Changes between Version 73 and Version 74 of WebKitIDL

Timestamp:

Jul 30, 2012 12:10:58 AM (12 years ago)

Author:

Vineet

Comment:

Support for [Clamp] extended attribute.

WebKitIDL

@@ -63 +63 @@
  - [#ArrayClass ArrayClass(i)][[br]]
  - [#OmitConstructor OmitConstructor, Immutable, MasqueradesAsUndefined, CustomGetOwnPropertySlot, ReplaceableConstructor, ExtendsDOMGlobalObject, IsIndex, V8DoNotCheckSignature, NumericIndexedGetter][[br]]
+ - [#Clamp Clamp(a,p)][[br]]
 
 = Overview = #Overview
@@ -1802 +1803 @@
 
 Might be deprecated. Discussion is on-going.
+
+== [Clamp](a,p) == #Clamp
+
+ * [http://www.w3.org/TR/2012/CR-WebIDL-20120419/#Clamp The spec of Clamp]
+
+Summary: [Clamp] indicates that when an ECMAScript Number is converted to the IDL type, out of range values will be clamped to the range of valid values, 
+rather than using the operators that use a modulo operation (ToInt32, ToUint32, etc.).
+
+Usage: The [Clamp] extended attribute MUST NOT appear on a read only attribute, or an attribute, operation argument or dictionary member 
+that is not of an integer type. It also MUST NOT be used in conjunction with the [EnforceRange] extended attribute.
+
+[Clamp] can be specified on  writable attributes:
+
+{{{
+    interface XXX {
+        attribute [Clamp] unsigned short attributeName;
+    };
+}}}
+
+[Clamp] can be specified on  extended attributes on methods arguments:
+
+{{{
+    interface GraphicsContext {
+        void setColor(octet red, octet green, octet blue);
+        void setColorClamped([Clamp] octet red, [Clamp] octet green, [Clamp] octet blue);
+    };
+}}}
+
+Calling the non-[Clamp] version of setColor() uses ToUint8 to coerce the Numbers to octets.
+Hence calling context.setColor(-1, 255, 257); // Is equivalent to calling setColor(255, 255, 1).
+
+Calling the [Clamp] version of setColor() uses clampTo() to coerce the Numbers to octets.
+Hence calling context.setColor(-1, 255, 257); // Is equivalent to calling setColorClamped(0, 255, 255).