bug 27164; need to use em square height to compute line-height; added new

APIs for this purpose; this is the Windows implementation; r=kmcclusk

gfx/public/nsIFontMetrics.h

@@ -132,7 +132,7 @@ public:
    */
   NS_IMETHOD  GetHeight(nscoord &aHeight) = 0;
 
-#if defined(XP_UNIX)
+#if defined(XP_UNIX) || defined(XP_PC)
 #define NEW_FONT_HEIGHT_APIS 1
 #endif
 #ifdef NEW_FONT_HEIGHT_APIS

gfx/src/windows/nsFontMetricsWin.cpp

@@ -2534,10 +2534,13 @@ HDC   dc1 = NULL;
 #endif
   }
 
-  mHeight = NSToCoordRound(metrics.tmHeight * dev2app);
-  mAscent = NSToCoordRound(metrics.tmAscent * dev2app);
-  mDescent = NSToCoordRound(metrics.tmDescent * dev2app);
   mLeading = NSToCoordRound(metrics.tmInternalLeading * dev2app);
+  mEmHeight = NSToCoordRound((metrics.tmHeight - metrics.tmInternalLeading) *
+                             dev2app);
+  mEmAscent = NSToCoordRound((metrics.tmAscent - metrics.tmInternalLeading) *
+                             dev2app);
+  mEmDescent = NSToCoordRound(metrics.tmDescent * dev2app);
+  mMaxHeight = NSToCoordRound(metrics.tmHeight * dev2app);
   mMaxAscent = NSToCoordRound(metrics.tmAscent * dev2app);
   mMaxDescent = NSToCoordRound(metrics.tmDescent * dev2app);
   mMaxAdvance = NSToCoordRound(metrics.tmMaxCharWidth * dev2app);
@@ -2606,7 +2609,14 @@ nsFontMetricsWin :: GetUnderline(nscoord& aOffset, nscoord& aSize)
 NS_IMETHODIMP
 nsFontMetricsWin :: GetHeight(nscoord &aHeight)
 {
-  aHeight = mHeight;
+  aHeight = mMaxHeight;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFontMetricsWin :: GetNormalLineHeight(nscoord &aHeight)
+{
+  aHeight = mEmHeight + mLeading;
   return NS_OK;
 }
 
@@ -2617,6 +2627,34 @@ nsFontMetricsWin :: GetLeading(nscoord &aLeading)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsFontMetricsWin :: GetEmHeight(nscoord &aHeight)
+{
+  aHeight = mEmHeight;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFontMetricsWin :: GetEmAscent(nscoord &aAscent)
+{
+  aAscent = mEmAscent;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFontMetricsWin :: GetEmDescent(nscoord &aDescent)
+{
+  aDescent = mEmDescent;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFontMetricsWin :: GetMaxHeight(nscoord &aHeight)
+{
+  aHeight = mMaxHeight;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsFontMetricsWin :: GetMaxAscent(nscoord &aAscent)
 {

gfx/src/windows/nsFontMetricsWin.h

@@ -116,7 +116,12 @@ public:
   NS_IMETHOD  GetUnderline(nscoord& aOffset, nscoord& aSize);
 
   NS_IMETHOD  GetHeight(nscoord &aHeight);
+  NS_IMETHOD  GetNormalLineHeight(nscoord &aHeight);
   NS_IMETHOD  GetLeading(nscoord &aLeading);
+  NS_IMETHOD  GetEmHeight(nscoord &aHeight);
+  NS_IMETHOD  GetEmAscent(nscoord &aAscent);
+  NS_IMETHOD  GetEmDescent(nscoord &aDescent);
+  NS_IMETHOD  GetMaxHeight(nscoord &aHeight);
   NS_IMETHOD  GetMaxAscent(nscoord &aAscent);
   NS_IMETHOD  GetMaxDescent(nscoord &aDescent);
   NS_IMETHOD  GetMaxAdvance(nscoord &aAdvance);
@@ -193,10 +198,11 @@ protected:
 
   nsDeviceContextWin  *mDeviceContext;
   nsFont              *mFont;
-  nscoord             mHeight;
-  nscoord             mAscent;
-  nscoord             mDescent;
   nscoord             mLeading;
+  nscoord             mEmHeight;
+  nscoord             mEmAscent;
+  nscoord             mEmDescent;
+  nscoord             mMaxHeight;
   nscoord             mMaxAscent;
   nscoord             mMaxDescent;
   nscoord             mMaxAdvance;