Issue #1647 - Part 1: Implement percentage for CSS opacity keywords

This preliminary step allows percentages to be computed and display correctly,
but unfortunately it fails a test after changing VARIANT_HN to VARIANT_HPN because that allows values to be serialized as percentages. However, not doing this means percentages are rejected as valid values for the user to input. The way the style system is setup makes it hard to change this for opacity without changing it for everything else, especially since some code-saving speed hacks in Bug 636029 and Bug 441367 that make a lot of assumptions about this stuff very rigid.

1 files changed, 15 insertions, 0 deletions

diff --git a/layout/style/nsRuleNode.cpp b/layout/style/nsRuleNode.cpp
index 036d97f86..3863ec292 100644
--- a/layout/style/nsRuleNode.cpp
+++ b/layout/style/nsRuleNode.cpp
@@ -1579,6 +1579,21 @@ SetFactor(const nsCSSValue& aValue, float& aField, RuleNodeCacheConditions& aCon
   case eCSSUnit_Null:
     return;
 
+  case eCSSUnit_Percent:
+    aField = aValue.GetPercentValue();
+    if (aFlags & SETFCT_POSITIVE) {
+      NS_ASSERTION(aField >= 0.0f, "negative value for positive-only property");
+      if (aField < 0.0f)
+        aField = 0.0f;
+    }
+    if (aFlags & SETFCT_OPACITY) {
+      if (aField < 0.0f)
+        aField = 0.0f;
+      if (aField > 1.0f)
+        aField = 1.0f;
+    }
+    return;
+
   case eCSSUnit_Number:
     aField = aValue.GetFloatValue();
     if (aFlags & SETFCT_POSITIVE) {