ColorChooser : Custom layout for color field row

The previous approach was causing they layout to often be resized
multiple times because we were resizing the color field widget within
the resize event. This creates a custom widget and custom layout to
achieve the same layout constraints without multiple resize events.

python/GafferUI/ColorChooser.py

@@ -163,32 +163,11 @@ def _displayTransformChanged( self ) :
 		GafferUI.Slider._displayTransformChanged( self )
 		self._qtWidget().update()
 
-class _ColorFieldWidget( QtWidgets.QWidget ) :
-
-	def __init__( self, parent = None ) :
-
-		QtWidgets.QWidget.__init__( self, parent )
-
-		self.__size = 216
-
-	def resizeEvent( self, event ) :
-
-		w = event.size().width()
-		h = event.size().height()
-
-		if w != h :
-			self.__size = h
-			self.setMinimumWidth( h )
-
-	def sizeHint( self ) :
-
-		return QtCore.QSize( self.__size, self.__size )
-
 class _ColorField( GafferUI.Widget ) :
 
 	def __init__( self, color = imath.Color3f( 1.0 ), staticComponent = "s", **kw ) :
 
-		GafferUI.Widget.__init__( self, _ColorFieldWidget(), **kw )
+		GafferUI.Widget.__init__( self, QtWidgets.QWidget(), **kw )
 
 		self._qtWidget().paintEvent = Gaffer.WeakMethod( self.__paintEvent )
 
@@ -472,6 +451,121 @@ def __paintEvent( self, event ) :
 
 		self.__drawValue( painter )
 
+class _ColorFieldRowLayout( QtWidgets.QLayout ) :
+
+	def __init__( self ) :
+
+		QtWidgets.QLayout.__init__( self, None )
+
+		# No spacing between color field and sliders so the active component icons
+		# line up against the color field. Do add a little space between the sliders
+		# and the options button.
+		self.setSpacing( 0 )
+		self.__buttonSpacing = 4
+
+		self.__items = []
+
+	def addItem( self, item ) :
+
+		self.__items.append( item )
+
+	def count( self ) :
+
+		return len( self.__items )
+
+	def expandingDirections( self ) :
+
+		return QtCore.Qt.Orientations( QtCore.Qt.Orientation( 0 ) )
+
+	def itemAt( self, index ) :
+
+		return self.__items[index] if index >= 0 and index < len( self.__items ) else None
+
+	def takeAt( self, index ) :
+
+		return self.__items.pop( index ) if index >= 0 and index < len( self.__items ) else None
+
+	def minimumSize( self ) :
+
+		assert( len( self.__items ) == 3 )
+
+		return self.__size( self.__items[1].minimumSize(), self.__items[2].minimumSize() )
+
+	def maximumSize( self ) :
+
+		return QtCore.QSize( QtWidgets.QLayout.maximumSize( self ).width(), self.sizeHint().height() )
+
+	def sizeHint( self ) :
+
+		assert( len( self.__items ) == 3 )
+
+		return self.__size( self.__items[1].sizeHint(), self.__items[2].sizeHint() )
+
+	def setGeometry( self, rect ) :
+
+		assert( len( self.__items ) == 3 )
+
+		size1 = self.__items[1].sizeHint()
+		size2 = self.__items[2].sizeHint()
+
+		leftSize = 0
+		if not self.__items[0].isEmpty() :
+			self.__items[0].setGeometry( QtCore.QRect( rect.left(), rect.top(), size1.height(), size1.height() ) )
+			leftSize = size1.height()
+
+		self.__items[1].setGeometry(
+			QtCore.QRect(
+				rect.left() + leftSize,
+				rect.top(),
+				rect.width() - leftSize - size2.width() - self.__buttonSpacing,
+				size1.height()
+			)
+		)
+		self.__items[2].setGeometry(
+			QtCore.QRect( rect.right() - size2.width(), rect.top(), size2.width(), size2.height() )
+		)
+
+	def __size( self, size1, size2 ) :
+
+		return QtCore.QSize(
+			size1.height() + size1.width() + size2.width() + self.__buttonSpacing,
+			max( size1.height(), size2.height() )
+		)
+
+class _ColorFieldRowContainer( GafferUI.ContainerWidget ) :
+
+	def __init__( self, **kw ) :
+
+		GafferUI.ContainerWidget.__init__( self, QtWidgets.QWidget(), **kw )
+
+		self.__qtLayout = _ColorFieldRowLayout()
+		self.__qtLayout.setSizeConstraint( QtWidgets.QLayout.SetMinAndMaxSize )
+
+		self._qtWidget().setLayout( self.__qtLayout )
+
+		self.__widgets = []
+
+	def addChild( self, child ) :
+
+		assert( isinstance( child, GafferUI.Widget ) )
+		assert( len( self.__widgets ) <=3 )
+
+		oldParent = child.parent()
+		if oldParent is not None :
+			oldParent.removeChild( child )
+
+		self.__widgets.append( child )
+
+		self.__qtLayout.addWidget( child._qtWidget() )
+
+		child._applyVisibility()
+
+	def removeChild( self, child ) :
+
+		self.__widgets.remove( child )
+		child._qtWidget().setParent( None )
+		child._applyVisibility()
+
 class ColorChooser( GafferUI.Widget ) :
 
 	ColorChangedReason = enum.Enum( "ColorChangedReason", [ "Invalid", "SetColor", "Reset" ] )
@@ -496,7 +590,7 @@ def __init__( self, color=imath.Color3f( 1 ), **kw ) :
 		self.__componentValueChangedConnections = []
 
 		with self.__column :
-			with GafferUI.ListContainer( GafferUI.ListContainer.Orientation.Horizontal, spacing = 0 ) :
+			with _ColorFieldRowContainer() :
 
 				self.__colorField = _ColorField( color )
 				self.__colorValueChangedConnection = self.__colorField.valueChangedSignal().connect( Gaffer.WeakMethod( self.__colorValueChanged ) )
@@ -563,8 +657,7 @@ def __init__( self, color=imath.Color3f( 1 ), **kw ) :
 				GafferUI.MenuButton(
 					image = "gear.png",
 					menu = GafferUI.Menu( Gaffer.WeakMethod( self.__optionsMenuDefinition ) ),
-					hasFrame = False,
-					parenting = { "verticalAlignment": GafferUI.VerticalAlignment.Top }
+					hasFrame = False
 				)
 
 			# initial and current colour swatches