diff --git a/content/html/content/src/nsGenericHTMLElement.cpp b/content/html/content/src/nsGenericHTMLElement.cpp
index 39cd59874482..7365eb54abe8 100644
--- a/content/html/content/src/nsGenericHTMLElement.cpp
+++ b/content/html/content/src/nsGenericHTMLElement.cpp
@@ -1462,7 +1462,8 @@ nsGenericHTMLElement::MapImageAttributesInto(nsIHTMLAttributes* aAttributes,
   if (nsnull != aAttributes) {
     nsHTMLValue value;
 
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsStylePosition* pos = (nsStylePosition*)
       aContext->GetMutableStyleData(eStyleStruct_Position);
     nsStyleSpacing* spacing = (nsStyleSpacing*)
@@ -1534,7 +1535,8 @@ nsGenericHTMLElement::MapImageAlignAttributeInto(nsIHTMLAttributes* aAttributes,
         aContext->GetMutableStyleData(eStyleStruct_Text);
       nsStyleSpacing* spacing = (nsStyleSpacing*)
         aContext->GetMutableStyleData(eStyleStruct_Spacing);
-      float p2t = aPresContext->GetPixelsToTwips();
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
       nsStyleCoord three(NSIntPixelsToTwips(3, p2t));
       switch (align) {
       case NS_STYLE_TEXT_ALIGN_LEFT:
@@ -1575,7 +1577,8 @@ nsGenericHTMLElement::MapImageBorderAttributesInto(nsIHTMLAttributes* aAttribute
       value.SetPixelValue(2);
     }
 
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nscoord twips = NSIntPixelsToTwips(value.GetPixelValue(), p2t);
 
     // Fixup border-padding sums: subtract out the old size and then
diff --git a/content/html/content/src/nsHTMLBodyElement.cpp b/content/html/content/src/nsHTMLBodyElement.cpp
index 29d1b091ea11..725b8b1075f2 100644
--- a/content/html/content/src/nsHTMLBodyElement.cpp
+++ b/content/html/content/src/nsHTMLBodyElement.cpp
@@ -405,7 +405,7 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
     // marginwidth/marginheight
     // XXX: see ua.css for related code in the BODY rule
     float p2t;
-    p2t = aPresContext->GetPixelsToTwips();
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsStyleSpacing* spacing = (nsStyleSpacing*)
       aContext->GetMutableStyleData(eStyleStruct_Spacing);
     aAttributes->GetAttribute(nsHTMLAtoms::marginwidth, value);
diff --git a/content/html/content/src/nsHTMLHRElement.cpp b/content/html/content/src/nsHTMLHRElement.cpp
index 01e4f6dacb75..90537b812513 100644
--- a/content/html/content/src/nsHTMLHRElement.cpp
+++ b/content/html/content/src/nsHTMLHRElement.cpp
@@ -222,7 +222,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
     }
 
     // width: pixel, percent
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsStylePosition* pos = (nsStylePosition*)
       aContext->GetMutableStyleData(eStyleStruct_Position);
     aAttributes->GetAttribute(nsHTMLAtoms::width, value);
diff --git a/content/html/content/src/nsHTMLIFrameElement.cpp b/content/html/content/src/nsHTMLIFrameElement.cpp
index 59da213f9e49..468befa4fdf0 100644
--- a/content/html/content/src/nsHTMLIFrameElement.cpp
+++ b/content/html/content/src/nsHTMLIFrameElement.cpp
@@ -232,7 +232,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
 
     nsHTMLValue value;
 
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsStylePosition* pos = (nsStylePosition*)
       aContext->GetMutableStyleData(eStyleStruct_Position);
     nsStyleSpacing* spacing = (nsStyleSpacing*)
diff --git a/content/html/content/src/nsHTMLImageElement.cpp b/content/html/content/src/nsHTMLImageElement.cpp
index b2b33d46b029..ef558f19d3a7 100644
--- a/content/html/content/src/nsHTMLImageElement.cpp
+++ b/content/html/content/src/nsHTMLImageElement.cpp
@@ -245,7 +245,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
       nsStyleSpacing* spacing = (nsStyleSpacing*)
         aContext->GetMutableStyleData(eStyleStruct_Spacing);
 
-      float p2t = aPresContext->GetPixelsToTwips();
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
       nsStyleCoord three(NSIntPixelsToTwips(3, p2t));
       switch (align) {
       case NS_STYLE_TEXT_ALIGN_LEFT:
diff --git a/content/html/content/src/nsHTMLInputElement.cpp b/content/html/content/src/nsHTMLInputElement.cpp
index 357d514a4a6d..c7ea4d0e3e0b 100644
--- a/content/html/content/src/nsHTMLInputElement.cpp
+++ b/content/html/content/src/nsHTMLInputElement.cpp
@@ -567,7 +567,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
       case NS_FORM_INPUT_CHECKBOX:
       case NS_FORM_INPUT_RADIO: 
       {
-        float p2t = aPresContext->GetPixelsToTwips();
+        float p2t;
+        aPresContext->GetScaledPixelsToTwips(p2t);
         nscoord pad = NSIntPixelsToTwips(3, p2t);
 
         // add left and right padding around the radio button via css
diff --git a/content/html/content/src/nsHTMLTableCellElement.cpp b/content/html/content/src/nsHTMLTableCellElement.cpp
index 046679b01f85..327b2689082a 100644
--- a/content/html/content/src/nsHTMLTableCellElement.cpp
+++ b/content/html/content/src/nsHTMLTableCellElement.cpp
@@ -350,7 +350,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
     }
 
     // width: pixel
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsStylePosition* pos = (nsStylePosition*)
       aContext->GetMutableStyleData(eStyleStruct_Position);
     aAttributes->GetAttribute(nsHTMLAtoms::width, widthValue);
diff --git a/content/html/content/src/nsHTMLTableColElement.cpp b/content/html/content/src/nsHTMLTableColElement.cpp
index 11cef3b1f1ed..d54635f1aa05 100644
--- a/content/html/content/src/nsHTMLTableColElement.cpp
+++ b/content/html/content/src/nsHTMLTableColElement.cpp
@@ -223,7 +223,6 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
   NS_PRECONDITION(nsnull!=aPresContext, "bad presentation context arg");
   if (nsnull != aAttributes) {
 
-    float p2t;
     nsHTMLValue value;
     nsStyleText* textStyle = nsnull;
 
@@ -238,7 +237,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
         break;
 
       case eHTMLUnit_Pixel:
-        p2t = aPresContext->GetPixelsToTwips();
+        float p2t;
+        aPresContext->GetScaledPixelsToTwips(p2t);
         position->mWidth.SetCoordValue(NSIntPixelsToTwips(value.GetPixelValue(), p2t));
         break;
       }
diff --git a/content/html/content/src/nsHTMLTableColGroupElement.cpp b/content/html/content/src/nsHTMLTableColGroupElement.cpp
index 9c92d1130bb5..7674ee328946 100644
--- a/content/html/content/src/nsHTMLTableColGroupElement.cpp
+++ b/content/html/content/src/nsHTMLTableColGroupElement.cpp
@@ -212,7 +212,6 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
   NS_PRECONDITION(nsnull!=aPresContext, "bad presentation context arg");
   if (nsnull != aAttributes) {
 
-    float p2t;
     nsHTMLValue value;
     nsStyleText* textStyle = nsnull;
 
@@ -227,7 +226,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
         break;
 
       case eHTMLUnit_Pixel:
-        p2t = aPresContext->GetPixelsToTwips();
+        float p2t;
+        aPresContext->GetScaledPixelsToTwips(p2t);
         position->mWidth.SetCoordValue(NSIntPixelsToTwips(value.GetPixelValue(), p2t));
         break;
       }
diff --git a/content/html/content/src/nsHTMLTableElement.cpp b/content/html/content/src/nsHTMLTableElement.cpp
index f02bcf8b3455..03ec0402fe2e 100644
--- a/content/html/content/src/nsHTMLTableElement.cpp
+++ b/content/html/content/src/nsHTMLTableElement.cpp
@@ -526,7 +526,8 @@ MapTableBorderInto(nsIHTMLAttributes* aAttributes,
       aContext->GetMutableStyleData(eStyleStruct_Spacing);
     nsStyleTable *tableStyle = (nsStyleTable*)
       aContext->GetMutableStyleData(eStyleStruct_Table);
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsStyleCoord twips;
     if (borderValue.GetUnit() == eHTMLUnit_Empty) {
       tableStyle->mRules=NS_STYLE_TABLE_RULES_ALL;  // non-0 values of border imply default rules=all
@@ -561,7 +562,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
 
   if (nsnull!=aAttributes)
   {
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsHTMLValue value;
 
     // width
diff --git a/content/html/content/src/nsHTMLTableRowElement.cpp b/content/html/content/src/nsHTMLTableRowElement.cpp
index 35a9a52877f7..aa4c3ca0e4f7 100644
--- a/content/html/content/src/nsHTMLTableRowElement.cpp
+++ b/content/html/content/src/nsHTMLTableRowElement.cpp
@@ -314,7 +314,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
     // height: pixel
     aAttributes->GetAttribute(nsHTMLAtoms::height, value);
     if (value.GetUnit() == eHTMLUnit_Pixel) {
-      float p2t = aPresContext->GetPixelsToTwips();
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
       nsStylePosition* pos = (nsStylePosition*)
         aContext->GetMutableStyleData(eStyleStruct_Position);
       nscoord twips = NSIntPixelsToTwips(value.GetPixelValue(), p2t);
diff --git a/content/html/content/src/nsHTMLTableSectionElement.cpp b/content/html/content/src/nsHTMLTableSectionElement.cpp
index 40d6df0504f7..e8ad6a53b422 100644
--- a/content/html/content/src/nsHTMLTableSectionElement.cpp
+++ b/content/html/content/src/nsHTMLTableSectionElement.cpp
@@ -265,7 +265,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
     // height: pixel
     aAttributes->GetAttribute(nsHTMLAtoms::height, value);
     if (value.GetUnit() == eHTMLUnit_Pixel) {
-      float p2t = aPresContext->GetPixelsToTwips();
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
       nsStylePosition* pos = (nsStylePosition*)
         aContext->GetMutableStyleData(eStyleStruct_Position);
       nscoord twips = NSIntPixelsToTwips(value.GetPixelValue(), p2t);
diff --git a/content/html/style/src/nsCSSStyleRule.cpp b/content/html/style/src/nsCSSStyleRule.cpp
index 752992c60a36..a1cea01163c7 100644
--- a/content/html/style/src/nsCSSStyleRule.cpp
+++ b/content/html/style/src/nsCSSStyleRule.cpp
@@ -717,7 +717,9 @@ nscoord CalcLength(const nsCSSValue& aValue,
       return NSToCoordRound(aValue.GetFloatValue() * (float)capHeight);
     }
     case eCSSUnit_Pixel:
-      return NSFloatPixelsToTwips(aValue.GetFloatValue(), aPresContext->GetPixelsToTwips());
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
+      return NSFloatPixelsToTwips(aValue.GetFloatValue(), p2t);
   }
   return 0;
 }
diff --git a/layout/base/nsCSSRendering.cpp b/layout/base/nsCSSRendering.cpp
index e5a91adbdbb7..42fe42d72253 100644
--- a/layout/base/nsCSSRendering.cpp
+++ b/layout/base/nsCSSRendering.cpp
@@ -873,7 +873,8 @@ nsCSSRendering::PaintBackground(nsIPresContext& aPresContext,
 #endif
 
     // Convert image dimensions into nscoord's
-    float p2t = aPresContext.GetPixelsToTwips();
+    float p2t;
+    aPresContext.GetScaledPixelsToTwips(p2t);
     nscoord tileWidth = NSIntPixelsToTwips(imageSize.width, p2t);
     nscoord tileHeight = NSIntPixelsToTwips(imageSize.height, p2t);
     if ((tileWidth == 0) || (tileHeight == 0)) {
@@ -937,7 +938,7 @@ nsCSSRendering::PaintBackground(nsIPresContext& aPresContext,
       PRIntn x = xstart;
       nscoord xpos = xpostart;
       for (; x <= xCount; ++x, xpos += tileWidth) {
-        aRenderingContext.DrawImage(image, xpos, ypos);
+        aRenderingContext.DrawImage(image, xpos, ypos, tileWidth, tileHeight);
       }
     }
     aRenderingContext.PopState(clipState);
diff --git a/layout/base/nsPresContext.cpp b/layout/base/nsPresContext.cpp
index 673bcdcb1000..207099475f52 100644
--- a/layout/base/nsPresContext.cpp
+++ b/layout/base/nsPresContext.cpp
@@ -447,6 +447,21 @@ nsPresContext::GetTwipsToPixels() const
   return 1.0f;
 }
 
+NS_IMETHODIMP nsPresContext :: GetScaledPixelsToTwips(float &aScale) const
+{
+  if (nsnull != mDeviceContext)
+  {
+    float p2t, scale;
+    mDeviceContext->GetDevUnitsToAppUnits(p2t);
+    mDeviceContext->GetCanonicalPixelScale(scale);
+    aScale = p2t * scale;
+  }
+  else
+    aScale = 1.0f;
+  
+  return NS_OK;
+}
+
 nsIDeviceContext*
 nsPresContext::GetDeviceContext() const
 {
diff --git a/layout/base/nsPresContext.h b/layout/base/nsPresContext.h
index 533f597aa1f6..e56a0d88eba6 100644
--- a/layout/base/nsPresContext.h
+++ b/layout/base/nsPresContext.h
@@ -214,6 +214,13 @@ public:
   virtual float GetPixelsToTwips() const = 0;
   virtual float GetTwipsToPixels() const = 0;
 
+  //XXX this is probably not an ideal name. MMP
+  /** 
+   * Do pixels to twips conversion taking into account
+   * differing size of a "pixel" from device to device.
+   */
+  NS_IMETHOD GetScaledPixelsToTwips(float &aScale) const = 0;
+
   //be sure to Relase() after you are done with the Get()
   virtual nsIDeviceContext * GetDeviceContext() const = 0;
 
diff --git a/layout/base/nsPresShell.cpp b/layout/base/nsPresShell.cpp
index 509a724c602e..e61f51346c1a 100644
--- a/layout/base/nsPresShell.cpp
+++ b/layout/base/nsPresShell.cpp
@@ -755,19 +755,16 @@ NS_IMETHODIMP PresShell :: CreateRenderingContext(nsIFrame *aFrame,
     view->GetParent(view);
   }
 
-  if (nsnull != view)
-  {
-    nsIDeviceContext  *dx;
+  nsIDeviceContext  *dx;
 
-    dx = mPresContext->GetDeviceContext();
+  dx = mPresContext->GetDeviceContext();
+
+  if (nsnull != view)
     rv = dx->CreateRenderingContext(view, aContext);
-    NS_RELEASE(dx);
-  }
   else
-  {
-    rv = NS_ERROR_FAILURE;
-    aContext = nsnull;
-  }
+    rv = dx->CreateRenderingContext(aContext);
+
+  NS_RELEASE(dx);
 
   return rv;
 }
diff --git a/layout/base/public/nsIPresContext.h b/layout/base/public/nsIPresContext.h
index 533f597aa1f6..e56a0d88eba6 100644
--- a/layout/base/public/nsIPresContext.h
+++ b/layout/base/public/nsIPresContext.h
@@ -214,6 +214,13 @@ public:
   virtual float GetPixelsToTwips() const = 0;
   virtual float GetTwipsToPixels() const = 0;
 
+  //XXX this is probably not an ideal name. MMP
+  /** 
+   * Do pixels to twips conversion taking into account
+   * differing size of a "pixel" from device to device.
+   */
+  NS_IMETHOD GetScaledPixelsToTwips(float &aScale) const = 0;
+
   //be sure to Relase() after you are done with the Get()
   virtual nsIDeviceContext * GetDeviceContext() const = 0;
 
diff --git a/layout/base/public/nsPresContext.h b/layout/base/public/nsPresContext.h
index 533f597aa1f6..e56a0d88eba6 100644
--- a/layout/base/public/nsPresContext.h
+++ b/layout/base/public/nsPresContext.h
@@ -214,6 +214,13 @@ public:
   virtual float GetPixelsToTwips() const = 0;
   virtual float GetTwipsToPixels() const = 0;
 
+  //XXX this is probably not an ideal name. MMP
+  /** 
+   * Do pixels to twips conversion taking into account
+   * differing size of a "pixel" from device to device.
+   */
+  NS_IMETHOD GetScaledPixelsToTwips(float &aScale) const = 0;
+
   //be sure to Relase() after you are done with the Get()
   virtual nsIDeviceContext * GetDeviceContext() const = 0;
 
diff --git a/layout/base/src/nsFrameImageLoader.cpp b/layout/base/src/nsFrameImageLoader.cpp
index 67920373d2da..0f2af9654b0a 100644
--- a/layout/base/src/nsFrameImageLoader.cpp
+++ b/layout/base/src/nsFrameImageLoader.cpp
@@ -29,6 +29,7 @@
 #include "prlog.h"
 #include "nsISizeOfHandler.h"
 #include "nsIStyleContext.h"
+#include "nsIDeviceContext.h"
 
 static NS_DEFINE_IID(kIFrameImageLoaderIID, NS_IFRAME_IMAGE_LOADER_IID);
 static NS_DEFINE_IID(kIImageRequestObserverIID, NS_IIMAGEREQUESTOBSERVER_IID);
@@ -206,7 +207,7 @@ nsFrameImageLoader::Notify(nsIImageRequest *aImageRequest,
     mImageLoadStatus |= NS_IMAGE_LOAD_STATUS_IMAGE_READY;
 
     // Convert the rect from pixels to twips
-    p2t = mPresContext->GetPixelsToTwips();
+    mPresContext->GetScaledPixelsToTwips(p2t);
     changeRect = (const nsRect*)aParam3;
     damageRect.x = NSIntPixelsToTwips(changeRect->x, p2t);
     damageRect.y = NSIntPixelsToTwips(changeRect->y, p2t);
@@ -283,6 +284,8 @@ nsFrameImageLoader::DamageRepairFrame(const nsRect* aDamageRect)
          ("nsFrameImageLoader::DamageRepairFrame frame=%p status=%x",
           mTargetFrame, mImageLoadStatus));
 
+#if 0
+  // XXX I #if 0'd this per troy's instruction... MMP
   // XXX this should be done somewhere else, like when the window
   // is created or something???
   // XXX maybe there should be a seperate notification service for
@@ -297,6 +300,7 @@ nsFrameImageLoader::DamageRepairFrame(const nsRect* aDamageRect)
     gXXXInstalledColorMap = PR_TRUE;
   }
   NS_RELEASE(window);
+#endif
 
   // Determine damaged area and tell view manager to redraw it
   nsPoint offset;
diff --git a/layout/base/src/nsPresContext.cpp b/layout/base/src/nsPresContext.cpp
index 673bcdcb1000..207099475f52 100644
--- a/layout/base/src/nsPresContext.cpp
+++ b/layout/base/src/nsPresContext.cpp
@@ -447,6 +447,21 @@ nsPresContext::GetTwipsToPixels() const
   return 1.0f;
 }
 
+NS_IMETHODIMP nsPresContext :: GetScaledPixelsToTwips(float &aScale) const
+{
+  if (nsnull != mDeviceContext)
+  {
+    float p2t, scale;
+    mDeviceContext->GetDevUnitsToAppUnits(p2t);
+    mDeviceContext->GetCanonicalPixelScale(scale);
+    aScale = p2t * scale;
+  }
+  else
+    aScale = 1.0f;
+  
+  return NS_OK;
+}
+
 nsIDeviceContext*
 nsPresContext::GetDeviceContext() const
 {
diff --git a/layout/base/src/nsPresContext.h b/layout/base/src/nsPresContext.h
index 992be3964065..00754a094d76 100644
--- a/layout/base/src/nsPresContext.h
+++ b/layout/base/src/nsPresContext.h
@@ -74,6 +74,7 @@ public:
   virtual void SetVisibleArea(const nsRect& r);
   virtual float GetPixelsToTwips() const;
   virtual float GetTwipsToPixels() const;
+  NS_IMETHOD GetScaledPixelsToTwips(float &aScale) const;
   virtual nsIDeviceContext* GetDeviceContext() const;
   NS_IMETHOD GetEventStateManager(nsIEventStateManager** aManager);
 
diff --git a/layout/forms/nsFieldSetFrame.cpp b/layout/forms/nsFieldSetFrame.cpp
index 355398f3695b..e3b9ae1df003 100644
--- a/layout/forms/nsFieldSetFrame.cpp
+++ b/layout/forms/nsFieldSetFrame.cpp
@@ -241,7 +241,8 @@ nsFieldSetFrame::Reflow(nsIPresContext& aPresContext,
                         nsReflowStatus& aStatus)
 {
   nsSize availSize(aReflowState.maxSize);
-  float p2t = aPresContext.GetPixelsToTwips();
+  float p2t;
+  aPresContext.GetScaledPixelsToTwips(p2t);
   const PRInt32 minTopBorder = NSIntPixelsToTwips(MIN_TOP_BORDER, p2t);
 
   const nsStyleSpacing* spacing =
diff --git a/layout/forms/nsFormControlFrame.cpp b/layout/forms/nsFormControlFrame.cpp
index ec9bb3bd88a5..179300091075 100644
--- a/layout/forms/nsFormControlFrame.cpp
+++ b/layout/forms/nsFormControlFrame.cpp
@@ -798,7 +798,8 @@ nsFormControlFrame::CalculateSize (nsIPresContext* aPresContext, nsFormControlFr
   if (nsnull != aSpec.mColSizeAttr) {
     colStatus = hContent->GetAttribute(aSpec.mColSizeAttr, colAttr);
   }
-  float p2t = aPresContext->GetPixelsToTwips();
+  float p2t;
+  aPresContext->GetScaledPixelsToTwips(p2t);
 
   // determine the width
   nscoord adjSize;
diff --git a/layout/forms/nsHTMLButtonControlFrame.cpp b/layout/forms/nsHTMLButtonControlFrame.cpp
index 71b5f8823809..4a8b715c7e16 100644
--- a/layout/forms/nsHTMLButtonControlFrame.cpp
+++ b/layout/forms/nsHTMLButtonControlFrame.cpp
@@ -387,7 +387,8 @@ nsHTMLButtonControlFrame::ShiftContents(nsIPresContext& aPresContext, PRBool aDo
   nsStyleSpacing* spacing =
     (nsStyleSpacing*)mStyleContext->GetStyleData(eStyleStruct_Spacing); // cast deliberate
 
-  float p2t = aPresContext.GetPixelsToTwips();
+  float p2t;
+  aPresContext.GetScaledPixelsToTwips(p2t);
   nscoord shift = (aDown) ? NSIntPixelsToTwips(1, p2t) : -NSIntPixelsToTwips(1, p2t);
   nsStyleCoord styleCoord;
 
@@ -573,7 +574,8 @@ nsHTMLButtonControlFrame::Paint(nsIPresContext& aPresContext,
       nsMargin border;
       spacing->CalcBorderFor(this, border);
 
-      float p2t = aPresContext.GetPixelsToTwips();
+      float p2t;
+      aPresContext.GetScaledPixelsToTwips(p2t);
       nscoord onePixel = NSIntPixelsToTwips(1, p2t);
 
       nsRect outside(0, 0, mRect.width, mRect.height);
diff --git a/layout/generic/nsFrameFrame.cpp b/layout/generic/nsFrameFrame.cpp
index 074b11fc625d..5a2d3b8987a8 100644
--- a/layout/generic/nsFrameFrame.cpp
+++ b/layout/generic/nsFrameFrame.cpp
@@ -237,7 +237,8 @@ nsHTMLFrameOuterFrame::GetDesiredSize(nsIPresContext* aPresContext,
                                       nsHTMLReflowMetrics& aDesiredSize)
 {
   // <frame> processing does not use this routine, only <iframe>
-  float p2t = aPresContext->GetPixelsToTwips();
+  float p2t;
+  aPresContext->GetScaledPixelsToTwips(p2t);
 
   // XXX this needs to be changed from (200,200) to a better default for inline frames
   if (aReflowState.HaveFixedContentWidth()) {
@@ -532,7 +533,8 @@ PRInt32 nsHTMLFrameInnerFrame::GetMarginWidth(nsIPresContext* aPresContext, nsIC
   nsIHTMLContent* content = nsnull;
   mContent->QueryInterface(kIHTMLContentIID, (void**) &content);
   if (nsnull != content) {
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsHTMLValue value;
     content->GetAttribute(nsHTMLAtoms::marginwidth, value);
     if (eHTMLUnit_Pixel == value.GetUnit()) { 
@@ -552,7 +554,8 @@ PRInt32 nsHTMLFrameInnerFrame::GetMarginHeight(nsIPresContext* aPresContext, nsI
   nsIHTMLContent* content = nsnull;
   mContent->QueryInterface(kIHTMLContentIID, (void**) &content);
   if (nsnull != content) {
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsHTMLValue value;
     content->GetAttribute(nsHTMLAtoms::marginheight, value);
     if (eHTMLUnit_Pixel == value.GetUnit()) { 
diff --git a/layout/generic/nsFrameSetFrame.cpp b/layout/generic/nsFrameSetFrame.cpp
index 6604c7c81eef..f19ec0d3ba34 100644
--- a/layout/generic/nsFrameSetFrame.cpp
+++ b/layout/generic/nsFrameSetFrame.cpp
@@ -190,7 +190,8 @@ void nsHTMLFramesetFrame::CalculateRowCol(nsIPresContext* aPresContext, nscoord
   PRInt32 free    = 0;
   PRInt32 percent = 0;
   PRInt32 pixel   = 0;
-  float p2t = aPresContext->GetPixelsToTwips();
+  float p2t;
+  aPresContext->GetScaledPixelsToTwips(p2t);
 
   int i; // feeble compiler
   for (i = 0; i < aNumSpecs; i++) {
@@ -323,7 +324,8 @@ void nsHTMLFramesetFrame::CalculateRowCol(nsIPresContext* aPresContext, nscoord
 
 PRInt32 nsHTMLFramesetFrame::GetBorderWidth(nsIPresContext* aPresContext) 
 {
-  float p2t = aPresContext->GetPixelsToTwips();
+  float p2t;
+  aPresContext->GetScaledPixelsToTwips(p2t);
   nsHTMLValue htmlVal;
   PRInt32 intVal;
   nsIHTMLContent* content = nsnull;
diff --git a/layout/generic/nsImageFrame.cpp b/layout/generic/nsImageFrame.cpp
index 60d7fcaef7d5..4521b55847a2 100644
--- a/layout/generic/nsImageFrame.cpp
+++ b/layout/generic/nsImageFrame.cpp
@@ -245,7 +245,8 @@ nsHTMLImageLoader::GetDesiredSize(nsIPresContext* aPresContext,
         aDesiredSize.height = 1;
       }
       else {
-        float p2t = aPresContext->GetPixelsToTwips();
+        float p2t;
+        aPresContext->GetScaledPixelsToTwips(p2t);
         nsSize imageSize;
         mImageLoader->GetSize(imageSize);
         float imageWidth = imageSize.width * p2t;
@@ -283,7 +284,8 @@ nsHTMLImageLoader::GetDesiredSize(nsIPresContext* aPresContext,
       aDesiredSize.width = 1;
       aDesiredSize.height = 1;
     } else {
-      float p2t = aPresContext->GetPixelsToTwips();
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
       nsSize imageSize;
       mImageLoader->GetSize(imageSize);
       aDesiredSize.width = NSIntPixelsToTwips(imageSize.width, p2t);
@@ -570,7 +572,8 @@ ImageFrame::DisplayAltFeedback(nsIPresContext&      aPresContext,
   nsRect  inner;
   GetInnerArea(&aPresContext, inner);
 
-  float p2t = aPresContext.GetPixelsToTwips();
+  float p2t;
+  aPresContext.GetScaledPixelsToTwips(p2t);
   nsRecessedBorder recessedBorder(NSIntPixelsToTwips(1, p2t));
   nsCSSRendering::PaintBorder(aPresContext, aRenderingContext, this, inner,
                               inner, recessedBorder, 0);
@@ -652,7 +655,8 @@ ImageFrame::Paint(nsIPresContext& aPresContext,
     nsRect inner;
     GetInnerArea(&aPresContext, inner);
     if (mImageLoader.GetLoadImageFailed()) {
-      float p2t = aPresContext.GetPixelsToTwips();
+      float p2t;
+      aPresContext.GetScaledPixelsToTwips(p2t);
       inner.width = NSIntPixelsToTwips(image->GetWidth(), p2t);
       inner.height = NSIntPixelsToTwips(image->GetHeight(), p2t);
     }
diff --git a/layout/generic/nsObjectFrame.cpp b/layout/generic/nsObjectFrame.cpp
index 9f3ec856c5e6..38f2330ce3f9 100644
--- a/layout/generic/nsObjectFrame.cpp
+++ b/layout/generic/nsObjectFrame.cpp
@@ -324,7 +324,8 @@ nsObjectFrame::GetDesiredSize(nsIPresContext* aPresContext,
       aMetrics.width = aMetrics.height;
     }
     else {
-      float p2t = aPresContext->GetPixelsToTwips();
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
       aMetrics.width = NSIntPixelsToTwips(EMBED_DEF_DIM, p2t);
     }
   }
@@ -333,7 +334,8 @@ nsObjectFrame::GetDesiredSize(nsIPresContext* aPresContext,
       aMetrics.height = aMetrics.width;
     }
     else {
-      float p2t = aPresContext->GetPixelsToTwips();
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
       aMetrics.height = NSIntPixelsToTwips(EMBED_DEF_DIM, p2t);
     }
   }
diff --git a/layout/generic/nsSpacerFrame.cpp b/layout/generic/nsSpacerFrame.cpp
index 67f1f43bc061..381dd653609a 100644
--- a/layout/generic/nsSpacerFrame.cpp
+++ b/layout/generic/nsSpacerFrame.cpp
@@ -115,7 +115,8 @@ SpacerFrame::Reflow(nsIPresContext&          aPresContext,
     NS_RELEASE(hc);
   }
 
-  float p2t = aPresContext.GetPixelsToTwips();
+  float p2t;
+  aPresContext.GetScaledPixelsToTwips(p2t);
   switch (type) {
   case TYPE_WORD:
     if (0 != width) {
diff --git a/layout/html/base/src/nsBodyFrame.cpp b/layout/html/base/src/nsBodyFrame.cpp
index 740f2ac04c37..cc0d106031d1 100644
--- a/layout/html/base/src/nsBodyFrame.cpp
+++ b/layout/html/base/src/nsBodyFrame.cpp
@@ -556,7 +556,8 @@ nsBodyFrame::DidSetStyleContext(nsIPresContext* aPresContext)
   }
 
   nsHTMLValue value;
-  float p2t = aPresContext->GetPixelsToTwips();
+  float p2t;
+  aPresContext->GetScaledPixelsToTwips(p2t);
   nsIHTMLContent* hc;
   if (NS_OK == mContent->QueryInterface(kIHTMLContentIID, (void**) &hc)) {
     hc->GetAttribute(nsHTMLAtoms::marginwidth, value);
diff --git a/layout/html/base/src/nsHRFrame.cpp b/layout/html/base/src/nsHRFrame.cpp
index 87bfc5362d50..871f0410b533 100644
--- a/layout/html/base/src/nsHRFrame.cpp
+++ b/layout/html/base/src/nsHRFrame.cpp
@@ -31,6 +31,7 @@
 #include "nsStyleConsts.h"
 #include "nsCSSRendering.h"
 #include "nsIDOMHTMLHRElement.h"
+#include "nsIDeviceContext.h"
 
 static NS_DEFINE_IID(kIDOMHTMLHRElementIID, NS_IDOMHTMLHRELEMENT_IID);
 
@@ -96,7 +97,8 @@ HRuleFrame::Paint(nsIPresContext&      aPresContext,
     return NS_OK;
   }
 
-  float p2t = aPresContext.GetPixelsToTwips();
+  float p2t;
+  aPresContext.GetScaledPixelsToTwips(p2t);
   nscoord thickness = NSIntPixelsToTwips(GetThickness(), p2t);
 
   // Get style data
@@ -222,7 +224,9 @@ HRuleFrame::Reflow(nsIPresContext&          aPresContext,
   // HR's do not impact the max-element-size, unless a width is specified
   // otherwise tables behave badly. This makes sense they are springy.
   if (nsnull != aDesiredSize.maxElementSize) {
-    nscoord onePixel = NSIntPixelsToTwips(1, aPresContext.GetPixelsToTwips());
+    float p2t;
+    aPresContext.GetScaledPixelsToTwips(p2t);
+    nscoord onePixel = NSIntPixelsToTwips(1, p2t);
     if (aReflowState.HaveFixedContentWidth()) {
       aDesiredSize.maxElementSize->width = aReflowState.minWidth;
       aDesiredSize.maxElementSize->height = onePixel;
@@ -242,12 +246,15 @@ HRuleFrame::GetDesiredSize(nsIPresContext* aPresContext,
                            const nsHTMLReflowState& aReflowState,
                            nsHTMLReflowMetrics& aDesiredSize)
 {
+  float p2t;
+  aPresContext->GetScaledPixelsToTwips(p2t);
+
   if (aReflowState.HaveFixedContentWidth()) {
     aDesiredSize.width = aReflowState.minWidth;
   }
   else {
     if (NS_UNCONSTRAINEDSIZE == aReflowState.maxSize.width) {
-      aDesiredSize.width =  nscoord(aPresContext->GetPixelsToTwips());
+      aDesiredSize.width =  nscoord(p2t);
     }
     else {
       aDesiredSize.width = aReflowState.maxSize.width;
@@ -265,7 +272,6 @@ HRuleFrame::GetDesiredSize(nsIPresContext* aPresContext,
   nscoord lineHeight;
 
   // Get the thickness of the rule (this is not css's height property)
-  float p2t = aPresContext->GetPixelsToTwips();
   nscoord thickness = NSIntPixelsToTwips(GetThickness(), p2t);
 
   // Compute height of "line" that hrule will layout within. Use the
diff --git a/layout/html/base/src/nsHTMLImage.cpp b/layout/html/base/src/nsHTMLImage.cpp
index c820c8971ee2..4505deb9d414 100644
--- a/layout/html/base/src/nsHTMLImage.cpp
+++ b/layout/html/base/src/nsHTMLImage.cpp
@@ -319,7 +319,8 @@ nsHTMLImageLoader::GetDesiredSize(nsIPresContext* aPresContext,
         aDesiredSize.height = 1;
       }
       else {
-        float p2t = aPresContext->GetPixelsToTwips();
+        float p2t;
+        aPresContext->GetScaledPixelsToTwips(p2t);
         nsSize imageSize;
         mImageLoader->GetSize(imageSize);
         float imageWidth = imageSize.width * p2t;
@@ -358,7 +359,8 @@ nsHTMLImageLoader::GetDesiredSize(nsIPresContext* aPresContext,
       aDesiredSize.height = 1;
 //      printf ("in image loader, dummy size of 1 returned\n");
     } else {
-      float p2t = aPresContext->GetPixelsToTwips();
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
       nsSize imageSize;
       mImageLoader->GetSize(imageSize);
       aDesiredSize.width = NSIntPixelsToTwips(imageSize.width, p2t);
@@ -627,7 +629,8 @@ ImageFrame::Paint(nsIPresContext& aPresContext,
         nsRect  inner;
         GetInnerArea(&aPresContext, inner);
 
-        float p2t = aPresContext.GetPixelsToTwips();
+        float p2t;
+        aPresContext.GetScaledPixelsToTwips(p2t);
         nsRecessedBorder recessedBorder(NSIntPixelsToTwips(1, p2t));
         nsCSSRendering::PaintBorder(aPresContext, aRenderingContext, this, inner,
                                     inner, recessedBorder, 0);
@@ -649,7 +652,8 @@ ImageFrame::Paint(nsIPresContext& aPresContext,
     nsRect inner;
     GetInnerArea(&aPresContext, inner);
     if (mImageLoader.GetLoadImageFailed()) {
-      float p2t = aPresContext.GetPixelsToTwips();
+      float p2t;
+      aPresContext.GetScaledPixelsToTwips(p2t);
       inner.width = NSIntPixelsToTwips(image->GetWidth(), p2t);
       inner.height = NSIntPixelsToTwips(image->GetHeight(), p2t);
     }
diff --git a/layout/html/base/src/nsImageFrame.cpp b/layout/html/base/src/nsImageFrame.cpp
index 60d7fcaef7d5..4521b55847a2 100644
--- a/layout/html/base/src/nsImageFrame.cpp
+++ b/layout/html/base/src/nsImageFrame.cpp
@@ -245,7 +245,8 @@ nsHTMLImageLoader::GetDesiredSize(nsIPresContext* aPresContext,
         aDesiredSize.height = 1;
       }
       else {
-        float p2t = aPresContext->GetPixelsToTwips();
+        float p2t;
+        aPresContext->GetScaledPixelsToTwips(p2t);
         nsSize imageSize;
         mImageLoader->GetSize(imageSize);
         float imageWidth = imageSize.width * p2t;
@@ -283,7 +284,8 @@ nsHTMLImageLoader::GetDesiredSize(nsIPresContext* aPresContext,
       aDesiredSize.width = 1;
       aDesiredSize.height = 1;
     } else {
-      float p2t = aPresContext->GetPixelsToTwips();
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
       nsSize imageSize;
       mImageLoader->GetSize(imageSize);
       aDesiredSize.width = NSIntPixelsToTwips(imageSize.width, p2t);
@@ -570,7 +572,8 @@ ImageFrame::DisplayAltFeedback(nsIPresContext&      aPresContext,
   nsRect  inner;
   GetInnerArea(&aPresContext, inner);
 
-  float p2t = aPresContext.GetPixelsToTwips();
+  float p2t;
+  aPresContext.GetScaledPixelsToTwips(p2t);
   nsRecessedBorder recessedBorder(NSIntPixelsToTwips(1, p2t));
   nsCSSRendering::PaintBorder(aPresContext, aRenderingContext, this, inner,
                               inner, recessedBorder, 0);
@@ -652,7 +655,8 @@ ImageFrame::Paint(nsIPresContext& aPresContext,
     nsRect inner;
     GetInnerArea(&aPresContext, inner);
     if (mImageLoader.GetLoadImageFailed()) {
-      float p2t = aPresContext.GetPixelsToTwips();
+      float p2t;
+      aPresContext.GetScaledPixelsToTwips(p2t);
       inner.width = NSIntPixelsToTwips(image->GetWidth(), p2t);
       inner.height = NSIntPixelsToTwips(image->GetHeight(), p2t);
     }
diff --git a/layout/html/base/src/nsObjectFrame.cpp b/layout/html/base/src/nsObjectFrame.cpp
index 9f3ec856c5e6..38f2330ce3f9 100644
--- a/layout/html/base/src/nsObjectFrame.cpp
+++ b/layout/html/base/src/nsObjectFrame.cpp
@@ -324,7 +324,8 @@ nsObjectFrame::GetDesiredSize(nsIPresContext* aPresContext,
       aMetrics.width = aMetrics.height;
     }
     else {
-      float p2t = aPresContext->GetPixelsToTwips();
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
       aMetrics.width = NSIntPixelsToTwips(EMBED_DEF_DIM, p2t);
     }
   }
@@ -333,7 +334,8 @@ nsObjectFrame::GetDesiredSize(nsIPresContext* aPresContext,
       aMetrics.height = aMetrics.width;
     }
     else {
-      float p2t = aPresContext->GetPixelsToTwips();
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
       aMetrics.height = NSIntPixelsToTwips(EMBED_DEF_DIM, p2t);
     }
   }
diff --git a/layout/html/base/src/nsPresShell.cpp b/layout/html/base/src/nsPresShell.cpp
index 509a724c602e..e61f51346c1a 100644
--- a/layout/html/base/src/nsPresShell.cpp
+++ b/layout/html/base/src/nsPresShell.cpp
@@ -755,19 +755,16 @@ NS_IMETHODIMP PresShell :: CreateRenderingContext(nsIFrame *aFrame,
     view->GetParent(view);
   }
 
-  if (nsnull != view)
-  {
-    nsIDeviceContext  *dx;
+  nsIDeviceContext  *dx;
 
-    dx = mPresContext->GetDeviceContext();
+  dx = mPresContext->GetDeviceContext();
+
+  if (nsnull != view)
     rv = dx->CreateRenderingContext(view, aContext);
-    NS_RELEASE(dx);
-  }
   else
-  {
-    rv = NS_ERROR_FAILURE;
-    aContext = nsnull;
-  }
+    rv = dx->CreateRenderingContext(aContext);
+
+  NS_RELEASE(dx);
 
   return rv;
 }
diff --git a/layout/html/base/src/nsSpacerFrame.cpp b/layout/html/base/src/nsSpacerFrame.cpp
index 67f1f43bc061..381dd653609a 100644
--- a/layout/html/base/src/nsSpacerFrame.cpp
+++ b/layout/html/base/src/nsSpacerFrame.cpp
@@ -115,7 +115,8 @@ SpacerFrame::Reflow(nsIPresContext&          aPresContext,
     NS_RELEASE(hc);
   }
 
-  float p2t = aPresContext.GetPixelsToTwips();
+  float p2t;
+  aPresContext.GetScaledPixelsToTwips(p2t);
   switch (type) {
   case TYPE_WORD:
     if (0 != width) {
diff --git a/layout/html/content/src/nsGenericHTMLElement.cpp b/layout/html/content/src/nsGenericHTMLElement.cpp
index 39cd59874482..7365eb54abe8 100644
--- a/layout/html/content/src/nsGenericHTMLElement.cpp
+++ b/layout/html/content/src/nsGenericHTMLElement.cpp
@@ -1462,7 +1462,8 @@ nsGenericHTMLElement::MapImageAttributesInto(nsIHTMLAttributes* aAttributes,
   if (nsnull != aAttributes) {
     nsHTMLValue value;
 
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsStylePosition* pos = (nsStylePosition*)
       aContext->GetMutableStyleData(eStyleStruct_Position);
     nsStyleSpacing* spacing = (nsStyleSpacing*)
@@ -1534,7 +1535,8 @@ nsGenericHTMLElement::MapImageAlignAttributeInto(nsIHTMLAttributes* aAttributes,
         aContext->GetMutableStyleData(eStyleStruct_Text);
       nsStyleSpacing* spacing = (nsStyleSpacing*)
         aContext->GetMutableStyleData(eStyleStruct_Spacing);
-      float p2t = aPresContext->GetPixelsToTwips();
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
       nsStyleCoord three(NSIntPixelsToTwips(3, p2t));
       switch (align) {
       case NS_STYLE_TEXT_ALIGN_LEFT:
@@ -1575,7 +1577,8 @@ nsGenericHTMLElement::MapImageBorderAttributesInto(nsIHTMLAttributes* aAttribute
       value.SetPixelValue(2);
     }
 
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nscoord twips = NSIntPixelsToTwips(value.GetPixelValue(), p2t);
 
     // Fixup border-padding sums: subtract out the old size and then
diff --git a/layout/html/content/src/nsHTMLBodyElement.cpp b/layout/html/content/src/nsHTMLBodyElement.cpp
index 29d1b091ea11..725b8b1075f2 100644
--- a/layout/html/content/src/nsHTMLBodyElement.cpp
+++ b/layout/html/content/src/nsHTMLBodyElement.cpp
@@ -405,7 +405,7 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
     // marginwidth/marginheight
     // XXX: see ua.css for related code in the BODY rule
     float p2t;
-    p2t = aPresContext->GetPixelsToTwips();
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsStyleSpacing* spacing = (nsStyleSpacing*)
       aContext->GetMutableStyleData(eStyleStruct_Spacing);
     aAttributes->GetAttribute(nsHTMLAtoms::marginwidth, value);
diff --git a/layout/html/content/src/nsHTMLHRElement.cpp b/layout/html/content/src/nsHTMLHRElement.cpp
index 01e4f6dacb75..90537b812513 100644
--- a/layout/html/content/src/nsHTMLHRElement.cpp
+++ b/layout/html/content/src/nsHTMLHRElement.cpp
@@ -222,7 +222,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
     }
 
     // width: pixel, percent
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsStylePosition* pos = (nsStylePosition*)
       aContext->GetMutableStyleData(eStyleStruct_Position);
     aAttributes->GetAttribute(nsHTMLAtoms::width, value);
diff --git a/layout/html/content/src/nsHTMLIFrameElement.cpp b/layout/html/content/src/nsHTMLIFrameElement.cpp
index 59da213f9e49..468befa4fdf0 100644
--- a/layout/html/content/src/nsHTMLIFrameElement.cpp
+++ b/layout/html/content/src/nsHTMLIFrameElement.cpp
@@ -232,7 +232,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
 
     nsHTMLValue value;
 
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsStylePosition* pos = (nsStylePosition*)
       aContext->GetMutableStyleData(eStyleStruct_Position);
     nsStyleSpacing* spacing = (nsStyleSpacing*)
diff --git a/layout/html/content/src/nsHTMLImageElement.cpp b/layout/html/content/src/nsHTMLImageElement.cpp
index b2b33d46b029..ef558f19d3a7 100644
--- a/layout/html/content/src/nsHTMLImageElement.cpp
+++ b/layout/html/content/src/nsHTMLImageElement.cpp
@@ -245,7 +245,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
       nsStyleSpacing* spacing = (nsStyleSpacing*)
         aContext->GetMutableStyleData(eStyleStruct_Spacing);
 
-      float p2t = aPresContext->GetPixelsToTwips();
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
       nsStyleCoord three(NSIntPixelsToTwips(3, p2t));
       switch (align) {
       case NS_STYLE_TEXT_ALIGN_LEFT:
diff --git a/layout/html/content/src/nsHTMLInputElement.cpp b/layout/html/content/src/nsHTMLInputElement.cpp
index 357d514a4a6d..c7ea4d0e3e0b 100644
--- a/layout/html/content/src/nsHTMLInputElement.cpp
+++ b/layout/html/content/src/nsHTMLInputElement.cpp
@@ -567,7 +567,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
       case NS_FORM_INPUT_CHECKBOX:
       case NS_FORM_INPUT_RADIO: 
       {
-        float p2t = aPresContext->GetPixelsToTwips();
+        float p2t;
+        aPresContext->GetScaledPixelsToTwips(p2t);
         nscoord pad = NSIntPixelsToTwips(3, p2t);
 
         // add left and right padding around the radio button via css
diff --git a/layout/html/content/src/nsHTMLLayerElement.cpp b/layout/html/content/src/nsHTMLLayerElement.cpp
index 9445217ed2b7..48eec44fa941 100644
--- a/layout/html/content/src/nsHTMLLayerElement.cpp
+++ b/layout/html/content/src/nsHTMLLayerElement.cpp
@@ -207,7 +207,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
   // Note: ua.css specifies that the 'position' is absolute
   if (nsnull != aAttributes) {
     nsHTMLValue      value;
-    float            p2t = aPresContext->GetPixelsToTwips();
+    float            p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsStylePosition* position = (nsStylePosition*)
       aContext->GetMutableStyleData(eStyleStruct_Position);
 
diff --git a/layout/html/content/src/nsHTMLTableCellElement.cpp b/layout/html/content/src/nsHTMLTableCellElement.cpp
index 046679b01f85..327b2689082a 100644
--- a/layout/html/content/src/nsHTMLTableCellElement.cpp
+++ b/layout/html/content/src/nsHTMLTableCellElement.cpp
@@ -350,7 +350,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
     }
 
     // width: pixel
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsStylePosition* pos = (nsStylePosition*)
       aContext->GetMutableStyleData(eStyleStruct_Position);
     aAttributes->GetAttribute(nsHTMLAtoms::width, widthValue);
diff --git a/layout/html/content/src/nsHTMLTableColElement.cpp b/layout/html/content/src/nsHTMLTableColElement.cpp
index 11cef3b1f1ed..d54635f1aa05 100644
--- a/layout/html/content/src/nsHTMLTableColElement.cpp
+++ b/layout/html/content/src/nsHTMLTableColElement.cpp
@@ -223,7 +223,6 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
   NS_PRECONDITION(nsnull!=aPresContext, "bad presentation context arg");
   if (nsnull != aAttributes) {
 
-    float p2t;
     nsHTMLValue value;
     nsStyleText* textStyle = nsnull;
 
@@ -238,7 +237,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
         break;
 
       case eHTMLUnit_Pixel:
-        p2t = aPresContext->GetPixelsToTwips();
+        float p2t;
+        aPresContext->GetScaledPixelsToTwips(p2t);
         position->mWidth.SetCoordValue(NSIntPixelsToTwips(value.GetPixelValue(), p2t));
         break;
       }
diff --git a/layout/html/content/src/nsHTMLTableColGroupElement.cpp b/layout/html/content/src/nsHTMLTableColGroupElement.cpp
index 9c92d1130bb5..7674ee328946 100644
--- a/layout/html/content/src/nsHTMLTableColGroupElement.cpp
+++ b/layout/html/content/src/nsHTMLTableColGroupElement.cpp
@@ -212,7 +212,6 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
   NS_PRECONDITION(nsnull!=aPresContext, "bad presentation context arg");
   if (nsnull != aAttributes) {
 
-    float p2t;
     nsHTMLValue value;
     nsStyleText* textStyle = nsnull;
 
@@ -227,7 +226,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
         break;
 
       case eHTMLUnit_Pixel:
-        p2t = aPresContext->GetPixelsToTwips();
+        float p2t;
+        aPresContext->GetScaledPixelsToTwips(p2t);
         position->mWidth.SetCoordValue(NSIntPixelsToTwips(value.GetPixelValue(), p2t));
         break;
       }
diff --git a/layout/html/content/src/nsHTMLTableElement.cpp b/layout/html/content/src/nsHTMLTableElement.cpp
index f02bcf8b3455..03ec0402fe2e 100644
--- a/layout/html/content/src/nsHTMLTableElement.cpp
+++ b/layout/html/content/src/nsHTMLTableElement.cpp
@@ -526,7 +526,8 @@ MapTableBorderInto(nsIHTMLAttributes* aAttributes,
       aContext->GetMutableStyleData(eStyleStruct_Spacing);
     nsStyleTable *tableStyle = (nsStyleTable*)
       aContext->GetMutableStyleData(eStyleStruct_Table);
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsStyleCoord twips;
     if (borderValue.GetUnit() == eHTMLUnit_Empty) {
       tableStyle->mRules=NS_STYLE_TABLE_RULES_ALL;  // non-0 values of border imply default rules=all
@@ -561,7 +562,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
 
   if (nsnull!=aAttributes)
   {
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsHTMLValue value;
 
     // width
diff --git a/layout/html/content/src/nsHTMLTableRowElement.cpp b/layout/html/content/src/nsHTMLTableRowElement.cpp
index 35a9a52877f7..aa4c3ca0e4f7 100644
--- a/layout/html/content/src/nsHTMLTableRowElement.cpp
+++ b/layout/html/content/src/nsHTMLTableRowElement.cpp
@@ -314,7 +314,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
     // height: pixel
     aAttributes->GetAttribute(nsHTMLAtoms::height, value);
     if (value.GetUnit() == eHTMLUnit_Pixel) {
-      float p2t = aPresContext->GetPixelsToTwips();
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
       nsStylePosition* pos = (nsStylePosition*)
         aContext->GetMutableStyleData(eStyleStruct_Position);
       nscoord twips = NSIntPixelsToTwips(value.GetPixelValue(), p2t);
diff --git a/layout/html/content/src/nsHTMLTableSectionElement.cpp b/layout/html/content/src/nsHTMLTableSectionElement.cpp
index 40d6df0504f7..e8ad6a53b422 100644
--- a/layout/html/content/src/nsHTMLTableSectionElement.cpp
+++ b/layout/html/content/src/nsHTMLTableSectionElement.cpp
@@ -265,7 +265,8 @@ MapAttributesInto(nsIHTMLAttributes* aAttributes,
     // height: pixel
     aAttributes->GetAttribute(nsHTMLAtoms::height, value);
     if (value.GetUnit() == eHTMLUnit_Pixel) {
-      float p2t = aPresContext->GetPixelsToTwips();
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
       nsStylePosition* pos = (nsStylePosition*)
         aContext->GetMutableStyleData(eStyleStruct_Position);
       nscoord twips = NSIntPixelsToTwips(value.GetPixelValue(), p2t);
diff --git a/layout/html/document/src/nsFrameFrame.cpp b/layout/html/document/src/nsFrameFrame.cpp
index 074b11fc625d..5a2d3b8987a8 100644
--- a/layout/html/document/src/nsFrameFrame.cpp
+++ b/layout/html/document/src/nsFrameFrame.cpp
@@ -237,7 +237,8 @@ nsHTMLFrameOuterFrame::GetDesiredSize(nsIPresContext* aPresContext,
                                       nsHTMLReflowMetrics& aDesiredSize)
 {
   // <frame> processing does not use this routine, only <iframe>
-  float p2t = aPresContext->GetPixelsToTwips();
+  float p2t;
+  aPresContext->GetScaledPixelsToTwips(p2t);
 
   // XXX this needs to be changed from (200,200) to a better default for inline frames
   if (aReflowState.HaveFixedContentWidth()) {
@@ -532,7 +533,8 @@ PRInt32 nsHTMLFrameInnerFrame::GetMarginWidth(nsIPresContext* aPresContext, nsIC
   nsIHTMLContent* content = nsnull;
   mContent->QueryInterface(kIHTMLContentIID, (void**) &content);
   if (nsnull != content) {
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsHTMLValue value;
     content->GetAttribute(nsHTMLAtoms::marginwidth, value);
     if (eHTMLUnit_Pixel == value.GetUnit()) { 
@@ -552,7 +554,8 @@ PRInt32 nsHTMLFrameInnerFrame::GetMarginHeight(nsIPresContext* aPresContext, nsI
   nsIHTMLContent* content = nsnull;
   mContent->QueryInterface(kIHTMLContentIID, (void**) &content);
   if (nsnull != content) {
-    float p2t = aPresContext->GetPixelsToTwips();
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
     nsHTMLValue value;
     content->GetAttribute(nsHTMLAtoms::marginheight, value);
     if (eHTMLUnit_Pixel == value.GetUnit()) { 
diff --git a/layout/html/document/src/nsFrameSetFrame.cpp b/layout/html/document/src/nsFrameSetFrame.cpp
index 6604c7c81eef..f19ec0d3ba34 100644
--- a/layout/html/document/src/nsFrameSetFrame.cpp
+++ b/layout/html/document/src/nsFrameSetFrame.cpp
@@ -190,7 +190,8 @@ void nsHTMLFramesetFrame::CalculateRowCol(nsIPresContext* aPresContext, nscoord
   PRInt32 free    = 0;
   PRInt32 percent = 0;
   PRInt32 pixel   = 0;
-  float p2t = aPresContext->GetPixelsToTwips();
+  float p2t;
+  aPresContext->GetScaledPixelsToTwips(p2t);
 
   int i; // feeble compiler
   for (i = 0; i < aNumSpecs; i++) {
@@ -323,7 +324,8 @@ void nsHTMLFramesetFrame::CalculateRowCol(nsIPresContext* aPresContext, nscoord
 
 PRInt32 nsHTMLFramesetFrame::GetBorderWidth(nsIPresContext* aPresContext) 
 {
-  float p2t = aPresContext->GetPixelsToTwips();
+  float p2t;
+  aPresContext->GetScaledPixelsToTwips(p2t);
   nsHTMLValue htmlVal;
   PRInt32 intVal;
   nsIHTMLContent* content = nsnull;
diff --git a/layout/html/forms/src/nsCheckboxControlFrame.cpp b/layout/html/forms/src/nsCheckboxControlFrame.cpp
index d5e3e3800f71..044b220393ed 100644
--- a/layout/html/forms/src/nsCheckboxControlFrame.cpp
+++ b/layout/html/forms/src/nsCheckboxControlFrame.cpp
@@ -113,7 +113,8 @@ nsCheckboxControlFrame::GetDesiredSize(nsIPresContext* aPresContext,
                                             nsHTMLReflowMetrics& aDesiredLayoutSize,
                                             nsSize& aDesiredWidgetSize)
 {
-  float p2t = aPresContext->GetPixelsToTwips();
+  float p2t;
+  aPresContext->GetScaledPixelsToTwips(p2t);
 #ifdef XP_PC
   aDesiredWidgetSize.width  = NSIntPixelsToTwips(12, p2t);
   aDesiredWidgetSize.height = NSIntPixelsToTwips(12, p2t);
diff --git a/layout/html/forms/src/nsFieldSetFrame.cpp b/layout/html/forms/src/nsFieldSetFrame.cpp
index 355398f3695b..e3b9ae1df003 100644
--- a/layout/html/forms/src/nsFieldSetFrame.cpp
+++ b/layout/html/forms/src/nsFieldSetFrame.cpp
@@ -241,7 +241,8 @@ nsFieldSetFrame::Reflow(nsIPresContext& aPresContext,
                         nsReflowStatus& aStatus)
 {
   nsSize availSize(aReflowState.maxSize);
-  float p2t = aPresContext.GetPixelsToTwips();
+  float p2t;
+  aPresContext.GetScaledPixelsToTwips(p2t);
   const PRInt32 minTopBorder = NSIntPixelsToTwips(MIN_TOP_BORDER, p2t);
 
   const nsStyleSpacing* spacing =
diff --git a/layout/html/forms/src/nsFormControlFrame.cpp b/layout/html/forms/src/nsFormControlFrame.cpp
index ec9bb3bd88a5..179300091075 100644
--- a/layout/html/forms/src/nsFormControlFrame.cpp
+++ b/layout/html/forms/src/nsFormControlFrame.cpp
@@ -798,7 +798,8 @@ nsFormControlFrame::CalculateSize (nsIPresContext* aPresContext, nsFormControlFr
   if (nsnull != aSpec.mColSizeAttr) {
     colStatus = hContent->GetAttribute(aSpec.mColSizeAttr, colAttr);
   }
-  float p2t = aPresContext->GetPixelsToTwips();
+  float p2t;
+  aPresContext->GetScaledPixelsToTwips(p2t);
 
   // determine the width
   nscoord adjSize;
diff --git a/layout/html/forms/src/nsHTMLButtonControlFrame.cpp b/layout/html/forms/src/nsHTMLButtonControlFrame.cpp
index 71b5f8823809..4a8b715c7e16 100644
--- a/layout/html/forms/src/nsHTMLButtonControlFrame.cpp
+++ b/layout/html/forms/src/nsHTMLButtonControlFrame.cpp
@@ -387,7 +387,8 @@ nsHTMLButtonControlFrame::ShiftContents(nsIPresContext& aPresContext, PRBool aDo
   nsStyleSpacing* spacing =
     (nsStyleSpacing*)mStyleContext->GetStyleData(eStyleStruct_Spacing); // cast deliberate
 
-  float p2t = aPresContext.GetPixelsToTwips();
+  float p2t;
+  aPresContext.GetScaledPixelsToTwips(p2t);
   nscoord shift = (aDown) ? NSIntPixelsToTwips(1, p2t) : -NSIntPixelsToTwips(1, p2t);
   nsStyleCoord styleCoord;
 
@@ -573,7 +574,8 @@ nsHTMLButtonControlFrame::Paint(nsIPresContext& aPresContext,
       nsMargin border;
       spacing->CalcBorderFor(this, border);
 
-      float p2t = aPresContext.GetPixelsToTwips();
+      float p2t;
+      aPresContext.GetScaledPixelsToTwips(p2t);
       nscoord onePixel = NSIntPixelsToTwips(1, p2t);
 
       nsRect outside(0, 0, mRect.width, mRect.height);
diff --git a/layout/html/forms/src/nsRadioControlFrame.cpp b/layout/html/forms/src/nsRadioControlFrame.cpp
index 56e87e1fc173..30f716f73dc7 100644
--- a/layout/html/forms/src/nsRadioControlFrame.cpp
+++ b/layout/html/forms/src/nsRadioControlFrame.cpp
@@ -82,7 +82,8 @@ nsRadioControlFrame::GetDesiredSize(nsIPresContext* aPresContext,
                                   nsHTMLReflowMetrics& aDesiredLayoutSize,
                                   nsSize& aDesiredWidgetSize)
 {
-  float p2t = aPresContext->GetPixelsToTwips();
+  float p2t;
+  aPresContext->GetScaledPixelsToTwips(p2t);
   aDesiredWidgetSize.width  = NSIntPixelsToTwips(12, p2t);
   aDesiredWidgetSize.height = NSIntPixelsToTwips(12, p2t);
   aDesiredLayoutSize.width  = aDesiredWidgetSize.width;
diff --git a/layout/html/style/src/nsCSSRendering.cpp b/layout/html/style/src/nsCSSRendering.cpp
index e5a91adbdbb7..42fe42d72253 100644
--- a/layout/html/style/src/nsCSSRendering.cpp
+++ b/layout/html/style/src/nsCSSRendering.cpp
@@ -873,7 +873,8 @@ nsCSSRendering::PaintBackground(nsIPresContext& aPresContext,
 #endif
 
     // Convert image dimensions into nscoord's
-    float p2t = aPresContext.GetPixelsToTwips();
+    float p2t;
+    aPresContext.GetScaledPixelsToTwips(p2t);
     nscoord tileWidth = NSIntPixelsToTwips(imageSize.width, p2t);
     nscoord tileHeight = NSIntPixelsToTwips(imageSize.height, p2t);
     if ((tileWidth == 0) || (tileHeight == 0)) {
@@ -937,7 +938,7 @@ nsCSSRendering::PaintBackground(nsIPresContext& aPresContext,
       PRIntn x = xstart;
       nscoord xpos = xpostart;
       for (; x <= xCount; ++x, xpos += tileWidth) {
-        aRenderingContext.DrawImage(image, xpos, ypos);
+        aRenderingContext.DrawImage(image, xpos, ypos, tileWidth, tileHeight);
       }
     }
     aRenderingContext.PopState(clipState);
diff --git a/layout/html/style/src/nsCSSStyleRule.cpp b/layout/html/style/src/nsCSSStyleRule.cpp
index 752992c60a36..a1cea01163c7 100644
--- a/layout/html/style/src/nsCSSStyleRule.cpp
+++ b/layout/html/style/src/nsCSSStyleRule.cpp
@@ -717,7 +717,9 @@ nscoord CalcLength(const nsCSSValue& aValue,
       return NSToCoordRound(aValue.GetFloatValue() * (float)capHeight);
     }
     case eCSSUnit_Pixel:
-      return NSFloatPixelsToTwips(aValue.GetFloatValue(), aPresContext->GetPixelsToTwips());
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
+      return NSFloatPixelsToTwips(aValue.GetFloatValue(), p2t);
   }
   return 0;
 }
diff --git a/layout/html/table/src/nsTableCellFrame.cpp b/layout/html/table/src/nsTableCellFrame.cpp
index b8ec25859340..4d156fc6c479 100644
--- a/layout/html/table/src/nsTableCellFrame.cpp
+++ b/layout/html/table/src/nsTableCellFrame.cpp
@@ -399,7 +399,9 @@ NS_METHOD nsTableCellFrame::Reflow(nsIPresContext& aPresContext,
       grandChild->ChildCount(childCount);
       if (0!=childCount)
       {
-        nscoord one = ((nscoord)(NSIntPixelsToTwips(1, aPresContext.GetPixelsToTwips())));
+        float p2t;
+        aPresContext.GetScaledPixelsToTwips(p2t);
+        nscoord one = ((nscoord)(NSIntPixelsToTwips(1, p2t)));
         cellWidth = 1;
         if (gsDebug) 
           printf ("setting cellWidth=1 because it was 0 but there's some content\n");
@@ -645,7 +647,9 @@ void nsTableCellFrame::MapBorderMarginPadding(nsIPresContext* aPresContext)
   {
     // XXX: need to get border width here
     // in HTML, cell borders are always 1 pixel by default
-    border = NSIntPixelsToTwips(1, aPresContext->GetPixelsToTwips());
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
+    border = NSIntPixelsToTwips(1, p2t);
     MapHTMLBorderStyle(aPresContext, *spacingData, border, tableFrame);
   }
   
diff --git a/layout/html/table/src/nsTableFrame.cpp b/layout/html/table/src/nsTableFrame.cpp
index e2bfb2c3ba8f..8e47b406bf23 100644
--- a/layout/html/table/src/nsTableFrame.cpp
+++ b/layout/html/table/src/nsTableFrame.cpp
@@ -3347,7 +3347,7 @@ void nsTableFrame::MapBorderMarginPadding(nsIPresContext& aPresContext)
   {
     PRInt32 intValue = 0;
 
-    if (ConvertToPixelValue(border_value,1,intValue))
+    if (ConvertToPixelValue(border_value,1,intValue)) //XXX this is busted if this code is ever used again. MMP
       border = NSIntPixelsToTwips(intValue, p2t); 
   }
   MapHTMLBorderStyle(*spacingData,border);
diff --git a/layout/style/nsCSSStyleRule.cpp b/layout/style/nsCSSStyleRule.cpp
index 752992c60a36..a1cea01163c7 100644
--- a/layout/style/nsCSSStyleRule.cpp
+++ b/layout/style/nsCSSStyleRule.cpp
@@ -717,7 +717,9 @@ nscoord CalcLength(const nsCSSValue& aValue,
       return NSToCoordRound(aValue.GetFloatValue() * (float)capHeight);
     }
     case eCSSUnit_Pixel:
-      return NSFloatPixelsToTwips(aValue.GetFloatValue(), aPresContext->GetPixelsToTwips());
+      float p2t;
+      aPresContext->GetScaledPixelsToTwips(p2t);
+      return NSFloatPixelsToTwips(aValue.GetFloatValue(), p2t);
   }
   return 0;
 }
diff --git a/layout/tables/nsTableCellFrame.cpp b/layout/tables/nsTableCellFrame.cpp
index b8ec25859340..4d156fc6c479 100644
--- a/layout/tables/nsTableCellFrame.cpp
+++ b/layout/tables/nsTableCellFrame.cpp
@@ -399,7 +399,9 @@ NS_METHOD nsTableCellFrame::Reflow(nsIPresContext& aPresContext,
       grandChild->ChildCount(childCount);
       if (0!=childCount)
       {
-        nscoord one = ((nscoord)(NSIntPixelsToTwips(1, aPresContext.GetPixelsToTwips())));
+        float p2t;
+        aPresContext.GetScaledPixelsToTwips(p2t);
+        nscoord one = ((nscoord)(NSIntPixelsToTwips(1, p2t)));
         cellWidth = 1;
         if (gsDebug) 
           printf ("setting cellWidth=1 because it was 0 but there's some content\n");
@@ -645,7 +647,9 @@ void nsTableCellFrame::MapBorderMarginPadding(nsIPresContext* aPresContext)
   {
     // XXX: need to get border width here
     // in HTML, cell borders are always 1 pixel by default
-    border = NSIntPixelsToTwips(1, aPresContext->GetPixelsToTwips());
+    float p2t;
+    aPresContext->GetScaledPixelsToTwips(p2t);
+    border = NSIntPixelsToTwips(1, p2t);
     MapHTMLBorderStyle(aPresContext, *spacingData, border, tableFrame);
   }
   
diff --git a/layout/tables/nsTableFrame.cpp b/layout/tables/nsTableFrame.cpp
index e2bfb2c3ba8f..8e47b406bf23 100644
--- a/layout/tables/nsTableFrame.cpp
+++ b/layout/tables/nsTableFrame.cpp
@@ -3347,7 +3347,7 @@ void nsTableFrame::MapBorderMarginPadding(nsIPresContext& aPresContext)
   {
     PRInt32 intValue = 0;
 
-    if (ConvertToPixelValue(border_value,1,intValue))
+    if (ConvertToPixelValue(border_value,1,intValue)) //XXX this is busted if this code is ever used again. MMP
       border = NSIntPixelsToTwips(intValue, p2t); 
   }
   MapHTMLBorderStyle(*spacingData,border);