Layouts are now attributes

attribute.go

@@ -85,6 +85,8 @@ type AttrFace struct { font.Face }
 type AttrAlign struct { X, Y Align }
 // AttrOverflow sets the overflow, if the box is a ContentBox.
 type AttrOverflow struct { X, Y bool }
+// AttrLayout sets the layout, if the box is a ContentBox.
+type AttrLayout struct { Layout }
 
 // AColor is a convenience constructor for the color attribute.
 func AColor (col color.Color) AttrColor {
@@ -134,6 +136,10 @@ func AAlign (x, y Align) AttrAlign {
 func AOverflow (x, y bool) AttrOverflow {
 	return AttrOverflow { X: x, Y: y }
 }
+// ALayout is a convenience constructor for the overflow attribute.
+func ALayout (layout Layout) AttrLayout {
+	return AttrLayout { Layout: layout }
+}
 
 // Equals returns true if both attributes can reasonably be declared equal.
 func (this AttrColor) Equals (other Attr) bool {
@@ -232,6 +238,7 @@ func (this AttrAlign) Equals (other Attr) bool {
 	}
 }
 
+// Equals returns true if both attributes can reasonably be declared equal.
 func (this AttrOverflow) Equals (other Attr) bool {
 	if other, ok := other.(AttrOverflow); ok {
 		return this == other
@@ -240,6 +247,15 @@ func (this AttrOverflow) Equals (other Attr) bool {
 	}
 }
 
+// Equals returns true if both attributes can reasonably be declared equal.
+func (this AttrLayout) Equals (other Attr) bool {
+	if other, ok := other.(AttrLayout); ok {
+		return this == other
+	} else {
+		return false
+	}
+}
+
 // AttrNumber returns the number of an attribute. Each attribute type has a
 // unique number. The exact values of these numbers are not part of the API and
 // may change.
@@ -259,3 +275,4 @@ func (AttrDotColor)    attr () int { return  8 }
 func (AttrFace)        attr () int { return  9 }
 func (AttrAlign)       attr () int { return 10 }
 func (AttrOverflow)    attr () int { return 11 }
+func (AttrLayout)      attr () int { return 12 }

object.go

@@ -204,9 +204,6 @@ type ContainerBox interface {
 	Len () int
 	// At returns the child Object at the specified index.
 	At (int) Object
-	// SetLayout sets the layout of this Box. Child Objects will be
-	// positioned according to it.
-	SetLayout (Layout)
 	// SetInputMask sets whether or not user input events will be sent to
 	// this Box's children. If false, which is the default, input events
 	// will be sent to this Box as well as all of its children. If true,