMORY;
   
@@ -1145,8 +1147,8 @@ nsPresContext::GetDefaultFontExternal(PRUint8 aFontID) const
 void
 nsPresContext::SetFullZoom(float aZoom)
 {
-  float oldWidth = mVisibleArea.width * mFullZoom;
-  float oldHeight = mVisibleArea.height * mFullZoom;
+  float oldWidth = mVisibleArea.width / float(mCurAppUnitsPerDevPixel);
+  float oldHeight = mVisibleArea.height / float(mCurAppUnitsPerDevPixel);
   if (!mShell) {
     return;
   }
@@ -1155,9 +1157,10 @@ nsPresContext::SetFullZoom(float aZoom)
   }
   if (mFullZoom != aZoom) {
     mFullZoom = aZoom;
-    GetViewManager()->SetWindowDimensions(oldWidth / aZoom, oldHeight / aZoom);
+    GetViewManager()->SetWindowDimensions(oldWidth * AppUnitsPerDevPixel(), oldHeight * AppUnitsPerDevPixel());
     ClearStyleDataAndReflow();
   }
+  mCurAppUnitsPerDevPixel = AppUnitsPerDevPixel();
 }
 
 imgIRequest*
diff --git a/mozilla/layout/base/nsPresContext.h b/mozilla/layout/base/nsPresContext.h
index 93ec0f28969..9930fa64b90 100644
--- a/mozilla/layout/base/nsPresContext.h
+++ b/mozilla/layout/base/nsPresContext.h
@@ -773,6 +773,7 @@ protected:
 
   float                 mTextZoom;      // Text zoom, defaults to 1.0
   float                 mFullZoom;      // Page zoom, defaults to 1.0
+  PRInt32               mCurAppUnitsPerDevPixel;
   PRInt32               mAutoQualityMinFontSizePixelsPref;
 
 #ifdef IBMBIDI