structlayout-svg: add background, struct and padding colors

structlayout-svg/structlayout-svg.go

@@ -12,10 +12,13 @@ import (
 	"honnef.co/go/structlayout"
 )
 
-var title string
+var title, bgcolor, scolor, pcolor string
 
 func init() {
 	flag.StringVar(&title, "t", "Structure Layout", "title")
+	flag.StringVar(&bgcolor, "bgcolor", "rgb(240,240,240)", "background color")
+	flag.StringVar(&scolor, "scolor", "steelblue", "structure color")
+	flag.StringVar(&pcolor, "pcolor", "maroon", "padding color")
 }
 
 func main() {
@@ -30,7 +33,7 @@ func main() {
 	if len(fields) == 0 {
 		return
 	}
-	
+
 	// layout variables
 	top := 50
 	structheight := 50
@@ -41,37 +44,37 @@ func main() {
 	width := 600
 
 	// Determine the height of the canvas
-	height := top
+	height := top + gutter
 	for _, f := range fields {
 		height += byteheight * int(f.Size)
 		height += gutter
 	}
 	x := width / 10
 	y := top
-	
+
 	// Set up the canvas
 	canvas := svg.New(os.Stdout)
 	canvas.Start(width, height)
-	canvas.Rect(0, 0, width, height, "fill:rgb(240,240,240)")
+	canvas.Rect(0, 0, width, height, "fill:"+bgcolor)
 	canvas.Gstyle(fmt.Sprintf("font-size:%dpx;font-family:sans-serif", fontsize))
 	canvas.Text(x+structwidth/2, top/2, title, "text-anchor:middle;font-size:120%")
 
 	// For every field, draw a labled box
 	pos := int64(0)
 	var fillcolor string
-	nudge := (fontsize*2)/3
+	nudge := (fontsize * 2) / 3
 	for _, f := range fields {
 		name := f.Name + " " + f.Type
 		if f.IsPadding {
 			name = "padding"
-			fillcolor = "fill:maroon"
+			fillcolor = pcolor
 		} else {
-			fillcolor = "fill:steelblue"
+			fillcolor = scolor
 		}
 		structheight = byteheight * int(f.Size)
-		canvas.Rect(x, y, structwidth, structheight, fillcolor)
+		canvas.Rect(x, y, structwidth, structheight, "fill:"+fillcolor)
 		canvas.Text(x+structwidth+10, y+nudge, fmt.Sprintf("%d", pos))
-		canvas.Text(x+structwidth+fontsize*4, y+nudge, fmt.Sprintf("%s (size %d, align %d)", name, f.Size, f.Align),)
+		canvas.Text(x+structwidth+fontsize*4, y+nudge, fmt.Sprintf("%s (size %d, align %d)", name, f.Size, f.Align))
 
 		if f.Size > 2 {
 			canvas.Text(x-10, y+structheight, fmt.Sprintf("%d", pos+f.Size-1), "text-anchor:end")