diff --git a/gfx/thebes/src/gfxWindowsFonts.cpp b/gfx/thebes/src/gfxWindowsFonts.cpp
index 728706a3b4f2..e51348a1a4cd 100644
--- a/gfx/thebes/src/gfxWindowsFonts.cpp
+++ b/gfx/thebes/src/gfxWindowsFonts.cpp
@@ -1137,8 +1137,24 @@ gfxWindowsFont::Measure(gfxTextRun *aTextRun,
}
}
- return gfxFont::Measure(aTextRun, aStart, aEnd,
- aBoundingBoxType, aRefContext, aSpacing);
+ gfxFont::RunMetrics metrics = gfxFont::Measure(aTextRun, aStart, aEnd,
+ aBoundingBoxType, aRefContext,
+ aSpacing);
+
+ // if aBoundingBoxType is LOOSE_INK_EXTENTS
+ // and the underlying cairo font may be antialiased,
+ // we can't trust Windows to have considered all the pixels
+ // so we need to add "padding" to the bounds.
+ // (see bugs 475968, 439831, compare also bug 445087)
+ if (aBoundingBoxType == LOOSE_INK_EXTENTS &&
+ mAntialiasOption != CAIRO_ANTIALIAS_NONE &&
+ metrics.mBoundingBox.size.width > 0) {
+ const PRUint32 appUnitsPerDevUnit = aTextRun->GetAppUnitsPerDevUnit();
+ metrics.mBoundingBox.pos.x -= appUnitsPerDevUnit;
+ metrics.mBoundingBox.size.width += 3 * appUnitsPerDevUnit;
+ }
+
+ return metrics;
}
FontEntry*
diff --git a/layout/reftests/bugs/308406-1-ref.html b/layout/reftests/bugs/308406-1-ref.html
index 7dd1af8dbac8..b12fa08c8e81 100644
--- a/layout/reftests/bugs/308406-1-ref.html
+++ b/layout/reftests/bugs/308406-1-ref.html
@@ -1,5 +1,10 @@
+
+
+
diff --git a/layout/reftests/bugs/308406-1.html b/layout/reftests/bugs/308406-1.html
index 15b70d73c21d..b4507aecc352 100644
--- a/layout/reftests/bugs/308406-1.html
+++ b/layout/reftests/bugs/308406-1.html
@@ -1,5 +1,10 @@
+
+
+
diff --git a/layout/reftests/bugs/308406-2-ref.html b/layout/reftests/bugs/308406-2-ref.html
index 307e9d66556f..d60c1997a7eb 100644
--- a/layout/reftests/bugs/308406-2-ref.html
+++ b/layout/reftests/bugs/308406-2-ref.html
@@ -1,4 +1,9 @@
+
+
+
diff --git a/layout/reftests/bugs/308406-2.html b/layout/reftests/bugs/308406-2.html
index d2ab236a522f..8da753e45b62 100644
--- a/layout/reftests/bugs/308406-2.html
+++ b/layout/reftests/bugs/308406-2.html
@@ -1,4 +1,9 @@
+
+
+