diff --git a/draw2d.go b/draw2d.go
index 25b0d12..d71158a 100644
--- a/draw2d.go
+++ b/draw2d.go
@@ -150,6 +150,7 @@ type StrokeStyle struct {
 	Dash []float64
 }
 
+// FillStyle is an empty interface you may want to use SolidFillStyle
 type FillStyle interface {
 }
 
@@ -165,22 +166,29 @@ type SolidFillStyle struct {
 type Valign int
 
 const (
+	// ValignTop top align text
 	ValignTop Valign = iota
-	ValignTopCenter
-	ValignTopBottom
-	ValignTopBaseline
+	// ValignCenter centered text
+	ValignCenter
+	// ValignBottom bottom aligned text
+	ValignBottom
+	// ValignBaseline align text with the baseline of the font
+	ValignBaseline
 )
 
 // Halign Horizontal Alignment of the text
 type Halign int
 
 const (
+	// HalignLeft Horizontally align to left
 	HalignLeft = iota
+	// HalignCenter Horizontally align to center
 	HalignCenter
+	// HalignRight Horizontally align to right
 	HalignRight
 )
 
-// TextStyle
+// TextStyle describe text property
 type TextStyle struct {
 	// Color defines the color of text
 	Color color.Color
@@ -194,6 +202,7 @@ type TextStyle struct {
 	Valign Valign
 }
 
+// ScalingPolicy is a constant to define how to scale an image
 type ScalingPolicy int
 
 const (
diff --git a/draw2dbase/curve_test.go b/draw2dbase/curve_test.go
index 750521a..d04b9fb 100644
--- a/draw2dbase/curve_test.go
+++ b/draw2dbase/curve_test.go
@@ -15,8 +15,8 @@ import (
 )
 
 var (
-	flattening_threshold float64 = 0.5
-	testsCubicFloat64            = []float64{
+	flatteningThreshold = 0.5
+	testsCubicFloat64   = []float64{
 		100, 100, 200, 100, 100, 200, 200, 200,
 		100, 100, 300, 200, 200, 200, 300, 100,
 		100, 100, 0, 300, 200, 0, 300, 300,
@@ -75,7 +75,7 @@ func TestCubicCurve(t *testing.T) {
 	for i := 0; i < len(testsCubicFloat64); i += 8 {
 		var p SegmentedPath
 		p.MoveTo(testsCubicFloat64[i], testsCubicFloat64[i+1])
-		TraceCubic(&p, testsCubicFloat64[i:], flattening_threshold)
+		TraceCubic(&p, testsCubicFloat64[i:], flatteningThreshold)
 		img := image.NewNRGBA(image.Rect(0, 0, 300, 300))
 		raster.PolylineBresenham(img, color.NRGBA{0xff, 0, 0, 0xff}, testsCubicFloat64[i:i+8]...)
 		raster.PolylineBresenham(img, image.Black, p.Points...)
@@ -91,7 +91,7 @@ func TestQuadCurve(t *testing.T) {
 	for i := 0; i < len(testsQuadFloat64); i += 6 {
 		var p SegmentedPath
 		p.MoveTo(testsQuadFloat64[i], testsQuadFloat64[i+1])
-		TraceQuad(&p, testsQuadFloat64[i:], flattening_threshold)
+		TraceQuad(&p, testsQuadFloat64[i:], flatteningThreshold)
 		img := image.NewNRGBA(image.Rect(0, 0, 300, 300))
 		raster.PolylineBresenham(img, color.NRGBA{0xff, 0, 0, 0xff}, testsQuadFloat64[i:i+6]...)
 		raster.PolylineBresenham(img, image.Black, p.Points...)
@@ -108,7 +108,7 @@ func BenchmarkCubicCurve(b *testing.B) {
 		for i := 0; i < len(testsCubicFloat64); i += 8 {
 			var p SegmentedPath
 			p.MoveTo(testsCubicFloat64[i], testsCubicFloat64[i+1])
-			TraceCubic(&p, testsCubicFloat64[i:], flattening_threshold)
+			TraceCubic(&p, testsCubicFloat64[i:], flatteningThreshold)
 		}
 	}
 }
diff --git a/draw2dbase/stack_gc.go b/draw2dbase/stack_gc.go
index b2a56c7..ff8f4f8 100644
--- a/draw2dbase/stack_gc.go
+++ b/draw2dbase/stack_gc.go
@@ -12,7 +12,7 @@ import (
 	"code.google.com/p/freetype-go/freetype/truetype"
 )
 
-var DefaultFontData = draw2d.FontData{"luxi", draw2d.FontFamilySans, draw2d.FontStyleNormal}
+var DefaultFontData = draw2d.FontData{Name: "luxi", Family: draw2d.FontFamilySans, Style: draw2d.FontStyleNormal}
 
 type StackGraphicContext struct {
 	Current *ContextStack
diff --git a/draw2dgl/gc.go b/draw2dgl/gc.go
index d47ff0e..b738a5e 100644
--- a/draw2dgl/gc.go
+++ b/draw2dgl/gc.go
@@ -223,9 +223,9 @@ func (gc *GraphicContext) FillStroke(paths ...*draw2d.Path) {
 	gc.fillRasterizer.UseNonZeroWinding = useNonZeroWinding(gc.Current.FillRule)
 	gc.strokeRasterizer.UseNonZeroWinding = true
 
-	flattener := draw2dbase.Transformer{gc.Current.Tr, draw2dimg.FtLineBuilder{gc.fillRasterizer}}
+	flattener := draw2dbase.Transformer{Tr: gc.Current.Tr, Flattener: draw2dimg.FtLineBuilder{Adder: gc.fillRasterizer}}
 
-	stroker := draw2dbase.NewLineStroker(gc.Current.Cap, gc.Current.Join, draw2dbase.Transformer{gc.Current.Tr, draw2dimg.FtLineBuilder{gc.strokeRasterizer}})
+	stroker := draw2dbase.NewLineStroker(gc.Current.Cap, gc.Current.Join, draw2dbase.Transformer{Tr: gc.Current.Tr, Flattener: draw2dimg.FtLineBuilder{Adder: gc.strokeRasterizer}})
 	stroker.HalfLineWidth = gc.Current.LineWidth / 2
 
 	var liner draw2dbase.Flattener
@@ -235,7 +235,7 @@ func (gc *GraphicContext) FillStroke(paths ...*draw2d.Path) {
 		liner = stroker
 	}
 
-	demux := draw2dbase.DemuxFlattener{[]draw2dbase.Flattener{flattener, liner}}
+	demux := draw2dbase.DemuxFlattener{Flatteners: []draw2dbase.Flattener{flattener, liner}}
 	for _, p := range paths {
 		draw2dbase.Flatten(p, demux, gc.Current.Tr.GetScale())
 	}
diff --git a/samples/helloworld/helloworld.go b/samples/helloworld/helloworld.go
index f9bf410..af5b47e 100644
--- a/samples/helloworld/helloworld.go
+++ b/samples/helloworld/helloworld.go
@@ -31,7 +31,7 @@ func Draw(gc draw2d.GraphicContext, text string) {
 	gc.FillStroke()
 
 	// Set the font luximbi.ttf
-	gc.SetFontData(draw2d.FontData{"luxi", draw2d.FontFamilyMono, draw2d.FontStyleBold | draw2d.FontStyleItalic})
+	gc.SetFontData(draw2d.FontData{Name: "luxi", Family: draw2d.FontFamilyMono, Style: draw2d.FontStyleBold | draw2d.FontStyleItalic})
 	// Set the fill text color to black
 	gc.SetFillColor(image.Black)
 	gc.SetFontSize(14)