ColorChooser : Use hollow circle for color sliders

Changes.md

@@ -6,7 +6,7 @@ Improvements
 
 - Light Editor : Added `is_sphere` column for Cycles lights.
 - Windows : Gaffer now uses the TBB memory allocator for significantly better performance.
-- ColorChooser : Changed color field indicator to a hollow circle so the chosen color is visible.
+- ColorChooser : Changed color field and color slider indicators to a hollow circle so the chosen color is visible.
 
 Breaking Changes
 ----------------

python/GafferUI/ColorChooser.py

@@ -100,6 +100,14 @@ def _rgbToTMI( c ) :
 	"i" : __Range( 0, 1, -sys.float_info.max, sys.float_info.max ),
 }
 
+def _indicator( radius ) :
+
+	circle = QtGui.QPainterPath()
+	circle.addEllipse( -radius, -radius, radius * 2.0, radius * 2.0 )
+	circle.addEllipse( -radius + 2.0, -radius + 2.0, radius * 2.0 - 4.0, radius * 2.0 - 4.0 )
+
+	return circle
+
 # A custom slider for drawing the backgrounds.
 class _ComponentSlider( GafferUI.Slider ) :
 
@@ -114,6 +122,7 @@ def __init__( self, color, component, **kw ) :
 
 		self.color = color
 		self.component = component
+		self.__indicatorPainterPath = None
 
 	# Sets the slider color in RGB space for RGBA channels,
 	# HSV space for HSV channels and TMI space for TMI channels.
@@ -158,6 +167,17 @@ def _drawBackground( self, painter ) :
 		brush = QtGui.QBrush( grad )
 		painter.fillRect( 0, 0, size.x, size.y, brush )
 
+	def _indicatorPainterPath( self, radius ) :
+
+		if self.__indicatorPainterPath is None :
+			self.__indicatorPainterPath = _indicator( radius )
+
+		return self.__indicatorPainterPath
+
+	def _indicatorColor( self, state ) :
+
+		return QtGui.QColor( 255, 255, 255, 255 )
+
 	def _displayTransformChanged( self ) :
 
 		GafferUI.Slider._displayTransformChanged( self )
@@ -184,10 +204,7 @@ def __init__( self, color = imath.Color3f( 1.0 ), staticComponent = "s", **kw )
 		self.__colorFieldToDraw = None
 		self.setColor( color, staticComponent )
 
-		self.__indicatorPainterPath = QtGui.QPainterPath()
-		radius = 4.5
-		self.__indicatorPainterPath.addEllipse( -radius, -radius, radius * 2.0, radius * 2.0 )
-		self.__indicatorPainterPath.addEllipse( -radius + 2.0, -radius + 2.0, radius * 2.0 - 4.0, radius * 2.0 - 4.0 )
+		self.__indicatorPainterPath = _indicator( 4.5 )
 
 	# Sets the color and the static component. `color` is in
 	# RGB space for RGB static components, HSV space for

python/GafferUI/Slider.py

@@ -82,6 +82,8 @@ def __init__( self, values=0.5, min=0, max=1, hardMin=None, hardMax=None, **kw )
 		self.__hoverPositionVisible = False
 		self.__hoverEvent = None # The mouseMove event that gives us hover status
 
+		self.__indicatorPainterPath = None  # Created in `_drawValue()` where we know the size
+
 		self.leaveSignal().connect( Gaffer.WeakMethod( self.__leave ) )
 		self.mouseMoveSignal().connect( Gaffer.WeakMethod( self.__mouseMove ) )
 		self.buttonPressSignal().connect( Gaffer.WeakMethod( self.__buttonPress ) )
@@ -333,10 +335,7 @@ def _drawValue( self, painter, value, position, state ) :
 		pen.setWidth( 1 )
 		painter.setPen( pen )
 
-		if state == state.NormalState :
-			color = QtGui.QColor( 128, 128, 128, 255 )
-		else :
-			color = QtGui.QColor( 119, 156, 255, 255 )
+		color = self._indicatorColor( state )
 		painter.setBrush( QtGui.QBrush( color ) )
 
 		if state == state.DisabledState :
@@ -363,7 +362,27 @@ def _drawValue( self, painter, value, position, state ) :
 				)
 			)
 		else :
-			painter.drawEllipse( QtCore.QPoint( position, size.y / 2 ), size.y / 4, size.y / 4 )
+			painter.drawPath( self._indicatorPainterPath( size.y / 4 ).translated( position, size.y / 2 ) )
+
+	## May be overriden by derived classes to customise the
+	# value indicator when it is within the min / max values.
+	# This will be called once for each `paintEvent`, derived
+	# classes should consider caching the path for better performance.
+	def _indicatorPainterPath( self, radius ) :
+
+		if self.__indicatorPainterPath is None :
+			self.__indicatorPainterPath = QtGui.QPainterPath()
+			self.__indicatorPainterPath.addEllipse( -radius, -radius, radius * 2.0, radius * 2.0 )
+
+		return self.__indicatorPainterPath
+
+	## May be overridden by derived classes to customize the
+	# color of the indicator.
+	def _indicatorColor( self, state ) :
+
+		if state == state.NormalState :
+			return QtGui.QColor( 128, 128, 128, 255 )
+		return QtGui.QColor( 119, 156, 255, 255 )
 
 	def __indexUnderMouse( self ) :